As high-precision automatic processing equipment, CNC lathes frequently suffer from collision accidents, which are the most common safety problems and can result in severe economic losses. Collisions may occur to both new operators and senior technicians due to program deviations, misoperations or environmental interference. Therefore, prevention and emergency handling are top priorities for machine tool management.
Machine collisions are rarely caused by a single factor.
In terms of environment: CNC lathes require strict temperature and humidity control, with a constant temperature maintained at approximately 20℃. High temperatures in summer greatly increase the failure rate of the numerical control system, and humid conditions tend to cause short circuits and system misoperation. In addition, if the machine is placed near vibration sources or electromagnetic interference equipment such as forging machines and welding machines, system signals will be disturbed, raising the risk of collision.
In terms of operation: Failure to perform machine zero return after startup is the leading cause of collisions. Zero return to the reference point must be carried out again after startup or after the emergency stop button is pressed. Wrong zeroing sequence (moving the Z-axis first) will cause the tool post to collide with the tailstock and center when moving right.
In terms of programming: Insufficient reserved space for tool change and incorrect coordinate measurement will trigger collisions. Especially for boring tools, inadequate tool change clearance will lead to impacts with workpieces or chucks during tool switching.
Moreover, the two-stage clamping fixture (clamping manual chuck with hydraulic jaws, then fixing the workpiece with the fixture) has poor clamping stability. Blind application without sufficient calculation and verification will cause workpiece displacement and subsequent collisions.
A full-process prevention system is essential to avoid collisions.
For environmental management: Control workshop temperature and humidity, and keep the machine away from vibration and electromagnetic interference. Install air conditioners and industrial dehumidifiers in hot summer months to stabilize working conditions. Clean dust inside the electric cabinet regularly to prevent short circuits and false triggering.
For manual operation: Strictly follow the zero return procedure. Before zeroing, move the tool post between the deceleration switch and negative limit switch. Complete X-axis zero return first, then the Z-axis. Confirm that the zero indicator lights of both axes are on to ensure successful zeroing.
For programming: Programmers shall improve operational proficiency. The coordinates of tool change positions must be measured on the actual machine. Double-check all parameters even after program simulation to eliminate programming errors.
For customized clamping fixtures, conduct clamping force calculation and stability testing in advance; avoid adopting two-stage clamping structures without demonstration.
Once a collision occurs, press the emergency stop button immediately and cut off the power to inspect damage to cutters, workpieces, chucks and tool posts.
For minor collisions: Reset tool compensation values and coordinate systems, then verify precision through trial cutting before resuming production.
For severe collisions with deformed or broken parts: Replace damaged components promptly and recalibrate machine accuracy; never continue production with faults.
Prevention is always better than troubleshooting collisions. Operators should master all functions of the CNC system and develop good habits of pre-operation checking and continuous observation during operation. This will drastically reduce collision risks and ensure safe production
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