The Effective Ways to Improve CNC Machining Accuracy

The automation and intelligence of CNC machines, have greatly reduced the impact of many human operations on machining accuracy. In actual production, we still improve CNC machining accuracy from the following aspects.

1. Adjust the process system.

• For the small quantity order, or sample production:

Proceed trial cutting method. Trial cutting- Measuring dimension- Adjust the engagement of the cutting edge- Proceed cutting- Trial cutting… Repeat this process, until achieve the required dimension.

• For the big quantity order, or bulk production:

Proceed adjustment method. The required dimension is obtained by adjusting the relative positions of the machine tool, jig, work-piece and tool in advance.

2. Reduce machining equipment error.

• Improve bearing rotation accuracy

– Choose high-precision rolling bearing.

– Choose high-precision multi-oil wedge dynamic pressure bearing.

– Choose high-precision hydrostatic bearing.

• Improve the accuracy of accessories with bearing

– Improve the machining accuracy of box support hole and spindle journal.

– Improve the machining accuracy of the mating surface with the bearing.

– Measure and adjust the radial run out range of corresponding parts to compensate or offset the error.

• Properly preload the rolling bearing

– Eliminate gaps.

– Increase bearing stiffness.

– Average rolling element error.

– The spindle rotation accuracy won’t be reflected on the work-piece.

3. Reduce the transmission error of the transmission chain.

• The number of transmission pieces is small, the transmission chain is short, and the transmission accuracy is high
• Reduce speed transmission, the closer the transmission pair is to the end, the smaller the transmission ratio should be
• The accuracy of the end pieces should be higher than other transmission parts

4. Reduce machining tooling wear

• The tool must be re-sharpened before the tool size wear reaches the sharp wear stage
• Choose special cutting oil for full lubrication
• The tool material should meet the process requirements

5. Reduce the forced deformation of the process system

• Improve the rigidity of the system, especially the rigidity of the weak links in the process system
• Reduce the load and its changes

6. Reduce the thermal deformation of the process system

• Reduce the heat generation of the heat source and isolate the heat source
• Equilibrium temperature field
• Use reasonable machine component structure and assembly standards
• Accelerate to heat transfer equilibrium
• Control the ambient temperature

7. Reduce residual stress

• Increase the heat treatment process to eliminate internal stress

Reasonably arrange the process