PEEK materials are commonly used to manufacture wafer carriers, electronic insulating diaphragms, and a variety of connecting devices, in addition to insulating films for wafer carriers, connectors, printed circuit boards, high-temperature connectors, and so on.
PEEK pure material performance is difficult to meet the different needs of different industry sectors, so in the special working environment needs to be modified PEEK, the main means of blending modification, copolymerization modification, composite enhancement modification, filler modification, nano-modification and surface modification and other technologies. Through the modification can increase the performance of PEEK in some aspects, such as wear resistance, impact strength, etc., thus expanding the scope of application of PEEK, reduce the cost of materials used, improve the processing performance of PEEK.
In some mechanical parts design manuals and mechanical manufacturing monographs, the surface roughness of mechanical parts and mechanical parts of the size of the relationship between the tolerance of the experience and the formula have a lot of introduction, and the list for readers to choose, but as long as the careful reading, it will be found that, although to take the exact same empirical formula, but the list of the value is not the same, and some of them there are big differences. This brings confusion to those who are not familiar with the situation. At the same time also increases their work in mechanical parts to select the surface roughness of the difficulties.
In the existing mechanical parts design manuals, the following three main types are reflected:
Type 1 is mainly used in precision machinery, with high requirements for the stability of the fit, requiring the parts to be used in the process or after many assemblies, the wear limit of the parts does not exceed 10% of the tolerance value of the part dimensions, which is mainly used in precision instruments, meters, precision gauge surfaces, friction surfaces of extremely important parts, such as the inner surface of the cylinder, the spindle necks of precision machine tools, the main journal of the coordinate boring machine, and so on.
The second category is mainly used in ordinary precision machinery, the stability of the fit requirements are high, the wear limit of the parts required to not exceed 25% of the size tolerance value of the parts, the requirements of a very good close contact surface, its main applications such as machine tools, tools, and rolling bearings with the surface, taper pin holes, and the relative movement of the contact surface of the higher speed, such as the sliding bearing with the surface, the gear gear tooth work surface, and so on.
Category 3 is mainly used in general-purpose machinery, mechanical parts are required to wear limit does not exceed 50% of the value of the size tolerance, no relative motion of the parts contact surface, such as box cover, sleeve, the requirements of the surface of the tightly fitting, keys and keyways of the working surface; the relative speed of motion is not high contact surfaces such as bracket holes, bushings, with the wheel axle hole of the working surface of the speed reducer and so on.
The processing performance of the material is mainly: casting, pressure processing, cutting, heat treatment and welding performance. The machining process performance of the good and bad directly affects the quality of parts, production efficiency and cost. Therefore, the process performance of the material is also an important basis for material selection.
(1) casting performance: generally refers to the low melting point, crystallization temperature range of small alloys have good casting performance. Such as: alloy eutectic composition casting.
(2) pressure processing performance: refers to the ability of steel to withstand hot and cold deformation. Cold deformation performance is a sign of good molding, processing surface quality is high, not easy to produce cracks; and hot deformation performance is a sign of good acceptance of the ability to heat deformation, high oxidation resistance, can be deformed by a wide range of temperatures and the tendency to thermal embrittlement is small.
(3) cutting performance: tool wear, power consumption and surface finish of the parts is to assess the metal material cutting performance of good and bad signs, but also a reasonable choice of materials is one of the important basis.
(4) weldability: a measure of the welding performance of the material is the strength of the weld zone is not lower than the base metal and does not produce cracks as a sign.
(5) heat treatment: refers to the behavior of steel in the heat treatment process.
Design of mechanical parts, not only should be made to meet the requirements of use, that is, with the required working capacity, but also to meet the production requirements, otherwise it may not be manufactured, or can be manufactured, but the labor and materials is very uneconomical. In specific production conditions, such as the design of mechanical parts easy to process and processing costs are very low, then such parts are known as a good process. The basic requirements of craftsmanship are:
(1) the blank selection of reasonable mechanical manufacturing in the blank preparation methods are: the direct use of profiles, casting, forging, stamping and welding. The choice of blanks and specific production technology conditions, generally depends on the production batch, material properties and processing possibilities.
(2) simple structure and reasonable design of the structural shape of the parts, police good use of the simplest surface (such as flat, cylindrical, spiral surface) and its combination, but also should try to minimize the number of machining surfaces and the minimum processing area.
(3) Specify the appropriate manufacturing accuracy and surface roughness parts processing costs increase with the increase in accuracy, especially in the case of higher accuracy, this increase is extremely ****. Therefore, high accuracy should not be pursued without adequate basis. Similarly, the surface roughness of the part should also be based on the actual needs of the matching surface, to make appropriate provisions.
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