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Sample Milling Program for I, J & K CNC functions

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.

Programming codes for CNC lathes Machine are:

• G00, Motion Positioning

Rapid positioning motion is motion without feeds.
G00 programming format is:
N .... / G00 / X ... .. / Z ... ...

• G01, linear interpolation motion with feeds.

That is a straight cutting movement in the direction parallel to the axes, or
cutting to form a certain angle (motion interpolation).
The command format: N ... / G01 / X ± ... / Z ± ... / F ...

• G02 and G03 circular interpolation

G02: clockwise circular interpolation
G03: circular interpolation counter clockwise
(Motion direction / counter-clockwise from the position determined
chisel on a work piece)
Input format: N ... / G02 / X ± ... / Z ± ... / F ...
: N ... / G03 / X ± ... / Z ± ... / F ...

• G78, Screw cutting cycle

Used for turning threaded longitudinal direction parallel to
axis machines.
Format command: N ... / G78 / X ± ... / Z ± ... / C ... / H ...

• G84, turning cycle length

G84 is an order turning lathe with chisel-shaped motion
cycle, which include: movement
1: chisel cutting preparation,movement
2: cutting to length, movement
3: cutting edge and the motion
4: return to the starting point begins the movement.
Format command: N ... / G84 / X ± ... / Z ± ... / F ... / H ...

• G92, Records and Decision Point Zero

G92 is an order of recording and setting the machine zero point
the absolute price programming.
Programming Format: N ... / G92

CNC milling machine is a machine to shape any kind of solid materials such as metal, wood, aluminum or brass. This milling machine is often used in many manufacturing shop. This machine can perform some tasks simple such as cutting, drilling to more complex task such as contouring.  This machine is perfect solutions for any light or heavy industrial work.  There are some models and types that you can choose.

CNC milling machine, as the name suggested, this machine is featured with computer numerical control technology. This technology will make this machine to work with less human intervention.  This machine is quite popular and often used by many manufacturers.  This machine can be used to shape any kind of solid materials with high precision. With its technology, this machine is quite small and can be placed anywhere. With its size, this will also save a lot of space.

Most of manufacturer in industry field often use this machine to perform some small production jobs. This machine is also quite inexpensive compared with the benefit that you can get. So if you have decided to buy this machine, you can get CNC milling machine that available in some online stores.

Benchtop CNC precision milling machine has some types, models, and sizes that you can choose. Milling machine is often used to perform some tasks in industry manufacturer such as shape wood, metal or other solid materials. With its new technology, most of milling machine now is equipped with computer numerical control technology, with this technology; the machine can work with less human intervention.

Benchtop CNC precision milling machine is quite popular in industry field. Milling machine can be used to shape to shape any kind of solid materials such as wood, metal, brass, steel, plastic or aluminum. This machine is quite small, the sizes will save a lot of space. Even if the size is small, this machine can perform many task in industry field.

Most of people often use this machine to do some small production jobs. The machine is quite simple, because it can be relocated and doesn’t require a lot of space. With its technology, this machine is often used by many manufacturers for their lighter productions jobs. The price for this machine is also quite affordable, compare with the benefit that you can get from this machine, buying benchtop CNC precision milling machine is really useful for your smaller productions needs.

Indicating the vise of your CNC milling machine vise is included in the most important thing of machining process. To cut the parts correctly, the fixture of work-holding is supposed to be definitely straight. Through digital indicator or a dial, you may get the vise become straight in .0001 from an inch, to result in accurate parts within the machining environment. Therefore, you need a wrench, mallet, and t-bolts. Pleas pay attention to the instructions.

First, clean the table of cnc milling machine vise of all metal chips and debris. It is essential that you clean the table and be flat. Then, use the stone of sanding to remove anykind of rust from your table and also compressed air in getting in crannies and nook to remove the debris which you cannot see through naked eyes. Next, you may place a vise to the table by the jaw plate to face to the front. The vise is supposed to be placed to make the vise C-slots are more than two T-slots corresponding toward the table. Tighten your bolts, then loosen enough to wiggle easily the vise by using one hand, then tap with a wrench or a mallet.

Next, bring in manual way the spindle toward the vice, and leave its bottom one foot from the vise. Then, attach the holder of indicator toward the spindle. You bring down the spindle so the tip would be between the two jaws vise. You move to the back the spindle to allow it pressing against the jaw at the back. Then, spin the indicator bezel to be zero. You may move  yoru spindle from the left to the right. Last, tap your jaw to get the solid zero. You may use the wrench and tighten carefully the jaw as well as re-check the axis of your cnc milling machine vise.

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 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

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.

It has been a privilege to be part of the Precision Machining
Technology Competition for the past 9 years. I am proud to have
the opportunity of working with the fine young people from all parts
of the United States. They deserve the best that the educational
system and VICA can provide to prepare them for a future in this
rapidly changing technological world and make their contribution
to the country’s economy.
My enthusiasm for VICA and the young competitors is still very
strong, however there seems to be a serious lack of preparation
for students from metalworking/manufacturing related courses in
the basic knowledge of CNC. CNC, not a new technology having
been around since 1957, is one of the key factors in the manufacture
of most products in the world today. A knowledge of CNC, for
a technology student, should rank in importance along with the
ability of speaking proper English and reading technical prints
(blueprints).
As a former educator and now the Team Leader of the CNC VICA
competition, I feel so sorry for contestants in the Milling and
Turning who sit in front of a computer and do not know how to load
a program or the basics of CNC programming. These students are
naturally frustrated that an educational system has shortchanged
them by not realizing that metalworking technology has changed
dramatically over the past 40 years. That some schools prepare
students for the National VICA Precision Machining Competition
with 50-year-old technical knowledge is something very difficult to
understand.
The International (World) competition eliminated conventional
machine tools from the precision machining competition in 1996,
and it now consists of 100% CNC competition. To send our national
winner to the world competition without a good background
in CNC programming and machining would be a reflection on, and
a disgrace to the US educational system.
The educational community and National VICA must work
together to correct this lack of CNC knowledge and training.

The VICA CNC Programming Guide covers the basic CNC principles
and gives detailed explanation of each step in the programming
and turning a part. The time and money spent to prepare and
distribute this Guide will be wasted unless the metalworking/
manufacturing teacher is committed to introducing CNC as part of
the curriculum.

The following suggestions can be used to introduce CNC theory
and technology to metalworking/manufacturing courses:
1. Teach the basics of CNC using the VICA CNC Programming
Guide that should be supplemented by a textbook, visuals, videotapes,
etc. - COST approximately $200.00.
2. Use the VICA CNC Programming Guide and textbook along
with CAD/CAM software that allows a student to simulate the
machining of a programmed part on the computer screen. - COST
approximately $600.00.
3. Use the VICA CNC Programming Guide, textbook, CAD/CAM
software, plus a CNC Bench-Top teaching size machine. This is
by far the best method since students can actually produce a real
part that they can hold and take home to show their parents. -
COST approximately $6,000.00

For more information from a leader in CNC educational
courseware, software, and Bench-Top Teaching machines contact:

The old argument that there are still many shops using old
technology is a fallacy used consciously or unconsciously by those
resisting changes. Over 90% of the machine tools manufactured
in the world have some form of CNC control, therefore conventional
(manual) machines should be used to provide only the basic
knowledge of machines and machining processes.

We must all do our part; State Directors, District Directors, School
Administrators, and Classroom Teachers to correct a problem long
overdue in technical education.

To make the machine is more effective, CNC code transmission machine controller is highly recommended to apply. For detailed functions, this controller plays significant role in stimulating the motion of axes, including doing what has been commanded by the operator. Once it’s applied the items which useful for the working loading process work based on their each role. Through this special program as well, the mistakes which probably made by the program are able to be fixed and removed to be replaced by the new one. While in the same time, when the program is doing something right, it’s also reporting as it is.

As long as this controller’s working well, that’s the machine can be trusted professionally. Principally, the work of CNC code transmission machine controller is separating the buffer and motion parts which already owned by the machine. Both of them have been standardized so everything’s relied on the program that’s operated by the operator get along with its each programming’s.

The motion controller is usually placed on the users’ personal computer which’s designed by simpler way since it doesn’t require additional software anymore. The users, even more, can apply t by using the portable device such as USB. When the machine’s provided by the controller, it results are more amazing since the users don’t have to panic for the mistake commands since it can be minimized by CNC code transmission machine controller.


DEFINITIONS

•  RS-232 -

Recommended Standard 232 (RS-232) is a standard for serial communications connecting between a
PC and a CNC controller.

• Port-

Serial communications port on PC. A 'port' serves as an interface between the computer and the CNC
controller.

• Baud -

A unit used to measure the speed of signaling or data transfer, equal to the number of pulses or bits per
second: baud rate.

• Parity-

The condition of the number of items in a set, particularly the number of bits per byte or word, being
either even or odd: used as a means for detecting certain errors.

• Data-

The Data rate is the number of bits that are conveyed or processed per unit of time.

• Stop-

The "stop bit" is actually a "stop period" in the transmission of information to the CNC controller.

• Flow-

In computer networking, flow control is the process of managing the rate of data transmission between
two nodes to prevent a fast sender from overrunning a slow receiver.

1. Hardware flow control (RTS / CTS)

Flow control can be done either by control lines in a data communication interface RTS (Request To
Send)/CTS (Clear To Send) and DSR (Data Set Ready)/DTR (Data Terminal Ready), which is usually
referred to as "hardware flow control".

1. Software flow control (XON / XOFF)

Or by reserving in-band control characters to signal flow start and stop (such as the ASCII codes for
XON/XOFF). Common RS 232 control lines are XON/XOFF is usually referred to as "software flow
control".

• Timeout-

A period of time after which an error condition is raised if data has not been sent or received. If the
software does not acknowledge the message within the preset timeout period, a error is assumed to
have occurred.

• DNC -

Direct Numerical Control, also known as Distributed Numerical Control, (both DNC) is a common
manufacturing term for networking CNC machine tools. On some CNC machine controllers, the
available memory is too small to contain the machining program (for example machining complex
surfaces), so in this case the program is stored in a separate computer and sent Direct to the machine,
one block at a time. While BobCAD-CAM has the

The CNC is call for computer numerical control and it is refer to a computer “controller” which specifically drives a machine tool and reads G-code instructions, typically a powered mechanical device used to fabricate components by the selective removal of material. CNC does numerically directed a cutting tool interpolation in the work envelope of a machine. The CNC operating parameters can be altered via software load program.

CNC was preceded by Numerically Controlled (NC) machines, which were hard wired and their operating parameters could not be changed. NC was developed in the late 1940s and early 1950s by John T. Parsons collaboration with the MIT Servomechanisms Laboratory. The first CNC systems used hardware of NC style, and the computer was used for the tool compensation calculations and sometimes for editing.

Punched tape was continued to be used as a medium for transferring G-codes into the controller for many decades after 1950, until it was eventually superseded by floppy disks, RS232 cables, and now is commonly tied directly into plant networks. The G-codes files to be interpreted by the controller are usually saved under the .NC extension. Most shops have their own saving format that matches their requirements of ISO certification.

The CNC machines introduction radically changed the manufacturing industry. Curves are as easy to cut as straight lines, complex 3-D structures are relatively easy to produce, and the number of machining steps that required human action has been reduced dramatically.

Continued from the article "Intelligent computer numerical control unit"
Now we will discuss about the description of the NN itself. Let's look at the picture "Schematic lay-out of NN device"


NN device consist of:
- A module for recognizing of geometric and technological features from CAD model of the part,
- Computer CAD model of the part, which contains geometric and technological features,
- NN device for milling, which has been learned for NC programming of milling, drilling and machining operations like drilling and
- NC control program for the part, which has been sent to control device, as a CAD model of the part.

In the phase of learning the NN device is connected to the module for learning of the neural network, which takes the data from the usual, commercial available CAD/CAM system, which is used for programming of NC/CNC machine tools. NN device automatically generates NC programs for CAD models of each individual product, which it becomes from the commercial CAD/CAM programming system. CNC control unit after this invention can receive the data for teaching of NN device from a special module for teaching, which is not the constituent part of the control unit. The task of the module for teaching is to teach the neural network, which is built-in into NN device, the principles and the technology of NC programming of all machining operations on CNC machining centres, mostly milling, drilling and operations alike.
In principle for this purpose different systems of neural network and different, also commercial developed software, can be used [9,10,11]. If we want to meet special criteria at machining (costs, time, quality of cutting, tool life, high speed cutting etc.) special developed neural network must be used.