Power housings are judged by hand before they are judged by a meter. A straight wall that drags, a bright line along the edge, or a parting line you can feel will lose a program even when every dimensional report is in tolerance. These are the three problems our engineering team has solved in production.
01 — Zero-draft molding, no slides
The market is moving towards straight walls with no draft, but most molders only achieve it within narrow limits: texture finer than VDI 24, part height below 40 mm, and white material, because black shows drag marks. Our engineering team set up a project group led by the general manager to break those limits.
The result is a straight-wall, zero-draft housing with no slide action: 163 mm tall, with a VDI 30 texture, molded without drag marks, stress marks or other surface defects. The method now covers the whole range of wall-plug housings we produce, not a single part.
02 — Edge stress marks on PC housings
A power housing has a lip where the two halves meet, and the wall thickness changes sharply at that lip. On PC, which flows poorly and needs high injection pressure, that thick-to-thin transition leaves a visible bright band along the edge. Customers increasingly specify no stress mark at all, with no acceptable limit.
For one adapter program the customer rejected any stress mark around the perimeter. The solution was a core-pull layout in the moving half combined with the part ejecting from the cavity half, plus a matched molding process. The mark disappeared and the part has been in stable mass production on a 1×8 cavity tool.
03 — Slide parting lines below hand-feel
Two- and four-side slide molds are normal for housings with side openings, but on tall parts the slides and the cavity run at different temperatures. The temperature difference changes the thermal growth of both, and the fit clearance that worked at the start of the batch stops working later in the run; the parting line becomes visible and can be felt.
Our approach is to calculate rather than to guess: the slide and cavity temperatures are set from the molding window, the thermal expansion of each part is calculated from its loaded area, and the fit clearance is derived from those numbers. The tool is then progressively refined in production. On a 108 mm four-side slide housing this keeps the parting line below hand-feel across the batch.
Why it matters for a buyer
Each of these solutions is a tool decision as much as a process decision, and each was validated on a real program before it was offered. If your drawing requires a straight wall, an edge without stress marks or a side opening with an invisible parting line, the conversation starts with the drawing review, not with a promise.