What should be paid attention to in the processing of dust cover for precision rubber and plastic components?

The processing of the dust cover of precision rubber and plastic components needs to focus on five core links: material property adaptation, mold precision control, molding process optimization, size and performance guarantee, dust prevention and pollution control, so as to ensure the sealing, wear resistance and dimensional accuracy of the products. The specific precautions are as follows:

Material selection and pretreatment, matching dust-proof use scenarios.

Rubber and plastic materials should be selected according to the use environment: for industrial equipment (such as machine tools and robots), oil-resistant and wear-resistant nitrile rubber (NBR), fluororubber (FKM) or high-strength polyurethane (PU) are preferred; If used in electronic precision components, anti-static silica gel can be selected to avoid electrostatic adsorption of dust.

Dehumidification and drying shall be carried out before material processing: rubber materials shall be dried in an oven at 40-60℃ for 2-4 hours in advance, and the drying temperature of plastic particles (such as PA and PP) shall be 80-120℃, so as to prevent bubbles and shrinkage cavities from occurring in the molding process, which will affect the dustproof and sealing performance.

Avoid mixing materials with impurities: raw materials should be stored in sealed containers, and particulate impurities should be screened out before feeding, so as to prevent the surface from protruding after molding and damage the fit of dust cover.

Mold design and precision control determine the basic quality of products.

The machining accuracy of mold cavity and core should be controlled within * **±0.02mm** *, and the surface roughness Ra should be less than 0.8 μ m, so as to ensure the dimensional accuracy and surface smoothness of dust cover and avoid product edge burr and dimensional deviation caused by mold defects.

The mold should be provided with reasonable exhaust grooves (0.03-0.05mm in width and 0.1-0.2mm in depth), especially at the sealing lip and corner of the dust cover, so as to prevent the lack of materials and bubbles caused by poor exhaust during molding, which will affect the sealing and dust prevention effect.

Mold cooling system should be evenly distributed to avoid uneven shrinkage and warping deformation of products caused by excessive local temperature difference, and the cooling water temperature should be controlled at 20-30℃ to ensure the dimensional stability of products after demoulding.

Optimization of molding process parameters to adapt to the characteristics of rubber and plastic materials

Rubber molding: The curing temperature (150-180℃), curing time (adjusted according to the product thickness, generally 2-8min) and curing pressure (10-20MPa) need to be accurately controlled. If the temperature is too high, it will easily lead to the aging and brittleness of the material, and if the temperature is too low, the vulcanization will be incomplete, which will affect the elasticity and wear resistance of the dust cover. The pressure should be uniform to avoid uneven thickness of the sealing lip.

Plastic injection molding: the injection temperature should be controlled by stages (the front part of the barrel is lower than the back part), such as the injection temperature of PU material is 180-220℃, the injection pressure is 80-120MPa, the holding pressure is 50%-70% of the injection pressure, and the holding time is 3-5s to prevent the product from shrinking and sagging; Injection speed should not be too fast to avoid weld marks and reduce the tensile strength of dust cover.

When demoulding, soft demoulding tools (such as silicone scraper) should be used to avoid scratching the sealing lip of the product. At the same time, special demoulding agent (even in Bo Tu) should be sprayed on the mold to prevent the product from sticking and deforming.

Post-treatment and detection to ensure dust-proof performance up to standard.

Deburring treatment shall be carried out for the molded product: manual grinding (fine sandpaper) or freezing deburring process shall be adopted, with emphasis on the sealing lip and the edge of the opening to ensure that the edge is smooth and burr-free, so as to avoid scratching the equipment or affecting the sealing performance during installation.

Dimension detection: use the secondary imager and caliper to detect the key dimensions such as the inner diameter, outer diameter and sealing lip thickness of the dust cover to ensure that it meets the requirements of the drawings; At the same time, the warpage of the product should be detected, and the warpage should be ≤0.5mm/m to prevent it from being tightly attached to the equipment after installation.

Performance test: sampling for sealing test (pressure leak detection method) to ensure that the dust cover has no air leakage under rated pressure; Wear resistance test and aging resistance test (high and low temperature cycle, ultraviolet aging) were carried out to verify its durability in the use environment.

Production environment and packaging protection to avoid secondary pollution.

The processing workshop needs to be kept clean and dust-free. It is recommended to adopt a 10,000-class clean workshop. Operators should wear anti-static dust-free clothes and gloves to prevent dust from adhering to the product surface and affecting the dust-proof effect.

The finished products should be packaged separately in antistatic sealed bags to avoid deformation caused by stacking and extrusion. The product model and batch should be marked outside the package and stored in a dry and ventilated warehouse (temperature 15-25℃, humidity 40%-60%), away from corrosive substances such as oil, acid and alkali.