模具设计和制造与塑料加工有密切关系
模具设计和制造与塑料加工有密切关系。塑料加工的成败,很大程度上取决于模具设计效果和模具制造质量,而塑料模具设计又以正确的塑料制品设计为基础。
Mold design and manufacture are closely related to plastic processing. The success or failure of plastic processing largely depends on the effect of mould design and the quality of mould manufacturing, and the design of plastic mould is based on the correct design of plastic products.
塑料模具设计要考虑的结构要素有:
The structural elements considered in the design of plastic moulds are as follows:
①分型面,即模具闭合时凹模与凸模相互配合的接触表面。它的位置和形式的选定,受制品形状及外观、壁厚、成型方法、后加工工艺、模具类型与结构、脱模方法及成型机结构等因素的影响。
The parting surface is the contact surface between the die and the punch when the die is closed. The selection of its position and form is influenced by the shape and appearance of the product, wall thickness, forming method, post-processing technology, die type and structure, demoulding method and the structure of the forming machine.
②结构件,即复杂模具的滑块、斜顶、直顶块等。结构件的设计非常关键,关系到模具的寿命、加工周期、成本、产品质量等,因此设计复杂模具核心结构对设计者的综合能力要求较高,尽可能追求更简便、更耐用、更经济的设计方案。
(2) Structural parts, i.e. slider, inclined top, straight top block of complex die, etc. The design of structural parts is very critical, which is related to the life, processing cycle, cost and product quality of the die. Therefore, the design of complex core structure of the die requires a higher comprehensive ability of the designer, and pursues a simpler, more durable and more economical design scheme as far as possible.
③模具精度,即避卡、精定位、导柱、定位销等。定位系统关系到制品外观质量,模具质量与寿命,根据模具结构不同,选择不同的定位方式,定位精度控制主要依靠加工,内模定位主要是设计者充分去考虑,设计出更加合理易调整的定位方式。
(3) Mould accuracy, that is, avoidance of cards, precise positioning, guide pillars, positioning pins, etc. The positioning system is related to the appearance quality of products, the quality and life of dies. According to the different structure of dies, different positioning modes are selected. The positioning accuracy control mainly depends on processing. The positioning of internal dies is mainly considered by the designer to design a more reasonable and easy-to-adjust positioning mode.
②浇注系统,即由注塑机喷嘴至型腔之间的进料通道,包括主流道、分流道、浇口和冷料穴。特别是浇口位置的选定应有利于熔融塑料在良好流动状态下充满型腔,附在制品上的固态流道和浇口冷料在开模时易于从模具内顶出并予以清除(热流道模除外)。
(2) The pouring system, i.e. the feeding passage from the nozzle of the injection machine to the cavity, includes the main passage, the shunt passage, the gate and the cold hole. In particular, the selection of gate location should be conducive to filling the cavity of molten plastics in a good flow state, and the solid runner attached to the product and the cold material of the gate are easy to eject and remove from the die when opening (except the hot runner die).
③塑料收缩率以及影响制品尺寸精度的各项因素,如模具制造和装配误差、模具磨损等。此外,设计压塑模和注塑模时,还应考虑成型机的工艺和结构参数的匹配。在塑料模具设计中已广泛应用计算机辅助设计技术。
(3) Shrinkage of plastics and various factors affecting dimensional accuracy of products, such as manufacturing and assembly errors of moulds, wear of moulds, etc. In addition, the matching of technological and structural parameters of the moulding machine should also be considered when designing the compression and injection moulds. Computer aided design technology has been widely used in plastic mould design.