The road of dream building

Release time:

2023-06-27 15:03

With the continuous development of science and technology, metal parts are gradually replaced by engineering plastic parts in the chemical, electrical, electronic, mechanical, instrumentation and other industries. There are many processing methods for engineering plastic parts, and cutting workers are often used, but engineering plastics do not have a certain degree of standardization like metal processing. Therefore, it is necessary to explore and study the machining of various engineering plastics.

characteristics of engineering plastics machining:

Engineering plastics of various structures can be machined, but engineering plastics have some characteristics different from metals, such as low cutting shear strength, poor thermal conductivity, resilience, unevenness, abrasive action and easy cracking, etc. Attention must be paid during the machining process.

Cutting strength and thermal conductivity

The cutting force required for cutting engineering plastics is much smaller than that of metal materials, so a large amount of cutting should be used for cutting engineering plastics. However, the thermal conductivity of plastic is very poor. After increasing the amount of cutting, the heat in the processing area increases, and the heat dissipation through the plastic is very small, and the heat removal mainly depends on the tool. Due to the high heat, the cutting tool will be passivated by overheating, and the plastic will be coking or melting due to overheating, and eventually become waste. Therefore, it is necessary to limit the use of large cutting amount. The way to solve the contradiction is to use high-speed fine chip cutting method, and use compressed air cooling, use large rear angle cutters and cutters with sharp cutting edges and smooth rake surfaces.

Resilience and inhomogeneity

Engineering plastics have greater elasticity, so the size and geometry of the cutting process often have deviations. For example, the hole diameter of the drilling part is less than the nominal size, the section of the turning part is not round but elliptical, the quality of the milling plane is rough, and the size is not allowed.

The amount of cutting has a greater impact on resilience and non-uniformity. Take laminated plastics as an example: when the cutting speed is small and the cutting depth is large, the cut layered filler is dumped along the cutting direction and straightened again after cutting, thus causing the surface to be uneven or rough; due to the unevenness of the filler and resin, it will also cause the surface to be uneven or rough. If the cutting rate is high and the cutting depth is small, the layered filler can be quickly cut off before it is poured, the resilience can be avoided or reduced, and the part deformation and dimensional accuracy can also be improved.

Abrasive action and cracking

Many plastics, such as phenolic or amino resin-based reinforced plastics, have an abrasive effect. During the cutting process, the cutter will quickly become dull, which is much more worn than cutting other plastics of the same strength and hardness. The difficulty of cutting is related to the type of filler. The filler of glass fabric is more difficult to process. The other difficult to process are mineral filler, cotton filler, fiber fabric filler, and wood powder filler is easy to process.

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