Constant lead Threading (G32) Interpolation Funtion

Tapered screws and scroll threads in addition to equal lead straight threads can be cut by using a G32 command.
The spindle speed is read from the position coder on the spindle in real time and converted to a cutting feedrate for feed-per minute mode, which is used to move the tool.

Example of threading

FORMAT

In general, threading is repeated along the same tool path in rough cutting through finish cutting for a screw. Since threading starts when the position coder mounted on the spindle outputs a one-spindle-rotation signal, threading is started at a fixed point and the tool path on the workpiece is unchanged for repeated threading. Note that the spindle speed must remain constant from rough cutting through finish cutting. If not, incorrect thread lead will occur.

LZ and LX of a tapered thread

In general, the lag of the servo system, etc. will produce somewhat incorrect leads at the starting and ending points of a thread cut. To compensate for this, a threading length somewhat longer than required should be specified.

Ranges of lead sizes that can be specified
Metric input = Least command increment 0.0001 to 500.0000 mm
Inch input = Least command increment 0.000001 to 9.999999 inch

Example

" WARNING "

1. Feedrate override is effective (fixed at 100%) during threading.

2. It is very dangerous to stop feeding the thread cutter without stopping the spindle.

This will suddenly increase the cutting depth. Thus, the feed hold function is

ineffective while threading. If the feed hold button is pressed during threading, the tool will stop after a block not specifying threading is executed as if the SINGLE BLOCK button were pushed. However, the feed hold lamp (SPL lamp) lights when

the FEED HOLD button on the machine control panel is pushed. Then, when the tool stops, the lamp is turned off (Single Block stop status).

3. When the FEED HOLD button is pressed again in the first block after threading mode that does not specify threading (or the button has been held down), the tool stops immediately at the block that does not specify threading.

4. When threading is executed in the single block status, the tool stops after execution of the first block not specifying threading.

5 When the mode was changed from automatic operation to manual operation during threading, the tool stops at the first block not specifying threading as when the feed hold button is pushed as mentioned in Warning 3.

However, when the mode is changed from one automatic operation mode to another, the tool stops after execution of the block not specifying threading as for the single block mode in Note 4.

6. When the previous block was a threading block, cutting will start immediately without waiting for detection of the one-spindle-rotation signal even if the present block is a threading block.

G32Z _ F_ ;

Z _; (A 1-turn signal is not detected before this block.)

G32 ; (Regarded as threading block.)

Z_ F_ ; (One turn signal is also not detected.)

7. Because the constant surface speed control is effective during scroll thread or tapered screw cutting and the spindle speed changes, the correct thread lead may not be cut. Therefore, do not use the constant surface speed control during threading. Instead, use G97.

8. A movement block preceding the threading block must not specify chamfering or corner R.

9. A threading block must not specifying chamfering or corner R.

10. The spindle speed override function is disabled during threading. The spindle speed is fixed at 100%.

11. Thread cycle retract function is ineffective to G32.

»»  CNC PROGRAMMING...“Constant lead Threading (G32) Interpolation Funtion”

Sample Milling Program for I, J & K CNC functions

Sample Milling Program for I, J & K CNC functions

»»  CNC PROGRAMMING...“Sample Milling Program for I, J & K CNC functions”

CNC Milling and Turning Program

CNC Milling Program
O1234;
Name of program
N10 G21 G40 G49;
Metric programming, tool compensation cancel
N20 G91 G30 Z0;
Incremental programming, Return to zero position for z
N30 T02 M06;
Change tool no. 2
N40 M03 S1000;
Spindle rotates clockwise 1000RPM
N50 G43 H5 Z2.;
Tool length compensation +ve direction up to 2 mm
N60 G55 G90 G00 X0 Y0;
Working coordinate G55, Absolute programming, Tool at X=0 Y=0 position
N70 G01 Z-5. F10;
Cutting in Z-direction until it reaches z = –5mm with feed 10mm/min
N80 G01 X0 Y50. F100;
Cutting to Y-direction to Y=50 with 100mm/min
N90 Y100.;
Cutting to Y-direction Y=100
N100 X100.;
Cutting to X-direction X=100
N110 X0;
Cutting to X-direction X=0
N120 G30 Z0
Return to zero position for z

CNC Turning Program
O1234;
Program name
N10 G28 U0 W0;
Go to Reference point (Machine Zero position)
N20 G92 S1200 M41 M03;
Max. spindle speed, 1200 RPM, Low gear, Spindle CW
N30 G96 S400 T0404;
Constant surface speed, 400 RPM, Tool no. 4 with tool offset no. 4
N40 G00 X2.6 Z0 M08;
Rapid positioning(without cutting) to position X=2.6, Z=0 in mm, coolant ON
N50 G01 X0.74 F0.5;
Facing process tool will move to position X=0.74 with feed 0.5mm/min
N60 G00 X3. Z5. M09;
Rapid positioning(without cutting) to position X=3, Z5 in mm, coolant OFF
N70 G28 U0 W0;
Go to Reference point (Machine Zero position)
N80 M30;
End of program

»»  CNC PROGRAMMING...“CNC Milling and Turning Program”

CNC Programming Circular Interpolation

Definisi G02, G03, I, J & K

• G02: Circular interpolation (CW)

• G03: Circular interpolation (CCW)

• I, J & K (Use when <=360 degree) " Incremental distance from SP to CP of arc "

• I: Specifies the incremental ±X distance from the center of the tool at the start of the arc to the center of the arc.

• J: Specifies the incremental ±Y distance from the center of tool at the start of the arc to the center of the arc

Circular interpolation
why R?

•R is easier to define, easier to make a mistake and get an incorrect radius.
•With R, the machine still do the work whether the R is correct or incorrect.
•With incorrect I, J & K, the machine will stop and gives an error message before executing.
•With R, to generate a circle path of over 180 degrees, then specify a negative R.

»»  CNC PROGRAMMING...“CNC Programming Circular Interpolation”

Learn how to run the machine by CNC machine programming

Running CNC machine, there are some CNC machine programming should be operated by operator for making sure that everything works well by the time it’s used for working. In general, at least two kinds of axes program, as followed the linear which produce straight stripe while the rotary that’s more rounded. Though they’re all dealt with the operator, the loading of working process is done automatically. Once the machine has greater axes, it’s subsequently called complex machine. Before it’s used for manufacturing, the motion that’s fitted in the machine should be controlled well so it’s able to be run the process of cutting the items.

The CNC machine programming can be successfully regarded once it’s able to replace the working process more than two axes. Instead of that occasion, you need to ask the operator just in case there’s something troubles with the machine. To enhance the performance of the CNC program, there are several items such as Automatic tool changer, Spindle speed and activation, and Coolant which those of them are having each factions while the machine’s processed.

For those who already engaged for quite some times with this machine, doing by their own isn’t big deal. However, those who haven’t yet, please contact the operator who guide you to run the machine, including the uploading the software of the CNC machine programming for better machine to produce the greatest result.

»»  CNC PROGRAMMING...“Learn how to run the machine by CNC machine programming”

Warming Up Machine is very important

CNC Program warming up  is very important
In a workshop using cnc machines are very important. for it takes care of very serious cnc machine. One of the things that have to do is "Warming Up". cnc program warming up much needed weeks to initiate activities in cnc machining process. especially when the engine quit in a long time (8 to 10 hours). This is very useful to sustainability cnc machine itself. According to the experience I have gained useful engines warming up the program include:
1. Streamlining the lubrication oil circulation after not circulate (stop)
2. Error check before mass production

    ATC Spindle
    X Y Z - Axis movement
    The flow of coolant

3. Check hydraulic oil for Clamp and Unclamp (clamping function) And much more

Here I give examples of CNC program warming up that I apply in the machine controller Toyosk TVT 313M1 with Fanuc Series 32i Model A

O1000 ( X Y Z - TRVRS RUNNING WARMING UP )
;
G0G91G28Z0M08M50;
G0G91G28X0Y0;
G80G40G49;
M10M12M60;
G4X3.0;
G0G90G53X-280.0Y-350.0;
M3S200M7;
G53Z-300.0;
G4X3.0;
M5M9;
M11M13M61;
/M99;
G0G91G80G28Z0;
G4X1.0;
G91G28X0Y0M9;
;
M30;
;
%

Make sure the movement of 0%, 25%, 50% and 100% (feed rate)
Make sure the first run the program with the command "single block"

If this is done with certain serious age of cnc machine component hardware and software will grow old

»»  CNC PROGRAMMING...“Warming Up Machine is very important”

Control Systems Computer Numerical Control ( CNC )

Control Systems
CNC (Computer Numerical Control) is a versatile and specialized form of Soft Automation  and  its  applications  cover  many  kinds,  although  it  was  initially developed to control the motion and operation of machine tools.
The CNC control system is divided into two, they are:

• Open Loop Systems

Open loop systems do not have access to the real time data about the performance of the system and therefore no immediate corrective action can be taken in case of system disturbance. This system is only applied normally to the case where the output is almost constant and predictable. Therefore, an open loop system is unlikely to be used to control machine tools since the cutting force and loading of a machine tool is never a constant. The only exception is the wire cut machine for which some machine tool builders still prefer to use an open loop system because there is virtually no cutting force in wire cut machining.

• Close Loop Systems

Feed back devices closely monitor the output and any disturbance will be corrected in the first instance in a close loop system. Therefore high system accuracy is achievable. This close loop system is more powerful than the open loop system and can be applied to the case where the output is subjected to frequent change. Nowadays, almost all CNC machines use this control system.

»»  CNC PROGRAMMING...“Control Systems Computer Numerical Control ( CNC )”

Other FUNCTION in CNC System

Modern CNC systems have some specially designed functions to simplify the manual programming. However, since most of these functions are system oriented, it is not intended to discuss them here in detail. The following paragraphs give a brief description of commonly used functions in modern CNC system. The user should refer to the programming manuals of the machine for the detail programming and operation.

• Mirror Image

This is the function that convert the programmed path to its mirror image, which is identical in dimension but geometrical opposite about one or two axes

• Pocketing Cycle

Pocketing is common process in machining. This is to excavate the material within a boundary normally in zigzag path and layer by layer. in a pocketing cycle, the pattern of cutting is pre-determined. The user is required to input parameter including the length, width and depth of the pocket , tool path spacing, and layer depth. The CNC system will then automatically work out the tool path.

• Drilling, Borring, Reaming and Tapping cycle

This is similar to pocketing cycle. In this function, the drilling pattern is pre- determine by the CNC system. What the user has to do is to input the required parameter such as the total depth of the hole, the down feed depth, the relief heigth and the dwell time at the bottom of the hole.

• Programme repetition and Looping

in actual machining, it is not always possible to machine to the final dimension in one go. This function enables the looping of a portion of the programme so that the portion can be executed repeatedly.
                                                                                      

»»  CNC PROGRAMMING...“Other FUNCTION in CNC System”

Step for CNC Programming ang Machining

The following is the procedures to be followed in cnc programming and machining. the most important poin is to verify the programme by test run it on the machine before the actual machining in order to ensure that the programme is free of mistake.

1. Study the part drawing carefully.
2. Unless the drawing dimension are cnc adapted,select a suitable programme zero point on the work piece. The tool will be adjusted to this zero point during the machine set up.
3. Determine the machining operetions and their sequence.
4. Determine the methode af work clamping ( jig and fixtures ).
5. Select cutting tools and determine spindle speed and feeds.
6. Write programme ( translate machining step into programme blocks ).If many solutions are possible, try the simplest solution first. It usually longer, but better to procced in this way.
7. Prepare tool chart or diagram, measure tool geometry (lengths,diameter) and note.
8. Clamp work piece and set up machine.
9. Enter compensation value if necessary.
10. Check and test programme. It is good practice to dry run programme.                                               

• without the workpiece 
• without the cutting tool 
• by raising the tool to safe heigth, If necessary, correct and edit programme and check again.

And than  Start machining.

»»  CNC PROGRAMMING...“Step for CNC Programming ang Machining”