Home > RLT Lab > Content
Eight Kinds Of Common Faults And Their Solutions In CNC Machining
Apr 03, 2018

1. Accurate workpiece size, poor surface finish

Cause of issue:

The tool tip is damaged and not sharp;

The machine tool has resonance and it is not stable;

The machine tool has a crawling phenomenon;

The processing process is not good.

Solution:

After the tool wears or is not sharp after being damaged, re-sharpening or selecting a better tool to re-arrange the tool; the machine will cause resonance or unstable placement, adjust the level, lay the foundation, and ensure a stable and stable; the reason for the mechanical creep is the wear of the guide rail Powerful, screw ball wear or loose, the machine should pay attention to maintenance, should clean the wire after work, and add lubricants in a timely manner to reduce friction; select the workpiece for the processing of coolant, in other processes can meet the processing requirements, Try to use a higher spindle speed.

2. The workpiece produces a taper head phenomenon

Cause of issue:

The level of the machine is not adjusted well, one high and one low, resulting in unstable placement;

When turning the long axis, the contribution of materials is relatively hard, the knife is relatively deep, causing knife phenomenon;

Tailstock ejector and spindle are not the same.

Solution:

Use a spirit level to adjust the level of the machine, lay a solid foundation, and fix the machine to improve its toughness; choose a reasonable process and appropriate cutting feed to avoid the tool being forced by the knife; adjust the tailstock.

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

Cause of issue:

Fast positioning is too fast and the drive and motor do not react.

After long-term frictional loss, the mechanical drag screw and the bearing are too tight;

After the tool changer is too loose, the lock is not tight;

The editor's procedural error, the head or tail did not respond or did not cancel the knife compensation is over;

The electronic gear ratio or step angle setting of the system is incorrect.

Solution:

If the fast positioning speed is too fast, then GO speed is properly adjusted. The cutting acceleration/deceleration and time allow the drive and motor to work normally at the rated operating frequency. After the machine tool wears, the carriage and the screw crane bearing are too tightly clamped. It must be re-adjusted and repaired. If the knife holder is too loose, check whether the reversal time of the knife holder is satisfied. Check whether the turbine worm inside the knife holder is worn, whether the clearance is too large, whether the installation is too loose, etc.; if it is caused by the program , you must modify the program, in accordance with the requirements of the workpiece drawings to improve, select a reasonable processing technology, according to the requirements of the instructions to write the correct program; if you find that the size deviation is too large, check whether the system parameters are set properly, especially the electronic gear and step angle Whether the parameters are destroyed or not, this phenomenon can be measured by dialing a dial indicator.

4. The workpiece size and the actual size of a few millimeters, or an axial change

Cause of issue:

Fast positioning is too fast and the drive and motor do not react.

After long-term frictional loss, the mechanical drag screw and the bearing are too tight;

After the tool changer is too loose, the lock is not tight;

The editor's procedural error, the head or tail did not respond or did not cancel the knife compensation is over;

The electronic gear ratio or step angle setting of the system is incorrect.

Solution:

If the fast positioning speed is too fast, then GO speed is properly adjusted. The cutting acceleration/deceleration and time allow the drive and motor to work normally at the rated operating frequency. After the machine tool wears, the carriage and the screw crane bearing are too tightly clamped. It must be re-adjusted and repaired. If the knife holder is too loose, check whether the reversal time of the knife holder is satisfied. Check whether the turbine worm inside the knife holder is worn, whether the clearance is too large, whether the installation is too loose, etc.; if it is caused by the program , you must modify the program, in accordance with the requirements of the workpiece drawings to improve, select a reasonable processing technology, according to the requirements of the instructions to write the correct program; if you find that the size deviation is too large, check whether the system parameters are set properly, especially the electronic gear and step angle Whether the parameters are destroyed or not, this phenomenon can be measured by dialing a dial indicator.

5. Processing arc effect is not ideal, the size is not in place

Cause of issue:

The resonance of the vibration frequency overlaps;

Unreasonable parameter setting and excessive feed rate make the arc machining out of step;

Looseness caused by large screw clearance or out-of-step caused by tight screw, wear of timing belt.

Solution:

Find out the components that generate resonance, change its frequency, avoid resonance; consider the processing technology of the workpiece material, and reasonably program; for the stepper motor, the processing rate F can not be set too large; whether the machine is installed firmly, the placement is stable, and the carriage is worn out After over-tightening, the gap is increased or the tool holder is loosened; replace the timing belt.

6. Occasionally, workpieces are out of tolerance in mass production

Cause of issue:

The fixtures must be carefully inspected, and taking into account the operator's method of operation, and the reliability of the fixture, due to the size change caused by the fixture, the fixture must be improved so that workers can avoid human error to make misjudgment;

The CNC system may be subject to fluctuations in the external power supply or automatically generate disturbing pulses after being disturbed, and is transmitted to the drive so that the drive receives an extra pulse to drive the motor to take away or to walk away.

Solution:

Learn to master its laws and try to use some anti-interference measures, such as: strong electric cable interference strong electric cable and weak signal signal line isolation, add anti-jamming absorption capacitance and use shielded wire isolation, in addition, check the ground wire is firmly connected , The grounding contact is closest and take all anti-jamming measures to avoid the system being disturbed.

7. The process of a part of the workpiece is changed, and the dimensions of other processes are accurate.

Cause of issue:

Whether the parameters of the program segment program are reasonable, whether it is within the predetermined trajectory and whether the programming format meets the requirements of the specification.

Solution:

If there are turbulences in the thread block and the thread pitch is incorrect, the external configuration of the thread (encoder) and the objective factors of the function will immediately be conceived.

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

Cause of issue:

Programming error;

System parameter settings are unreasonable;

Inappropriate configuration settings;

Mechanical transmission components have periodic and periodic failures.

Solution:

Check whether the instructions used by the program are executed according to the requirements specified in the manual. You can judge by dialing the dial indicator. Position the dial indicator at the starting point of the program and let the slider return to the starting position after the end of the program. Repeat the execution even if you observe it. The results, to grasp its laws; Check whether the system parameters are set or considered to be changes; related to the machine configuration in the calculation of the coupling parameters to calculate whether the requirements are met, the pulse equivalent is accurate; check whether the machine part is damaged, the gear coupling is uniform , check whether there are periodical, regular failure phenomena, if any, check the key parts and give them exclusion.

Summary:

In addition to the above solutions, we can also start from the roots and select high-quality cutting fluids to help prevent machine tool failures, better ensure smooth processing, and improve cutting efficiency. It is recommended that professional companies choose the most suitable products based on the machine tool and processing conditions.


Subscribe to our email list
Sign up with your name and email to get the latest proway updates, exclusive access to promotions, sales events, pre-order sales & more!
Connect with Rolitone
Become our fan, follow us & subscribe for the latest updates and deals
QR Code
  • About Us
  • Products
  • RLT Lab
  • knowlwdge
  • Contact Us
  • Feedback
  • Case
  • Copyright © Rolitone technology Co.,Ltd. All Rights Reserved.