What Should Be Paid Attention To In Aluminum CNC Machining?

Aluminum precision parts and products are popular because of their light weight and exquisite appearance, and they are more and more widely used in industrial and daily necessities. With the continuous advancement of science and technology, people’s demand for product diversity is getting stronger and stronger. Therefore, the process requirements of aluminum alloy products are getting higher and higher, and the market demand is getting higher and higher. In order to meet people’s needs for the diversity and high quality of aluminum alloy shell products, aluminum alloy CNC machining manufacturers summarize the process skills during the processing and the problems that should be paid attention to in aluminum CNC machining.

1. Choose Suitable Machining Method

CNC cutting is a processing method that rationalizes cutting and is also a common process in aluminum precision machining. It uses end mills with multi-directional cutting functions, spiral cutting interpolation, and contour cutting interpolation. A small number of holes are processed by a small number of tools.

2. Ball End Mills Can Be Used With Spiral Interpolation To Continuously Process Taper Holes.

The ball end mills and spiral interpolation drills can be used for boring and chamfering. The end milling cutter cooperates with the contour cutting interpolation, which can perform semi-finish machining and precision parts machining on the holes. The end milling cutter used for thread processing can be used with spiral interpolation to process various threaded holes.

If high-efficiency aluminum alloy precision parts are processed for high-precision holes of any size, the tool interpolation function can be used. Especially when high-speed milling is used, the load on each tooth is relatively light. Therefore, the same coated carbide end mill can be used to perform high-speed and high-precision hole machining on a variety of materials to be processed.

In addition, it is necessary to master the processing technique and processing skills in the aluminum CNC machining.

3. Choose A Reasonable Amount Of Cutting

The staff can choose the cutting speed to be used according to the material to be processed, the hardness, the cutting state, the type of material, and the depth of cutting. These conditions are necessary to effectively reduce machine wear.

4. Choose The Right Tool.

Rake angle: Under the condition of maintaining the strength of the cutting edge, the rake angle should be appropriately selected to be larger. One side can grind a sharp edge, which can also reduce cutting deformation, make chip removal more smoothly, and reduce cutting force and cutting heat. Never use negative rake angle tools.

Relief angle: The size of the relief angle has a direct effect on the wear of the flank surface and the quality of the machined surface. Cutting thickness is an important condition for selecting the relief angle. During rough milling, due to the large feed rate, heavy cutting load, and large heat generation, good heat dissipation conditions of the tool are required. Therefore, the relief angle should be selected smaller. When finishing milling, the cutting edge is required to be sharp, to reduce the friction between the flank face and the machined surface, and to reduce the elastic deformation. Therefore, the relief angle should be selected larger.

Aluminum Machining

Helix angle: In order to make the milling smooth and reduce the milling force, the helix angle should be selected as large as possible.

Entering angle: Appropriately reducing the entering angle can effectively improve the heat dissipation conditions and reduce the average temperature of the processing area.

Reduce the number of teeth of the milling cutter and increase the chip space.

Due to the greater plasticity of the aluminum alloy material, the larger cutting deformation during machining, and a larger chip holding space, the bottom radius of the chip pocket should be larger and the number of teeth of the milling cutter should be smaller. For example, milling cutters below φ20mm use two teeth, and milling cutters with φ30-φ60mm are better to use three teeth to avoid deformation of thin-walled aluminum alloy parts caused by chip clogging.

Fine grinding teeth: The roughness value of the cutting edge of the teeth should be less than Ra=0.4um. Before using a new knife, you should lightly sharpen the front and back of the teeth with a fine oil stone to eliminate residual burrs and slight serrations when sharpening the teeth. In this way, not only the cutting heat can be reduced, but also the cutting deformation is relatively small.

Strictly control the wear standard of the tool: After the tool is worn, the surface roughness value of the workpiece increases, the cutting temperature rises, and the deformation of the workpiece increases. Therefore, in addition to the selection of tool materials with good wear resistance, the wear standard should not be greater than 0.2mm, otherwise it is easy to produce built-up edge. When cutting, the temperature of the workpiece should generally not exceed 100°C to prevent deformation.

5. Choose A Reasonable Fixture.

The parts must fully meet the needs of the machine to reduce unnecessary positioning errors, and special clamping tools must be selected.

6. Determine A Reasonable Processing Route.

Try to shorten the machining route as much as possible to reduce the wear and tear of the machine.

In high-speed cutting, due to the large machining allowance and intermittent cutting, the milling process often produces vibration, which affects the machining accuracy and surface roughness. Therefore, the CNC high-speed cutting process can generally be divided into: rough machining-semi-finish machining, clear corner machining, finishing and other processes.

For parts with high precision requirements, it is sometimes necessary to perform secondary semi-finishing and then finishing. After rough machining, the parts can be cooled naturally to eliminate internal stress caused by rough machining and reduce deformation. The margin left after rough machining should be greater than the amount of deformation-generally 1 -2mm. During finishing, the finishing surface of the part should maintain a uniform machining allowance, generally 0.2-0.5mm is appropriate, so that the tool is in a stable state during the machining process, which can greatly reduce the cutting deformation, obtain a good surface machining quality, and ensure the accuracy of the product.

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