This article mainly introduces problems that arise during mold opening, mold trial and mass production processes after design of plastic parts is completed. It also provides a general understanding of how to solve them. Details are as follows, mainly following points:
Tag: multi-cavity molds
As a product structure or mechanical engineer, it is necessary to master basic understanding of injection molds. It can help you better develop products. Details are as follows:
In terms of mold design, factors that have a greater impact on product deformation mainly include rheology function design of mold and heat conduction function design of mold. Mechanical function design of mold also has a certain impact on product deformation, but it is not as significant as the previous two. Following is a detailed description of effects of these three aspects of mold design on product deformation and analysis of their causes.
Scanner base products are shown in Figure 1. Maximum dimensions of product are 371.37 mm * 285.93 mm * 65.83 mm; average thickness of plastic part is 2.50 mm, material of plastic part is PS HI, shrinkage rate is 1.005, and weight of plastic part is 391.30 grams. Technical requirements for plastic parts are that there should be no defects such as peaking, underfilled injection molding, flow lines, pores, warping deformation, silver streaks, cold material, and jetting lines, and meet ROSH environmental protection requirements.
N95 mobile phone inner holder product is shown in Figure 1. Maximum outer dimension of product is 93.86 mm * 47.55 mm * 8.29 mm; average glue thickness of plastic part is 1.00 mm, plastic part material is PC + ABS, shrinkage rate is 1.004, and plastic part weight is 5.30 grams. Technical requirements for plastic parts are that there must be no defects such as peaks, underfilling, flow lines, pores, warping deformation, silver streaks, cold materials, jet lines, etc. and they must comply with ROSH environmental requirements.
According to different types of gating system, plastic molds can be divided into three categories: (1) Large nozzle mold Runner and gate are on parting line and are demolded together with product when mold is opened. Design is the simplest, easy to process, and low cost, so more people use large nozzle system to work. Plastic mold structure is divided into two parts: movable mold and fixed mold. Movable part of injection machine is movable mold (mostly ejection side), injection end of injection machine is generally inactive and called fixed mold. Because fixed mold part of large nozzle mold is generally composed of two steel plates, this type of structural mold is also called "two-plate mold". Two-plate mold is the simplest structure in large nozzle mold.
One of reasons for surface problems of TPE injection molded parts is poor quality of raw materials, which is also related to uneven dispersion of formula, and secondly, it is also related to some parameter settings in injection molding process.
Gate of plastic mold refers to a section of short runner connecting sub runner and cavity, which is entrance for resin to be injected into cavity. Shape, quantity, size and location of gates in the mold will have a great impact on quality of plastic parts. Therefore, selection of gate is one of key points in … Continue reading Injection mold gate type and selection
(1) Design of mold cavity should try to ensure flow balance to reduce uneven penetration of gas. To ensure flow balance is also a design principle of ordinary injection molding molds, but it is more important for gas-assisted injection molding products. (2) Mold design should consider impact on process parameters, because gas-assisted injection molding is much more sensitive to process parameters than ordinary molding. In injection molding, slight differences in mold wall temperature or injection volume will cause asymmetry in gas penetration in symmetrical parts.
Gud Mould 