workbook modeling of multi- member machines

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Projekt współfinansowany ze środków Unii Europejskiej w ramach Europejskiego Funduszu Społecznego

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WORKBOOK MODELING OF MULTI- MEMBER MACHINES

LUBLIN 2014

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Author: Mirosław Ferdynus

Desktop publishing: Mirosław Ferdynus

Technical editor: Mirosław Ferdynus

Figures: Mirosław Ferdynus

Cover and graphic design; Mirosław Ferdynus

All rights reserved.

No part of this publication may be scanned, photocopied, copied or distributed in any form, electronic,

mechanical, photocopying, recording or otherwise, including the placing or distributing in digital form

on the Internet or in local area networks, without the prior written permission of the copyright owner.

Publikacja współfinansowana ze środków Unii Europejskiej w ramach Europejskiego Funduszu Społecznego w ramach projektu Inżynier z gwarancją jakości – dostosowanie oferty Politechniki Lubelskiej do wymagań europejskiego rynku pracy

© Copyright by

Mirosław Ferdynus, Lublin University of Technology

Lublin 2014

First edition

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TABLE OF CONTESTS

1. Model of the tilting pad…………………………………………………..……….. 3

2. Model of the spherical knob………………………………………………………. 4

3. Model of the rod…………………………………………………………………... 6

4. Model of the cap…………………………………………………………………... 9

5. Model of the nut………………………………………………………………….. 14

6. Model of the screw………………………………………………………………... 18

7. Model of the body………………………………………………………………… 24

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The main purpose of this publication is to present the basics of solid modeling on the example of a

specific device. Design exercises are supposed to enable the repetition of basic function and

procedures in solid modeling. The adequate level of detail allows the independent work for people

who previously did not use Catia v5 system. The order of subsequently performed elements of the

screw jackr, results from their degree of difficulty. The participants of the course are guided toward

more and more increased proficiency in handling of Catia v5 system. The individual elements of the

jack will comprise separate files, which a participant will save in his own directory.

We begin the design exercises with creating your own folder on the desktop. Then, we run Catia

v5 system using the icon on the desktop. The lift’s project is implemented in the Part Design

environment, which is launched with the command: Start + Mechanical Design + Part Design.

1. Model of the tilting pad

Tilting pad of the screw jack will be implemented using a method of base profile rotation.

Open an empty file and in the structure tree name this part as tilting pad.

Base profile must be implemented in the yz plane. Run Sketcher module and mark the mentioned

plane in the plane selection tool or in the structure tree of the module. The profile can be drawn in two

stages. In the first, an arc must be created using the Arc function and its center must be attached to

the V axis, while the arc’s endings for the convenience of drawing, end on H and V axis. Arc radius

should be dimensioned with the use of Constraint tool. It’s very important to make sure that the

system has created Coincidence constraints, which are visible on the screen in the form of a green

circle (fig.1.1a). If you didn’t draw the profile in a way that would create the constraints automatically,

then you must add them manually. b)

a)

c)

Figure 1.1. Stages of creating the tilting pad profile, completed model of the pad

In the second stage, the missing part of the profile must be drawn with the use of Profile function

(while drawing an open profile you need to remember about the double click when you want to

end profile or about the double Esc when you forget to end it).

Exit Sketcher using the Exit workbench button.

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Model of the tilting pad is formed through rotating the created profile by 360o angle around the V axis,

using the Shaft tool (fig.1.1c) Save the file in your directory and close it

2. Model of the spherical knob

Spherical knob in the screw lift is an ending of the rod, through which the drive is implemented.

Like the tilting pad, it will be created using a method of base profile rotation. Also, similar tools will

be used to implement this profile.

Open an empty file and in the structure tree name this part as knob.

2.1 Implementation of the main solid of the model



stages. In the first, an arc must be created using the Arc function and its center must be attached to

the center of the coordinate system, while the arc’s ending must be attached in some distance from this

axis. Arc radius should be dimensioned with the use of Constraint tool (fig. 2.1a). a) b) c)

Figure 2.1. Implementation stages of the spherical knob profile and model of the knob without the threaded hole

The profile can be completed using the Profile function (while drawing an open profile you need to

remember about the double click when you want to end the profile or about the double Esc when

you forget to end it). It’s very important to make sure that the system has created Horizontal and

Vertical constraints on the appropriate edges (fig. 2.1b). If you didn’t draw the profile in a way that

would create the constraints automatically, then you must add them manually.

Exit the Sketcher using Exit workbench button.

Model of the spherical knob is formed through rotating the created profile by 360o angle around the V

axis, with the use of Shaft tool (fig. 2.1c).

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2.2 Creation of the threaded hole in the knob

The last stage in the construction of spherical knob model is the creation of the threaded hole M8. In

order to do this, you need to use the Hole tool. Select the plane in which an hole is supposed to be

created and click near the place where you want to place it. A window will appear, in which you need

to set the parameters as shown in figure 2.2a, b. If you want to create the threaded hole, then the

parameters must be set starting from the third tab - Thread Definition. This way some of the

parameters in the first tab will be set automatically from the thread library. In the first tab in Bottom

option, you can declare the shape of the hole’s bottom. a)

b)

c)

d)

e)

Figure 2.2. Implementation stages of the threaded hole in the spherical knob

In option Positioning Sketch you need to definitely set the localization of the hole in the space (sketch

in option Hole fulfills positioning function and contains only the point visible as a white asterisk). In

this case, it’s best to use Coincidence constraints, available in Constraints Defined In Dialog Box .

You need to move the white point to the side, mark it along with the Origin point, while holding down

the Ctrl key (figure 2.2c). Then, you need to set the Coincidence constraints (figure 2.2d) – asterisk

changes its color to green – which means that it has been clearly assigned. Then if you exit the

Sketcher using Exit workbench and confirm the hole’s parameters with OK key, the operation

Hole is going to be carried out.

The final result is shown in figure 2.2e.

Save the file in your directory and close it.

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3. Model of the rod In the designed screw jack, the drive is implemented through the rod. It will be created using a

method of base profile rotation. To implement the profile, you may use the universal Profile function. Open an empty file and in the structure tree name it as rod.

3.1 Implementation of the main solid of the model



stages. a)

b)

c)

Figure 3.1. Implementation stages of the rod profile

In the first, a sketch must be created using the Profile function as shown in figure 3.1a and it’s best

to draw it in clockwise direction due to its arc. It’s very important to make sure that the system has

created Horizontal and Vertical constraints on the appropriate edges. If you didn’t draw the profile in

a way that would create the constraints automatically, then you must add them manually. Coincidence constraints must be added manually between the middle of the arc and the edge that is marked with

orange line in the figure.

In the second stage, the profile must be dimensioned with the use of Constraint tool. Due to the

fact that the target profile is supposed to be extended in one direction, it’s convenient to modify its

dimensions in thought out order. Figure 3.1b shows dimensions of the profile. Dimensions in black

color must be set first and dimensions in red color are unchanged – arbitrary and must be set in

accordance with figure 3.1c, starting from the larger one.

Exit Sketcher using the Exit workbench button.

Using the Shaft tool, we implement the model of the solid through rotating the created profile by

360o angle around the H axis. The results of this operation are shown in figure 3.2.

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Figure3.2. Effect of Shaft operation Figure3.3. Creating the chamfers

in the rod model

3.2 Features supplementing the model

Features supplementing the model are all kinds of roundings, chamfers, tilts, etc.

In a rod that we’re designing, it’s necessary to make chamfers with dimensions 0.5 x 45o at its ending.

The edges marked in figure 3.3 with red line must be chamfered with the use of Chamfer tool. The

effect of this operation is shown in the figure below.

Ending of the rod should be threaded in order to enable the fixing of the knob. To create a thread on

the outside surface, we need to use the Thread tool. After starting this function, we must define

parameters of the thread by selecting the appropriate settings in the appearing windows, as shown in

figure 3.4. As Lateral Face surface, you need to select the cylindrical surface marked in green in the

figure and as Limit Face – the front plane marked in purple. This operation will result in assignment

of thread’s feature to the surface of cylindrical ending of the rod (thread will not be visible on the

screen – figures 3.4 and 3.5, but as a feature of the model, it will appear in the structure tree).

Figure 3.4. Creation of the thread on the rod’s ending

The next stage is the creation of the mirror image in respect to zx plane. This operation is carried out

with the use of Mirror tool. The most effective way to do this is to perform these operations in the

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following order: highlight the Part Body in structure tree of the model, run Mirror function and

point to zx plane marked in figure 3.5 with yellow color. The complete model of the rod is shown in

figure 3.6.

Figure 3.5. Half model of the rod Figure 3.6. Model of the rod


4. Model of the cap

Open an empty file and in the structure tree name it as cap.

4.1 Implementation of the base part of the cap

Base profile of the cap must be implemented in yz plane with the use of the Profile tool and

dimensioned with Constraint tool as shown in figure 4.1.


Solid model of the cap is created through rotating the base profile by 3600 angle in respect to vertical

axis of the coordinate system - Shaft tool – figure 4.2.

Figure4.1 Base profile of the cap Figure 4.2 Solid model of the main part

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The cap will be fixed with the use of push screws. Prior to the implementation of the holes in the

cylindrical surface, a milling operation is conducted in order to obtain the proper support for the drill.

The removal of material from the side surface of the cap model will be carried out using the method of

subtracting other solids from the cap solid – in this case: two cuboids. To do this, using the command

from the top menu - Insert/Body, we put a new solid

object into the structure tree, which we name Prism ( –

command Properties - tab Product). Base profile of the

cuboid must be implemented in yz plane using the

Rectangle tool and dimensioned with the use of

Constraint tool in a way presented in figure 4.3.

During the drawing of the profile presented in Fig. 4.3, after you’ve drawn the rectangle, you need to assign

Coincidence constraints between the appropriate edges of

the cap and the horizontal sides of the rectangle.


Cuboid is obtained by pulling the base profile to dimension of 20 mm with the use of Pad tool,

with option Mirrored extent. After creating the cuboid with the use of Mirror tool, we need to

make its copy in regard to zx plane (first, we need to select Prism in the structure tree and after we

start the Mirror tool, we need to indicate zx as a plane of symmetric reflection) – figure 4.4.

Figure4.4. Implementation stages of the cuboid models

Then, with the use of Remove tool, we need to subtract the created Body named Prism from the

cap solid. The effect of this operation of subtraction is shown in figure 4.5.

Threaded holes M5 must be implemented in the obtained

flat surfaces. In order to do so, first you need to determine a

point in the middle of a flat surface using Point tool from

the Reference Element menu, with option On

Surface. In the dialog box called Point Definition in the

window Distance, we need to enter the value 0. Process of

point determination is shown in figure 4.6.

Figure4.3 Base profile of the cuboid

Figure 4.5. Results of the subtracting cuboids operation

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Figure 4.6. Entering the center point of the plane

Threaded holes M5 must be implemented using the Hole tool. Prior to the starting of this function,

we must select the created point. Then we launch the Hole tool and select a flat surface of the

milling. Such order guarantees that we will not have to position the Sketch (we can check it in the

Positioning Sketch window – there’s a green asterisk there, which indicate a full parameterization).

Hole’s parameters must be set in accordance with figure 4.7, starting from the Thread Definition tab,

and then going to the Extension tab.

After completion of the above-mentioned step, we will obtain two holes with M5 thread - figure 4.8.

Figure 4.7. Parameters of the Hole tool Figure 4.8. Result of the Hole operation

4.2 Implementation of the notches on the surface of the cap model

Material notches on the top surface of the cap must be implemented in two mutually

perpendicular directions, based on the same base profile.

4.2.2 Implementation of the notching tool’s profile

Base profile should be implemented in the yz plane. Run Sketcher module and mark the mentioned

plane in the plane selection tool or in the structure tree of the module. To obtain the intersection of the

solid with a Sketch plane, we need to use Cut Part by Sketch Plane function. The profile can be

drawn in four steps:

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In the axis of created rotary solid, we draw a vertical line

using Axis function and system should automatically

assign Coincidence and Vertical constraints, if it does not,

then it have to be done manually (figure 4.9).

In the created axis using the Centered Rectangle function

draw a rectangle and using the Constraint tool assign a

dimension of 2 mm, which represents the depth of subsequent

selection (figure 4.10). We delete Vertical constraints from the vertical edges and by

gently pulling the corner of rectangle, we transform it into the

trapezoid as shown in figure 4.11.

Figure 4.10. Drawing stages- step 2

Figure 4.11. Drawing stages – step 3

Figure 4.12. Drawing stages- step 4

We assign the other dimensions in accordance with the figure

4.12.

Exit the Sketcher using Exit workbench button. The semi-

finished cap, along with the created profile is shown in figure

4.13.

4.2.3. Implementation of the grooves in the selected direction

A single groove can be implemented using the Pocket tool and as a secondary option in the

first and second limit we must select Up to next. The result of this operation is shown in figure 4.14.

In the structure tree of the model, we need to change the name of the function Pocket to milling ( –

Properties command - Feature Properties tab).

Figure 4.9. Stages of outline drawing-step 1

Figure 4.13 Semi-finished cap along with the profile of notching tool

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Figure 4.14. Semi-finished cap with a single groove. Changing of the name of the function in the tree structure

To duplicate the groove, we must use Rectangular Pattern function. In order to do so, it’s best to

highlight the “milling” in the structure tree and then run Rectangular Pattern function.

Figure 4.15. Window of the Rectangular Pattern option As Reference Element we need to indicate the top surface of the semi-finished product. In the tabs:

First Direction and Second Direction we set the parameters as shown in figure 4.15. Button More >>

enables to expand the window with very useful functions that allow to obtain the effect of feature

duplication on both sides of the original groove.

Figure 4.16 shows the operation of grooves duplication in the rectangular manner and with the end

results of this stage.

Figure 4.16. Creation of the first row of the grooves

milling

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4.2.4. Implementation of the grooves in the perpendicular direction

The next stage of the work is to copy the milling feature to

zx plane. We do it in the structure tree (milling → –

Copy command→ → –Paste command). To

distinguish the two millings, we change the name of the last

to milling2 . The result of the copying is shown in figure

4.17.

We again need to use the Rectangular Pattern function. In

order to do so, it’s best to highlight the “milling2” in the

structure tree and then run Rectangular Pattern function.

As Reference Element we need to indicate the top surface of

the semi-finished product. In the tabs: First Direction and

Second Direction we set the parameters as shown in figure 4.18.

Figure 4.18. Window of the Rectangular Pattern option

Figure 4.19 shows the operation of grooves duplication in the direction perpendicular to the first

series, along with the end result – finished model of the cap.

Save the finished file in your own directory and close it.

Figure 4.19. Creation of the second row of grooves. The end result – finished model of the cap

Figure 4.17. Semi-finished product of the cap after copying the groove to zx plane

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5. Model of the nut Nut of the screw jack is going to be implemented through the

rotating of the base profile (Shaft function). Trapezoidal thread will

be implemented as a result of the Slot operation, where the Helix

screw line is used as a central curve.

Open an empty file and in the structure tree name this part as nut

5.1. Implementation of the basic axially solid.

Define new Sketch in the yz plane. Indicate the mentioned plane and

run function.

Using the Profile function draw the base profile as shown in

figure 5.1, while making sure that its orientation in respect to the

coordinate axes is correct and that appropriate geometric constraints

are assigned. Then, assign the dimensions using Constraint tool.


With the use of the Shaft tool, implement the axially symmetrical solid through rotating the base

profile by 360o angle around the V axis. This solid is shown in figure 5.2.

5.2. Implementation of the chamfers.

Using the Chamfer function, we implement the chamfers with dimensions 4 x 45o of inner edges of

the hole. The most convenient way to do this is to indicate the inner surface of the hole, and then the

system will carry out the chamfers on both edges. The effect after the implementation of this operation

is shown in figure 5.3.

Figure 5.2 Effect of the Shaft operation Figure 5.3 After modeling of the chamfers

5.3. Implementation of the trapezoid thread.

Define a new Sketch in yz plane. Select the mentioned plane and run the Sketcher module. Then,

change the name of the sketch to „trapezoid outline” (in the structure tree of the model - Properties - Feature Properties tab). The profile of the trapezoid outline will be implemented in

twelve steps, which will be briefly presented:

Just below the created rotary solid, we need to draw, using the Axis tool, two lines: vertical and

horizontal.

Figure 5.1 Profile of the nut

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Using the Intersection Point function located in the Point- menu, we generate the intersection

point of these lines. The created point is of Standard

type– marked with a cross, we can change its

appearance e.g. to more visible square or asterisk

(Graphic Properties menu). If you generate this point

correctly, then double Coincidence constraints should

appear. Next, we scale the distances from this point to

H axis and V axis in accordance with the figure 5.4.

Figure 5.5. Stages of outline drawing – step 4 Figure 5.6. Stages of outline

drawing – steps 5.7

Draw a rectangle in the generated point using the Centered Rectangle function (figure 5.5). Delete the Horizontal constraints from the horizontal edges of the rectangle (marked with a red circle).

This operation facilitates you to easily obtain the shape of a trapezoid by gently pulling the corner of

the rectangle. Do that and in result you should get the profile with a shape as shown in figure 5.6.

You also need to delete the Equidistance constraints (marked with blue circle), which are responsible

for the symmetry of the vertical profile lines in respect to the vertical axis – the designed trapezoid

profile does not have this type of premises.

Using the Intersection Point function located in Point menu, we generate the intersection points

of the vertical axis and non-parallel sides of the trapezoid. The created points of Standard type are

automatically visualized with a cross. In the figure, their appearance is changed to red square. If you

generated the points properly, then each point should have double Coincidence constraints.

Figure 5.4 Stages of outline drawing– step 2 and 3

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Using the Constraint tool we assign dimensions in accordance with figure 5.7. To create the fillet, you need to use the Corner

function. To implement the fillet on the right

side of the profile (figure 5.8) in the Sketch

Tools menu, you need to set Trim All Elements

option and then you can created the fillets by

editing the value of the radius and setting it to

R= 1 mm.

To create the fillets on the left side of the

outline, you need to notice that they are located

outside of the profile, and you need to extend

the vertical line using the Trim tool in both directions (figure 5.9).

Then, using the Corner function with Trim First Element , we create the fillets by editing the

radius value and setting it to R= 0,5 mm. In this option, the order of lines selection while drawing

is very important (the rest of the first clicked line disappears).

You also need to delete unnecessary lines (marked in orange). The best way to do this is using Quick

Trim tool with Break And Rubber In option, while selecting the unnecessary lines. Fully

parameterized profile is shown in figure 5.11.

Figure 5.8 Stages of outline drawing- step 9

Figure 5.9 Stages of outline drawing- step 10

Figure 5.10 Stages of outline drawing – step 11 and 12

Then, you need to change the three points, which were created during Intersection Point operation -

from standard to construction. The most convenient way is to do this while testing the profile with

Sketch Analysis tool. You need to highlight the mentioned points and using Set In Construction

Mode located in the Corrective Actions group, you implement changes of the mentioned point to

construction. Prior to this operation, these points had the Isolated status, which made them unable to

be used in the sketch. Close the analyzer window and exit the Sketcher using Exit workbench

button.

Figure 5.7. Stages of outline drawing – step 8

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Figure 5.11. Outline of the trapezoid thread Figure 5.12 Window of the sketch analyzer

The next stage of the work is to generate Helix type screw line. It’s not

possible in the Part Design module. Before the exiting, it’s recommended

to create a point that will become the beginning of the screw line. Use the

Point function with Coordinates option in the Reference Element

menu to create a point with coordinates shown in figure 5.13. Change the application to Wireframe and Surface Design (Start-

Mechanical Design- Wireframe and Surface Design). Run Helix

function, which is located beneath the Spline function. The parameters

of screw curve must be entered to the window (figure 5.14), while as

starting point you need to select previously created point and as axis you need to select V axis. Set the

threat’s pitch to 7 mm and height to 80 mm. Other parameters must be left default.

Figure 5.14 Defining of the screw curve Figure 5.15. Generated screw curve

Now, we have created all components for the implementation of the trapezoid thread. For this

operation we must use Slot function with Pulling Direction option. Figure 5.16 shows the window

of the Slot operation and the effect of its implementation. After the operation, an alert window will

appear with information that in the notch there’s a fragment with radius equal to zero, which is not

possible to implement in the milling technology.

Figure 5.13 Starting point of the Helix

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Figure 5.16 Window of the Slot operation and the effect of its implementation

Save the file in your directory, but do not close it. Trapezoid profile of the thread will be needed in

model of the screw.

6. Model of the screw Model of the jack’s screw will be implemented using the method of base profile rotation. Open

an empty file and in the structure tree name this part as screw.

6.1. Implementation of the screw’s main part

Define a new Sketch in the yz plane. Select the mentioned plane and run Sketch function.

Using the Profile tool, you need to draw the profile shown in figure 6.1 and scale it with the help

of Constraint tool.

Figure 6.1 Profile of the screw’s main part Figure 6.2 Model of the screw’s main part

Exit the Sketcher using Exit workbench button

Using the Shaft tool implement the solid of the main part of the screw through rotating the profile

by 3600 angle in respect to the vertical axis - figure 6.2.

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6.2. Implementation of the recesses in the top part of the screw

Define a new Sketch in the yz

plane. Select the mentioned plane

and run Sketch function.

Implement the profile of recesses

in the screw using Rectangular

and Profile tool. Dimensioning

of the profile must be carried out

with the use of Constraint tool

in accordance with the figure 6.3.


With the use of the Groove tool,

you need to make an undercut in

the main part of jack’s screw

through rotating the created profile by 3600 angle in respect to axis of the screw. Effect of this

operation is shown in figure 6.4.

In the obtained main part, we need to thicken the plug cooperating with the rod using ThickSurface

tool. Select the cylindrical surface that you want to thicken. It’s important to check whether the

arrowhead direction of the thickening is correctly pointed outside – you can change its direction using

Reverse Direction button. Parameters of this operation, state during its implementation and the end

result are shown in figure 6.5.

Figure 6.5 Implementation of the thickening in the top part of the screw

6.3. Implementation of hole for the rod

Define a new Sketch in yz plane. Select the mentioned plane and run Sketch function.

Implement the profile of the hole using Circle tool and scale it using Constraint tool in

accordance with the figure 6.6. While drawing the circle, you must provide the Coincidence-type

relation assigning the center point of the circle to V axis.

Figure 6.3. Profile of the recesses in the screw’s top part

Figure 6.4. Undercuts in the top part of the screw

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Using the Pocket tool, you need to make an opening in the screw’s plug. In the following tabs:

First Limit and Second Limit set Up to Next. The effect of this operation is shown in figure 6.7.

Figure 6.6. Profile of the hole for the rod Figure 6.7 Finished hole for the rod

6.4 Implementation of chamfers and fillets for edges– Dress-Up Features operations

Using the Chamfer tool you need to make chamfers with dimension 1x45o of the edges

shown in figure 6.8. Change the color of the created surfaces to dark blue.

Using the Edge Fillet tool implement the fillets of the edges presented in green with a radius of

R = 1mm, and the edges presented in blue with a radius of R = 2mm. Change the color of created

fillets in accordance with figure 6.9.

Figure 6.8. Implementation of edges’ chamfers Figure 6.9. Implementation of fillets

on the screw’s edges

Using the Chamfer tool you need to create a

chamfer with dimensions 4x45o on the bottom

edge of the screw. Change the color of created

surface to dark blue. Chamfer Definition

window and the end result of the operation are

shown in figure 6.10.

Figure 6.10. Implementation of the chamfer on the bottom edge

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6.5. Implementation of the thread in the jack’s screw

Trapezoidal thread of the Tr 42 x 7 screw will be created in a manner similar to model of the nut. We

will use the profile of trapezoidal thread created

in the nut model. Copy it and paste to yz plane

in the screw model – the easiest way is to do it

in the structure tree ( trapezoidal profile

→ – Copy → → – Paste).

By double clicking on the copied Sketch -

trapezoidal profile in the structure tree of

the model, we can enter it to make the

necessary modifications. The copied profile is


The modifications include:

Rotating it by 1800 angle in respect to profile’s vertical axis. You need to select the entire profile

(without the symmetry axis, but necessarily with the constraints), then run Symmetry function and

select the vertical dividing axis of the thread. The results of this operation are shown in figure 6.12a.

Changing (from 10mm to 6.5mm) or assigning (17.2mm) the dimensions marked in red in figure

6.12b. The conducted modifications are necessary for precise configuration of the profile in respect to model

of the screw.


Figure 6.11. Copied profile of the nut’s thread

a)

b)

Figure 6.12. Modification of the thread’s profile

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Use the Point function - Coordinates option in the Reference

Element menu to create a point with the coordinates

presented in figure 6.13. This point will be a starting point for creation

of the Helix screw line.

Similarly as in the case of the nut, we need a Helix-type screw line to

cut thread on the screw. Change the application to Wireframe and

Surface Design (Start- Mechanical Design- Wireframe and Surface

Design). Run Helix function, which is located beneath the

Spline function. Parameters of the screw curve must be entered to

the window (figure 6.14), while as the starting point we must select

previously selected point and as the axis we

must select axis V. Set the threat’s pitch to 7

mm and height to 390 mm. Other

parameters must be left default.

After the implementation of the screw line,

return to Part Design module by going to

the top menu of the program: Start –

Mechanical Design - Part Design. Thread on the screw surface will be

implemented using the method of cutting the

thread profile along the screw line with the

help of Slot tool. First, you must set the profile control method (Profile control - Pulling Direction)

and as axis select screw’s axis or V axis. As Profile you need to select trapezoidal outline of the thread

and as Center curve you must select Helix screw line. Slot Definition window and notched screw are


Figure 6.15 Implementation of the screw’s thread

Figure 6.13. Starting point of the Helix screw line

Figure 6.14 Implementation of the Helix screw line

Control of the thread output in the upper recess is very important. In the case of irregularities you

need to correct the Helix’s height – preferably in the structure tree.

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6.6. Implementation of the holes in the bottom part of the screw

There are two holes in the bottom part of the screw. First is located in screw axis with M12 thread and

is used to fix the safety washer. Second is a socket of the cylinder pin that protects this washer from

loosening. To make the holes, we need to use the Hole tool. First hole must be implemented with

options shown in figure 6.16. Run the Hole tool and select the surface of the screw’s button around

the planned hole.

If we want to create a threaded hole, then we enter the parameters starting from the third tab - Thread

Definition. This way some of the parameters in the first tab will be set automatically from the thread

library. In the first tab in option Bottom, we can declare the shape of the hole’s bottom. Operation of

the holes implementation is shown in figure 6.17a. In option Positioning Sketch you need to definitely

set the localization of the hole in the space.

Sketch in the Hole option fulfills positioning function and contains only

the point visible as a white asterisk. In this case, it’s best to use

Coincidence constraints that are available in Constraints Defined In

Dialog Box . We need to move the white point to the side, mark it

along with the Origin point and enter Coincidence constraints – asterisk

changes its color to green – which means that it has been clearly

assigned. (figure 6.17b). Finished hole is shown in figure 6.17c. Second

hole is for cylindrical pin and we implement it in such manner so there’s

no need for its positioning. First, we create a point on the bottom surface

of the screw. Use Point function in the Reference Element

Figure 6.16. Implementation of the threaded hole in the bottom part of the screw a)

b)

c)

Figure 6.17. Implementation of a M12 threaded hole in the bottom part of the screw

Figure 6.18. Creation of the point

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menu – with On Plane option. Enter coordinates

of the point in Point Definition window as


Highlight the created point, then run the Hole

function and select bottom surface of the screw.

Coordinates of the point will be assumed as

conclusive location of the created point. In Hole Definition window, which will appear, set the

diameter and depth of the hole (figure 6.19), in

Type tab choose Countersunk type and the

deepening parameters might be set as desired.

Bottom of the screw with created holes is shown

in figure 6.20.


7. Model of the body

Body of the screw jack will be designed as a die-cast element, reinforced with three ribs.

Foundry slope value of the model walls should be assumed as 3o.

7.1. Implementing central part of the body

First stage in the construction of jack’s body

will be to create its central part, located

between the base and the nut. Model of this

body part will be implemented using method

of base profile rotation around the jack’s

axis. Base profile must be implemented in

the yz plane using the following sketcher

tools: Profile , Constraint - Fig.7.1

(!angular dimensions must be created after

the determination of the linear dimensions).

Exit the Sketcher using Exit workbench

button.

Using the Shaft tool create the solid of

the central part of the body through rotating

the profile by 3600 angle in respect to the

vertical axis – Fig.7.2.

Figure 6.19. Parameters of the hole for the pin

Figure 6.20. Bottom of the screw with holes

Figure 6.19. Parameters of the hole for the pin

Figure 6.20. Bottom of the screw with holes

Figure 7.1 Profile of body’s central part

Figure 7.2 Solid of body’s central part

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Using Shell tool you need to

choose the material from insides of

the obtained solid, by setting

thickness of the walls to 5mm and

selecting front walls of the solid for

removal marked in Fig.7.3.

7.2. Implementation of socket for the nut

Base profile of this part of the body must be implemented in yz plane in three steps:

- step 1: drawing of the profile must be started by creating a

line that will tie the implemented profile with already

existing solid. This is done by projecting (using Project 3D

Elements tool) body’s top edge into the surface of the

sketch (yellow horizontal line – Fig.7.4).

- step 2: using the Profile tool you need to draw the

profile presented in Fig. 7.5, starting the drawing from the

end point of yellow line and finishing on it (a Coincidence-type constraint should appear). The profile must close

through the yellow line (yellow line constitutes the bottom

edge of the profile). The profile must be dimensioned with

the use of Constraint tool in accordance with figure 7.5. - step 3: using the Trim tool you need to cut the yellow

line so that it will close the profile – Fig. 7.6.


Part of the body that constitutes the nut socket is

implemented through rotating the base profile with the use

of Shaft tool - Fig.7.7.

Figure 7.3 Model of body’s central part

Figure 7.4. Implementation of the nut socket’s profile – step 1

Figure 7.5 Implementation of the nut socket’s profile – step 2

Figure 7.6 Implementation of the nut socket’s profile – step 3

Figure 7.7 Part of the body that constitutes the nut socket

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26

7.3. Implementation of the body base

Base profile of the body base must be implemented in yz plane in the following steps:

- step 1: drawing of the profile must be started by creating a line

that will tie the implemented profile with already existing solid.

This is done by projecting (using Project 3D Elements tool)

body’s bottom edge into the surface of the sketch (yellow

horizontal line – Fig.7.8).

- step 2: using the Profile tool you need to draw the profile

presented in Fig. 7.9, starting the drawing from

the end point of yellow line and finishing on it

(a Coincidence-type tie should appear). The

profile must close through the yellow line

(yellow line constitutes the top edge of the

profile).

- step 3: using the Constraint tool assign the

dimension 4 mm between the starting point of

yellow edge and vertical edge of the profile –

Fig.7.10. You also need to check, whether

during drawing of the profile the contact

constraints have been automatically assigned at

both ends of the fillet arc. If not, then you must

to assign them manually using the Contact

Constraint tool or Constraints Defined In

Dialog Box - Tangency. - step 4: using the Trim tool you need to cut the yellow line so

that it will close the profile – Fig. 7.11.

- step 5: using the Constraint tool you need to assign the

appropriate dimensions and change their values in accordance with

Fig.7.12.

Figure 7.12. Profile of the body base – step 5





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Model of the jack’s base is implemented through rotating the base profile (Fig.7.12) by 3600 angle in

respect to axis of the jack, with the help of Shaft tool – the end result is shown in Fig.7.13. After implementation of the base, you need to create a radius of R = 4 mm on the edge between the

base and body of the lift using Edge Fillet tool – Fig.7.14.

Figure 7.13. Model of the lift’s base Figure 7.14. Implementation of fillet for the

base edge

7.4. Implementation of the ribs reinforcing the jack’s body

Profile of the rib must be implemented in yz plane. Using the

Line tool, you need to draw a line as shown in Fig.7.15.

While drawing the line, you must make sure that the

Coincidence-type relation is connecting its bottom end with

axis H. The line does not have to enter into the material of the

body. Then, using the Constraint tool, you must assign the

dimensions in accordance with Fig.7.15.


Model of the rib must be implemented using Stiffener tool

by setting the thickness of the profile to value 8mm – Fig.7.16

Figure 7.15. Profile of the rib reinforcing the lift’s body

Figure 7.16. Implementation of the rib reinforcing the lift’s body

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Using the Edge Fillet tool, you must implement

the fillets with a radius of R = 3 mm on the side

edges of the rib walls. In order to do so, you must

select the side walls of the rib (edges around the

selected surface will light up in red). The program

will create the fillets on all edges around these

walls Fig.7.17.

Other reinforcing ribs will be implemented by copying the finished

rib in a circular pattern with the use of the Circular Pattern

tool. This function is located in Patterns menu, along with the

Rectangular Pattern function.

In order to enable the possibility of duplicating the rib with the

fillets, it’s necessary that they are loaded into the function when it

is starting. To do this, you need to hold down the Ctrl button and

then select a rib (stiffener), as well as the edge fillets in the

structure tree of the model, and then turn on the Circular Pattern

tool.

In the dialog box, you must set the parameters in accordance with

figure 7.18. As a reference surface, you must select the top surface

of the lift’s base.

The ribs will be copied in the circular pattern with a spacing of

1200.

The model of completed jack’s body was shown in figure 7.19.

Figure 7.17. Fillet of the rib’s side edges

Figure 7.18. Circular Pattern window with entered parameters of the pattern

Figure 7.19. Completed model of jack’s body

workbook modeling of multi- member machines

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