Injection Molding Design Guidelines注塑模具设计指导

Much has been written regarding design guidelines for injection molding. Yet, the design guidelines can be summed up in just a few design rules.
已经有许多关于设计注塑模具的书了,但是设计准则可以被概括以下几点:

Use uniform wall thicknesses throughout the part. This will minimize sinking, warping, residual stresses, and improve mold fill and cycle times.
1.零件整体壁厚保持均匀.这样可以最小化缩坑,翘曲,强度减小,模具填充和循环时间.

Use generous radius at all corners. The inside corner radius should be a minimum of one material thickness.
2.在转角处大量采用圆角.圆角内部最小半径为一个壁厚.
Use the least thickness compliant with the process, material, or product design requirements. Using the least wall thickness for the process ensures rapid cooling, short cycle times, and minimum shot weight. All these result in the least possible part cost.
3.根据工艺,材料,产品设计需求.采用最小壁厚.最小壁厚的应用可以确保快速的冷却,短循环时间和减少喷射重量.所有这些最终达到最小的产品成本.
Design parts to facilitate easy withdrawal from the mold by providing draft (taper) in the direction of mold opening or closing.
4.在模具开合方向设置拔模角便于设备的运做.
Use ribs or gussets to improve part stiffness in bending. This avoids the use of thick section to achieve the same, thereby saving on part weight, material costs, and cycle time costs.
5.为了提高产品强度抵抗弯曲应该加筋或肋.避免用厚的结构达到同样的效果,以此减少了产品重量,材料成本,循环时间成本.
The use of ribs
筋的应用
Ribs increase the bending stiffness of a part. Without ribs, the thickness has to be increased to increase the bending stiffness. Adding ribs increases the moment of inertia, which increases the bending stiffness. Bending stiffness = E (Young’s Modulus) x I (Moment of Inertia)
如果没有筋来增加强度,厚度就必须增加(费话一堆).加强筋增加了转动惯量!
The rib thickness should be less than the wall thickness-to keep sinking to a minimum. The thickness ranges from 40 to 60 % of the material thickness. In addition, the rib should be attached to the base with generous radiusing at the corners.
筋的厚度要<壁厚,以降低缩坑.厚度推荐=40%~60%壁厚.另外筋应该在根部倒圆角.
At rib intersections, the resulting thickness will be more than the thickness of each individual rib. Coring or some other means of removing material should be used to thin down the walls to avoid excessive sinking on the opposite side.
在筋交叉的截面处,壁厚要>单独的筋,为了防止在反面产生缩坑,尽量出去交叉中心的材料.

The height of the rib should be limited to less than 3 x thickness. It is better to have multiple ribs to increase the bending stiffness than one high rib.
筋的高度<3倍的厚度.{zh0}多加几条代替一个.
The rib orientation is based on providing maximum bending stiffness. Depending on orientation of the bending load, with respect to the part geometry, ribs oriented one way increase stiffness. If oriented the wrong way there is no increase in stiffness.
筋的方向布置以增加产品强度为准,参考弯曲载荷方向(其他为费话)
Draft angles for ribs should be minimum of 0.25 to 0.5 degree of draft per side.
If the surface is textured, additional 1.0 degree draft per 0.025 mm (0.001 inch) depth of texture should be provided.
拔模角单边0.25~05度,表皮有皮纹,没增加0.025毫米+1度.