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Why do various error problems occur in CNC machining? How should this problem be solved?

2023/12/21 10:05:57 click:

As we all know, during the CNC machining process, once the processing accuracy of the finished workpiece cannot meet the customer's order requirements, it will cause considerable problems, increase the processing cost of this batch of orders, and also delay the delivery date.

 

Therefore, in CNC processing, production needs to be strictly according to the drawing requirements. Firmly control the accuracy within the range required by the customer.

The editor of this article will explain to you why precision errors occur in the machining of spare parts. And how should this problem be solved?

 

1-The taper of the finished workpiece is produced, and there is a situation where the head is large or small.

Reason: The horizontal position of the cnc customized machining equipment installed is unstable, with one high and one low. When cutting a long axis, if the material is too hard and the cutter is cut too deep, it will also aggravate the taper of the part and cause errors in machining accuracy.

Solution: Use a level to adjust the level of the equipment to make the equipment firm and improve the toughness of the equipment. Reasonably select the process and perform cutting feed appropriately to avoid knife collision. The situation of big and small heads will also be avoided.

2-The dimensions of precision parts are very accurate, but the surface finish of the parts is not ideal.

Possible reasons: The tool tip is worn, causing resonance in the machine tool. When the mechanical processing equipment was first deployed and installed, it was not stable enough, the equipment still crawled, and the process requirements were unqualified.

Solution: Check the tool holder, etc. frequently. Once there is significant wear, the tool should be re-polished or replaced with a new one; Install the processing equipment stably, adjust the horizontal position and foundation of the equipment, and install it firmly in the designated position. When commuting to and from get off work, perform necessary maintenance on equipment in a timely manner, clean wires, add lubricating oil, etc. to reduce crawling.

3-The driver phase light displays normally, but the size of the processed parts is abnormal.

Reason: The high-speed rotating spindle causes severe wear on the bearings, resulting in changes in the processing dimensions.

Solution: Use a dial indicator to lean against the bottom of the tool holder, and edit the fixed cycle program through the system to check the repeat positioning accuracy of the pallet, adjust the screw clearance, replace the bearings, use a dial indicator to check the repeat position accuracy of the home, and adjust the machine or Replace the tool holder and use a dial indicator to check if the part is ready to return to the start of the program.

4-The curvature is processed, the effect is not ideal, and the size is not adequate.

Reason: The superposition of vibration frequencies will cause resonance. If the machining process parameters are set unreasonably, it will cause the arc machining to be out of step, loose or too close, and the timing belt will wear out.

Solution: Find the site where the resonance occurs, change its vibration frequency, and avoid resonance. This requires taking into account the processing technology of the part material and the rationality of the CNC programming. The processing rate setting of the stepper motor cannot be too large. Replace it. Timing belt.

5-The size of the part differs by several millimeters from the actual size, or there is a large change in a certain axial direction.

Cause analysis: The rapid positioning speed is too fast, and the driver has not had time to react. After a long period of wear, the mechanical tow bar and bearings are too tight, the tool holder is too loose, the lock is not tight, the editing program is wrong, there is no response from the head to the tail, and the system electronic size Ratio or layout setting error;

Solution: Lower the go speed, cutting acceleration and time appropriately so that the drive and click can work normally at the rated operating frequency.

6-During batch processing, accidental errors may occur.

Cause analysis: This situation occurs due to human negligence or insufficient reliability of the fixture.

Solution: Use some anti-interference measures as much as possible, such as adding anti-interference capacitors or shielded wires for isolation. Check whether the grounding wire is firm and take all anti-interference measures to avoid interference to the CNC system. Avoid interference to the CNC system.

7-Every process of parts has an increase or decrease.

Cause analysis: Program writing errors, system parameter settings are not rigorous enough, and equipment transmission components produce regular failures within a fixed period;

Solution: It is necessary to check whether the instructions used by the program have been executed according to the trajectory specified in the instructions, observe the results, grasp the rules, check whether the system parameter settings are reasonable, whether the relevant equipment configuration meets the requirements of the coupling parameters of the link computer, and whether the pulse is accurate. wait.

 

Yixin Precision Metal & Plastic Ltd has established a complete quality management system to ensure that every product delivered to customers is qualified from material procurement, processing to shipment. Our factory has passed ISO-009001 and various quality system certifications. Welcome to Yixin Precision Metal & Plastic Ltd for an on-site inspection.