Optimization of cutting parameters for plastic parts processed by end mills

When using end mills to process plastic parts, optimizing cutting parameters requires a comprehensive consideration of factors such as the characteristics of plastic materials, tool geometry parameters, and processing efficiency. The following is a specific analysis:

Tool materials and geometric parameters

Tool material: High-speed steel or hard alloy can be adopted.

Tool geometric parameters:

Front Angle: Usually 15°-25°. Due to the extremely small elastic modulus and large elastic recovery of plastic materials, in order to reduce the friction of the rear tool face, the rake Angle can be taken as 15°-18°.

Relief Angle: To reduce the friction of the rear tool face, it can be taken as 15°-18°.

Helix Angle: To control the chip removal direction, the helix Angle of the end mill can be taken as 20°-25°. The main deflection Angle Kr of the face milling cutter can be taken as 45°.

Chip groove: The chip groove of the milling cutter should be as large as possible to facilitate chip removal.

Cutting parameter optimization

Cutting speed: Under the premise that the cutting temperature does not exceed the softening temperature of the material and the occurrence of coating, the cutting speed VC should be as high as possible to improve the processing efficiency.

Feed rate: The appropriate feed rate should be determined based on specific processing requirements and the condition of the cutting tool. When the feed rate is too large, it will cause small chipping when the cutting teeth enter and exit. Therefore, the feed rate should be limited. This is because when the feed rate increases, the force acting on the unit length of the milling cutter edge will increase.

Cutting depth: When the cutting depth increases, the cutting resistance also increases, and the end mill is prone to deflection. Therefore, when the cutting depth is large, end mills with larger outer diameters and higher rigidity should be selected. At the same time, the cutting depth should not exceed the depth of the tool groove. If a deeper cutting is required, a tool with a larger diameter can be used. Always keep the ratio of the tool diameter to the cutting depth at 1:1. The maximum cutting width should not exceed two-thirds of the tool diameter.

Processing example parameters

High-speed steel end mills and three-sided edge face mills: Taking the milling of grooves with high-speed steel end mills as an example, if the tool durability T=40 minutes, the cutting depth ap=3mm, the feed rate per tooth f=0.10mm/z, and the milling width aa=30mm, the cutting speed v can be calculated through the formula.

High-speed steel Angle milling cutter: Taking the milling of phenolic paper-based laminated plastic with a high-speed steel Angle milling cutter as an example, if the tool durability T=30 minutes, the cutting depth ap=3mm, the feed rate per tooth fx=0.3mm/z, and the milling width le=125mm, the cutting speed v can be calculated.

High-speed steel cylindrical milling cutter: Taking the milling of a flat surface of phenolic adhesive laminated plastic with a high-speed steel cylindrical milling cutter as an example, if the tool durability T=60 minutes, the cutting depth a=3mm, the feed rate per tooth f=0.10mm/z, and the milling width aa=100mm, the cutting speed v can be calculated.

Hard alloy cylindrical milling cutters and face milling cutters: Taking the milling of phenolic paper-based pressed plastic with a hard alloy cylindrical milling cutter as an example, if the tool durability T=350min, the cutting width ac=2mm, the feed rate per tooth f=0.3mm/z, the milling width ao=145mm, and the tool material YG4, the cutting speed v can be calculated.