CNC Machine Prestart Checking Steps

 OIL RESERVOIR
Examine the oil levels. Both levels should be filled up to one inch from the bottom of the
reservoir. The spindle oil reservoir may have oil in it for up to six months. The way lube
oil reservoir may run out of oil in one week.

AIR PRESSURE
Visually inspect the air pressure gauge to verify that it is set to at least 80-100 PSI. Air
is used to change belt ranges in the spindle, orient the spindle, activate the tool in-out
cylinder, and it is, also, used for the air blast during a tool change. The tool changes
gauge should not exceed 120 PSI.

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Sample Milling Program for I, J & K CNC functions

Sample Milling Program for I, J & K CNC functions

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Intelligent computer numerical control unit

The new control unit for CNC machining centres - milling, drilling and operations like drilling is shown on Figure. It has the capability of learning and intelligent, automated generating of NC part programs on the bases of neural network, which is built-in into a

The neural network for milling, drilling, reaming, threading and operations like this have learned to generate NC part programs in system for learning, which is not a constituent part of a new CNC control unit, and works independent.
The new control unit then completely automatically, without any intervention of the operator, on the bases of a CAD model of a part, generate NC part programs for different products, which are designed for the production on CNC machining centres and for which previously NC part programs have not been done.
CNC control unit consists of a modified microcomputer, which includes a module for decoding and a module for manual input of commands, which are mostly of technological nature (feed rate, revolution speed, switch on/off of cooling liquid etc.). Computer includes also the internal interface, which has the function of data transmission from the NN device into the position memory.

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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

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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.

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