塑料产品设计影响因素简介.ppt

塑料产品设计影响因素 制品设计要求 功能要求 制造要求 功能要求 首先: ? 性能 ? 结构 ? 装配 ? 外观 其次: ? 成本 产品制造要求 流动 / 充模 冷却 顶出 操作 结晶型塑料在厚壁处具有更大收缩 壁厚不均匀可能引起的后果 壁厚不均匀可能引起的后果 壁厚的不一致不可避免时采用逐步过渡 尽量避免不一致的壁厚 塑料制品设计的第二个原则 避免尖角 圆角半径对应力集中系数的影响 肋与加强筋 理想的肋结构 肋的设计对制品重量和强度的影响 肋的使用可以大大提高产品刚性 Lip Design for Rigidity 肋 翘 曲 翘曲 不一致的壁厚 各向异性的收缩行为 成型加工条件 模具设计 壁厚不一致 各向异性的收缩行为 各向异性的收缩行为 各向异性的取向行为 成型工艺条件 熔体温度 模具温度 注射保压时间 不一致的冷却也会导致不一致的收缩行为 模具设计的影响 熔接痕 浇口位置所导致的变形因素 由于浇口位置和浇口数量产生的翘曲 强 度 承受荷载能力较弱的部位 浇口 熔接痕 肋 尖角 空洞 一个项目成功的影响因素 制品设计 开模 材料性能 成型加工 Four different things that could cause warpage. Example of parts with non-uniform wall thickness that cause warpage, and how to fix the problem by modifying the design. Sharp corners, will cause turbulent flow at that region. In this case the glass fibers reorient themselves (normal to flow) and cause shrinkage and warpage. Difference in shrinkage of a disk gated at one end. Example of anisotropy material, in this case Delrin? 500. Material behaves differently in compression and tension. Core Gate Gate Gate 产生偏心现象 易困气 流动平衡无偏心现象 侧浇口 末端浇口 对环形制品, 由于浇口的形状不同, 最终产品的圆度也会受影响 Edge Gate Pin-Point 3-Pin Point Gate 4-Point Cross Gate Funnel Gate This slide can be customized for a specific customer. The plastic part has two requirements: Function: The designer needs to ask the following questions: What’s the part for? How is it going to work? Is it part of an assembly? How is it going to be assembled? Manufacturing: For manufacturing, we need to take into consideration the choice of the material, the molding process, the assembly and finally the handling. Functions: Performance: Would the design meet the requirements, ex: (mechanical requirements, electrical requirements and chemical requirements) Structural: What kind of stress and loads does the part see? Assembly: How will the part be assembled? Will it be easy to put it together? Appearance: Is the appearance a requirement? Is texturing a solution for ribs and sink marks? Cost: During the whole part design process, t