The bottom box is divided into dark and open. The hidden bottom box of the 86 series wall switch and socket wall switch is 86 mm, and the open bottom box is 77 mm. 118 series product bottom box and 120 series product bottom box have common, can be used with each other. -- -- -- < a href = "http://www.globalgd.com/" > < strong > saa certification < / strong > < / a > < / span > < / div >
(1) The composition of the wall switch: The wall switch is mainly composed of several components such as the panel (frame), the warping plate, the bracket, the base, and the functional parts.
(2) The composition of multi-functional socket: multi-functional socket mainly to the panel, spring plate, functional parts, protection door and other components. Constitute.
Material
(1) Panel: The general selection of PC material (polycarbonate), PC material is also called bulletproof glue, impact resistance, high temperature resistance, not easy to change color characteristics for the control of electrical switch is very important. Poor panels use general ABS material or other recycled materials, the elasticity is not too good, easy to crisp.
(2) Base: Adopt flame-retardant pc material, smell no odor, after burning with a lighter, there will be no flame, and white ash powder will be produced after burning. Poor quality brands smell smell, after burning the smell is more pungent, there is a certain flame when burning with a lighter, after extinguishing there is a lot of bubble on the base.
(3) Wall switch function parts: mainly reflected in the selected materials, the internal copper parts choose tin-phosphorus bronze, copper parts to meet the national standard weight, there are three main contacts, silver nickel alloy, silver cadmium alloy and sterling silver, nuts and card pads are made of brass materials.
(4) Multi-functional socket parts: The main selection of high-strength tin-phosphorus bronze copper sheet, continuous insertion and removal 5000 times will not be a problem.
(1) PC material
Drying of resin
The air entering the hopper first removes water in the dehumidifier cylinder equipped with many small molecular sieves. The blower forces the wet air through the dehumidifier cylinder, and the water in the air is absorbed by the dehumidifier to reduce the dew point of the air. The dry air after dehumidification is heated by the heater, and then the plastic particles in the hopper are heated and dried, so that the water in the plastic particles migrates into the air, thereby establishing a balance. The wet air is recycled, first through a filter to filter any fine particles or contaminants in the air, and then returned to the dehumidifier cylinder and heater for recycling. Dehumidifier water absorption saturation must be activated regularly to ensure the best drying results, most drying systems use two dehumidifier cylinders automatically alternate activation, thus ensuring continuous drying.
After drying, the charge particles will be transported from the dryer to the machine hopper, it should be noted that during this process, the material should not come into contact with water. In other words, dry and hot air should be used in the transportation process. For the use of a central feed dryer, the machine hopper should only hold a small amount of material or use a drying hopper to avoid reabsorption of water by the dry material when production stops. Special attention should be paid to the tightness of the conveying pipe to avoid the suction of wet air into the material conveying system. The hygroscopicity of polycarbonate resin depends on several factors: climatic conditions or the moisture content of the air, the temperature of the ambient air and the plastic particles, and the time the plastic is exposed to the wet air will affect the water content of the plastic particles.
To achieve the best results, special attention must be paid to the basic injection molding process parameters: Melting temperature, injection pressure, holding pressure, injection speed, back pressure, mold temperature, screw speed and withdrawal, and clamping force, etc., for a variety of different injection or injection molding machines, adjusting each process parameter and finding a balance between them is the key to meet the reduction of cycle time and meet the quality requirements of the disc.
(2) PC material characteristics and injection molding process
PC excellent performance, high transparency, good impact toughness, creep resistance, the use of a wide temperature range, PC process characteristics are: melt viscosity to shear rate sensitivity is small, and temperature sensitivity is large, no obvious melting point, high melt viscosity, high temperature resin hydrolysis, products easy to crack. In view of these characteristics, we should pay special attention to different treatment: to increase the fluidity of the melt, not by increasing the injection pressure, but by increasing the injection temperature. It is required that the flow path and gate of the mold be short and thick to reduce the pressure loss of the fluid, and at the same time, the injection pressure should be higher. The resin needs to be fully dried before forming and processing, so that its water content is controlled below 0.02%, in addition, thermal insulation measures should be taken during the processing of the resin to prevent re-moisture absorption. Not only a reasonable product design is needed, but also a correct grasp of the molding process, such as increasing the mold temperature and post-processing the product, which can reduce or eliminate internal stress. Adjust the process parameters in time according to the different conditions of the product.
Molding process
1. The injection temperature must be integrated with the shape, size and mold structure of the product. Product performance, requirements and other aspects of the situation to be considered before making. Generally in the molding selection temperature between 270~320℃, too high material temperature such as more than 340℃, PC will appear decomposition, product color darkening, surface silver wire, filaments, black spots, bubbles and other defects, while the physical and mechanical properties are also significantly reduced.
2, the injection pressure has a certain impact on the physical and mechanical properties of PC products, internal stress, molding shrinkage, etc., has a greater impact on the appearance and release of the product, too low or too high injection pressure will cause some defects in the product, the general injection pressure is controlled between 80-120MPa, for thin-walled, long process, complex shape, small gate products, In order to overcome the resistance of melt flow and fill the mold cavity in time, a higher injection pressure (120-145MPa) is selected. To obtain a complete and smooth surface of the product.
3, the size of the holding pressure and the length of the holding pressure and the length of the holding time have a greater impact on the internal stress of PC products, the holding pressure is too small, the feeding effect is small, the vacuum bubble or the surface of the concave, the holding pressure is too large, and the internal stress around the gate is easy to produce a large, in the actual processing, often with high material temperature, low holding pressure method to solve. The selection of pressure holding time should depend on the thickness of the product, the size of the gate, the mold temperature, etc. Generally, small and thin products do not need a long pressure holding time, on the contrary, large and thick products should have a longer pressure holding time. The length of the holding time can be determined by the test of the sealing time of the gate.
4, the injection speed has no significant effect on the performance of PC products, in addition to thin-wall, small gate, deep hole, long process products, generally use medium or slow processing, it is best to multi-stage injection, generally use slow-fast-slow multi-stage injection method.
5, the mold temperature is generally controlled at 80-100 ° C, for complex shapes, thinner, higher requirements of the product, can also be increased to 100-120 ° C, but can not exceed the mold thermal deformation temperature.
6, screw speed and back pressure due to the large viscosity of PC melt, from the favorable plasticization, favorable exhaust, favorable maintenance of the plastic machine, to prevent the screw load is too large
