Strategies to Improve CNC Machining Quality for Thin-Walled Parts

Thin-walled parts are widely used in auto parts manufacturing and other industries. High-efficiency, high-precision CNC cutting of thin-walled parts is the cornerstone of modern high-tech industry, highlighting the core competitiveness of the manufacturing industry, while reflecting the manufacturing level of a country. In-depth study of thin-walled parts of the CNC machining process and forming process, reasonable design of machining methods, can effectively solve the processing of thin-walled parts of the problem, to ensure the accuracy and quality of the product.

1. Enhancing CNC Machine Performance

The use of CNC machine tools cutting thin-walled parts, must solve the two major problems of clamping position and manufacturing accuracy. On the one hand, to determine the clamping position. When using CNC machine tools for workpiece cutting, not only to ensure the reliability of workpiece clamping, but also to ensure the accuracy of thin-walled parts. If the workpiece is too thin, the three-jaw chuck can not be installed.

In the CNC programming of precision thin-walled parts, it is necessary to analyse the position of the workpiece and clamping equipment in detail, explore the size and direction of the external load that may lead to deformation of the workpiece, and design special fixtures suitable for machining according to the specific requirements of machining.

When the rigidity of the workpiece is insufficient, the force is large, easy to produce vibration, can be used to temporarily increase the thickness of the wall of the part, such as in the hollow part of the injection of gypsum, alum or rosin and other substances, to be processed and then remove them.

2. Determining Reasonable Cutting Parameters and Technical Solutions

In the process of CNC machining and manufacturing services of thin-walled parts, according to the workpiece material, structure and processing needs, select the cutting speed, feed rate, feed volume and so on. Under the premise of ensuring machining accuracy, the vibration and resonance of the tool should be reduced as much as possible, taking into account the material of the tool and the quality of the cutting edge. In order to ensure the accuracy and quality of the part, the material characteristics of the workpiece and tool stiffness should also be considered.

Technology path is the production process is broken down into multiple steps, and the specific process parameters, tools, equipment, etc. for each step is described. For the CNC machining of thin-walled parts, it is necessary to select the appropriate machining path according to its complexity and difficulty, so that the production efficiency and quality can be optimised. In the development of technical routes, pay attention to the intermediate processes in production, and carefully analyse the problems in production.

3. Ensuring Dimensional Accuracy

Thin-walled parts with poor rigidity, easy to deform after the force in the CNC machining process, dimensional accuracy is difficult to ensure. Thin-walled parts machining generally use internal clamping, external clamping and overall fixture clamping, the process route usually includes positioning with internal clamping, external clamping and overall fixture clamping.

Internal clamping can play a role in supporting, positioning and fixing the parts. The fixture has good rigidity and can effectively eliminate vibration during the cutting process. External clamping is mainly used to control the deformation of the parts in the machining process and to ensure the accuracy of the parts. The force situation when the parts are externally clamped is different from that of internally clamped parts. The external clamping fixture exerts pressure on the workpiece, while the internal clamping fixture mainly relies on the mass of the fixture itself to act on the workpiece. For this reason, in the machining process, we should reasonably arrange the process, select the appropriate processing parameters to ensure the positioning accuracy of the external clamping.

For example, the first processing of the inner hole and the outer circle, and then process the inner surface, so as to ensure the accuracy of the outer circle, but also to make the inner hole and the outer circle does not deform. In the process of CNC machine tool machining, under the action of the self-weight of the parts and the cutting force applied, the parts will be deformed, thus affecting the dimensional accuracy, so it is necessary to increase the positioning and support devices, fixtures and tools.

4. Preventing Deformation and Vibration

To prevent deformation and vibration of thin-walled parts, the following measures can be taken. On the one hand, choose a reasonable amount of cutting. When machining thin-walled parts, should try to avoid generating large vibration, reduce the impact on the accuracy of the parts, surface roughness and service life, specifically through the selection of a small depth of cut, small feed, low cutting speed method to achieve. On the other hand, the use of clamping when processing thin-walled parts, so that the workpiece and tool in a relatively stable state, to prevent deformation and vibration of the workpiece. The clamping force should generally not be greater than the strength limit of the part material.

5. Optimizing and Adjusting Clamping Schemes for CNC Machining of Thin-Walled Parts

To effectively optimize and adjust the clamping scheme for CNC machining of thin-walled parts in the CNC machining process, and improve the internal load and clamping force of thin-walled parts. For certain large thin-walled parts with less rigidity, it is necessary to improve its support bearing force to ensure that the machining strength of thin-walled parts is improved.

Here it is necessary to consider the use of clamping cards to directly assist the clamping process, and the detailed data therein, analyse the content of the workpiece based on different stress and deformation, optimize the clamping ratio of the thin-walled parts, and form an auxiliary clamping bracket and retaining ring. Throughout the process, it is necessary to ensure that the level of stress support for thin-walled parts processing is increased and the clamping programme is optimised.