CNC machining refers to precision mechanical machining controlled by computers, mainly used for the processing of various precision parts. What are the common causes of malfunctions in ordinary CNC machining? What are the reasons for over cutting during the processing?
1, The causes of common faults in CNC machining
1. Overload. Reason: Excessive cutting volume, frequent forward and reverse rotation, spindle motor failure, and spindle drive installation failure.
2. The spindle does not rotate. Reason: The installation of the spindle drive failed, the CNC installation was unable to output speed signals, the spindle motor failed, the spindle drive installation failed, and the transmission belt broke.
3. The spindle speed deviates from the command value. Reason: Motor overload, problem with spindle speed command output from CNC system, speed measurement installation failure, or disconnected speed response signal.
4. Abnormal spindle noise and vibration. Reason: During the deceleration process, there is a problem with the installation of the spindle drive, such as a malfunction in the regeneration circuit of the AC drive.
2, Reasons for CNC machining showing over cutting
1. The machining center's arc machining is excessively cut. When CNC machining stops and internal arc machining is summarized, if the selected tool radius rD is too large, exceeding the required arc radius r, it is likely to cause over cutting. The CNC machining program is compiled based on the theoretical summary of the workpiece trajectory, without considering the motion trajectory of the tool during the actual machining process. Due to the presence of tool radius, the actual trajectory of the tool becomes thicker and does not coincide with the programmed trajectory. In order to obtain a correct summary of the appearance of the workpiece, it is necessary to use a tool radius compensation command between the tool path and the programming path. Otherwise, over cutting of the workpiece is unavoidable.
2. Overcutting discrimination during linear machining process. When CNC machining workpieces composed of straight segments, if the tool radius is too large, it is likely to exhibit over cutting phenomenon, leading to workpiece failure. It can be distinguished by the positive or negative scalar product of the correction vector corresponding to the programming vector.
