Cnc Programming:
Computerized Numerical Control refers to the CNC machining center, which is the kind of ordinary processing machine that is controlled by a computer.
Typical Example:
CNC machine tool is a mechanical and electrical integration processing configuration with a high degree of technical integration and automation. It is a high-tech product that comprehensively applies planning machines, automatic control, automatic detection, and precision machinery. With the development and popularization of CNC machine tools, the demand of modern enterprises for skilled talents who understand CNC processing skills and can carry out CNC processing programming will continue to grow. The cnc lathe is one of the most widely used cnc machine tools today. This article explores the steps and styles in the processing of CNC lathe parts.
Programming Essentials:
There are two methods of cnc programming: manual programming and automatic programming. Manual programming refers to the programming process that is mainly completed manually from the steps of part drawing analysis, process processing, data planning, preparation of step sheets, input steps to step verification. It is suitable for point-to-point processing or the processing of parts with less complicated geometric shapes, as well as places with relatively simple planning, few steps, and easy programming, etc. However, for some parts with complex shapes (especially those composed of space surfaces), and some parts with not complicated elements but requiring a large number of design steps, because the labor of calculating values during programming is quite long-winded, labor-intensive, and easy to make mistakes, the steps Verification is also difficult, and it is difficult to complete with manual programming, so active programming should be adopted. The so-called automatic programming means that most or all of the procedure-based work is completed by a computer, which can effectively solve the processing problem of complex parts, and it is also the future development trend of cnc programming. At the same time, it should also be seen that manual programming is the basis of automatic programming. Many core experiences in automatic programming come from manual programming, and the two complement each other.
Programming Steps:
After getting a part drawing, you should finally analyze the part drawing to determine the processing process, that is, determine the processing method of the part (such as the tool and fixture used, the clamping and positioning method, etc.), the processing route (such as the feed route, tool setting method, etc.) point, tool change point, etc.) and process parameters (such as feed rate, spindle speed, cutting rate and depth of cut, etc.). Secondly, numerical calculations should be carried out. Most of the cnc systems have tool compensation function, just calculate the coordinate value of the intersection point (or tangent point) of adjacent several elements of the shape, and get the coordinate value of the starting point end of each geometric element and the center of the arc. Finally, according to the calculated tool movement trajectory coordinates, the determined processing parameters and auxiliary actions, combined with the coordinate instruction codes and step section shapes used by the CNC system rules, the part processing step list is written step by step, and input into the memory of the CNC device middle.
Case Analysis:
The cnc lathe is mainly used to process rotary parts. Typical processing surfaces are nothing more than outer cylinders, outer cones, threads, arc surfaces, grooving, etc. For example, to process parts whose shape is shown in the overview diagram, it is more appropriate to use manual programming. Because different cnc systems have different programming instruction codes, they should be programmed according to the type of configuration. Taking the Siemens 802Sncc system as an example, the following arrangements should be made.
(1) Determine the processing route
The machining route is determined according to the machining principle of first roughing and then finishing, and the external shape is roughed with the steady cycle command, then finished, and then the groove is turned, and finally the thread is processed.
(2) Selection of clamping essentials and tool setting point
The three-jaw self-centering chuck is used for self-centering clamping, and the tool setting point is selected at the intersection of the right end surface of the workpiece and the rotation axis of the reverse rotation.
(3) Select tool
According to the processing requirements, four knives are selected, No. 1 is the outer circle turning tool for rough machining, No. 2 is the outer circle turning tool for finishing machining, No. 3 is the grooving knife, and No. 4 is the thread turning knife. Take the trial cutting method to set the knife, and process the end face at the same time.
(4) Determine the amount of cutting
Turn the outer circle, the rough turning spindle speed is 500r/min, the feed rate is 0.3mm/r, the finish turning spindle speed is 800r/min, the feed rate is 0.08mm/r, when cutting grooves and threads, the spindle speed is 300r/min, the feed rate is 0.1mm/r.
(5) Step specification
Determine the intersection point of the axis line and the center of the ball head as the programming origin, and the processing steps of the part are as follows:
main step
JXCP1.MPF
N05 G90 G95 G00 X80 Z100 (tool change point)
N10 T1D1 M03 S500 M08 (External rough turning tool)
-CNAME="L01"
R105=1 R106=0.25 R108=1.5 (Configure blank cutting cycle parameters)
R109=7 R110=2 R111=0.3 R112=0.08
N15 LCYC95 (call blank cutting cycle for rough machining)
N20 G00 X80 Z100 M05 M09
N25 M00
N30 T2D1 M03 S800 M08 (External round finishing tool)
N35 R105=5 (Configure blank cutting cycle parameters)
N40 LCYC95 (call blank cutting cycle finishing)
N45 G00 X80 Z100 M05 M09
N50 M00
N55 T3D1 M03 S300 M08 (grooving tool, tool width 4mm)
N60 G00 X37 Z-23
N65 G01 X26 F0.1
N70 G01 X37
N75 G01 Z-22
N80 G01 X25.8
N85 G01 Z-23
N90 G01 X37
N95 G00 X80 Z100 M05 M09
N100 M00
N105 T4D1 M03 S300 M08 (triangular thread turning tool)
R100=29.8 R101=-3 R102=29.8 (Configure thread cutting cycle parameters)
R103=-18 R104=2 R105=1 R106=0.1
R109=4 R110=2 R111=1.24 R112=0
R113=5 R114=1
N110 LCYC97 (call thread cutting cycle)
N115 G00X80 Z100 M05 M09
N120 M00
N125 T3D1 M03 S300 M08 (cutting tool, tool width 4mm)
N130 G00 X45 Z-60
N135 G01 X0 F0.1
N140 G00 X80 Z100 M05 M09
N145 M02
substep
L01.SPF
N05 G01X0 Z12
N10 G03 X24 Z0 CR=12
N15 G01 Z-3
N20 G01 X25.8
N25 G01 X29.8 Z－5
N30 G01 Z－23
N35 G01 X33
N40 G01 X35 Z－24
N45 G01 Z－33
N50 G02 X36.725 Z－37.838 CR=14
N55 G01 X42 Z-45
N60 G01 Z－60
N65 G01 X45
N70 M17
Perfect Language:
To realize cnc processing, programming is the key. Although this article only analyzes the programming of a CNC lathe processing part, it is definitely representative. Because CNC lathes can process complex curved surfaces that cannot be processed by ordinary lathes, the processing accuracy is high, the quality is easy to guarantee, and the development prospects are very broad. Therefore, it is particularly important to master the processing and programming skills of CNC lathes.
Precautions:
1. The rotation speed of the white steel knife should not be too fast.
2. Copper workers seldom use white steel knives for rough cutting, but use flying knives or alloy knives more.
3. When the workpiece is too high, it should be roughed with different length cutters in layers.
4. After roughing with a large knife, use a small knife to remove the remaining material to ensure that the remaining amount is consistent before finishing the knife.
5. The plane should be processed with a flat-bottomed knife and less with a ball knife to reduce the processing time.
6. When the copper worker cleans the corner, first check the size of R on the corner, and then determine the size of the ball knife to use.
7. The four corners of the calibration plane should be flat.
8. Where the slope is an integer, it should be processed with a slope knife, such as the pipe position.
9. Before doing each process, think clearly about the remaining allowance after the previous process, so as to avoid empty cutting or excessive processing.
10. Try to use simple tool paths, such as shape, grooving, single side, and less contouring.
11. When going to WCUT, if you can go to FINISH, don't go to ROUGH.
12. When polishing the shape of the knife, first rough polish and then finish. When the workpiece is too high, first polish the edge and then polish the bottom.
13. Reasonably set tolerances to balance machining accuracy and computer calculation time. When roughing, the tolerance is set to 1/5 of the allowance, and when the light knife is used, the tolerance is set to 0.01.
14. Do a little more work to reduce the time of empty cutting. Do a little more thinking to reduce the chance of error. Make more auxiliary lines and auxiliary surfaces to improve the processing conditions.
15. Build a sense of responsibility and double check every parameter to avoid rework.
16. Be diligent in learning, good at thinking, and keep improving.
For non-plane milling, use more ball cutters, less end cutters, and don't be afraid of receiving cutters;
A small knife clears the corners, and a large knife is refined;
Don't be afraid to make up the surface. Appropriately make up the surface can increase the processing speed and beautify the processing effect.
The hardness of the rough material is high: up milling is better
The rough material has low hardness: Climb milling is better
The machine tool has good precision, good rigidity, and finishing: it is more suitable for down milling, otherwise it is more suitable for up milling
Climb milling is strongly recommended for finishing inside corners of parts.
Rough machining: up milling is better, finish machining: down milling is better
The tool material has good toughness and low hardness: it is more suitable for rough machining (machining with large cutting volume)
The tool material has poor toughness and high hardness: it is more suitable for finishing.
