PART PART PROGRAMMINGPROGRAMMING

PART PART PROGRAMMINGPROGRAMMING

MANUFACTURINGMANUFACTURINGThe process in which we can produce a The process in which we can produce a geometrical shape from a raw material is geometrical shape from a raw material is known as manufacturing.known as manufacturing.It is the last stage of productionIt is the last stage of production..

PRODUCTION

The entire process to The entire process to manufacture a component is manufacture a component is known as productionknown as production..

VARIABLES AFFECTING VARIABLES AFFECTING MANUFACTURINGMANUFACTURING

** ManMan

**MachineMachine

**MaterialMaterial

MachineThe device which is used to convert an

effort to an useful work is known as machine.

Machine toolIt has the ability to produce it’s own

parts as well as other parts.

Machining CenterIt can perform no of operation at a

time with the help of ATC & AWCATC-Automatic Tool Changer

AWC-Automatic Work ChangerAccording to tool holding capacity &

magazine shape ATC is up 3 types Drum type(40 tools) Elliptical type(8-20 tools) Loop chain type(200 tools)

Machining center type

Vertical machining center Horizontal machining center

Spindle in vertical position Spindle in horizontal position

Conventional Machining ProcessThe machining process where the

tool is directly contact with the job is known as conventional machining.

In this machining the tool must be harder than the job.

Ex-cnc milling, cnc turning, grinding milling, turning, etc

Non Conventional Machining Non Conventional Machining ProcessProcess

The machining process where the tool is not directly in contact with the job is known as Non conventional machining.

Here the tool can be softer than the job.Ex- ECM EBM AJM EDM Wire EDM

Cutting SpeedCutting Speed The speed at which the cutting

edges of the tool travels over the job is known as cutting speed.

C.S = ∏*D*N/1000 where D =Diameter of the cutter N =RPM of the machine Unit = m/min

FeedFeedThe advancement of the tool towards

the job is known as feed. Unit- mm When feed is compared with time it is

known as feed rate. Unit- mm/min The advancement between consecutive

tooth of cutter is known as feed per tooth.

Unit- mm/tooth The advancement of tool in one

revolution is known as feed per revolution.

Unit- mm/rev

Types of Feed rateTypes of Feed rateRapid Feed rate-The idle movement

of the tool with max. available federate

of the m/c is known as Rapid feed.Plunge Feed rate-The feed rate at

the time of taking depth of cut.Cutting Feed rate-The feed rate at

the time of cutting operation. Feed rate = F*Z*N F = feed/tooth Z = No of flutes or teeth N = RPM of the machine

CNC-Computer Numerical Control

Need For CNC- A machine tool has several controllable function i.e

- Speed - Feed - Tool positioning - Clamping the work piece - Coolant flow etc… All these can be done either manually or Automatically, for automatic control

several technologies are adopted and CNC

is the latest among them.

CNC Advantages--Difficult contours & surfaces are easily

made.-Closer geometrical & dimensional

tolerances are possible.-Higher rate of production.-Very low lead time.-One m/c can perform several operation.-Rejection is almost nil.-No dependence over human operational. skill. -Dimensional variation can be correctable very easily. -Reduces inspection cost. -Reduces tooling cost.

Disadvantages-Higher initial cost.Maintenance is expensive.May need A.C & voltage stabilizer.Productivity depends on the

programmer.Classification of NC System- According to no of axis- -2 axis m/c -3axis m/c -4axis m/c -5 axis m/c

Five Axis machinesTable rotates round two simultaneous continuous axes

Designed for five axis precision machining of workpieces having small dimensions and a complex geometry.

C-axisA-axis

z

y

x

Location of Rotary axes on compound NC Tilt Round Table

According to Tool position--Absolute System-Incremental system According to Feed back Device--Analog Type-Digital type According to Servo control

System--Open Loop-Closed Loop

According to Motion control system-

-Point to point control-Straight cut-Contouring

Part Program-The set of instruction by which we can produce a part is known as part program.

It has 2 parts -Main Block -Sub Block

Main Program- It contains machine definition, tool definition & raw material definition. It doesn’t deals with tool movement.Sub Program- It only contains of tool movement.DNC-Direct Numerical ControlWhen a program is generated in computer & send to a single m/c ,then it is known as direct

numerical control.

DNC-Distributed Numerical Control If the program is send to a no of m/c for mass

production is known as distributed numerical control.

*The cables used for DNC in CTTC are RS-232

& RS-422.

Transducer (Feedback device)

Transducer is of two types1.Analog type2.digital type

Analog transducer is a feed back device which produces a variable electrical voltage. This voltage varies in proportion to the rotational speed of the input shaft and can be easily measured and converted into linear distances to indicate corresponding positions of m/c table.

Digital transducer : It is normally employed to convert the rotary motion of the machine lead screws into countable electrical pulses. The number of these pulses indicates the linear distance moved by the table of the m/c corresponding to the rotation of the lead screws obviously, this device must be attached to the lead screw of the m/c table

Controller-The soft ware which controls the

program in different languages is known as controller.

Ex- *FANUC *HEIDEN HEIN *SINUMERIC *LAXMI NUMERIC(Indian Controller) *MAZATROL *MAZAC

Codes--ISO-Dialog Mode-In ISO mode we have to write the

program with G-code & M-code.Ex-G99 T1 L0 R5-In Dialog mode we have to write the

program in English language.Ex-Tooldef T L R

Program Variables-

G- is known as Preparatory codeM-is known as Miscellaneous or

machine codeN- is known as Block noS- is known as Spindle speedF- is known as Feed rateR- is known as Radius compensationL- is known as Length offset T- is known as Tool no

Steps to write a program-* Read the drawing.*Think about all sequential operation.*Specify raw material size.*Tool definition.*Tool call.*Specify the tool position.*Specify the Z0 position.*Specify the depth of cut.*Specify co-ordinates for cutting operation.*Retract the tool at the end of the cut. -End of program.

G-codeG00-Rapid movement of the tool.G01-Linear interpolation with control feed rate.G17-Tool orientation in XY plane in Z axis.G18-Tool orientation in ZX plane in Y axis.G19-Tool orientation in YZ plane in X axis.G71-Metric programming mode.G70-Inch programming mode. G30-Lower left corner of the job. G31-Upper right corner of the job.

G90-Absolute programming mode.G91-Incrimental programming mode.

M-codeM00-Program stop.M01-Optional stop.M02-Program endM30-Program end & resetM03-Spindle orientation clock wise.M04-Spindle orientation anti clock wise.M08-Coolant on. M09-Coolant `

M13-Spindle orientation clock wise with coolant on.(M03+M08)M14-Spindle orientation anti clock wise

with coolant on.(M04+M08)M05-Spindle stop.M06-Toolcall or Tool change.Maximum movement of tool-X-290Y-170 Max.Lines & columns in CNC

editor Z-235

Lines-32647 Columns-241

Functional keys-F1-HelpF2-For saveF3-For load or openF5-Machine informationF7-To mark a blockF8(2 times)-To cancel a markF9-For simulationF10-Main menu

*To run a program- F9 Run program enter*Datum setting-The process of defining the origin

of the w/p to the m/c is known as datum setting.*To set the datum-F9 set datum enter Use the navigation Keys to set the values in x & y enter*To save the file-F2 Define the file name(max.-8 character) enter

*To create new file- F10 cnc files enter new enter *To open a file- F3 enter Select the file enter

*To save as the file-F10 cnc files enter save as enter file name

enter*To minimize the gap between the block- Place the curser in the Gap Ctrl + Y*To close the soft ware- Alt + Q*To delete the block-F7 Use down & up navigation keys to define the block to delete Alt + D Y*To copy the block- F7 Use navigation keys to define the block to copy F8 move the curser to the desired place Alt + C Y

*To move the block- Same as copy but use Alt + M

*To change the simulation type- F10 Settings enter Simulation enter Show 3D enter (To change from yes yes to

no Or no to yes) F9 run program enter

OFFSET- The value which is given to compensate the

structure of the tool is known as offset. It is up 3types- * Length Offset * Diameter Offset * Wear Offset

Length Offset-The value which is given in the offset table to

compensate the difference in length between primary & secondary tool

is known as length offset.

Diameter Offset- The value which is given to compensate the

co-ordinate from the center of the tool to the periphery is known as diameter offset.

Wear Offset- The value which is given to compensate the

worn out of the tool is known as wear

offset.

Sl no Material Cutting   Feeds in mm per revolution    

    Tool 0.1 0.2 0.4 0.8 1.6 3.2

        Cutting Speed mm/min.  

1Plain Carbon or HSS   60 45 34 25 19

Mild Steel TCT 280 236 200 170 67 56

2Cast Steel HSS   34 25 19 14 11

  TCT 118 100 85 71 24 20

3Alloy Steel HSS   24 17 12 8.5 6

  TCT 150 118 95 75 24 20

4Mn-steel,Cr-Ni-steel HSS   16 11 8 5--6  

Cr-Mo-steel TCT 95 75 60 50 16 13

5Tool Steel HSS            

  TCT 50 40 32 27 8.5 6.7

6Other Steel Alloys HSS   9.5 6      

  TCT 60 48 38 32 10 8

7Cast Iron HSS   48 27 18 14 9.5

  TCT 140 118 95 80 67  

8Copper alloys Brass HSS   125 85 56 36  

  TCT 600 530 450 400 355  

9Tin Bronze HSS   85 63 48 34 24

  TCT 500 450 375 335 300  

10Cast Bronze HSS   63 53 43 36 28

  TCT 355 280 236 200 180  

11Light Alloys HSS 400 300 200 118 75  

Pure Aluminium TCT 1320 1120 950 850 710  

12Aluminium Alloys HSS 100 67 45 30    

  TCT 224 190 160 140 118  

C.SAsPerJob,Tool&FeedPerRev.