Chong Wei Choon Cnc Report

1.0 INTRODUCTION

In industry, it is not efficient and profitable to make every product by using our hand. On Computer Numerical Control (CNC) machine tool, it is possible for us to make hundreds or even thousands with the same product in a day.

CNC is the machine controller that reads the code and instruction and sends electric signals to motor and drive the machine tools and machining table to make a specific product that required. In other words, computer will control all the machine tool instead of a person to control it.

There are few main parts in CNC machine that are machining table, machine tool(spindle), NC control panel and motor.

There are two axis in machining table which is X-axis and Y-axis. Another Z-axis is the moving of spindle up and down. (As shown in Figure 1).

Each machine has a very rigid machine base to hold the moving parts, the table can move left to right and in and out. Attached to the table are accurate lead screws used to position the table to the proper location.

A CNC machine tool also have computer to control the motors, and sensors to keep track of the table position velocity.

Figure 1

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XY

spindle

Machining table

Z

There are many type of machine tools in CNC machine, below are few example for it.

The machine tools or spindle in CNC used to mount and as cutting tool on a work piece.

Example of machine tools

The CNC machine tools and machining table are very similar to the conventional machine as shown below.

In fact, many CNC machine tool manufacturers sell models that are available as a conventional machine tool or fitted with CNC control system via NC control panel.

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Conventional machine

CNC milling machine

This is the example of CNC control panel, it is the control system by typing the program into it, usually a simple program will key in ourself.

For the complex design of product, we will use the software of Computer Aided Design (CAD) and Computer Aided Manufacturing (CAM) to creating the part of design that is impossible done by us.

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NC control panel

2.0 OBJECTIVE This project will allow the student to understand the basic working of CNC Milling

Machine. To understand the fundamentals of parts programming in terms of various steps needed

to be taken for completing a successful CNC program. Students also will expose with common G-code as well as M-code on NC programming. The capability of students to construct the basic programming for basic machining will

be emphasize. Safety procedure during machining operation is compulsory expose to the students.

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3.0 PROJECT

3.1 Write the NC programming for drilling process:

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G80 G40;

G49 M6 T1;

G90 G00 G54 X0.0 Y0.0;

G43 Z20.0 H1;

M3 S8000;

G99 G81 X175.0 Y30.0 R-2.0 R5.0 F100;

X175.0 Y68.0;

G98X110.0 Y49.0;

G00 Z20.0;

M5;

G80 G40;

G49 M6 T7;

G90 G00 G54 X0.0 Y0.0;

G43 Z20.0 H7;

M3 S1000;

G99 G82 X175.0 Y30.0 Z-20.0 R5.0 F100;

X175.0 Y68.0;

G98 X110.0 Y49.0;

G00 Z20.0;

M5;

G80 G40;

G91 G28 Z0.0;

X0.0 Y0.0;

G49;

M30;

3.2 Write the NC programming for slotting process:

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G80 G40; G00 Z20.0;

G49 M6 T3; M5;

G90 G00 G54 X0.0 Y0.0; G80 G40;

G43 Z20.0 H3; G91 G28 Z0.0;

M3 S8000; X0.0 Y0.0;

G49;

G00 X-15.0 Y25.0; G30;

Z-2.0;

G01 X165.0 Y25.0 F100;

G00 X165.0 Y25.0;

Z-4.0;

G01 X-15.0 Y25.0 F100;

G00 X-15.0 Y25.0;

Z-6.0;

G01 X165.0 Y25.0 F100;

G00 X165.0 Y25.0;

Z-8.0;

G01 X-15.0 Y25.0 F100;

G00 X-15.0 Y25.0;

Z-10.0;

G01 X165.0 Y65.0 F100;

G00 X165.0 Y65.0;

Z-2.0

G01 X-15.0 Y65.0 F100;

G00 X-15.0 Y65.0;

Z-4.0;

G01 X165.0 Y65.0 F100;

G00 X165.0 Y65.0

Z-6.0;

G01 X-15.0 Y65.0 F100;

G00 X-15.0 Y65.0;

Z-8.0;

G01 X165.0 Y65.0 F100;

G00 X165.0 Y65.0;

Z-10.0;

G01 X-55.0 Y65.0 F100;

3.3 Write the NC programming for circular process:

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G80 G40;

G49 M6 T4;

G00 G90 G54 X0.0 Y0.0;

G43 Z20.0 H4;

M3 S8000;

G00 X5.0 Y50.0;

G01 Z-2.0 F100;

G02 X65.0 Y50.0 R30.0 F100;

G01 X150.0 Y50.0 F100;

G03 X210.0 Y50.0 R30.0 F100;

G01 Z-4.0 F100;

G02 X150.0 Y50.0 R30.0 F100;

G01 X65.0 Y50.0 F100;

G03 X5.0 Y50.0 R30.0 F100;

G01 Z-6.0 F100;

G02 X65.0 Y50.0 R30.0 F100;

G01 X150.0 Y50.0 F100;

G03 X210.0 Y50.0 R30.0 F100;

G01 Z-8.0 F100;

G02 X150.0 Y50.0 R30.0 F100;

G01 X65.0 Y50.0 F100;

G03 X5.0 Y50.0 R30.0 F100;

G01 Z-10.0 F100;

G02 X65.0 Y50.0 R30.0 F100;

G01 X150.0 Y50.0 F100;

G03 X210.0 Y50.0 R30.0 F100;

G00 Z20.0;

M5;

G80 G40;

G91 G28 Z0.0;

X0.0 Y0.0;

G49;

M30;

3.4 Write the NC programming for process:

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G80 G40; G43 Z20.0 H2;

G49 M6 T1; M3 S8000;

G90 G00 G54 X0.0 Y0.0; G98 G81 X107.5 Y50.0 Z-0.5 F100;

G43 Z20.0 H1; G00 Z20.0;

M3 S1000; M5;

G00 X-10.0 Y84.0; G80 G40;

Z-2.0; G49 M6 T3;

G01 X181.0 Y84.0 F100; G90 G00 G54 X0.0 Y0.0;

X181.0 Y16.0; G43 Z20.0 H3;

X225.0 Y16.0; M3 S8000;

G00 X225.0 Y16.0; G98 G82 X107.5 Y50.0 Z-10.0 F100;

Z-4.0; G00 Z20.0;

G01 X181.0 Y16.0 F100; G80 G40;

X181.0 Y84.0; G49 M6 T4;

X-10.0 Y84.0; G90 G00 G54 X0.0 Y0.0;

G00 X-10.0 Y84.0; G43 Z20.0 H4;

Z-6.0; M3 S8000;

G01 X181.1 Y84.0 F100; G00 X0.0 Y31.0;

X181.0 Y16.0; G01 Z-2.0 F100;

X225.0Y16.0; G02 X31.0 Y0.0 R31.0 F100;

G00 X225.0 Y16.0; G01 Z-4.0 F100;

Z-8.0; G03 X0.0 Y31.0 F100;

G01 X181.0 Y16.0 F100; G01 Z-6.0 F100;

X181.0Y84.0; G02 X31.0 Y0.0 R31.0 T100;

X-10.0 Y84.0; G01 Z-8.0 F100;

G00 X-10.0 Y84.0; G03 X0.0 Y31.0 R31.0 F100;

Z-10.0; G01 Z-10.0 F100;

G01 X181.0 Y84.0 F100; G02 X31.0 Y0.0 R31.0 F100;

X181.0 Y16.0; G00 Z20.0;

X225.0 Y16.0; M5;

G00 Z20.0; G80 G40;

M5; G91 G28 Z0.0;

G80 G40; X0.0 Y0.0;

G49 M6 T2; G49;

G90 G00 G54 X0.0 Y0.0; M30;

4.0 QUESTION

4.1 Briefly, explain the different between G-code and M-code in NC programming.

Answer: G-code is written in the used of performing in CNC processor, it is a code to operate the motion of tooling move and control the other part of machine like rigid machine base. While M-code is MACHINE code which written to control the electrical control function in machine such as coolant , tool changers , safety equipment and so on.

4.2 Interpret each block of programming below into machine operation: N1 G80 G40; N2 G49 M6 T10; N3 G90 G00 G54 X0 Y0; N4 G43 Z15.0 H10;

Answer:N1 G80

G40

cancel the memory from G81 to G89.cancel cancel the memory from G41 to G42.

N2 G49

M6

T10

cancel the memory of tool length. change tooling. type of tooling with certain diameter.

N3 G90

G00

G54

X0

Y0

absolute command or coordinate system which measure all dimensions from origin.

Positioning. coordinate of origin on work piece selection. coordinate at 0 on x-axis.

coordinate at 0 on y-axis.N2 G43

Z15.0

H10

increment up from surface of work piece show + direction while increment down below the work piece surface show – direction. safety height (tooling will slow down when reach at height of 15.0mm from surface of work piece). recall the memory of data (tool length) that set up in the processor.

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4.3 Draw the actual dimension for NC programming below:

N1 G80 G40;N2 G49 M6 T1;N3 G90 G00 G54 X0 Y0;N4 G43 Z20.0 H1;N5 M3S1000;N6 G90 G00 Z-10.0;N7 G01 X0 Y80.0 F500;N8 X120.0 Y80.0;N9 G03 X150.0 Y50.0 R30.0 F500;N10 G01 X150.0 Y30.0 F500;N11 G02 X120.0 Y0 R30.0 F500;N12 G01 X90.0 Y40.0 F500;N13 X50.0 Y40.0;N14 X50.0 Y0;N15 X0 Y0;N16 G80 G40;N17 G91 G28 Z0;N18 G28 X0 Y0;N19 G49;N20 M30;

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Answer:

Front view

Top view

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5.0 DISCUSSION After the lecture for seven weeks we have learn to write the basic program that used to

run in CNC Milling Machine. Every G-code and M-code we have learn are represent to a meaning and every program

we have written must avoid any mistakes otherwise the effect will be worse. With the help of CNC Milling Machine, we can observe that it is very fast and efficient to

make a product with the program we have done. Compare to the conventional machine, CNC machine is more efficient and able cut with

more equally smooth. Based on our knowledge, we have make the program in 3.1, 3.2, 3.3 and 3.4 in our

group discussion, there are many ways to written the program. In our group discussion, some of the careless mistake still happen in our program. For project 3.1:

1. MISTAKE : G99 G81 X175.0 Y30.0 Z-0.5 R5.0 F100;

G99 G81 X175.0 Y68.0;

CORRECTIVE STEP:G99 G81 X175.0 Y30.0 Z-0.5 R5.0 F100;

X175.0 Y68.0;

We have repeating the code (G99 G81) that are not necessary, too many repeating code will make confuse and easy to make mistake. Some of the program can simplify will easy to check for us.

2. MISTAKE :G99 G81 X175.0 Y30.0 Z-0.5 R5.0 F100;

X175.0 Y68.0;G99 G82 X110.0 Y49.0;M5; Spindle stop in G80 G40; the work pieceG91 G28 Z0.0;X0.0 Y0.0;G49;G30;

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CORRECTIVE STEP:G99 G81 X175.0 Y30.0 Z-0.5 R5.0 F100;

X175.0 Y68.0;G99 G82 X110.0 Y49.0;G00 Z20.0; Spindle is pull up at 20.0mm M5; height then the spindle stop G80 G40; G91 G28 Z0.0;X0.0 Y0.0;G49;G30;

In the program we have stop the spindle in the work piece, this is not a better program to stop in the work piece. So we add the code(G00 Z20.0) to pull spindle up before we stop spindle.

For project 3.2:1. MISTAKE:

G00 X165.0 Y25.0 F100;

Z-8.0;

G01 X-15.0 Y25.0 F100;

CORRECTIVE STEP:

G00 X165.0 Y25.0;

Z-8.0;

G01 X-15.0 Y25.0 F100;

For project 3.2, the code (F100) is not require in the positioning of code(G00). G00 will

not effect by the speed and with written the wrong code will effect to the machine.

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For project 3.3:

1. MISTAKE:

G00 X5.0 Y50.0;

G00 Z-2.0 ;

G02 X65.0 Y50.0 R30.0 F100;

G01 X150.0 Y50.0 F100;

G03 X210.0 Y50.0 R30.0 F100;

G00 Z-4.0;

CORRECTIVE STEP:

G00 X5.0 Y50.0;

G01 Z-2.0 F100;

G02 X65.0 Y50.0 R30.0 F100;

G01 X150.0 Y50.0 F100;

G03 X210.0 Y50.0 R30.0 F100;

G01 Z-4.0 F100;

In this mistake, we cannot used G00 to start drilling to work piece, because G00 code

will very fast drill into the work piece. This will consequently break the tooling with high

speed.

Therefore, G01 is appropriate because we can adjust the speed to avoid crush.

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For project 3.4:

1. MISTAKE:

G98 G81 X107.5 Y50.0 Z-0.5 R5.0 F100;

G00 Z20.0;

M5;

G80 G40;

G49 M6 T3;

G90 G00 G54 X0.0 Y0.0;

M3 S8000;

G43 Z20.0 H3;

G98 G82 X107.5 Y50.0 Z-10.0 R5.0 F100;

CORRECTIVE STEP:

G98 G81 X107.5 Y50.0 Z-0.5 F100;

G00 Z20.0;

M5;

G80 G40;

G49 M6 T3;

G90 G00 G54 X0.0 Y0.0;

M3 S8000;

G43 Z20.0 H3;

G98 G82 X107.5 Y50.0 Z-10.0 F100;

In the project, G98 refer to tooling return to the position at Z20.0. But we add another

R5.0 will make the machine cannot interpret which one to read. This will result the

machine cannot operate due to confusion in the program.

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6.0 CONCLUSION

After I study CNC Milling Machine in this few weeks, I have learned and expert on the

basic written of CNC program.

In the CNC program we are divided into three parts which is opening, body content and

closing. Every parts must in correct sequence and every block must not contain any

error.

During the lecture class, we able to learn how to type the program to NC control panel

and also able to experience how the machine operate with our naked eye.

Through the discussion we also able to learn from mistake that everybody have made.

Our tutor also help us when we are in needs.

After the discussion, we learned also must always very careful and cautions in written a

program, no matter any mistakes will ruin the specimen or even will damage the

machine.

Most of the engineering industrial using CNC Milling Machine to make their product,

CNC will be very important in our future century.

All engineering industrial using CNC Milling Machine:

1. Volume of production is higher compare to hand making.

2. More safety and with higher quality.

3. Save time instead of doing rough work.

4. High repeatability and precision.

5. Flexibility in job change, automatic tool setting.

7.0 REFERENCE

CNC Programming Reference Book; Author Micheal Peterson.

An Introduction to CNC Machining and Programming: Author Tom Crandell and David

Gibbs

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