Influencing Factors and Adjustment Methods of Cutting Precision of CNC Cutting Machine

When many customers buy CNC cutting machines, they always ask how the cutting precision of CNC cutting machines is? The precision of cutting machines can be guaranteed to be 0.01mm/step before leaving the factory, and the precision error is about 0.5m, which is higher than The error of the cutting machine itself is several times, but this error is not formed by the equipment itself, but by the thickness of the steel plate, the process, the cutting nozzle, and the fire adjustment during the cutting process. Here are some reasons that affect the cutting accuracy of CNC cutting machines:

Programming Software Problems: If the programming software has defects or no cumulative error correction function, it will cause errors in the generated NC code. For example, the generated code size data is wrong or the compensation direction is wrong; or the code has accumulated errors, resulting in no problem in small-scale size, and there are large errors when there are many line segments, resulting in the phenomenon of misalignment of entry point introduction and extraction, which will also cause full board sleeves The deviation of workpiece spacing during feeding.

Graphic Size Error: There may be a negligence in the drawing or nesting process that causes the graphic size error. At this time, you can find out the reason by checking the size. It is easy to check program problems, as long as the NC code is converted to CAD graphics for measurement, and the compensation direction can be seen through simulation to see if it is correct.

Cutting Tip Quality and Kerf Compensation: The quality of the cutting tip will affect the surface quality of the workpiece and the flatness of the cutting side. The kerf compensation must be consistent with the actual cut kerf width. The way to reduce this kind of error is to choose a cutting nozzle with qualified quality. The specification of the cutting nozzle should also be suitable for the thickness and material of the plate to be cut. You can try cutting and adjusting on the waste material until the width of the cutting seam is uniform and the section is flat without slag. Cut a fixed-length rectangle without compensation, and measure it at the end, and make up as much as the width of the kerf is as small as possible.

Machine Tool Running Accuracy: The cutting machine accuracy includes mechanical accuracy and electronic accuracy. The mechanical accuracy is mainly affected by the straightness, parallelism, levelness of the guide rail, the transmission accuracy of gears or steel belts, etc. The levelness of the cutting platform also affects the accuracy of the workpiece. The electronic accuracy is affected by the CNC system software, motion control card, pulse equivalent, servo and servo drive, etc. In particular, if the pulse equivalent is not adjusted accurately, it will cause problems such as non-circular cutting circles and large parts size. It is also very simple to check the accuracy of the cutting machine, as long as a scribe needle is installed on the cutting torch, and the program to correct the error of the cutting machine is run to check the scribe line.

Thermal Deformation: deformation mainly includes thermal deformation and deformation caused by gravity. Reasonable lead position and cutting direction can be used in programming to reduce deformation. Some cooling devices can be added as needed, and a cutting platform with reasonable structure can be used.

Random and Accidental Variables: voltage fluctuations, loose data lines, poor contact between the system and servo control lines, loss of servo feedback signals, and unstable servo drive circuits may all cause the cutting machine to run around irregularly.

How to adjust the cutting accuracy of the CNC cutting machine Method: Test the interval between the diagonal and the intersection point to determine the cutting accuracy of the equipment. After purchasing a CNC cutting machine, most customers do not know how to adjust the diagonal adjustment method of the CNC cutting machine when using it. Below we will give our customers a detailed introduction to the adjustment method of the diagonal cutting of the CNC cutting machine:

1. Attach a liner to the torch.

2. Paste 4 sheets of A4 line drawing paper on the steel plate. The best one with glue on the back is to stick it flat, and the distance between the line drawing papers should be about two meters.

3. Move the torch to draw a cross pattern on the 4 pieces of drawing paper, draw a long horizontal line on the drawing paper on the right, and then move it to the drawing paper on the left to draw a horizontal line, Then draw a vertical line to form a cross-shaped pattern, continue to move down, draw a vertical line on the line drawing paper below, then draw a horizontal line, move to the right horizontally, and so on to form a rectangular pattern.

4. Measure the lengths of the two opposite corners to see if they are equal. If they are not equal, it means that the beam of the machine is not aligned. Need to continue to adjust the diagonal. Look at the difference between them by a few millimeters, and the normal error should be controlled within 0.5m

5. Press the back button to move the machine to a place about 200mm from the edge of the guide rail, and measure the distance from the edge of the two guide rails to the Y-axis machine under the condition of electrification. If the left side is 200m and the right side is 205mm, then the distance between them The benchmark is to adjust according to the diagonal error value measured in the previous step after 5mm.

6. According to the measured diagonal dimension, the dimension measured in the lower left corner and upper right corner is 3mm long, then use a strong clamp on the right rear guide rail of the Y-axis, and then open the left and right sides of the X-axis beam. On the side cover, loosen 8 fixing screws and 4 locking bolts, turn off the power, push the left beam to move inward by 3mm, then turn on the power, and measure the distances from the edges of the two guide rails to the Y-axis machine again. The original benchmark is 5m, if their current benchmark is 2mn, then tighten the 8 fixing screws and 4 locking bolts.

7. Remove the strong pliers on the right rear of the Y-axis of the CNC cutting machine.

8. Draw a cross-shaped diagonal line on the line drawing paper again, and then measure the size of the diagonal line. If the size is about 0.5mm, the job is completed.