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1. The workpiece size is accurate and the surface finish is poor

Causes of failure: The tool tip is damaged and not sharp; the CNC shearing machine resonates and the placement is not stable; the CNC shearing machine has a crawling phenomenon; the processing technology is not good.

Solution: The tool is not sharp after wear or damage, then re-sharpen the knife or choose a better tool to re-align the knife; the shearing machine resonates or the placement is not stable, adjust the level, lay the foundation, and fix it smoothly; mechanically generated The reason for crawling is that the guide rail of the carriage is worn out, the ball of the lead screw is worn or loose, the shearing machine should be maintained, the wire should be cleaned after going to get off work, and lubricating oil should be added in time to reduce friction; choose a coolant suitable for workpiece processing, in If it can meet the processing requirements of other processes, try to choose a higher spindle speed.

2. The workpiece produces taper size head phenomenon

Cause of failure: The placement level of the CNC shearing machine is not adjusted properly, one is high and the other is low, resulting in unstable placement; when turning the long axis, the contribution material is relatively hard, and the tool eats the knife deeply, resulting in the phenomenon of knife yielding; tailstock The thimble is not concentric with the spindle.

 

Solution: Use a spirit level to adjust the level of the shearing machine, lay a solid foundation, and fix the shearing machine to improve its toughness; choose a reasonable process and appropriate cutting feed to avoid the force on the tool and let the knife; adjust tailstock.

3. The phase light of the driver is normal, but the size of the workpiece is large and small

The reason for the failure: The long-term high-speed operation of the shearing machine carriage leads to the wear of the lead screw and bearing; the repeated positioning accuracy of the tool holder deviates during long-term use; the carriage can accurately return to the processing starting point every time, but the workpiece is processed. Dimensions still vary. This phenomenon is generally caused by the main shaft. The high-speed rotation of the main shaft causes serious bearing wear, resulting in changes in machining dimensions. Metal processing WeChat, the content is good, it is worthy of attention.

Solution: Use the dial indicator to lean against the bottom of the tool holder, and edit a fixed cycle program through the system to check the repeatability of the carriage, adjust the screw clearance, and replace the bearing; use the dial indicator to check the repetition of the tool holder Positioning accuracy, adjust the machine or replace the tool holder; use the dial indicator to check whether the workpiece is accurately returned to the starting point of the program, if possible, repair the spindle and replace the bearing.

4. The workpiece size differs from the actual size by a few millimeters, or there is a great change in a certain axis

Causes of failure: The speed of rapid positioning is too fast, and the drive and motor cannot respond; after long-term friction loss, the mechanical carriage screw and bearing are too tight and stuck; the tool holder is too loose after changing the tool and cannot be locked tightly; The edited program is wrong, the head and tail do not respond or the tool compensation is not canceled; the electronic gear ratio or step angle of the system is set incorrectly.

Solution: If the fast positioning speed is too fast, adjust the speed of the GO appropriately, and the cutting acceleration and deceleration speed and time will make the driver and motor work normally under the rated operating frequency; If the rod crane bearing is too tight and stuck, it must be re-adjusted and repaired; if the tool holder is too loose after changing the tool, check whether the reversal time of the tool holder is satisfied, check whether the turbine worm inside the tool holder is worn, whether the clearance is too large, and whether the installation is too loose etc.; if it is caused by the program, you must modify the program, improve it according to the requirements of the workpiece drawing, select a reasonable processing technology, and write the correct program according to the instructions of the manual; if it is found that the size deviation is too large, check whether the system parameters are set reasonable. In particular, whether parameters such as electronic gear and step angle are damaged, this phenomenon can be measured by playing a dial indicator.

5. The arc processing effect is not ideal, and the size is not in place

Causes of failure: resonance caused by the overlapping of vibration frequencies; processing technology; unreasonable parameter settings; excessive feed speed, which makes arc machining out of step; looseness caused by large screw clearance or out-of-step caused by too tight screw ; Timing belt wear.

Solution: find out the parts that generate resonance, change their frequency to avoid resonance; consider the processing technology of the workpiece material, and make a reasonable program; for the stepping motor, the processing rate F cannot be set too large; whether the shearing machine is firmly installed , the placement is stable, whether the carriage is too tight after wear, the gap increases or the tool holder is loose, etc.; replace the timing belt. Metal processing WeChat, the content is good, it is worthy of attention.

6. In mass production, occasionally the workpiece is out of tolerance

Cause of failure: The tooling fixture must be carefully checked, and considering the operator's operation method and the reliability of the clamping, due to the dimensional change caused by the clamping, the tooling must be improved so that workers try to avoid misjudgment due to human negligence; The numerical control system may automatically generate interference pulses after being fluctuated by external power supply or interfered with, which will be transmitted to the driver, causing the driver to receive excess pulses to drive the motor to take away or less.

Solution: Understand and master its laws, try to take some anti-interference measures, such as: isolation of strong electric cables with strong electric field interference from signal lines of weak electric signals, adding anti-interference absorbing capacitors and using shielded lines to isolate, in addition, Check whether the ground wire is firmly connected, the ground contact is closest, and take all anti-interference measures to avoid system interference.

7. There are changes in one process of the workpiece, and the dimensions of other processes are accurate

Cause of failure: Whether the parameters of this block program are reasonable, whether they are within the predetermined trajectory, and whether the programming format meets the requirements of the manual

Solution: If there are random threads in the thread block and the pitch is wrong, then immediately think of the peripheral configuration (encoder) of the thread processing and the objective factors of this function.

8. Each process of the workpiece has the phenomenon of increasing or decreasing

Cause of failure: programming error; unreasonable system parameter settings; improper configuration settings; regular and periodic changes in mechanical transmission parts

Solution: Check whether the instructions used by the program are executed according to the required trajectory specified in the manual. You can judge by playing the dial indicator. Position the dial indicator at the starting point of the program and let the carriage return to the starting position after the program ends. Repeat the execution even if you observe the results and grasp the law; check whether the system parameters are set reasonably or are considered to be changed; whether the relevant shearing machine configuration meets the requirements in the connection calculation coupling parameters, and whether the pulse equivalent is accurate; check the shearing machine Whether the transmission part is damaged, whether the gear coupling is uniform, check whether there are periodic and regular failures, and if so, check the key parts and eliminate them.

9. The size change caused by the system is unstable

Causes of failure: unreasonable system parameter settings; unstable working voltage; system is affected by external interference, causing the system to lose synchronization; capacitors have been added, but the impedance between the system and the driver does not match, resulting in loss of useful signals; the system and the driver are lost Abnormal signal transmission between; system damage or internal failure.

Solution: Whether the speed, acceleration time is too large, the spindle speed and cutting speed are reasonable, whether the operator's parameter modification causes the system performance to change; Add anti-interference absorbing capacitors to the output contacts; select the appropriate capacitor model; check whether the signal connection line between the system and the driver is shielded, whether the connection is reliable, check whether the system pulse signal is lost or increased; send it to the factory for repair or replace the main board .