The common problems and solutions in CNC Machining are as follows:

1. Bullet knife: This is usually due to insufficient, too long or too small tool strength. The solution is to follow the knife principle of "can be big or small, can be short or not", choose the appropriate strength of the tool, and try to leave a uniform cutting allowance.

2. Inaccurate operation: Inaccurate manual operation by the operator may lead to machining errors. The solution is to perform repeated checks to ensure that operations such as centering and tool setting are carried out at the same point and at the same height, while improving the operator‘s proficiency.

3. Collision: This may be caused by improper safety height setting, program error or operator manual operation error. The solution is to ensure that the safety height is set above the workpiece, the program sheet is consistent with the actual program tool, and the operator strengthens the inspection during manual operation to ensure that the program is executed correctly in sequence.

4. Poor cutting effect: unreasonable cutting parameters, sharp cutting edges, and poor chip removal can all lead to poor cutting results. The solution is to adjust the cutting parameters reasonably, check and replace the tools regularly, and ensure that the clamping tool is as short as possible, and the cutting edge should not be too long. At the same time, consider programming methods such as straight milling.

5. Chipping and wear: This is usually due to too fast feed speed, insufficient clamping force, insufficient tool rigidity, etc. The solution is to slow down the feed speed, clamp the tool and workpiece, use a rigid machine tool and handle, and use the shortest knife allowed, with a deeper handle. For worn tools, it should be ground at the beginning.

The above are just some of the common problems and solutions. The problems encountered in CNC machining may vary depending on the specific situation and need to be adjusted and dealt with according to the actual situation.