Use Of Plastic Molds

Precautions for plastic mold assembly: Different types of plastic molds and different types of molding plastics (the same mold) have different assembly methods due to different requirements for start and accuracy. Therefore, the assembly drawings and parts drawings should be carefully studied and analyzed before assembly. Determine the assembly benchmark by understanding the functions, characteristics and technical requirements of each part. After careful assembly, all the quality indicators of the product are reached, including the accuracy of the mold movement and other technical requirements in use. Assembly datum Assembly datum refers to the datum used to determine the relative position of parts or components in the product during the assembly process. It can be roughly divided into: core, cavity, insert and other main working parts are used as the assembly reference; the base surface of the guide post and guide sleeve or the mold template side is the assembly reference surface.

Assembly accuracy Assembly accuracy refers to geometric accuracy, machining accuracy, movement accuracy, etc. After the equipment is assembled. The assembly accuracy of the plastic mold includes: the mutual accuracy of various parts, such as distance dimensional accuracy, coaxiality, equality, perpendicularity, etc. Relative motion accuracy, such as transmission accuracy, linear motion and rotational motion accuracy; 3) Coordination accuracy and contact accuracy, such as matching clearance and interference contact conditions; The wall thickness of plastic molded parts. When making a new mold, the wall thickness of the molded part should be at the lower limit of the size.

The principle of plastic mold repair: repair the demoulding slope. In principle, the size of the cavity must be within the tolerance range of the workpiece size, and the size of the core must be within the tolerance range of the workpiece size; the fillet radius, cavity and core should be smaller and smaller; When there is a horizontal parting surface and a vertical parting surface, there should be a slight gap when the horizontal parting surface is in contact with the vertical parting surface during calibration. Small molds only need to be painted red and contact each other. The gap between the large molds is about 0.02mm; 4) For molds that are closed with a bevel, after the bevel is closed, there should be a gap of 0.02-0.03 mm on the parting surface; the repair surface is round The connection between the arc and the straight line should be smooth, the surface should not have dents, and the file pattern should be consistent with the opening direction.

Injection molding of plastic molds is a processing method for mass production of parts with complex shapes. Specifically, a material melted by heating is injected into a mold cavity by high pressure, and a molded product is obtained after cooling and solidification. Plastic molds are important process equipment for the production of various industrial products. With the rapid development of the plastics industry and the popularization and application of plastic products in aviation, aerospace, electronics, machinery, ships, automobiles and other fields, products have higher and higher requirements for molds, and traditional mold design methods can no longer meet today's requirements. Compared with traditional mold design, computer-aided engineering (CAE) technology can not only increase productivity and ensure product quality, but also reduce costs and labor. In the processing of injection molds, various CNC machining is used, and the most widely used are CNC milling and machining centers. The application of CNC wire cutting and CNC EDM in the CNC machining of molds is also very common. Wire cutting is mainly used for processing various straight-wall molds, such as concave and convex molds in stamping, inserts and sliders in injection molds, and electrodes for EDM. For high-hardness mold parts, machining cannot be performed, and EDM is often used. In addition, EDM is also used for sharp corners, deep cavities and narrow grooves of mold cavities.