Collision is a serious problem during CNC lathe machining, which can lead to equipment damage, workpiece damage and even personal injury. Here are some of the main causes of collisions on CNC lathes:

1. Program errors: CNC lathe programming errors are one of the most common causes of collisions. It could be due to errors made by the programmer when creating the CNC program, such as wrong tool paths, wrong workpiece coordinates, or misunderstanding of the workpiece geometry.

2. Wrong tool selection: Selecting inappropriate tools for CNC lathes may lead to collisions. If the tool length, diameter or shape is not suitable for the required machining task, it may cause the tool to collide with the workpiece or fixture.

3. Tool wear: CNC lathe tool wear may change the cutting characteristics and cause collisions. A severely worn tool may increase cutting forces, causing the tool to bend or deviate from its intended path.

4. Workpiece fixation problem: If the workpiece is not clamped or positioned correctly on a CNC lathe, it may cause the workpiece to move or rotate during the machining process, thereby colliding with the tool.

5. Machine tool mechanical problems: Failure or wear of the mechanical components of the CNC lathe (such as guide rails, bearings, etc.) may cause unstable motion, causing the tool to deviate from the expected path and cause collisions.

6. Wrong processing parameters: Wrong cutting speed, feed speed or cutting depth of CNC lathe may cause excessive cutting force, causing the tool to deviate from the path and cause collision.

7. Control system failure: CNC system failure may cause incorrect motion instructions to be sent to the machine tool, causing the tool to collide with the workpiece or fixture.

8. Operational errors: Operational errors by CNC lathe operators, such as wrong start-up procedures, wrong zero-point settings or improper operation, may also lead to collisions.

To reduce the occurrence of collisions, measures need to be taken, such as carefully reviewing CNC programs, regularly checking the status of cutting tools and machine tools, setting up workholding devices correctly, and providing operational training to ensure operators can operate CNC lathes correctly.