Structure of printer cover plastic part is shown in Figure 1. Its top view has a "convex" shape, width of convex position is 99mm, maximum external dimension is 296mm * 173mm, wall thickness is 2.5mm, and plastic part material is ABS.
Tag: mold parts
In recent years, with rapid development of 3D printing technology, great progress has been made in molding manufacturing applications, printing material development and technology at home and abroad. Metal 3D printing technology has been widely used in cutting-edge fields such as aviation, aerospace and medical care. At present, use of laser 3D printing technology to directly and rapidly manufacture molds has not been widely used in enterprises in China. However, a few companies have tried to use 3D printing technology to print mold parts to realize complex internal conformal cooling water channels that cannot be processed by traditional processes (see figure 1) to improve cooling uniformity and efficiency of precision molds.
Figure 1 shows shield spring, part material is QBeMg1.9 beryllium bronze plate, plate thickness is 0.15 mm, surface of formed part is required to be free of pits, steps, burrs, deformation, cracks and other defects, production batch is not large. In order to save manufacturing costs, stamping and forming are carried out in different steps.
Figure 1 shows a sliding part in an electronic product, which is composed of an iron part and a plastic part. TIron part is made of stainless steel W304 to support and connect other parts; plastic part is made of polyoxymethylene POM 500P. It is main part of inner chute, which acts as a sliding guide rail, allowing parts to slide along guide rail to realize reciprocating movement of parts. The overall size of part is about 23 mm*5 mm*2 mm, and inner chute is high polished SPI A3. Effect of high polishing makes surface of contact surface smooth and reduces frictional resistance, so that part slides smoothly.
Arc-shaped base assembly is a 1/3 ring structure, diameter of outer ring is φ125mm, diameter of inner ring is φ112mm, maximum wall thickness is 6.5mm, minimum wall thickness is 2.5mm, thickness of the entire base is 5mm, there are 2 metal shrapnel embedded in the middle, 3 screw holes are evenly distributed in thickness direction for later installation and fixation, material is PA66, including 33 %glass fiber. From shape and structure of plastic part, it can be seen that due to change of wall thickness and open 1/3 circle structure, the biggest difficulty in injection molding lies in control of its warpage deformation, followed by positioning of metal shrapnel in-mold injection molding.
Multiple different plastic parts formed in same pair of molds are called family molds. Advantages are that it can improve utilization rate of molds, reduce number of molds, and reduce mold manufacturing costs. Points to pay attention to when designing family molds: ①When using one pair of molds for injection molding of plastic parts with large differences in volume, if a common runner gating system is used, a runner balance design needs to be carried out; ②Design of demolding mechanism of molded plastic parts should be set by the overall method to save space of mold base; ③Cavity plate and core should be closed and positioned to ensure accuracy of mold closed positioning. This article introduces same mold injection molding of a complete set of plastic parts for a self-generating fitness bicycle fork seat, which can provide a reference for molding of similar complete sets of plastic parts.
When designing a plastic mold, after mold structure is determined, each part of mold can be designed in detail, that is, size of each mold plate and parts, size of cavity and core, etc. At this time, main design parameters related to material shrinkage will be involved. Therefore, size of each part of cavity can be determined only by mastering shrinkage rate of molded plastic. Even if selected mold structure is correct, but parameters used are not correct, it is impossible to produce qualified plastic parts.
With development of automobile industry, consumers have higher and higher requirements for appearance quality of automobiles. One of important functions of automobile plastic parts is surface decoration. Therefore, surface quality requirements of automobile plastic parts are more stringent. Position of plastic part parting line is one of important factors that affect surface quality. A reasonable parting design requires that parting line can be hidden after plastic part is assembled. However, due to reasons such as automobile modeling and engineering assembly, parting line of some plastic parts has to be designed on exterior surface, which affects quality of appearance perception.
【Abstract】Before CNC programming, plastic part structure and mold structure should be analyzed first, then entity of heater movable model core should be analyzed to distinguish clearly parting surface, glue plane, ejector hole, inclined top hole, insert, etc. on entity. Block or delete features such as thimble holes, inclined top holes, and stud inserts on core of movable model that do not require CNC machining. Then program surfaces with different functions on moving model core separately, leave a proper margin for collision surface, process glue surface in place, and overcut avoiding surface properly, using tool path milling flow of shape milling road. In order to reflect streamlined structure of curved surface on plastic part, curved surfaces of different structures are programmed separately. Using UG software as a programming tool, CNC milling programming is performed on heater movable model core, programming tool path is simulated.
Material of outer decorative panel of plastic roof is generally ABS, modified PP, such as PP-20, PP-T30, etc. Considering cost and performance, material of outer decorative panel of plastic roof of new energy vehicle is PP-T30[3] . Figure 1 shows outer decorative panel of top cover of new energy vehicle. The overall dimensions are 1 249 mm * 1 267 mm * 238 mm, main wall thickness is 3 mm, and weight is 5.48 kg. Top cover outer decorative plate is an appearance sprayed part, and appearance surface cannot have defects such as weld lines, flow marks, and shrinkage. At the same time, because it is directly assembled on sheet metal, it also has higher requirements for size after injection molding.
Gud Mould 