In the processing classification in the manufacturing industry, similar quality inspection standards are not allowed, because a similar product may not have much impact, but what if a bunch of similar products are combined? Then the shortcomings of each product will be infinitely magnified until serious accidents are caused. The problem of workpiece deformation during processing has always been a headache for workers. So, for the problem of workpiece deformation during processing, can we have any effective solutions or countermeasures?
1. The influence of product structure and material on deformation
The size of the product deformation is directly proportional to the product shape, wall thickness, aspect ratio, material stability and rigidity. Therefore, designers must consider the influence of these factors on the deformation of the product during processing when designing products. Especially the structure of large-scale products should be carefully considered. At the same time, the hardness and material of the product blank must be controlled before processing to ensure that the quality of the blank meets the processing standards and reduce the impact of the product itself.
2. Deformation caused by product clamping
When using a fixture to clamp a workpiece, we should choose the most correct clamping point, and adjust the clamping force according to the position of the clamped workpiece. Make the clamping point and the support point as consistent as possible, so that the clamping force can be perfectly applied to the support point, and the clamping position should be as close as possible to the processing surface, and the force should be uniform so that the workpiece will not be deformed by the clamp.
Increasing product rigidity is also a very effective way to solve the clamping deformation. For thin-walled products, due to its own shape and structural characteristics, its rigidity is low, so it is easy to deform under the action of clamping.
Enlarging the contact area between the fixture and the product can also effectively reduce the clamping deformation of the workpiece. When processing thin-walled workpieces, you can use a large number of elastic press plates that increase the force area; when turning thin-walled workpieces, you can use elastic mandrels and full-arc jaws that increase the contact area; these elastic clamps can be used for The load-bearing clamping force is very helpful and can effectively avoid the deformation of the workpiece.
3. Deformation during parts processing
Due to the influence of cutting force during the machining process, product parts will inevitably produce elastic deformation in the direction of the force, which is what we commonly call the phenomenon of giving up the knife. We should pay special attention to and avoid the phenomenon of letting the knife occur. This requires us to have stricter requirements on the tools during finishing, for example, the tools should be sharp. When the tool is sharp, in addition to reducing the frictional resistance of the tool and the workpiece during processing, it can also improve the heat dissipation capacity of the tool and reduce the residual internal stress on the part.
Use the single-edge chip method to process large planes of thin-walled parts. If in order to reduce the resistance during cutting, you can choose a tool with a larger entering angle and rake angle. The cutting tool of this structure is relatively light and fast, which can reduce the processing deformation of thin-walled parts, which has been proved in actual use. However, if the rake angle of the tool is too large, the strength of the tool will be weakened, the heat dissipation capacity of the tool will also become poor, and the wear will also be accelerated.
The heat generated in the cutting process is extremely easy to deform the workpiece. For this situation, we can choose high-speed cutting. In the high-speed cutting process, the waste chips generated will be removed in a very short time, and the heat generated will also be taken away with the waste chips, which can greatly reduce the thermal deformation of the workpiece. In addition, in high-speed cutting, the softening of the cutting layer material can be reduced, which is of great help in reducing part deformation and ensuring part size and shape accuracy. In addition, in the machining process, the cutting fluid also plays a great role in reducing the heat. The selection of a reasonable and good cutting fluid has an extraordinary effect on improving the life of the tool and the accuracy and quality of the machined surface.
In order to ensure the accuracy of the parts, a reasonable cutting amount should be used. For thin-walled parts that require relatively high machining accuracy, we should usually use symmetrical machining so that the two opposite faces can be balanced in force, so that the processed workpiece will be flat. If the cutting amount is unreasonable or too large, the workpiece will be unbalanced in force during processing, resulting in deformation.
To sum up, for easily deformable workpieces, corresponding countermeasures must be adopted in the blank and processing technology. It is necessary to analyze different situations and find a suitable process route. Of course, the above method only further reduces the deformation of the workpiece. If you want to obtain a more precise workpiece, you still need to continue learning, discussion and research.