Key points of the process for machining aluminum alloy door and window profiles with end mills

When using end mills to process aluminum alloy door and window profiles, attention should be paid to key process points such as tool selection, cutting parameter setting, fixture choice, and processing route planning. The following is a specific analysis:

Tool selection

Material selection: For end mills, tool materials suitable for aluminum alloys should be chosen. Common ones include carbide and high-speed steel (HSS). Hard alloy cutting tools have high hardness and wear resistance, and are suitable for high-speed cutting. High-speed steel cutting tools have better toughness and heat resistance, and are suitable for some processing scenarios where high toughness of the cutting tools is required.

Coating selection: Consider choosing coatings with good wear resistance and heat dissipation, such as TiAlN or TiCN, to enhance tool life. These coatings can reduce the friction between the tool and the workpiece, lower the cutting temperature, and thereby extend the service life of the tool.

Number of cutting edges and edge type: Considering the cutting characteristics of aluminum alloys, milling cutters with a larger number of cutting edges are usually selected to enhance cutting efficiency. Common edge types include ball-end tools and flat-end tools. Select the appropriate edge type based on different processing requirements. For instance, when processing some curved or complex-shaped profiles, ball-end mills might be more suitable. When processing flat surfaces or simple grooves, flat-bottomed end mills may be more effective.

Cutting parameter setting

Cutting speed: Adjust the cutting speed of the tool according to the hardness of the aluminum alloy to ensure operation within the optimal cutting range. Generally speaking, the cutting speed of aluminum alloy is relatively high, but the specific cutting speed still needs to be adjusted according to factors such as the material of the tool, coating, and the number of cutting edges.

Feed rate: Adjust the feed rate appropriately to balance the processing efficiency and tool life. Excessive feed rate may lead to accelerated tool wear and a decline in the quality of the machined surface. A feed rate that is too slow will reduce the processing efficiency.

Cutting depth: According to the workpiece requirements and tool performance, the cutting depth should be reasonably selected to avoid excessive tool wear. When processing aluminum alloy door and window profiles, the cutting depth should not be too large to avoid generating excessive cutting force and cutting heat, which may cause workpiece deformation or tool damage.

Fixture selection

Positioning accuracy: The parts must fully meet the requirements of the machine to reduce unnecessary positioning errors. Special clamping tools should be selected to ensure that the profiles can be stably fixed during the processing, avoiding the impact on processing accuracy due to vibration or displacement.

Uniform clamping force: When processing thin-walled and thin plate workpieces, it is best to use vacuum suction cups to obtain a evenly distributed clamping force. Processing with smaller cutting parameters can effectively prevent the workpiece from deforming.

Processing route planning

The division of processing procedures: CNC high-speed cutting processing can generally be divided into rough machining, semi-finish machining, corner cleaning, finish machining and other procedures. For parts that require high precision, secondary semi-finishing may be necessary before finishing. After rough machining, the parts cool naturally to eliminate internal stress and reduce deformation. The allowance left after rough machining should be greater than the deformation (generally 1-2mm). During the finish machining process, the finish machined surface of the part should maintain a uniform machining tolerance, usually 0.2-0.5mm is appropriate, to keep the tool stable during the machining process, reduce cutting deformation and ensure product accuracy.

Cutting parameter setting

Cutting speed: Adjust the cutting speed of the tool according to the hardness of the aluminum alloy to ensure it operates within the optimal cutting range. Higher cutting speeds can enhance processing efficiency, but excessively high speeds may lead to accelerated tool wear. A balance needs to be struck between efficiency and tool life.

Feed rate: Adjust the feed rate appropriately to balance the processing efficiency and tool life. Too fast a feed rate may lead to excessive tool load, while too slow a rate reduces production efficiency. The optimal parameters need to be determined through experiments.

Cutting depth: Select the cutting depth reasonably based on the workpiece requirements and tool performance to avoid excessive tool wear. The reasonable range of cutting depth needs to be determined through process tests.

Fixture selection

Vacuum clamping system: The use of a high-tech vacuum clamping system can approach the ideal environment for precision machining. This system is composed of a vacuum adsorption fixture dedicated to the heat conduction frame and a vacuum pump. After rough machining, the allowance is reserved on both sides of the deep groove and the inner frame surface. During fine machining, the adsorption surface of the fixture is kept in close contact with the installed bottom surface of the fixture, and a deformation-free clamping force working environment is achieved through fine-tuning with nuts.

General fixture selection principles: The parts must fully meet the needs of the machine to reduce unnecessary positioning errors, and special clamping tools should be selected. For thin-walled and thin plate workpieces, it is best to use vacuum suction cups to obtain evenly distributed clamping force, and then process with smaller cutting parameters to prevent workpiece deformation.

Processing route planning

Processing route optimization: Try to keep the processing route as short as possible to reduce machine wear. In high-speed cutting, the machining allowance is large and the cutting is intermittent. During the milling machine’s processing, vibration occurs, which affects the machining accuracy and surface roughness. Therefore, CNC high-speed cutting processing can generally be divided into rough machining, semi-finish machining, corner cleaning, finish machining and other processes. For parts that require high precision, secondary semi-finishing may be necessary before finishing.

Process allowance control: After rough machining, the parts are naturally cooled to eliminate the internal stress generated by rough machining and reduce deformation. The allowance left after rough machining should be greater than the deformation (generally 1-2mm). During the finish machining process, the finish machined surface of the part should maintain a uniform machining tolerance, usually 0.2-0.5mm is appropriate, to keep the tool stable during the machining process, significantly reduce cutting deformation, obtain good surface machining quality, and ensure product accuracy.