Top 7 Tips to CNC machining milling Accuracy

December 10, 2021

Introduction of CNC machining milling

If you have been to a CNC machining milling workshop. And you must have seen how a CNC machine works. Therefore, who have never been in contact, it is difficult to imagine a CNC machine performing a certain machining process.

But that doesn't mean that if you haven't seen a CNC machine. People never seen it machined in person, you can't know about it. In the age of technology with easy information sharing in a flat world. And you can watch videos of CNC machines in action and machining quickly. And realistically on the Internet. It's also a useful way of accessing information.

However, when you carefully read this article of ours, you are also accessing very interesting knowledge, in a different way.

CNC machining milling

What is a CNC machining milling?

A CNC machine, also known as a machine tool, is a processing machine to create molds or create details, components, and spare parts to build other machines. Common CNC machining methods include: milling, turning, wire cutting, cutting, grinding, reaming, boring, drilling, etc.

It is also the names of CNC machining milling according to the above processing method. The CNC machine works under the control of the G-code generated based on the drawing of the CAM program. The G-code contains information to tell the machine how to make the exact part you designed.

Process for CNC machining milling to work

First, full drawings are making with CAD software (computer aided design software) such as PTC Creo, NX, Catia, Solid works, inventor, etc., then the program is included. postprocessor converts it to G-Code (code that Machine can understand)

The G-code passed to the CNC Machine controls all the machine's features.

  • such as coordination
  • Setting position
  • and cutting speed
  • and feed.

The operator then performs checks to ensure that the code is error-free to ensure smooth CNC machining milling afterwards.

CNC machining milling has good accuracy and consistency

This gives very good accuracy and consistency, and the machine can make quite complex shapes and surfaces that are difficult to handle with conventional machining.

In traditional methods, these machines are run by operators who are experts. Most jobs need to be precisely machined, and the operator must be skilled enough to carry out the high-precision jobs.

But in CNC machines, the role of the operator is less. The operator simply provides the instruction program in the computer, loads the necessary tools in the machine and the rest of the work is done automatically by the computer.

The computer directs the machine tool to perform various CNC machining milling operations according to the instruction program provided by the operator. This process is very fast, safe and accurate.

Experience is must to operate CNC machining milling

With simple machine parts and professional machine operators. The G-code and M-code segments is easy to prepare manually by the operator directly by entering commands on the control panel's keypad.

Basically, the CNC cutting tool is fed into a spindle either vertically or horizontally. And the workpiece is held on the machine table by a vise or jigs, JIG for machining. Therefore, the rotary motion is adopted by the main shaft and the feeding motion with feed is adopted by the movement of the table.

CNC machining milling axes

The movement of these auxiliary axes is making by combining multiple simultaneous movements, translation and rotation of the table and the main shaft.

Thin-walled parts are widely common in many fields due to their light weight, material saving and compact structure. But to CNC machining milling thin-walled parts is relatively difficult, as it is easy to deform during turning due to its poor stiffness and strength, making it difficult to maintain good machining quality.

CNC machining milling 2021

CNC machining milling how to perform

For this reason, combined with many years of work experience, we will analyze and discuss in depth how to perform CNC turning work for thin-walled parts. The content will include how to clamp thin-walled parts, reasonable in the selection of cutting tools, selection of cutting parameters, selection of cutting fluids.

Tips to improve machining accuracy of thin-walled parts on CNC lathes.

Before starting the topic, we should first understand the factors that cause thin-walled parts to deform:

Force – Due to the thin wall of the workpiece, it is easy to produce deformation under the clamping force, affecting the dimensional accuracy and shape accuracy of the workpiece.

Heat – Since the workpiece is thinner, thermal cutting will cause thermal deformation and make the workpiece size difficult to control.

Vibration – Under the action of cutting force (especially radial shear), it is easy to produce vibration and deformation, affecting the dimensional accuracy, shape, position accuracy and surface roughness of the machine. Embryo.

1. Reasonable selection of clamping methods

If the ordinary clamping method is common to CNC machining milling thin-walled parts, it will produce large deformation and can ensure the machining accuracy. Therefore, for thin-walled parts, the clamping method is usually as follows:

Increase the supporting surface and clamping area of ​​the workpiece, or increase the clamping point to make the force uniform, and reduce the clamping stress and contact stress. If necessary, add supporting jigs to increase the rigidity of the workpiece. But this method has limitations in application and will cause waste of materials.

How to reduce or homogenize the deformation

Increase the clamping point or area to reduce or homogenize the deformation of the parts by increasing the clamping point or area. For example: use special claws or open transition ring clamps. Use a liquid plastic self-centering chuck or a spring chuck clamp. Using force transfer clamps, etc.

  1. Reasonable selection of cutting parameters when turning CNC

When CNC turning thin-confine parts with high precision, symmetrical processing is often apply to balance the relative stresses. Moreover, on the both sides and achieve a stable state, and the workpiece is smooth after machining. When a process has a large amount of shear again, the stress is easy to balance.

Conclusion

  • For thin-walled parts requiring
  • high precision
  • roughing
  • semi-finishing
  • and fine machining are optional.

Separation of roughing, semi-finishing and fine machining can avoid all kinds of deformation caused by roughing, including elastic deformation caused by clamping force, thermal deformation caused by thermal shearing and deformation. form due to redistribution of internal stress after roughing. When roughing, the feedback and feed is large.

Loading