Wall Thickness/Nominal Wall
It is of utmost importance to initiate collaboration with a mold builder at the early stage of the design process in order to mitigate potential issues. Thanks to the advancements in additive manufacturing, engineers now have the capability to utilize 3D printing for prototyping purposes and manufacture parts with features that cannot be replicated through injection molding. This mini-series encompasses essential considerations for implementing Design for Manufacturing (DFM) principles.
The pivotal determination of wall thickness integrated into a design will have a significant impact on the overall moldability of a part, encompassing all other design decisions. There are many factors to consider, including:
Part stiffness is directly affected by wall thickness. For example, if the wall thickness increases or changes by 10%, this can add roughly 33% more stiffness. Larger parts with longer flow lengths require thicker nominal walls to allow the part to fill properly, otherwise this can impact resistance and entail cracking at high stress areas. Another area to consider is the UL-94 FR rating. Wall thickness of a part has a direct correlation to the UL rating as most materials achieve a higher UL rating as the wall section gets thicker. Part cosmetics are also influenced by wall thickness in addition to part cost which dictates material usage and cycle time.