Suzhou Jiupeng Intelligent Introduction: What are the requirements for the development of plastic molds for injection molded parts in the field of home appliances?
The development of plastic molds for injection-molded parts in the field of household appliances needs to focus on the mass production requirements, appearance quality requirements, structural adaptability requirements and cost control objectives of household appliances. Combined with the diversity of injection-molded parts for household appliances (such as shells, liners, functional components, seals, etc.), mold development needs to meet the following core requirements:
Accurately match the structural and functional requirements of plastic parts
Injection molded parts for household appliances cover refrigerator door panels, washing machine inner cylinder, air conditioning shell, rice cooker liner bracket and other components. The structural complexity and stress characteristics of different components are very different, so the mold development needs targeted design. For exterior parts of household appliances (such as refrigerator panels and air-conditioning housings), the molds should be made of high-finish die core steel (such as S136 and NAK80) and polished by mirror to ensure that there are no defects such as flow marks, weld marks and shrinkage marks on the surface of plastic parts to meet the aesthetic requirements of household appliances; For structural load-bearing parts (such as the motor bracket of washing machine and the fixed bracket of air-conditioning compressor), the mold should be provided with reasonable reinforcing ribs and demoulding inclination to avoid deformation of plastic parts during demoulding, and at the same time, the gate position should be optimized to ensure uniform melt filling and improve the structural strength and stability of plastic parts; For sealed plastic parts (such as refrigerator door seal mold and washing machine seal mold), it is necessary to adopt high-precision parting surface design and wear-resistant sealing strip structure to prevent flash during injection molding and ensure the sealing performance of plastic parts. In addition, the mold needs to reserve the assembly positioning benchmark to ensure that the injection molded parts and other parts of household appliances (such as hardware and electronic components) are accurately adapted to avoid assembly jamming caused by dimensional deviation.
Meet the requirements of high efficiency and stability in mass production.
The household appliance industry generally has the characteristics of mass production and high beat, so the production efficiency and service life should be fully considered in mold development. First of all, the mold needs to adopt an efficient cooling system. According to the characteristics of uneven wall thickness of plastic parts of household appliances (such as thick edges and thin middle of refrigerator doors), a conformal cooling waterway is designed to ensure uniform cooling of plastic parts and shorten the molding cycle (usually the molding cycle of household appliances injection parts needs to be controlled at 30-60 seconds); Secondly, the mold should be equipped with a reliable demoulding mechanism. For large plastic parts (such as the inner cylinder mold of washing machine), a hydraulic ejection system can be used to ensure smooth ejection and avoid top injury of plastic parts. For small precision plastic parts (such as household appliance switch button mold), pin-point ejection can be used to reduce top marks. At the same time, wear-resistant and corrosion-resistant steel should be selected as the core components of the mold, and nitriding treatment or chromium plating should be carried out on the surface to prolong the service life of the mold (the service life of household appliances mold should be no less than 500,000 mold times, and some high-end molds should be more than 1 million mold times); The mold also needs to have a quick mold changing structure to meet the flexible production requirements of the home appliance production line, shorten the mold changing time and improve the overall efficiency of the production line.
Meet the environmental protection and compliance standards of home appliance industry.
Household appliances should meet the stringent environmental protection standards at home and abroad (such as RoHS, REACH, FDA, etc.), and mold development should follow up the compliance requirements simultaneously. On the one hand, environmental protection steel should be selected as the mold material to avoid harmful substances produced by mold surface treatment process (such as electroplating) from migrating to plastic parts; On the other hand, for food contact plastic parts of household appliances (such as rice cookers and drinking cups), the mold should be designed with no residual release agent, or a special food-grade demoulding system should be selected to prevent the release agent from polluting the plastic parts and ensure that the plastic parts meet the food contact safety standards. In addition, the adaptability of recycled materials should be considered in mold development. Some home appliance enterprises use recycled plastic raw materials to produce non-critical parts. The mold needs to optimize the runner design, reduce the flow resistance of recycled materials during injection molding, and reduce defects such as bubbles and impurities, so as to help the green manufacturing transformation of the home appliance industry.
Considering cost control and convenience of later maintenance.
The competition in home appliance industry is fierce, and the cost of mold development needs to be controlled on the premise of ensuring quality. When designing the mold, it is necessary to optimize the cavity layout and adopt a reasonable multi-cavity scheme (for example, the switch button mold of small household appliances can be designed with 16 cavities or 32 cavities) to reduce the mold sharing cost of single plastic parts; At the same time, simplify the mold structure, avoid excessively complicated slider and inclined top design, and reduce the processing difficulty and manufacturing cost of the mold. In addition, the mold should be easy to maintain, and the vulnerable parts of the mold (such as guide posts, guide sleeves and thimbles) should adopt standardized design to facilitate later replacement; The maintenance channel should be reserved for the mold, which is convenient for cleaning the carbon deposit in the exhaust groove and checking the wear of the cavity, reducing the maintenance cost of the mold and prolonging the effective service cycle of the mold.
