1. The workpiece is of accurate size and poor surface finish
Cause of failure: the tool tip is damaged and not sharp; The machine tool resonates and is placed unsteadily; The machine tool has creeping phenomenon; The processing process is not good.
Dongguan CNC processing factory solution: tool wear or damage after not sharp, then re grinding or choose better tool to re align; The machine tool produces resonance or is not placed smoothly, adjust the level, lay the foundation, and fix it stably; The reason for the creeping of the machine is that the guide rail of the drag plate is worn severely, the screw ball is worn or loose. The machine tool should pay attention to maintenance. After going to and after work, the wire should be cleaned and lubricating oil should be added in time to reduce friction; Choose the coolant suitable for workpiece processing, and select the high spindle speed as far as possible when it can meet the requirements of other processes.
2. Large taper and small head phenomenon of workpiece
Cause of failure: the level of machine tool placement is not adjusted well, one high and one low, resulting in unstable placement; When turning long axis, the contribution material is hard and the tool is deep, which causes the phenomenon of making the tool; The pin of the tail seat is not concentric with the spindle.
Dongguan CNC processing factory solution: use level to adjust the levelness of the machine tool, lay down solid foundation, fix the machine tool to improve its toughness; Choose reasonable technology and proper cutting feed to avoid tool force; Adjust the tailstock.
3. The phase light of the driver is normal, and the size of the workpiece processed is small and large
Cause of failure: the long-term high-speed operation of the machine tool drag plate causes the screw rod and bearing wear; The repeated positioning accuracy of the tool holder has deviation in long-term use; The trawling can return to the start point accurately every time, but the dimension of the workpiece still changes. This phenomenon is usually caused by the spindle, the high speed rotation of the spindle causes the bearing to wear seriously, resulting in the change of processing size. The wechat of metal processing is good in content and deserves attention.
Solution: use dial indicator to lean against the bottom of tool holder, edit a fixed cycle program through the system, check the repeated positioning accuracy of the drag plate, adjust the screw rod clearance, and replace the bearing; Check the repeated positioning accuracy of the tool holder with dial indicator, adjust the machine or replace the tool holder; Use dial indicator to check whether the workpiece is accurately returned to the program starting point after machining. If it is possible, repair the spindle and replace the bearing.
4. The workpiece size is several millimeters different from the actual size, or there is a great change in an axial direction
Cause of failure: the speed of quick positioning is too fast, and the drive and motor can not react; After long-term friction loss, the mechanical drag screw rod and bearing are too tight and stuck; The tool holder is too loose to lock after changing the tool; The editing program is wrong, the head and tail do not echo or cancel the knife repair to end; The electronic gear ratio or step angle of the system is set incorrectly.
Dongguan CNC processing factory solution: if the fast positioning speed is too fast, the speed of go shall be adjusted appropriately, and the cutting speed and time shall be adjusted to make the driver and motor work normally at rated operating frequency; If the drag plate and crane bearing are too tight and stuck after the machine tool wear, it must be readjusted and repaired; If the tool holder is too loose after tool change, check whether the reversal time of the tool holder meets the requirements, check whether the worm and worm in the tool holder are worn, whether the clearance is too large, and whether the installation is too loose; If it is caused by the program, the procedure must be modified, the work piece drawing requirements improved, reasonable processing technology selected, and the correct procedure should be prepared according to the instruction requirements of the instruction manual; If the dimension deviation is too large, check whether the system parameters are set properly, especially if the parameters such as electronic gear and step angle are damaged. If this phenomenon occurs, it can be measured by dial indicator.
5. The machining arc effect is not ideal and the dimension is not in place
Failure reason: the overlapping of vibration frequency leads to resonance; Processing technology; The parameter setting is unreasonable, the feed speed is too large, which makes the arc machining out of step; Loose or out of step caused by the big gap of the screw rod; The synchronous belt is worn.
Dongguan CNC processing factory solution: find out the resonance components, change its frequency, avoid resonance; Considering the processing technology of the workpiece material, the program should be reasonably prepared; For step motor, the machining speed f cannot be set too large; Whether the machine tool is installed firmly, placed stably, whether the drag plate is too tight after wearing, the gap increases or the tool holder is loose, etc; Replace the synchronous belt. The wechat of metal processing is good in content and deserves attention.
6. In batch production, occasionally, the workpiece is out of tolerance
Cause of failure: the fixture must be carefully checked, and the operator's operation method and the reliability of the clamp must be taken into account. The size change caused by the clamping must be improved so that the workers should avoid the mistake of judgment by negligence; The numerical control system may be subject to the fluctuation of external power or automatically generate interference pulse after being disturbed, and it will be transmitted to the drive, which causes the drive to accept the redundant pulse driving motor to take away or walk less,
Solution: understand and master its laws, and try to adopt some anti-interference measures, such as: strong electric cable with strong electric field interference is isolated from signal line of weak current signal, absorbing capacitance of anti-interference and shielded wire isolation is adopted. In addition, check whether the ground wire is connected firmly and the grounding contact is nearest, and take all anti-interference measures to avoid system interference.
9. System induced size change instability
Fault reason: unreasonable setting of system parameters; The working voltage is unstable; The system is disturbed by external, which leads to the system out of step; The capacitance has been added, but the impedance between the system and the driver does not match, which leads to the loss of useful signals; Signal transmission between system and driver is abnormal; System damage or internal failure.
Dongguan CNC processing factory solution: speed, acceleration time is too large, spindle speed, cutting speed is reasonable, whether the operator parameter modification causes system performance change; Install voltage stabilizing equipment; The grounding wire is connected reliably and the anti-interference absorption capacitance is added at the output contact of the driver pulse; Select the appropriate capacitance model; Check whether the signal connecting wire between the system and the driver is shielded, whether the connection is reliable, and whether the signal of system pulse occurrence is lost or increased; Send to the factory for maintenance or replace the main board.