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[Shona Fraser]

Hi everyone, I’m working on a small pump housing for a chemical metering application. The part will be injection molded in PEEK, exposed to roughly 180 °C fluid and aggressive solvents. It’s a compact geometry (80 × 50 × 40 mm), with an internal channel and 3 mm wall thickness, but I’m worried about warpage and stresses. I’ve read that PEEK needs at least 2 mm uniform wall thickness, generous radii, and symmetry to reduce voids and warping, but does anyone have practical experience with these tips on similar parts? Especially in chemical pump housings, what gating strategies, wall tweaks, or cooling methods helped you minimize distortion?

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[Ruaridh MacFarlane]

Yes, PEEK is tricky. Your 3 mm walls are good; thinner than 2 mm emphasizes voids and knit. Symmetry helps, so keep channels centered and mass balanced for even shrinkage. For something like a pump housing, I’d suggest a valve gate or edge gate feeding from a thicker boss region, not thin walls. Multi-gating = weld lines where you don’t want them. And keep flow paths as short as possible to reduce shear heating.

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