Join our MCAD Central community forums, the largest resource for MCAD (Mechanical Computer-Aided Design) professionals, including files, forums, jobs, articles, calendar, and more.
L/T or L/D? This isn't closely related to plastic part design. Remarkably long and narrow parts can be molded in plastic. But it is true that longer parts generally need more wall thickness.
There is a long list of requirements or guidelines for the design of injection molded parts: too long to effectively list here. But a few of these are:
1) Uniform wall thickness, except for ribs (which generally should be about 63% of wall thickness).
2) Beware of undercuts, and other features that prevent getting the part out of the tool. Think in terms of the steel needed to make the part.
3) Be aware of tolerances: remember that plastic parts shrink as they solidify, and the tolerance needed on a feature increases withit's size.
4) You have to get the part out of the tool, so draft angles are required in the direction of pull. The required draft varies depending from almost nothing to several degrees depending on the feature, the material and surface texture desired.
5) Be aware that most plastics are a small fraction of the stiffness of metals: roughly 1/20 or less that of aluminum, for example. While adding fillers can increase stiffness, it's generally undesirable.
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.
