final_report_complied

ME 4020 Spring 2016 Quick Change Turbine Blade Fixture April 21st, 2016

Table of ContentsList of Figures..........................................................................................................................3

List of Tables...........................................................................................................................4

Project Overview.....................................................................................................................5

Problem Definition..................................................................................................................7Key Features....................................................................................................................................7

HAAS Rotating Table...........................................................................................................................7Dove Tail Clamp..................................................................................................................................8Dove Tail Clamp Support.....................................................................................................................8S3 Datum Support...............................................................................................................................8Secondary Clamp................................................................................................................................8

Problem Statement..........................................................................................................................8Project Requirement Checklist.........................................................................................................9Analysis of points of improvement.................................................................................................10

Solution.................................................................................................................................13Interchangeable Baseplate...............................................................................................................13Guide Features..................................................................................................................................14Dovetail Profile Support....................................................................................................................15Dovetail Clamp..................................................................................................................................15S3 Datum Support.............................................................................................................................15Tooling Balls......................................................................................................................................16Fastener Selection.............................................................................................................................16Quick Connect Hydraulic Fittings......................................................................................................16Storage Fixture..................................................................................................................................16Gusset Design for Cleaning...............................................................................................................17

Constraint and Criteria Checklist....................................................................................................17

Conclusion.............................................................................................................................19Future Recommendations..............................................................................................................19

Appendix A: Product Design Specifications............................................................................20

Appendix B: Morphological Chart..........................................................................................22

Appendix C: Weighted Analysis Criteria.................................................................................23

Appendix D: Dove Tail Clamp Design and Weighted Analysis.................................................24

Appendix E: S3 Datum Support Design and Weighted Analysis..............................................27

Appendix F: Baseplate Design and Weighted Analysis...........................................................29

Appendix G: Possible Interchangeable Baseplate Designs......................................................32

Appendix H: Design Calculations and FEA Analysis.................................................................34Machining Force Calculations...........................................................................................................34

Anderson, Gregory, Luther, Thomas 1


Appendix I: Displacement Calculations for the Dove Tail........................................................36Main Block Displacements.............................................................................................................36

Hand Calculations.............................................................................................................................37Modeling...........................................................................................................................................38Conclusion........................................................................................................................................40

Appendix J: Bolt Requirements..............................................................................................41Assumptions..................................................................................................................................41Hand Calculations..........................................................................................................................41

Friction..............................................................................................................................................41Force in a bolt...................................................................................................................................42

Calculations...................................................................................................................................42Base Plate to Master Plate................................................................................................................42Base Plate to Dovetail support..........................................................................................................43Master plate to side supports...........................................................................................................43Bolt safety.........................................................................................................................................44

Conclusion.....................................................................................................................................44

Appendix K: FEA Analysis.......................................................................................................46Proposed Fixture............................................................................................................................46Main Clamp....................................................................................................................................48

Appendix L: Design Considerations for the Dovetail Clamp....................................................50Objective:..........................................................................................................................................50Requirements:..................................................................................................................................50Similarities........................................................................................................................................50Angle Choice.....................................................................................................................................52Conclusion........................................................................................................................................55

Appendix M: Hydraulic Schematic.........................................................................................56

Appendix N: Master Plate and Base Plate Connection Work Instructions...............................57

Appendix O: Base Plate Configuration Work Instructions.......................................................59

Appendix P: Bill of Materials Purchased.................................................................................62

Appendix Q: Bill of Custom-Made Parts.................................................................................63

Appendix R: Time Analysis.....................................................................................................65

Appendix S: Drafts of Created Parts.......................................................................................66

References.............................................................................................................................67



List of FiguresFigure 1. An example of a gas turbine…….……………………………………………………….4Figure 2. A gas turbine blade located on the fixture………………………………………….……5 Figure 3. A gas turbine blade’s important features………..………………………………….……5Figure 4. Current fixture setup……………………………..………………………………….…...6Figure 5. Potential points of improvement………….…………………………………………....10Figure 6. SolidWorks model of the proposed fixture…………………...…………………….….12Figure 7. SolidWorks model of the interchangeable baseplate …………………………….…….13Figure 8. SolidWorks model of the dovetail support …………………….……………………....13Figure 9. SolidWorks model of the dovetail clamp ……………………..…………………….…14Figure 10. SolidWorks model of the storage rack ……………………………………….………15Figure D-1. Alligator clamp schematic…………………………………………………….……..23Figure D-2. Matching profile clamp schematic…………………………………………….….…23Figure D-3. Ball screw clamp schematic………………………………………………………....24Figure E-1. Matching profile S3 datum support……………………………………………….…26Figure E-2. Simple roller S3 datum support………………………………………………….…..26Figure E-3. Suction cup S3 datum support…………………………………………………….…27Figure F-1. Interchangeable piece parts concept...………………………………………….……28Figure F-2. Interchangeable base plate concept..…………………………………………….…...29Figure F-3. Ball screw base plate concept………………………………………………….…….29Figure G-1. Tapered dowel pin concept…………………………………………………….……31Figure G-2. Drop in base plate concept…………………………………………………….…….32



Figure G-3. Lock in hinge design concept………………………………………………….…….32Figure H-1. Specific energy values……………………………………………………….………34Figure I-1. Naming convention for the dovetail support…………………………………………35Figure I-2. Naming convention for the dovetail support…………………………………………36Figure I-3. FEA analysis dovetail support maximum deflection………………………………....38Figure I-4. FEA analysis dovetail support maximum deflection…………………………………38Figure I-5. FEA analysis dovetail support maximum deflection………………………………....39Figure J-1. Explanation of applied friction……………………………………………………….40Figure J-2. Dovetail support free body diagram…………………………………………………..42Figure J-3. Master plate connection free body diagram…………………………………………..43Figure K-1. FEA analysis - displacement of the fixture………………………………………….45Figure K-2. FEA analysis – factor of safety of the fixture……………………………………….45Figure K-3. FEA analysis – mesh size chosen……………………………………………………46Figure K-4. FEA analysis – fixed points chosen…………………………………………………46Figure K-5. FEA analysis – position of force applied……………………………………………47Figure K-6. FEA analysis – resulting Von Mises Stress…………………………………………47Figure K-7. FEA analysis – dovetail clamp Von Mises Stress…………………………………...48Figure K-8. FEA analysis – displacement of dovetail clamp…………………………………….48Figure L-1.Figure L-2.Figure L-3.Figure L-4.Figure L-5.Figure L-6.Figure M-1. Hydraulic Schematic………………………………………………………………..49

List of Tables



Table 1. Current project constraints……………………………………………………….………8Table 2. Current project criteria……………………………………………………….……….…..9Table 3. Project constraint checklist………………………………………………………….…..16Table A-1. Product Design Specifications…………………………………………………….….19Table B-1. Morphological chart………………………………………………………………….21Table C-1. Criteria used in weighted analysis……………………………………………….…...22Table D-1. Weighted analysis of dovetail clamp concepts………………………………….……24Table F-1. Weighted Analysis of baseplate designs………………………………………….…..30



Project OverviewGas turbines are marvel of today’s society and have revolutionized today’s industry. Used to power multiple different vehicles ranging from airplanes to ships and especially generate electrical power, modern society would not be the same without the use of gas turbines.

Gas turbines function off of a simple Brayton cycle, first compressing air, then heating the compressed air through the combustion of fuel, and finally using the heated compressed air to power at least one turbine thus converting energy into a usable form [4]. An example of a gas turbine using a Brayton Cycle is located below in Figure 1.

Figure 1. An example of a gas turbine’s inner workings. Gas is first compressed, then heated in the combustor, and finally run through a turbine to generate power [2].

Inside this turbine, the hot air moving from the combustor forces turbine blades to rotate about a central axis, thus powering a generator and creating power. The gas turbine blades located within the turbine must be able to withstand high temperatures and pressures within the turbine and be precisely machined as to capture as much energy as possible [1].

General Electric Power and Water creates entire gas turbines and a critical component is the gas turbine blades. These gas turbine blades must be able to withstand high temperatures and pressures within the turbine and capture as much energy as possible. Also to be noted is the problems that arise if a blade is damaged or has defects and breaks mid-cycle. If this happens, the entire gas turbine will need to be shut down and repaired costing millions of dollars. As such, it is imperative that gas turbine blades are precisely manufactured to reduce the possibility of a catastrophic failure.

In order to machine out defects associated with gas turbine blades, General Electric has a precision fixture attached to a HRT310 rev C HAAS Rotary Table device. This device must be properly aligned in order to ensure accurate machining. Currently, each gas turbine design requires a different fixture to be used. An example of the current fixture with a gas turbine blade in place is shown below in Figure 2.



Figure 2. A gas turbine blade placed in the current fixture.

The current design of each fixture is a main clamp attached at the dove tail design with a roller underneath the S3 point of the blade. A secondary clamp provides another point of contact over the S3 point to reduce the possibility of vibrations.

Currently, General Electric is only machining specific features of the gas turbine blade including the angel wings and the Z-form. Other points on the turbine blade such as the blade are not machined during this specific operation and thus can be obstructed from the cutting tool in the CNC machine. These important features are shown below in Figure 3.

Figure 3. A gas turbine blade’s important features. Labeled features include the Dove tail, angel wings, blade, and z-form.



Problem DefinitionWith General Electric’s current fixture design, a major problem occurs when a different style of gas turbine blade is required to be machined and the fixture is subsequently changed. Each gas turbine blade has a different fixture associated with it in order to ensure the gas turbine blade is machined properly in the CNC machine. The current fixture design is not conducive to a quick turnaround time and as such can take upwards of three hours to remove the current fixture and attach a new fixture. Because of the high cost of the turbine blades, every hour the machine is not functioning is a significant loss of money.

Key Features

In order to address the significant problems facing General Electric, a thorough examination of the current equipment setup is required. Figure 4 shows the current fixture arrangement.

Figure 4. Current fixture setup. Features include the main clamp, roller, and secondary clamp.

There are five key individual parts to General Electric’s current fixture arrangement, these are the HAAS Rotating Table, the dovetail clamp, the dovetail profile support, the S3 datum support, and the secondary clamp. These features are shown in Figure 4 labeled as 1 through 5 respectively. This next section will dive into the importance of each feature and the key requirements each feature should meet.

HAAS Rotating TableThe HAAS Rotating Table is shown in Figure 4 and marked by the number 1. This key feature is what provides the fixture the ability to rotate 360 degrees. Having a maximum torque of 300 ft-



lbs [5], this is the one part of the fixture General Electric has required to be used on the next version.

Dove Tail ClampDenoted as number 2 in Figure 4 above, the dovetail clamp is what provides the stability and support for the gas turbine blade. Designed as a simple toggle clamp, the dovetail clamp grasps onto the dovetail of the gas turbine blade and supply roughly 3000 psi in order to hold the gas turbine blade in place. It is important for the dovetail clamp to be made of a softer material than the gas turbine blade so as to refrain from damaging the gas turbine blade when the clamp actuates. The dovetail clamp also contains multiple mechanical stops, thus allowing the operator to physically check if the gas turbine blade is in the correct position.

The hydraulic system operating the clamp must also be able to adjust the pressure it distributes to the dove tail clamp. This variation in pressure supplied must allow the dove tail clamp to distribute an adjustable amount of force to the gas turbine blade in 100 pound intervals and be able to exert a maximum force of 6000 pounds.

Dove Tail Clamp SupportEach gas turbine blade has a different profile for the dovetail which results in a different profile being required for each dovetail clamp that is used. Shown as number 3 in Figure 4, there are two different main clamp support designs that allow for all gas turbine blades to be used. The dove tail clamp supports need to be precision machined in order for the gas turbine blade to sit properly in the fixture.

S3 Datum SupportShown in Figure 4 as number 4, the S3 datum support point can be described as a simple roller. This feature is the second support point for the gas turbine blade and arguably the most important. This feature must be precision machined and be at the correct point every time as it has a direct effect on the location of the turbine blade. Currently, this fixture is immobile and is unique for every gas turbine blade.

Secondary ClampThe secondary clamp, shown in Figure 4 as number 5, does not exert a significant amount of force on the gas turbine blade and is simply another point of contact. The secondary clamp is a simple toggle clamp with a rubber stopper located over the S3 datum point and provides the final point of stability. While it is not necessary for this clamp to be located directly over the S3 datum point, that is the optimal position in order to ensure the least amount of motion of the gas turbine blade.

Problem Statement

General Electric has requested Clemson University students to create a quick change fixture to support five current gas turbine blade designs. The project objective is to design a system that secures turbine blades of various geometries during a machining operation with a repeatable and accurate alignment while minimizing changeover time.



Project Requirement Checklist

In order to create an applicable solution to the current situation facing GE, a list of constraints and criteria were established to ensure the project is heading in the correct direction. With the approval from GE, the project’s constraints and criteria are listed below in Table 1 and Table 2 respectively.

Table 1. Current project constraints

Number Project Constraint Value

1 Final blade location must have a maximum deviation of 0.0002” from the machine setup. 0.0002”

2 Must be crane accessible if required (OSHA). N/A

3 Fixture(s) must hold all supplied blade styles. 5 blade styles

4 Must allow for three side access. 3 side access

5 Change over time must less than 30 minutes. 30 minutes

6 Must use GE supplied turntable HRT310 rev C HAAS rotating table. N/A

7 Fixture(s) must contain a tooling ball for program locating purposes. N/A

8 Must be able to withstand cutting fluid N/A

9 Must support the S3 datum N/A

10 Any contact points must be less than 50 Rockwell hardness 50 Rockwell

11 All hydraulic equipment must be able to operate off of 3000 psi 3000 psi

12 All pneumatic equipment must be able to operate off of 90 psi 90 psi

13 Fixture must resist 2500lbs of force in the x and y direction 2500 lbs

14 Fixture must resist 900lbs of force in the z direction 900 lbs

15 Fixture must be able to fit in the CNC machine through the door 50 inches in length



Table 2. Current project criteria

Number Project Criteria Value

1 Five minute change over. 5 minutes

2 Use current clamping equipment (Hydraulic and Pneumatic).

N/A

3 Each component should be as light as possible. N/A

4 Base plate costs should be as low as possible. N/A

5 Piece part locator costs should be as low as possible.

N/A

6 Storage system costs should be minimized. N/A

7 Easily cleaned after operation (chips, cutting fluid, etc.).

N/A

8 Fixture should be adaptable to future designs. N/A

9 Fixture storage should be small. N/A

10 Part should have a maximum deviation of 0.0001” during operation

0.0001”

11 Parts should come off the shelf and be supported N/A

12 The main clamp should expose as much of the dovetail as possible when not engaged

N/A

13 The height of the centerline should be as low as possible

N/A

14 Interference fits should not support loads N/A

15 Hardware should be consistent in size throughout the fixture

N/A

16 Bolt locations should be accessible to a torque-wrench

N/A

Analysis of points of improvement



Since all the key features of the fixture have been discussed, it is now possible to dive into an analysis of the possible points of improvement that could be made to General Electric’s gas turbine blade fixture. As stated before, the current changeover time for this fixture is well over three hours, resulting in significant downtime. This is the current focus of Clemson’s project and most improvements to the fixture are aimed at reducing this downtime. Potential points for improvement are shown below in Figure 5.

Figure 5. Potential points for improvement in the current design.

After examining Figure 5, it is also important to note the amount of different style bolts that have been incorporated into this fixture. Shown in Figure 5 as number 1, 2, 3, 6 and 9, there are over four different styles of bolts used in the installation/teardown of the fixture. Each different bolt style is wasted time for the operator and extra down time for the gas turbine blade. It would be helpful to reduce the overall number of bolts as well as the number of different styles of bolts.

Another point of improvement for the functionality of the fixture is located on the dovetail clamp. It can be easily seen in Figure 2 that the current design for the dovetail clamp does not have a significant amount of points in contact with the gas turbine blade. It would be advantageous to increase the surface area exposed to the clamp and therefore limit the possible motion of the turbine blade. Also, it would be a significant improvement if the dovetail clamp could be modified to be adaptable to multiple different dovetail blade styles instead of only allowing for a single dovetail style.

The final point of improvement is number 7. The hydraulic fittings currently used screw on fittings and could take a significant amount of time of attach every time the baseplate is changed over. Using quick-connect hydraulic fittings would reduce minutes from the installation/disassembly time.



Currently, General Electric has no designated storage area for the multiple baseplates that they use. Because the changeover process is so lengthy, General Electric is able to store the unused baseplates in a warehouse and find them when they are needed. This process itself is time consuming and would be simpler if there was a designated storage area.

The biggest point of possible improvement that was identified was the overall lack of any adaptability in the gas turbine blade fixture. As stated before, each gas turbine blade requires its own unique baseplate to be used which subsequently results in a lengthy changeover process. If the removal of the entire fixture can be at least minimized, a significant amount of changeover time can be saved.



SolutionIn order to create a solution for General Electric’s current situation, a full engineering design process has been carried out starting with concept generation and concept selection. During the concept generation phase, product design specifications were created to keep the solution within the required criteria. The product design specifications are located in Appendix A. A morphological chart, a tool used to generate possible solutions, is located in Appendix B.

Once multiple solutions were generated, each solution was weighed against a set of criteria in order to determine the solution’s ability to remedy General Electric’s current situation. The weighted criteria is located in Appendix C while the weighted analysis of the dovetail clamp, S3 datum support design, and baseplate designs are located in Appendix D, E, and F respectively. The best solution from the concept generation phase was chosen as the solution.

The solution that has been proposed is an interchangeable baseplate that attaches to a master gas turbine blade fixture. This interchangeable plate will allow for a variable dovetail clamp profile and variable S3 datum support location so any gas turbine blade can be used with a small amount of modification. A SolidWorks model of this interchangeable base plate design is shown in Figure 6.

Figure 6. A SolidWorks model of the proposed gas turbine blade fixture design.

Interchangeable BaseplateIt was decided that two interchangeable base plates would be preferable for the solution, one for current usage and one for setting up the next gas turbine blade design that will be used. Furthermore, while one baseplate is in use, the other baseplate will be used to construct the next configuration for that specific turbine blades’ dimensions. It is worth noting that the time to change over a baseplate configuration is not included in the changeover time of the machine.



This change over is viewed as an external process since it can be constructed while another blade is being machined. A closer look at the features of the interchangeable baseplate can be seen below in Figure 7.

Figure 7. SolidWorks model of the interchangeable baseplate.

Of particular note in Figure 7 above, the interchangeable baseplate is outfitted with a variable dovetail clamp profile, variable S3 datum support location, three tooling balls for locating purposes, similar bolts for easy removal, quick connect hydraulic fittings, gussets designed for ease of chip removal, and storage. Other possible ideas for an interchangeable baseplate are located in Appendix G.

Guide FeaturesIn order to ensure a surface that is constantly placed in the correct location, alignment pins have been added to the master plate as locator pins. These pins are shown below in Figure. These pins allow the interchangeable base plate to be placed at the same location every time they are used. By utilizing a precision fit, it is possible to achieve less than a 0.0002” deviation with this system.



Figure 8. a) Drawing of dovetail with gauge pins. b) Dovetail profile design

Dovetail Profile SupportA dovetail profile design created is based on the gauge pin locations shown in drawings provided by General Electric as shown in Figure 8. There are two dove tail profiles which have a 0.3258” diameter and three which have a 0.3910” diameter respectively. The first support is for the 850R, 332C, 889H, and 597A model turbine blades. The second clamp is for the 592E turbine blade. Two different profile supports are used due to a clearance issue where the dovetail of the 592E turbine blade would hit against the clamp support. This design provides a maximum amount of contact points on the dovetail. The profiles are precision machined in order to achieve the tolerance of 0.0002”. A detailed analysis of the design considerations and calculation for the dovetail profile support is shown in Appendix I.

Figure 9. SolidWorks model of the dovetail clamp

Dovetail Clamp Shown above in Figure 9, the dovetail clamp is the key feature securing the gas turbine blade in place during the machining operation. The clamp touches on the upper surface of the dove tail of the turbine blade, applying 6000 pounds of force and is made of 1020 hot rolled steel. This material is softer than 50 HRC, ensuring that there is no material removal of the gas turbine blade when the clamping force is applied. This clamp also has multiple stops in order to force the gas turbine blade to sit in the correct position. Grade 8 bolts are used for the clamp because they will be able to withstand a force of 7,500 pounds. The calculation may be found in Appendix L. A 50mm hydraulic cylinder, supplied by Parker, is used to to supply force to the clamp.

S3 Datum Support Another feature of the interchangeable baseplate is a variable S3 datum support location. Fixed in the base plate by using a compression fit, this allows for multiple locations of the S3 datum



support. Every gas turbine blade has a unique S3 datum location and this design allows for all datum locations to be located on a single interchangeable plate. Tooling BallsAs a cautionary addition to the system, three locating balls have been added to each interchangeable baseplate. These locator balls will allow the CNC machine to adjust to a variation in the placement of the baseplate. If the baseplate is not placed at the perfect position, the CNC machine can use ruby tip deflection in order to measure the difference and modify the cutting parameters and location accordingly.

Fastener SelectionOne of the leading points of improvement that was identified for improving a changeover process was to eliminate the number of different styled bolts used in the operation. Each different style of bolt requires a different set of hardware to install and remove, simply adding time to the operation. By making all the bolts used in the assembly as ½” -13 hex head bolts, it is easier for the operator to install and remove the fixture since the operator will not have to reach for another tool during the assembly/disassembly of the baseplate. Quick Connect Hydraulic FittingsEvery clamping device on the gas turbine blade fixture requires a hydraulic connection in order to power the clamp. In the previous design, the hydraulic fixtures were hard-mounted onto the base plate and required the hydraulic fittings to be screwed into place for every installation. In the recommended design, these hydraulic fittings have been replaced with ¼ size Quick-Disconnect couplings. These fittings are known as quick-connect fittings allowing time to be saved with an easier and simpler connecting method.

Storage FixtureWith the current fixture design, storage has been a secondary thought. The current solution’s design requires the interchangeable base plate to be modified before it is bolted down to the master plate. As such, a storage rack has been designed and optimized in order to meet any need the machinist may require. This storage rack is shown below in Figure 10.



Figure 10. SolidWorks Model of the storage rack for the interchangeable base plate.

On the top of the storage rack, there are two spots for the placement of the interchangeable base plates. Alongside of these places are locations for each type of screw, nut, and bolt that is necessary for assembling the interchangeable base plate. As stated earlier, the amount of bolts used has been minimized in order to reduce the amount of hardware used. On the lower rack is storage for every S3 datum support and dovetail clamp support. The storage rack is also equipped with casters for ease of movement. Everything necessary for the installation/disassembly of the fixture is located on the storage rack, reducing the amount of time the operator is searching for the right tool or fastener.

Gusset Design for CleaningA recurring problem with the current fixture design is cleaning the fixture. Chips are typically removed by the use of a pneumatic jet. When the air stream encounters an enclosed corner, such as a gusset, the air must find another place to go and subsequently blows directly back in the face of the machinist. The design of the solution will mitigate this problem with reliefs in the corners where the gusset intersects with the master plate. These reliefs will allow for a gateway the air can pass through to avoid the chips flying back in a machinist’s face. Also, these gussets are easily removable, which would allow the operator to avoid the problem entirely if they choose.

Constraint and Criteria Checklist

In order to evaluate if this solution meets the original constraints and criteria laid out at the beginning of the project, Table 3 below was created. Table 3 allows a quick comparison between the proposed solution and the constraints it is evaluated against.

Table 3. Project constraint checklist compared against proposed solution



Number Constraint Value Validation

1 Final blade location must have a maximum deviation of 0.0002” from

the machine setup.

0.0002” Yes

2 Must be crane accessible if required (OSHA).

N/A Yes

3 Fixture(s) must hold all supplied blade styles.

5 blade styles Yes

4 Must allow for three side access. 3 side access Yes

5 Change over time must less than 30 minutes.

30 minutes Yes

6 Must use GE supplied turntable HRT310 rev C HAAS rotating table.

N/A Yes

7 Fixture(s) must contain a tooling ball for program locating purposes.

N/A Yes

8 Must be able to withstand cutting fluid

N/A Yes

9 Must support the S3 datum N/A Yes

10 Any contact points must be less than 50 Rockwell hardness

50 Rockwell 40 Rockwell

11 All hydraulic equipment must be able to operate off of 3000 psi

3000 psi 3000 psi

12 All pneumatic equipment must be able to operate off of 90 psi

90 psi 90 psi

13 Fixture must resist 2500lbs of force in the x and y direction

2500 lbs 2500 lbs

14 Fixture must resist 900lbs of force in the z direction

900 lbs 1000 lbs

15 Fixture must be able to fit in the CNC machine through the door

50 inches in length

Yes



ConclusionAfter comparing the proposed solution against Table 3 above, it can be shown the proposed solution meets all of the constraints laid out at the beginning of the project. While it was not possible to precisely account for the time the changeover process will take, it is possible to judge the approximate amount of time using SolidWorks models. This amount of time has been estimated at 6 minutes and 40 seconds. This estimation is below the required time of 30 minutes and well below the current changeover time of three hours. Since the reduction of the current changeover time was the top priority, the proposed interchangeable base plate solution can be considered a success. However, it can be noted many parts need to be custom manufactured directly contradicting the criteria, “parts should come off the shelf and be supported.”

Future Recommendations

With more time in this project, there are a few potential solutions that would be pursued. In an effort to completely error-proof the fixture design, it is possible to install a visual camera into the left side support that could check if the z-form was installed or not. The Z-form of the gas turbine blade is the one part that is impossible for the current design to check for. With a visual camera, this problem can be remedied and removed as a potential possibility.

An expensive and time consuming engineering feat would be to create an automated ball screw system for the S3 datum support. This would allow for a singular design and remove the need for an interchangeable baseplate as the S3 support would be able to adapt to any gas turbine blade placed in the CNC machine. However, there are significant questions about the ability of the ball screw system to withstand a manufacturing environment with chips and cutting fluid. A significant amount of time would be necessary to error-proof the design so chips would not prevent the ball screw system from functioning.

A final recommendation would be to create a more form fitting dovetail clamp design. Currently, the dovetail clamp design is a simple roller that touches the dovetail in two specific spots. With a more form fitting dovetail design, the contact area would be increased resulting in less pressure per unit area. However, the same amount of force would be applied so there should be no chance of any slipping occurring.



Appendix A: Product Design SpecificationsIn order to correctly assess the requirements of the project, a Product Design

Specifications (PDS) chart was created. The PDS was used to brainstorm necessary requirements and was slowly compiled over the course of the project.

Table A-4: Product design specifications

No. Requirement Class Constraint

Crit Wt. Tar. Val.

1.01 The blade and fixture location tolerance must be 0.0002” at all points Operation YES - 0.0002"

1.02 Must meet OSHA standards Safety YES -

1.03 Fixture(s) must hold all blade styles Operation YES - 7 fixtures

1.04 Must allow for 3-side access Operation YES - 360°

1.05 Change over tme must be less than 30 min Operation YES - < 30 min

1.06 Use GE supplied turntable HRT310 HAAS rotab. Operation YES -

1.07 Five minute change over Operation NO 9 5 min

1.08 Use current Hydraulic and Pneumatic devices Operation NO 3

1.09 Keep each component as light as possible Weight NO 3 < 40 lbs

1.10 Base plate costs under as low as possible Cost NO 9 $20,000.00

1.11 Piece part locators costs as low as possible Cost NO 9 $10,000.00

1.12 Storage system costs as low as possible Cost NO 9 $10,000.00

1.13 Easily cleaned after operation Safety NO 9 < 1min

1.14 Adaptable to future designs Operation NO 3



1.15 Fixture storage should be small Size NO 3 Not quantifiable

1.16 Part can move a maximum of 0.0001" during operation Operation YES - <0.0001"

1.17 Must support S3 datum Operation YES-

1.18 Fixture must contain a tooling ball Operation YES

1.19 Interfacing materials must be softer than the bladeOperation YES

1.2 Parts should come off the shelf and be supportedOperation YES



Appendix B: Morphological ChartDuring concept generation, it is important to consider all options and possible methods for completing a required task. In order to assess those options, a morphological chart was created. For each operation or function the quick-change fixture must fulfill, there are a range of options that could be pursued for the new fixture to function properly.

Table B-1: Morphological chart



Appendix C: Weighted Analysis CriteriaIn order to conduct a weighted analysis of generated concepts, a set of criteria was established that all concepts must be weighed upon. This set of criteria is located below in Table C-1.

Table C-1. Criteria used in weighted analysis

Criteria Justification Weight

Cost There is significant leeway with cost 3

Safety No employee is allowed to get hurt with this design 10

Time Reduce changeover time 8

Weight With a crane available, weight is a secondary concern 2

Support availability Parts must come from off the shelf 7

Flexibility Adaptable to future designs 7

Maintenance Design must reduce produce down time 7

Manufacturability Any parts not off the shelf must be able to be created easily 4

Repeatability Consistent results 10

Size Must fit in given space 2

Ease of assembly Intuitive design 5

Controllability Error-proofed design 10



Appendix D: Dove Tail Clamp Design and Weighted AnalysisOne of the highlights of the proposed solution was the design of the main clamp. This dove tail clamp was required to be precision machined, able to output 6000 lbs of force, and have checks so an operator will be able to ensure the gas turbine blade is placed in the perfect location every single iteration. Appendix D contains all the concepts generated to satisfy the necessary criteria. A weighted analysis is included below in Table D-1.

Figure D-1 below is the first concept, an alligator clamp aptly named so due to the shape of the clamp jaws.

Figure D-1. An alligator clamp that functions with a single pinned connection and a mechanical adjustment

Figure D-2 below is the second concept, a matching profile clamp. This clamp would have an exact match of the gas turbine dove tail so that the clamping surface was increased. This would subsequently error-proof the design as no two gas turbine blades have exact matching dove tail profiles and reduce the stress exerted on the gas turbine blade by the dove tail clamp, rendering it less likely to fracture.



Figure D-2. The matching profile clamp concept

The final concept for he main dove tail clamp is shown below in Figure D-3. This concept is drive by a ball screw and motor with the general idea of the clamp being programmed into he CNC machine. This would be the most error-proofed design as it requires the least input from the operator and would be the most adaptable of all concepts as any gas turbine blade dove tail would be able to fit.

Figure D-3. The ball screw clamp concept

The weighted analysis of the three clamps as compared to the current clamp design used on General Electric’s gas turbine fixture is shown below in Table D-1.

Table D-1. Weighted analysis of the possible clamp design.Clamp Designs

Criteria Weight Current Design Alligator Matching Ball ScrewCost 3 9 9 1 1

Safety 10 9 3 9 9Time 8 9 9 9 9

Weight 2 9 9 9 9Support 7 1 1 1 1



availabilityFlexibility 7 1 3 1 9

Maintenance 7 9 3 9 1Manufacturability 4 9 1 1 3

Repeatability 9 9 9 9 9Size 2 9 9 9 3

Ease of assembly 5 9 3 9 3Controllability 10 3 3 9 9

Total Score: 494 344 498 464

As it can be seen from Table D-1, the highest scoring clamp design was the current clamp design. It is much simpler, easier to manufacture, and has built in checks to ensure the gas turbine blade is in the correct position. As such, it was decided to continue using the current design.



Appendix E: S3 Datum Support Design and Weighted AnalysisThe analysis of a profile matching secondary clamp to replace the current design shows that the profile match is a better design due to it’s ability to reject an incorrect turbine blade from being inserted into this fixture and the amount of contact points on the surface that will further reduce the probability of slip. This design was presented to General Electric and rejected based off of the reasoning that the casting variation in the curvature between different turbine blades is 0.025”. Due to this large variation General Electric did not want to proceed with the development of this clamping method. This design allows variation in turbine blade height by means of uniquely designed profile matched interchangeable profiles.

Figure E-1. The matching profile S3 datum support concept

The roller design is based off of General Electric’s current design. This design uses a simple roller, which is cylindrical and circular in cross section, where the turbine blade can come into contact with the roller at a single contact point while supported above by a clamp in order to dampen vibrations due to the machining process. This design allows variation in turbine blade height by means of interchangeable rollers which are uniquely designed for each specific blade.

Figure E-2. The current S3 datum support design



The suction cup concept incorporates a vacuum operated suction process with a precision placed suction cup in order to support the S3 datum point of the turbine blade. This design will allow three sided access to the turbine blade. This design allows variation in turbine blade height by means of a mechanical adjuster. This concept is shown below in Figure E-3. There are significant concerns over this design’s ability to function in a machining environment as well as the lack of any error-proofing design.

Figure E-3. A schematic of the suction cup S3 datum support concept



Appendix F: Baseplate Design and Weighted AnalysisDuring the concept generation phase, many different ideas were created for the design of the baseplate. The top three concepts were then analyzed and weighed against each other to determine the direction of the solution. The three concepts discussed in this appendix are the interchangeable parts concept, the interchangeable baseplate concept, and the controlled moving parts concept.

The first concept discussed in this appendix is the interchangeable parts concept. This concept is shown below in Figure F-1. The interchange parts concept is a very simple design that functions off of a single master plate idea with multiple slots and holes for each S3 datum support and main clamp support to be moved about easily. This was the simplest idea generated and would be the cheapest concept, although it is not adaptable to future designs and is easy for an operator to use the wrong interchangeable piece with a given turbine blade.

Figure F-1. The interchangeable parts concept

The second concept generated is the interchangeable baseplate concept. The idea is that each gas turbine blade has its own specific interchangeable baseplate that can then be inserted into the master plate located on the quick change fixture. This design would allow all the changeover process to occur while a different blade is being machined, eliminating most of the time required in the changeover process. However, this idea would have the highest associated cost as each baseplate would have to be precision manufactured. The interchangeable baseplate concept is shown below in Figure F-2.



Figure F-2. The interchangeable baseplate concept

The final concept generated was the controlled moving parts concept. This concept featured a set of ball screws located below the S3 datum support and on the main dove tail clamp in order to allow for complete adaptability. Every gas turbine design would be able to fit on the fixture design and as long as future designs are not too long, they also would be able to adapt, costing General Electric nothing. The problems associated with this design are questions raised about the ball screw motor’s ability to function in a machining environment as well as the associated cost.

Figure F-3. The controlled moving parts concept

The weighted analysis of the proposed baseplate solutions was conducted in order to compare and contrast the current baseplate design to the proposed solutions. The weighted criteria is located below in Table F-1. Although the automated base plate is the highest rated solution, there are significant concerns over its ability to function in a machining environment as well as the associated cost.



Table F-1: Weighted analysis of proposed baseplate solutions. Base Plate Designs

Criteria WeightCurrent Design

Interchangeable base plate

Interchangeable parts

Controlled moving parts

Cost 3 1 1 1 9Safety 10 3 3 3 9Time 8 1 9 9 9

Weight 2 1 3 9 9Support

availability 7 1 1 1 3Flexibility 7 1 3 3 9

Maintenance 7 9 9 9 1Manufacturability 4 3 3 3 3

Repeatability 9 9 9 9 9Size 2 1 3 3 9

Ease of assembly 5 3 9 9 9Controllability 10 9 9 9 9

Total 320 436 448 544



Appendix G: Possible Interchangeable Baseplate Designs The interchangeable baseplate design requires some form of alignment on the master plate so as to ensure the interchangeable baseplate is located correctly every iteration. The first concept generated is the alignment pin design. This design requires lowering the baseplate down onto the master plate in the Z-direction by means of a magnetic crane. The baseplate has three precision alignment sleeves which are precise up to 0.0002”. The master plate incorporates the alignment pins which are compressively inserted into the master plate in precision machined hole. These alignment pins are also machined to a tolerance of 0.0002”. The alignment pins feature a 0.010” fillet which acts as a lead in for the sleeve for ease of installation. Once lowered onto the alignment pins the baseplate should be in the correct placement, but just as a check, a program will be run to check the placement with respect the current global coordinate system of the machine. This will ensure the precision required in the constraints. It is worth noting that the baseplate is to be secured in it’s final position by four bolts which are conveniently located to maximize change over time reduction. The alignment pin design is shown below in Figure G-1.

Figure G-1. Alignment pin concept

Another concept generated is the slot design. This design incorporates the use of an overhead magnetic crane to lower the baseplate into a tapered slot cut into the master plate. This slot is precision machined to the required tolerance and is tapered to reduce the possibility of binding during installation. The baseplate will have identical taper machined onto its sides. This baseplate design also uses bolts to secure it in its final position.

Similar to the slot design, the embossed design will have an extrusion out of the master plate and the baseplate will have the slot cut into it’s bottom side. The final placement will also be secured with bolts. The embossed design is shown in Figure G-2.



Figure G-2. Drop in embossed base plate concept

The final concept is the hinge design. This design is the most unique and incorporates the technology behind installing hardwood floors which use a tongue and groove system in order to interlock each individual piece together. This design requires the baseplate to enter the machine at an angle which is a more complex and general motion from just lowering it into place. This makes installation as a whole much more complicated and hard to train an operator to complete properly. This design requires less hardware to secure the baseplate in it's final location. A conceptual model of the hinge design is shown below in Figure G-3.

Figure G-3. Lock in place hinge concept



Appendix H: Design Calculations and FEA AnalysisMachining Force Calculations

Assumptions-Sharp ¾” Carbide Mill

-w=23Dcutter

-t 0=0.010- Specific Energy taken for the Hardest Alloy Steel available on the chart and used as the Specific Energy for the super alloy of the turbine blade.α=10°β=60°φ=45°Cutting Force Equation( EQn 20.21)

F c=U t0wMerchant Equation( EQn 20.16)

φ=45°+ α2− β

2Thrust Force Equation

F t=F c tan (β−α )Where (definitions),F c - cutting forceF t -thrust(plunge) forceU - specific energyt 0 - chip thickness(cutting depth)w - chip width (cutting width)α - rake angleβ - friction angleφ - clearance angle

Results-

F c=(640,000 ¿−lbs¿3 )∗¿

F t=(3,200 lbf )∗tan (50 ° )=3813.61 lbf



Figure H-1. Table from Groover of Specific Energy values for various metals [5].



Appendix I: Displacement Calculations for the Dove TailMain Block Displacements

The purpose of this section is to show that the blocks that contact the dovetail will not have enough displacement and be over the allowed amount of 0.0002 inches. There are three different blocks that will be used in this design of which the primary analysis will be on the one that is the least wide (5.91”) because all other dimensions (height, length) will be kept the same.

In Figure I-1 the block is broken up into two different parts. The first is the section that is the majority of the mass. That is on the bottom and is idealized as a rectangular prism which has a height of “Height Body” (Hb), Width of “Width” (w) and a length of “Length Body” (Lb). The second is the section that goes and touches the dovetail, idealized also as a rectangular prism. It has a height of “Height Dovetail” (Hd), width of “Width” (w) and a length of “Length Dovetail” (Ld). Where the height of the dovetail extends from the point where the body height ends to the top of the rounded portion of the dovetail. See Figure I-2 for a depiction.

Anderson, Gregory, Luther, Thomas

Length Dovetail

Height Dovetail

Figure I-1: Name convention for dovetail block

37


In Figure I-2, it is possible to see a better understanding of how the two bodies are broken up into the two different sections. The problem with idealizing the second body as a rectangular prism is all of the area that is subsequently not considered in the actual design. This is acceptable in the actual problem because the dovetail will be sitting there which will help support that mass and prevent it from yielding. The area titled “Not Considered” is a section of mass that is added after running the simulations to strengthen the second body because of the inconsistencies in assuming the second body is a rectangular prism. It is also important to note that in the simplified example, the first body is mounted to the base plate and is considered to not yield and acts as a cantilever beam. It is justified to have it be a cantilever beam because it is only mounted on one side and will have a load acting on it the body in a direction perpendicular to the length.

The forces shown in Figure I-2 are the force created due to cutting (Force X) and the clamping force (Force Z). There will have the values of 2,550 lbs and 6000 lbs respectively. The force due to cutting was determined because that is the maximum force created during a cut in the X or Y direction on a VF-4 Haas vertical CNC mill. The clamping force was provided as a constant for all clamps to be used. The cutting force was calculated in this direction because this direction has the greatest chance of having too much yielding since its moment of inertia is lowest in this configuration.

Hand Calculations

Maximum displacement for cantilever beams:

ymax=F L3

3 EI


Critical point

Force Z z

Force X

Base Plate

Not Considered

Second Body

First Body

Figure I-2: Simplified drawing of Figure I-1

38


Where ymax is the maximum deflection in the member, F is the force acting perpendicular to the member, L is the length of the member which in our scheme is the height, E is the modulus of elasticity and I is the moment of inertia which for our case will be a rectangle.

Moment of inertia for a rectangle:

I x=bh3

12

Where b is a dimension in this case the width and h is the length of the body. To be able to account for there being two different bodies the total deflection will be broken up into the two different groups which is satisfied by the following equation:

Disptotal=Dispbody+Dispdovetail

In this equation the total displacement is the sum of the displacement of the body and the dovetail; where the total displacement needs to be less than 0.0001 in order to satisfy the criteria in the PDS, located in Appendix A, where F=2550 lbf, E=29.5*10^6 psi, b = width which is 5.91 inches. H and L vary based on which of the bodies is being considered. Where L for the first body is 8.785 and L for the second body is about 1.6. These values were determined by trying to maximize the size of the first body while not touching the second body. H is 2 inches for the second body and is determined to be 7 inches for the second body after solving for total displacement.

ModelingThe following section is dedicated to modeling since there is great uncertainty created in the hand calculation due to the assumptions made about the second body as explained earlier. After applying the loads to the areas depicted in Figure I-2 the simulations were assumed to have passed the requirements if the maximum yielding at the critical point was less than .0002 inches. After running the simulation, the critical point yielded more than expected and was corrected by increasing the length of the dovetail to a length such that it would not contact the clamp. The not considered section was also added to add a little more strength to that section while still not touching the turbine blade at any point. After making these corrections

Figure H-3, Figure H-4 and Figure H-5 show the resulting displacement on the dovetail profile supports. These are calculated using a fine mesh as denoted on the SolidWorks option. It can be seen that at the worst points that it goes above the allowed tolerance of 0.0002 inches. This is allowable though because these sections will not yield that much because there will be a dovetail on top of them providing extra support. This is why the critical point was selected because this is a point which the dovetail will not touch and thus has no extra support. If this section yields beyond the desired amount, then the dovetail is not strong enough.



Figure H-3: 5.91” width dovetail showing the maximum displacement.





ConclusionThe dovetail supports will be able to withstand the force of machining and clamping on them and not yield above the allowed tolerance (0.0002 inches). While some sections appear to yield above the tolerance these areas are not of concern because they are contacted by the dovetail which will provide an even stronger surface to interface with.



Appendix J: Bolt RequirementsThe following section is dedicated to determining the mentality which will be followed for every other bolt that will be used in these sections. The primary concern that is of worry on the sections detailed below is if the bolts end up slipping after they have been loaded. This is the largest worry because the bolts will not fail due to yield and if the fixtures end up slipping then the base plate will need to be zeroed again. This is especially a problem because of all of the fluid on the table which characterizes the table as being lubricated.

AssumptionsThe following are assumptions that are used in the following analysis. Since the table is considered lubricated the coefficient of static friction (μs) is 0.16 [4]. The force of cutting is 2550 lbf which acts in just the x and y direction [1]. There is also a clamping force of 6000 lbs which acts in only the z direction.

Hand CalculationsThe overall schematic of how friction works which will be applied subsequently to the base plate-master plate interaction, the dovetail base plate interaction, and the mater plate - side supports. Figure J-1 shows the basics of how friction is depicted.

Friction

Figure J-1: Friction Basics

In Figure J-1 FN is the force that is normal to the plane that the object is resting on. Fcut is the force acting in which ever direction in this case it is perpendicular to the force applied. F s is the static force keeping the object in that position. Where Fsmax=FN*μs If Fcut is greater than Fsmax then Fs is no longer a valid force since μs is only valid for static cases. From this it is possible to determine the force required on all the bolts.


Fs

FN

Fcut

42


Force in a boltThis section will cover how to calculate the force required in a bolt. It is important to note that in this section this is for standard bolts that can be purchased off of the shelf and use standard hex bolts to lock them down.

Equation 1: Force in a bolt [4]:Fb=Pb+F i=CP+Fi

Equation 1 reduces to:Fb=F i

Where in this equation Fb is the force in the bolt, Pb is the portion of the overall load taken by the bolt, F i is the preload on the bolt, C is the fraction of external load P carried by the bolt and P is the external tensile load per bolt. Pb is not considered for this analysis because the moment created from the load is not considered. This reduces what Fi would need to be, so by not considering Pb it is adding an extra level of safety.

Calculating Fi:The overall equation that is used to define the torque requirements on a bolt are as follows.

Equation 2: Torque in a bolt:

T=F idm

2 ( l+πf dm sec (α )π dm−fl sec (α))+ F idc f c

2This equation reduces down to:

Equation 3: Torque in a bolt:

T=K Fi d

To reduce this equation, it is under the assumption of how standard bolts work and defining the coefficient of friction between standard bolts and steel, see reference for the entire derivation [4]. In this equation T is the torque on the bolt, K is the Bolt Condition, and d is the diameter of the bolt. Since we know that the surface is considered lubricated then K = 0.18 and d will be a standard size of .5 inches for everything on the plate itself.

Calculations

In the following section all of the calculations for the bolts on the different surfaces will be calculated and a recommended torque setting will be given.

Base Plate to Master Plate See Figure J-2 for a visual. In this calculation Fcut is 2550 as explained earlier, Fsmax is equal to 2550, so FN is equal to 17000 lbf, this tell us what our total force in the bolts needs to be. Since there are 4 bolts 17000 lbf is divided by 4 to equal 4250 lbf. This is plugged into Equation 3 which results in the overall torque being 382.5 lbf*in or 31.875 lbf*ft.



Base Plate to Dovetail support

Figure J-2: Dovetail Support Free Body Diagram

Figure J-2 shows the free body diagram of the expected dovetail support. Where Fb is represented by 2 bolts in this picture but actually has 4 bolts in the actual design. The reason for this difference is to allow for an even greater factor of safety in these bolts. Where Fclamp is 6000 lbf, Fcut is 2550 lbf. In this sense FN = Fb*2+Fclamp and FN* μs =Fcut. So Fb ends up being about 5500 lbf. After plugging this into Equation 3: Torque in a bolt:T= about 40 lbf. To verify that this is the maximum required torque in these bolts then next analysis was done.

Equation 4: sum of the forces about the right interface

∑M x=0=Fb∗.6+Fb∗10+F clamp∗5−Fcut∗10.33831

Where in this equation it is summing the moments about the point indicated as the right interface in Figure J-2. Where 10.33831 is the location to the centerline for the turbine blade and the other measurements are the distances from the right hand interface to those points. The result form this equation is that Fb = -343.142 lbf. Since this number is negative there is actually no need to have the bolts when considering a moment equation.

Master plate to side supportsThis section summarizes the bolt requirements between the master plate and the side supports, Figure J-6 shows the free body diagram by which the analysis will occur. Where the blue section is the master plate and the orange section is the side support. The scenario is the worst possible configuration because it does not consider the attachment on the other side, which is why a


Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

Right Interface

44


moment is not considered necessary because the moment will end up causing the force to be distributed amongst both sides.

3*Fb*μs=Fs and Fs=Fcut are the equations that describe the scenario described above. After Solving for Fb the result is 5666.67 lbf, which after plugging into Equation 3 the result becomes Fi is 510 lbf*in or 42.5 lbf*ft. Since this is the greatest torque requirement required all bolts need to be tighter than this scenario. Based off of this all bolts should be torque to 50 lbf*ft to achieve a safe torque with a little safety factor.

Bolt safetyThe recommended bolt requirement is 50lbf*ft which causes a stress of 6666.7lbf in the bolts. Since the bolts being used are ½ inch coarse thread bolts the Tensile Stress Area (A t) is 0.1419 in2.

Equation 5: Uniform Distributed Stress σ= FA

After plugging the stresses listed above into Equation 5 where σ is the stress in the bolt, F is the force and A is the area, the result is σ = 46981 psi. Based off of this measure the minimum bolt requirement is grade 2 but to keep all bolt styles consistent across the fixture the recommended bolt grade is 8 which has a yield strength of 130Kpsi which means this bolt will have a safety factor of 2.76 [4].

Conclusion

Using Shigley’s analysis the minimum torque required to prevent any bolt from slipping is 42.5 lbf*ft, because of this we recommend a minimum torque requirement of 50 lbf*ft and would


Fs FcutFB

FB

Figure J-6: Master Plate to Side support

45


allow a range of 50lbf*ft to 55 lbf*ft. This range was chosen to allow for most scales on torque wrenches and knowing that the minimum recommended torque is 50 lbf*ft.



Appendix K: FEA Analysis In order to validate the proposed fixture, it is important to run an FEA analysis on the key components to confirm the fixture will not break during operation or be displaced more than 0.0002 inches. The following FEA analysis cover the main fixture during a cutting operation and the force applied to the Dove Tail clamp during actuation.

Proposed Fixture

During a milling operation, the CNC machine will apply approximately 3200 pounds of force in the downward Z direction to the gas turbine blade. This is a major concern for the proposed fixture as it is required for the fixture to deviate less than 0.0002 inches from the original, intended position. Figure K-1 below details what would happen if a gas turbine blade placed in the fixture were to experience 3200 pounds of cutting force applied to it.

Figure K-1. The displacement of the fixture during a milling operation

As it can be see in Figure K-1 above, if a cutting force is applied to the gas turbine blade, the fixture itself will not move during operation. A further analysis into the factor of safety of the overall fixture is shown below in Figure K-2.

Figure K-2. The factor of safety of the fixture.



As Figure K-2 clearly displays, the fixture is not at risk of failure as the factor of safety is over 5. In order to conduct this analysis, a mesh size and fixed points must be chosen. Figure K-3 below shows the Mesh chosen and Figure K-4 details where the points were chosen to be fixed. Finally, Figure K-5 displays where the cutting force was applied.

Figure K-3. The chosen Mesh size for the FEA analysis

Figure K-4. The fixed points chosen for the FEA analysis



Figure K-5. Where the force was applied in the FEA analysis

With the mesh size and fixed points chosen as well as the cutting force applied, the resulting Von Mises stress is shown below in Figure K-6. From Figure K-6, it can be seen that the proposed solution is not at risk of failure or a deviation over 0.0002 inches during operation, satisfying the requires given in Table 1.

Figure K-6. The resulting Von Mises Stresses

Main Clamp

The dovetail clamp will exert up to 6000 lbs of force on the gas turbine blade. As such, an FEA analysis was conducted to ensure the clamp will be able to withstand the force without breaking. Figure K-7 below shows the Von Mises stress applied to the clamp while Figure K-8 shows the Factor of Safety.



Figure K-7. The Von Mises stress applied to the clamp

Figure K-7 shows the stress analysis of the clamp section that touches the dovetail. The stress analysis shows a stress around the bolt holes of around 12ksi. These are the critical sections because the worry is that these points will rip out if the plate is too thin. Since the clamp is made out of 1020 hot rolled steel with a yield strength of about 30 ksi, this part therefore has a safety factor of 2.5. The sections that are greater than 30 ksi as shown in the image are inaccuracies in the simulation itself and are not considered.

Figure K-8. The Factor of Safety of the clamp



Appendix L: Design Considerations for the Dovetail ClampObjective:The objective of this section is to show the considerations that went into designing the dovetail clamp. This section will be organized in the fashion about which the design process was conducted. In the end the final product will be presented along will all specification for the use of that product. Ideas for improvement will also be presented in this discussed.

Requirements: The dovetail clamp needs to be softer than 50 rockwell. The dovetail needs to be as short as possible so the base plate is as short as possible The dovetail needs to be made from purchasable parts The dovetail need to be as short as possible to reduce the moment created on the dovetail

support and clamp. Design hand calculations

Similarities

Figure L-1: Dovetail Design

Figure L-1 shows the scheme by which Table L-1 was created. From here it is possible to see that there are 3 different dovetail designs, 850 R and 597 A, 332 C and 889 H, and 592 E where these are the last 3 digits and letter of the drawing that the blade corresponds to. To ensure that the shortest design was created the design had to be such that 6000 lbf or greater has to be applied to the clamp. The overall distances were then compared in the x direction denoted X and compared to the critical distance denoted Crit to ensure that the clamps would not end up running


Y

XCrit

51


into that wall. What this lead to was 850 R, 597 A, 332 C, and 889 H to all be on the same clamp and 592 E being on a different clamp because the 592 E clamp would have caused the overall length of the design to increase which was something to be avoided.

Table L-1: Dimensions of Figure L-1

Drawing # Y (Inches) X (inches)850 R 1.66742 1.97745332 C 1.38949 1.64767889 H 1.38949 1.64767597 A 1.66742 1.97745592 E 1.80615 2.33869

The following is the schematic created to determine the distances that the clamp needed to be and the equations following.

Figure L-2: Overall dimensions of the clamp

FR=6000lbfFR is the required force on the turbine blade of 6000 lbf


X

FR

FP

F

Y

B

Bx

By

Bd

B

52


FP=3000 psi∗A p

FP is the force exerted by the piston and Ap is the area of the piston

Ap=(By−Bd

2 )2

π

This equation describes the maximum size of the piston assuming that the wall thickness is zero for the piston. Where By – Bd/2 is the radius of this piston. Where By = Bxx in order for there to be no forces in the horizontal direction acting on the piston because most pistons are not designed to have tangential loads.

x−(B xx+12Bd)=2∨2.4

To ensure that the turbine blade does not run into the member of length B it has to have a length of 2 inches for the common clamp and 2.4 for the clamp that has only one turbine blade (592 E). Summing moments about the right side of the clamp yields

0=FB∗B xx−6000∗x

Where in the design described previously the user has to settle for a few cylinder sizes and standard lengths. This is also with the understand that the longer that Y becomes the taller the overall assembly is.

Angle ChoiceIn this section how much space the dove tail will receive is described when the piston is retracted.

Figure L-3: Piston Retracted schematic


B

Bx

B

Bxx

Bt

BL

53


B=Y +Bx

Describes the total length of B as is described when Y is at full extension. x∗sin (θ )=clearing distance

The previous equation describes by how much the blade will be cleared byBxx−B xx∗cos (θ )=BL

sin (θ )∗B xx+B x=BT

√BL2+BT

2 =BAfter these equations are created it is possible to generate the schematic for the clamp above. What ends up being the design considerations to be considered is what are the piston configurations that will allowed based on these equations that minimizes the overall length. After running these equations based on certain popular sizes found for different companies, a piston size of 50mm was chosen that had a stroke length of 25 mm. This was done because this piston sized allowed for it to be the smallest overall design while still allowing for other possible cylinders to be used. Based on the size consideration created here it was determined that Fmax was 15130 lbf and Fp was 9130 lbf. From here the pins were designed to withstand the forces shown in the free body diagram in Figure L-4.

V= Fmax/2 determined by summing moments about any point. So V=7565 lbf. Since the expected failure is shear and the bolts are ductile materials the failure method was determined to be Maximum Shear Stress Theory. So the following equation was used to determine the amount of shear in the member.

τ=VQ¿

Since τ is normally half of the yield strength which for class 8 bolts is 130 * 106 psi the required diameter of the bolt is between .44” and .63” for a safety factor of 1 and 2 respectively. Since the bolts are the cheapest parts to replace the safety factor should be less than 2 but greater than one. So a round English size for this was 9/16”.


S Fmax

VV

Figure L-7: bolt free body diagram

54


To determine the width of these supports an overall calculation was run to figure out how thick they needed to be.

σ= FA

This ball park estimate was used to base the SolidWorks stress simulation off of to verify that the simulation was accurate. Where F is 7565 and A=1.5in^2 (1” x 1.5”) which yields a stress of 35 MPa. As can be seen the center of the member experiences that level of stress. Which shows this is a proper loading scenario. It is possible to see the red region as being above the yield stress but this an exaggeration of the stress because there will be a bolt in that pocket which will help distribute the stress. So an more accurate stress interpretation is the top pocket.

Figure L-5. Yield stress on the connecting pin

The next portion of the design considered was the creation of the clamp section that touches the dovetail and ensuring that the stresses were appropriate. The following simulation was verified using the following equation:

σ=MyI

Where M is the moment on the member, y is the distance from the center and I is the moment of inertia. This is interchangeable with the previous equation for shear because the member is in between the area of being dominated by shear stress vs being dominated by bending stress. After verifying the stress, the following simulation was run.



Figure L-6. Yield Stress of the clamp

From the stress simulation shown there was 9130 lbf on the piston link and 15130 lbf on the center link. From those it is possible to see that at the very worst the safety factor is 1.628 and averages out at a little greater that two. Based on this the clamp is considered safe.

ConclusionThe clamp is designed to be as small as possible and provide 6000 lbf to the dovetail without using a material harder than the dovetail. These reasons have led to the dovetail clamp to be made out of 1020 Hot Rolled steel.



Appendix M: Hydraulic Schematic Included in this Appendix is the Hydraulic Schematic of the proposed solution. There are only two clamps attached, the main and dove tail clamp. The hydraulic schematic is shown below in Figure M-1.

Figure M-1. Hydraulic Schematic of the proposed solution.



Appendix N: Master Plate and Base Plate Connection Work Instructions

Master plate and Base Plate Connection Instructions

The Figure above shows the master plate and baseplate attached to one another.

1. Remove bolts located above.2. Place the magnetic crane’s magnet on

the X area located above. Be sure to NOT touch the locator balls.

3. Move base plate to storage rack.

4. Place base plate onto the open base plate storage area on the top level shown above.

5. Pick other previoulsy assembled base plate up move to master plate.

6. Align locator holes on base plate (top) with locator pins on master plate (bottom) and slowly lower base plate onto masterplate. See step 7 for ref.

7. Location of locator pins. 8. Place and tighten ½“ bolts in holes located above. Tighten to 55 ft∙lb.



9. The fixture should look similar to the picture above when completed.



Appendix O: Base Plate Configuration Work InstructionsBase Plate Configuration Instructions

Removing and assembling the Dovetail support, S3 support and Dovetail clamp on the base plate.

9. Remove bolts located above.10. Wiggle to release.

11. Remove all four bolts located above.

12. Wiggle to release.

13. Remove four bolts.14. Pry using a screwdriver to

release the spacer from the clamp. Pry area shown in figure above.

15. Remove spacer plate by prying with a screwdriver.

16. Wipe entire plate with a rag to remove cutting fluid and excess chips.

17. Select appropriate s3 support, dovetail support, spacer plate and clamp.



18. Align interference fit pins with proper holes and hit down with dead blow hammer or rubber mallet. The proper hole placement is found on page #.

19. Align clamp pins with spacer holes.

20. Place and tighten all four ½“ bolts to 55 Ft∙Lb each.

21. Align Dovetail support interfence pins with appropriote location. See Page # for location.

22. Place four ½“ bolts in the holes depicted above. Tighten to 55 Ft∙Lb.

23. Ensure that the appropriate Parallel piece is attached.

24. Place the compression fit into the correct hole

25. Place two ½“ bolts in the holes depicted above. Tighten to 55 Ft∙Lb.

26. Align S3 support interfence pins with appropriote location. See Page # for location.

27. Place four ½“ bolts in the holes depicted above. Tighten to 55 Ft∙Lb.

28. The Base Plate should look similar to the figure above when all steps are completed correctly.




Indicates 107T5592_E Dovetail support.

Indiccates Dovetail support for all other turbine blades.

Indicates 107T5592_E S3 support.

Indicates 144E7889_H S3 support.

Indicates 104T3332_C S3 support.

Indicates 116E3850_R & 107T5597_A S3 support.

Indicates Clamp Location interference fit for spacer plate.

62


Appendix P: Bill of Materials PurchasedAppendix P covers the parts of the proposed solution that are purchased from outside sources. The part’s supplier, part number, quantity used, and total cost are included below in Table P-1.

Table P-1. Parts purchased and subsequent cost

Purchased Parts

Part Supplier Part Number Cost per Part Quantity TotalT-slot Tool MSC Direct 52706975 $470.00 1 $470.00

Alignment pins and sleeves McMaster Carr 31335A14 $6.78 3 $20.34

Alignment pins and sleeves McMaster Carr 31335A54 $6.75 3 $20.25

Handles McMaster Carr 11255A140 $30.78 1 $30.78Hardware - flat

washer McMaster Carr 96765A160 $0.28 22 $6.10

Hardware - rotab McMaster Carr 91286A322 $1.45 4 $5.81

Hardware - bearing McMaster Carr 92620A716 $0.85 3 $2.54

Hardware - master McMaster Carr 91286A325 $1.07 4 $4.26

Hardware - M3 handle McMaster Carr 91294A133 $0.06 4 $0.24

Hardware - Nuts McMaster Carr 94895A823 $0.15 4 $0.61

Hardware - Rotab McMaster Carr 91286A321 $0.96 3 $2.89

Tooling balls McMaster Carr 8481A33 $19.38 3 $58.14Grade 8 steel

cap screw 9/16- 12 X 4"

McMaster Carr 91257A773 $10.15 1 $10.15

Grade 8 1/2-13- 1.5" McMaster Carr 92620A716 $8.47 2 $16.94

Hydraulic Hose with Quick Disconnect Couplings

McMaster Carr 1147N11 $100.00 1 $100.00

Parker cylinder Parker 50JJHMIRN14M25M1100 800 1 $800.00

Connecting Rod Parker 143480 20 1 $20.00

Rod Clevis Parker 143450 50 1 $50.00

Total: $1,619.05



Appendix Q: Bill of Custom-Made PartsAppendix Q covers the parts of the proposed solution that are custom made. The quantity used, part description, and total cost are included below in Table Q-1.

Table Q-1. Quote of custom made parts and subsequent costQuality Custom Components Quote

Contact Information: 3216 Industry Drive, Suite A

North Charleston, SC 29418Tel.: 843-225-4097

Quotation for:Jacob Luther

Date: 4/19/2016

Quantity Description Unit Price2 Manufacture common clamp per drawing $450.00 ea.

2 Manufacture base plate per drawing$4500.00

ea.

1 Manufacture rototab spacer per drawing$3600.00

ea.

5 Manufacture 3258 dovetail support per drawing$6800.00

ea.

1 Manufacture left side support spacer per drawing$3200.00

ea.

5 Manufacture 107T5597 S3 block per drawing$4500.00

ea.

3 Manufacture 592 parallel plate per drawing$3700.00

ea.

1 Manufacture common clamp mount per drawing $475.00 ea.



2 Manufacture gusset Assembly per drawing $130.00 ea

1 Manufacture left side plate per drawing$2800.00

ea

1 Manufacture rotab side plate$4200.00

ea

1 Manufacture left support per drawing$4800.00

ea 1 Manufacture cylinder per drawing $800.00 ea

1 manufacture master plate per drawing $4500.00

ea

Total: $102,135.0

0

Other Comments or Special Instructions Delivery:



Appendix R: Time AnalysisA time analysis was used to find the minimum amount of time the disassembly and assembly of the base plate configuration, as well as the master plate and baseplate changeover would take to complete. The time analysis used is based on the Manual Handling-Estimated Times and the Manual Insertion-Estimated Times charts on pages 83 and 84 in Boothroyd’s and Dewhurst’s ProductDesignforManufacturingandAssembly. Using these charts, the minimum estimated time for the baseplate configuration is 4.13 minutes. The minimum estimated time for the master plate and base plate changeover is 2.65 minutes. These times are based upon how long each step of the Work Instructions, located in Appendix N and O would take to complete. The estimated time of each step may be found in Table R-1 for the interchangeable baseplate and Table R-2 for the changeover process.

Table R-1. Estimated time of interchangeable baseplate assembly and disassembly

Item Name Number of Items

Manual Handling

Code

Handling Time per Item [s]

Manual Insertion

Code

Insertion Time per Item [s]

Total Operation Time [s]

Disassembly S3 support

Bolts 2 1 1 1.8 9 7 7 17.6Support (Removal) 1 9 5 4 0 3 3.5 7.5Main support 0

Bolts 4 1 1 1.8 9 7 7 35.2Support Removal 1 9 9 9 0 8 6.5 15.5

ClampBolts 4 1 1 1.8 9 7 7 35.2

Clamp Removal 1 9 5 4 0 3 3.5 7.5Spacer plate removal 1 1 1 1.8 0 3 3.5 5.3

Assembly Clamp

Spacer plate insert 1 1 1 1.8 0 3 3.5 5.3Clamp Insert 1 9 5 4 0 3 3.5 7.5

Bolts 4 1 1 1.8 9 7 7 35.2Main Support

Support insert 1 9 9 9 0 8 6.5 15.5Bolts 4 1 1 1.8 9 7 7 35.2

S3 support Support insert 1 9 5 4 0 3 3.5 7.5

Bolts 2 1 1 1.8 9 7 7 17.6Totals 28 Total [s] 247.6

Total [min] 4.13



Table R-2. Estimated changeover time

Item Name Number of Items

Manual Handling

Code

Handling Time per Item [s]

Manual Insertion

Code

Insertion Time per Item [s]

Total Operation

Time [s]Disassembly

Bolt 4 1 1 1.8 9 7 7 35.2Magnet 1 0 0 1.13 0 0 1.5 2.63

Base Plate (Remove from masterplate) 1 9 9 9 1 6 8 17

Reorientation 1 9 8 9 9Base Plate (Insert on

Storage rack) 1 9 9 9 0 6 5.5 14.5

AssemblyMagnet 1 0 0 1.13 0 0 1.5 2.63

Base Plate (Remove from Storage rack) 1 9 9 9 0 6 5.5 14.5

Reorientation 1 9 8 9 9Base Plate (Attach to

masterplate) 1 9 9 9 2 8 10.5 19.5

Bolt 4 1 1 1.8 9 7 7 35.2Totals 16 Total [s] 159.16

Total [min] 2.65



Appendix S: Drafts of Created PartsThe drafts of parts are given via flash drive. The files include part files, surface files, and drafts of created parts.



References [1] "CNC Verticals: 40-Taper Standard," Haas Automation Inc, 2016. [Online]. Available:

http://www.haascnc.com/mt_spec1.asp?id=VF-4&webID=40_TAPER_STD_VMC#gsc.tab=0. [Accessed 11 April 2016].

[2] Cohen, H., Rogers, G. F., & Saravanamuttoo, H. I. (1987). GasTurbineTheory. Burnt Mill, Harlow, Essex, England: Longman Scientific & Technical.

[3] [Cross-section of a Gas Turbine]. Retrieved April 5, 2016 from http://cset.mnsu.edu/engagethermo/images/gasturbineanimation.png

[4] "Friction and Coefficeints of Friction," The Engineering Toolbox, [Online]. Available: http://www.engineeringtoolbox.com/friction-coefficients-d_778.html. [Accessed 11 April 2016].

[5] Fundamentals of Modern Manufacturing Materials, Processes, and Systems by Mikell P. Groover 5th ed. Power and Energy Relationships in Machining Ch. 20.4 pg.538

[6] Moran, M. J., Shapiro, H. N., Boettner, D. D., & Bailey, M. B. (2011). Fundamentalsofengineeringthermodynamics. Hoboken, N.J.?: Wiley.

[7] R. G. Budynas and J. K. Nisbett, Shigley's Mechanical Engineering Desing, New York: McGraw-Hill Education, 2015.

[8] [Specifications of the HAAS Rotary Table 310]. Retrieved February 10, 2016 fromhttp://int.haascnc.com/mt_spec1.asp?intLanguageCode=1033&id=HRT310&webID=ROTARY_TABLE_ROTARY&id1=HRT310SP#comparespec


final_report_complied

Documents