program course of production technology_photos

8/12/2019 Program Course of Production Technology_photos

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PROGRAM COURSE OF PRODUCTION TECHNOLOGY

1.- INTRODUCTION, MANUFACTURING TECHNOLOGY AS ASCIENCE, ITS DEVELOPMENT

Machine as a production object. Evolving of structural shapes of machines and their

parts. Dividing of the machine into component assembly units. Quality of indices of a

machine and its parts and methods of their evaluation.

2.- PRODUCTION AND MANUFACTURING PROCESSESDefinition (an operation, a workplace, a setting,, an element, a pass or cut, a station

(position), a batch,, a mass production, a moderate production, a job lot production, a

labor input, a continuous flow and not continuous flow production).

Operation:an activity of a business or organization. Performance of a practical work orof something involving the practical application of principles or processes. The activity

of operating something (a machine or business etc.). A process or series of acts

especially of a practical or mechanical nature involved in a particular form of work.

Workplace: The workplace is the physical location where someone works. Such a

place can range from a home office to a large office building or factory. The workplace

is one of the most important social spaces other than the home, constituting "a central

concept for several entities: the worker and his/her family, the employing organization,

the customers of the organization, and the society as a whole". The development of

new communication technologies have led to the development of the virtual workplace,a workplace that is not located in any one physical space.

Setting: The position, direction, or way in which something, such as an automatic

control, is set.

In precision mechanics, the setting is the way in which two parts of the same machine

are coupled together, so that one shaft engages a hole.

The coupling is related to the tolerance in the sizes of both parts. If one has a much

greater size than the other is not adjusted. Because of this ISO standards were

developed to standardize the measurements, allowing the interchangeability of partsand production. The tolerance value for an axis is identified with a lowercase letter,

while for holes capitals are used.

The machining tolerance is designated by the designer of the machine taking into

account parameters such as function and cost. The smaller the tolerance will be

increased machining cost.

Element:a component of a mechanical device. Refers to one of a number of separate

parts. An essential part of anything.


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Pass or cut:

-Pass:To go across; go through a piece.

-Cut:To penetrate with a sharp machine tool; strike a narrow opening in. Incision or

separation in a piece. Divide the piece in parts.

Station (position):a place or position in which a person or thing is normally located. A

place equipped for some particular kind of work, service.

Batch: A quantity required for or produced as the result of one operation. The amount

of a material needed or prepared for an operation.

Mass production: is the production of large amounts of standardized products,

including and especially on assembly lines. With job production and batch production itis one of the three main production methods. Mass Production involves making many

copies of products, very quickly, using assembly line techniques to send partially

complete products to workers who each work on an individual step, rather than having

a worker work on a whole product from start to finish.

Moderate production: Production of small amounts of something that could have bee

n mass produced and even original production only. It is used in items that require cust

omization or who wants to take the added value of relative scarcity.

Job lot production:Small number of a specific type of material, part, or product that is

produced at one time and/or sold as one group or unit. Job production, sometimes

called jobbing or one-off production, involves producing custom work, such as a one-off

product for a specific customer or a small batch of work in quantities usually less than

those of mass-market products.

Labor input: an indicator characterizing the expenditure of labor expressed in man-

hours on a production of a given consumer value or on a technical operation. The

reciprocal of labor productivity, labor input measures the efficiency with which labor

power, one of the main production resources, is used. The magnitude of the indicator is

influenced by a number of factors, including the technological level of production

(capital available per worker, power available per worker, usefulness of objects of

labor), the training level of the labor force, the organization of labor, the quality of

working conditions, and the complexity of the goods being produced.

Continuous flow production: is a flow production method used to manufacture,

produce, or process materials without interruption. Continuous production is called a

continuous process or a continuous flow process because the materials, either dry bulk

or fluids that are being processed are continuously in motion, undergoing chemical

reactions or subject to mechanical or heat treatment. Continuous processing is

contrasted with batch production.


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Continuous usually means operating 24 hours per day, seven days per week with

infrequent maintenance shutdowns, such as semi-annual or annual. Some chemical

plantscan operate for more than one or two years without a shutdown. Blast furnaces

can run four to ten years without stopping.

Not continuous flow production: The discontinuous plants are used for theproduction of sandwich panels with low production rates or for special applications.

They are always characterized by one or more presses for panel forming and by one

foaming and metering machine with an output flow rate suitable for the panel size to be

produced.

3.- SECURITY OF THE QUALITY PRODUCTSDeviation of quality characteristics. The laws of scatter. Establishment of the number of

production being outside the stated (tolerance) bonds.


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4.- FUNDAMENTALS OF LOCATION

4.1.- Three methods of location determining of the parts in machine

tools.

The three methods of location determining of the parts in machine tools are:

1- Determining of location. For example, if we dont move spindle in the

machine tool the work piece is located. The distance in the machine must be

marked, I mean dimensions of the piece must be given for locate the piece in the

machine tool. The plate of pattern is a circle.

Law of accuracy of location: +- 0.5 mm in the individual production for first

operation.

2- Accurate measurements. Measurement device touches different surfaces

(movement of table or something). It takes time; accuracy is 0.01 mm but only for

few pieces but high accuracy of location.


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3- Automatic accuracy location. Special devices created on location theory.


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4.2.- Location theory. The rule of six supporting points for different

methods of location.

Location theory is based on six location points (6 degrees of freedom) (hard

body). For define a plane is necessary to situate 3 points.

For cylindrical bodies, 2 points on axis project to x, y or z but for example there is

still possibility to turn around axis. If we position 2 more points (5, 6) there is no

possibility to turning.

Location of free points far from another gives us higher accuracy.

4.3.- Accommodation of the points.

4.4.- Kinds of datum surfaces.Setting up surface, surface which is defined

- By 3 location points, there is a big distance so high accuracy.

- By 2 location points: directing or guiding surface. The accuracy is higher when

distance of 2 location points is bigger.

- By 1 location point: supporting surfaces.

4.5.- Change of datum (=location) surfaces

Phenomenon when distances or turn which is necessary to achieve in operation are

shown in accordance with one surfaces but the part is located by the surfaces from

which is it necessary.

= + = +


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4.6.- Latent datum points and planes

In mality absent and materialized only by dumping (vuelco) forces. Real datum point is

absent. Latent point is realized after fixing of the part.

If coordinate planes are absent, line of symmetry to exist plans.

Dumping force is important when you need high accuracy.

4.7.- Uncertainty of location

When piece or spindle must move (sliding bearing) between spindle and bearing must

be left clearance (espacio libre) for spindle movement. In this case spindle can move

and change direction. This affects to accuracy.

Clearance absent according to interference and so on.


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4.8.- Necessity of a force application in location

When position of a piece was defined in a device, this position should be kept for all

operating time. Pieces are fixed in devices1 force.Requirements for these forces:

- 1. > for piece doesnt fall out.- 2. > - 3. = > = 0.1

= 2 3 !"#!#$ " %#&&' #!(# " )""$ *#% "%!#.

5.- PROCESS DESIGN OF MACHINE PRODUCTION

5.1.- Manufacturing process version selection.

- Version selected: universal machine program.

- Location of part: universal devices.

- Bedge production: programmed machines.

- Programmed machines: bigger operation (milling and drilling) one tool at same

time.

- Mass production (also programmed machines better). More universal; reset

possible from one production to another.

Special equipment/tools are no economical if the production changes when this

special machines.

- Multi spindle machining: expensive (special design); higher productivity.


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5.2.- Typical technological plans

The way one usually solves a problem. This is design similar to other machines

(requirements and possibilities similar to other machines). For example: cars are

similar to each other so we use similar machines for fabricate them.

Auto engine (characteristic design) some machine used in different branches(e.g engines for cars and ships).

Typical assembly units characteristic for that machines but used in different

machines.

Typical parts more similar to the type of parts, similar materials and quality

requirements.

Process plan: creation of process plan: scientists research and tests is progressive

(ground of newest scientist research) at the beginning expensive for typical plans but

can enable to solve the problem. There are cheaper plans for many other parts andmay be divided:

- Progressive: newest achievements, other producers seeing that plan can

achieve better production.

- Form/ enterprise: maybe not newest equipments (tools, ); plan depending on

former analysis: workers become to some decisions; on ground of possibilities

of that enterprise (new process plan)

New products: typical solution in this enterprise.

Example: programmed machines no completely new program only changes.

5.3.- Group technology

Similar to typical plans; difference: in typical plans/ technology in different enterprises/

time

Similar in design and equipment are selected into groups; all group produced by one

setting of the machine and after another produced in the same machine by using same

devices and tools and settings.

5.4.- Synthesis of the individual process plan fundamentals of

process plan selection and selection of datum surfaces.

- Individual plan

It is referring to a small badge and also individual production.

For the beginning is the selection of the blankof the piece: in this section,

the main task for the selection is to select forms of the blank and also

dimensions of it. These characteristics would be as near as possible to design

of the final part but limited by possibilities of blank production.

Individual plan: pieces produced from rod material

Body type part welded of steel or something else

Mass production: cast pieces


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After selection of blanks we must select datum surfaces (sometimes known)

First produce straight forms and center works

Gear cutting: prepare whole and end surface.

For body parts necessary to analyze how to locate parts

Once location surfaces are located and selected

Condition: machine as much surfaces as possible with one

tool/setting/operation. Divide body parts in rough and fine machine tool

for fabricate parts.

Material selection

Small batch production: rod material (no need to keep allowances)

Batch production: blanks are used final dimensions of piece- allowances

must be chosen or selected.

Method of tables: allowances for face and front

surfaces. Allowances in tables are for worst case.

- Special process plan is referring to big batches and mass production (analyze

every step)

Typical process plan and more details, these small details influence productivityand cost of pieces.


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6.- CALCULATION OF ALLOWANCES TO MACHINE THEBLANKS

If allowance is bigger than necessary: more material and additional number of croaks

increase machining time.

If allowance small: achieve not necessary quality.

The minimal allowance for stroke element is determined by calculation:

- From one side:

, -,= /,+ ,+ ,+ , Where:

/,: Surface roughness received in previous operation.,: Height of damaged surface layer received at previous operation.,: Area of non accuracy of the piece which is not evaluated by those tolerances(previous operations).

,: Error of location.- For diametrical things (from 2 sides):

4 546= 2 7894+ :4+ ;


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7.- SECURE OF PRODUCTION PRODUCTIVITYProcess rate-setting, calculation and rating of cutting rates.

If we have big batch and mass production is necessary to know what time is needed for

operation and fabricate our batch, also which equipments are necessary and how

many time is spent in every operation for having a good productivity process.

Time for operation:

=ABC + D Where:

T: time for operation.

Tsu: Time for setting up the machine. Must receive task, acknowledge with operation,

receive necessary tools put devices/tools in machine.N: Number of pieces in a batch. Worker sets machine for all pieces in a batch.

C =EFTp: Standart time for piece

D= D+ G+ A+ Where:

Tpr: Processing time, machining; time tool goes with a feed or assembly

Th: Handling time worker must do for operation/ strokes.

Ts: servicing time, servicing of workplace (coolant, )

Tf: fatigue time for rest of worker.

$ = 1000HI FJ))K


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8.- METHODS OF PRODUCTION PRODUCIBILITY INCREASE,PRODUCTION EFFECTIVENESS INCREASE

=ABC + D

D= D+ G+ A+ The productivity increases if TsuJLK reduces, N increases (MKand TpdecreasesJLK.Tsu (LK: (worker acknowledge) necessary tools, necessary blanks and devides will begiven to worker at his workplace (no need to search) for fixing device need to find point

zero (helping device).

N (MK: same device for groups of pieces Group technology.Tpr(LK: multi spindle / multi tool machines.Th: fixing of the part pneumatic/ electric faster than human.In machining centers fastertwo different places where one can work to fix at anotherplace its machined. Measurements automatically, location automatically.

Ts: get chip out of machine, refill oil/ coolant.

Topoperation time L=>TsLTfLIncrease effectivenessProductivity highest, price of pieces produced on machine issmallest more economical by analyze of cutting rate.

9.- PRODUCTION OF HOUSING (BODY) TYPE PARTS(Service function:; classification; main requirements; blanks; machinability; process

plan, its dependence on an accuracy and seriality of production; marking; machining of

planes, accurate and threaded holes in production of different accuracy and seriality;

finishing of external planes and accurate holes; checking of the parts)

9.1.- SERVICE FUNCTIONBody-type parts for location of other (assembly) parts of machine and hold their

accurate position, not only in statics but also dynamics (vibration, temperature, loading

forces).

9.2.- CLASSIFICATION6 different types:

1.- Box type: accurate holes, planes, device for location and direction.2.- Housings with many accurate holes (i.e engines)3.- Housing of a complex form (i.e. pumps different complex forms)4.- Supports, slides, carriges.

5.- Overhousing support (different arms, brakes, etc possible)6.- Covers, plates, bottoms.


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9.3.- MAIN REQUIREMENTSPlaneless of planes 0.01...0.05/100mmaccuracy of holes D h5...h7Parallelity holers to planes 0.01

All with Ra 2,5.

9.4.- BLANKSMethod of casting depends

( )patterns made of:-Wood (small, average batch production less accurate deform from humidity +- 1,5)-Plastics (wear resistance smaller more accurate than wooden patterns +- 1)-Al-alloys (wear resistance and accuracy higher than in other cases +-0,5)

investment, shellwood casting

9.5.- MACHINABILITYRequirements for better machiniability:

-Plane surfaces should be in 1 plane-Holes thhrough the whole part avoid blind holes-Not too thin holes (min M6) cut threats (M8)

Process plan dependence on accuracy and production:

9.6.- ACCURATE AND THREADED HOLES IN PRODUCTION OF

DIFFERENT ACCURACY AND SERIALITY3 types of accuracy:

-Bodies of small accuracy: threated holes, holes and planes in 1 operation after casting,1 rough then fine operations. After rough machining deforming possible, result of

dislocation of internal stresses in the beginning deformation faster.

-Normal accuracy: main allowances are out of rough machining-aging operation forreleasing of internal stresses-fine machining for some surfaces if their finalaccuracy/surface roughness is not achieved than that final machining is made inadditional operation. No internal stresses below 723.

9.7.- FINISHING OF EXTERNAL PLANES AND ACCURATE HOLESArtificial aging:-temperature: oven heated to 600...650C kept in this T from 3-12 hours according to wallthickness etc.-cooled 50C/h.Release of internal stresses-good accuracy.-Heat impacts: Piece quickly heated up to 600C-650C-quickly cooled. Some cycles of

heating and cooling- internal stresses are relaxed.-Vibration: pieces assembled on vibronplatform and acted by vibrations. Self vibrationincreasing amplitude after 15 min stresses relaxed. Heating through vibration.

Natural aging:After fine machining piece is conserved kept on sheller 3 months-2 years


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10.- PRODUCTION OF SHAFT TYPE PARTSBlanks of shafts; process plan, criterions of its dependence; machining operations in

production of different accuracy and seriality.

11.- PRODUCTION OF CYLINDRICAL GEARSTypes of gears, accuracy; blanks; process plan, criterions of its dependence;

machining operations in production of different accuracy and seriality.


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12.- PRODUCTION OF BEVEL GEARSTypes; accuracy; blanks; process plan; methods of a teeth cutting.


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13.- PRODUCTION OF WORMS AND WORM WHEELS


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14.- PRODUCTION OF BUSHES AND FLANGESProduction of turret type parts (of small parts, being machined on programmed turning

machines and turning centers and SWISS type automatic lathes.

15.- STIFFNESS OF A TECHNOLOGICAL SYSTEM

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