We’re weighing a move from a 6061 CNC’d enclosure (7 ops + anodize) to aluminum die casting to cut piece price at 10 - 30k/yr, but tooling amortization, porosity risk, and likely secondary ops to hit 0.05 mm flatness/position make the ROI fuzzy. Does anyone have a solid cost model or case study that rolls casting yield, secondary machining, scrap/anodize rework, and maintenance into TCO, plus a practical DFM checklist (gating/venting/fillets) to reduce post? Bonus if it includes a break-even curve vs cycle time and cavity count.
@OP We switched a 7‑op 6061 enclosure to A380 die cast at about 20k/yr; break‑even landed in month 11 after adding 0.3 mm stock on the “0.05 mm flatness” faces for a 1.5–2.0 min skim and doing selective vacuum impregnation on about 5% of parts. Our TCO model counted porosity as pre‑machining yield loss and only booked conforming, anodized parts, and the biggest win was redoing gating/overflows per NADCA guidance to tighten as‑cast planarity: 404. If that flatness is on a thin lid, a machined sealing ring beats chasing die‑only flatness every time.
@OP Anodizing A380 gets dull/patchy from silicon; we used Alodine/powder coat instead (NADCA: https://www.diecasting.org). If you need dyed anodize, reconsider.
We solved the porosity/ROI fuzziness by running a 1k‑shot pilot on A360 with vacuum and selective resin impregnation on the lid area of a 7‑op 6061 replacement — , porosity scrap was killing us. CT scans + porosity coupons gave us a real yield number, and the impregnation adder landed around $0.12–$0.15/pc, cheaper than chasing anodize rework. For tight flatness, let them coin and fixture‑mill only that face; if cosmetics matter, e‑coat beat anodize for us; quick primer: https://www.diecastingdesign.org@OP.
One thing that de-risked our jump to die cast was putting a ‘vacuum guarantee’ in the RFQ — <50 mbar at metal arrival and NADCA Class B X-ray on CTQs — with a per-part credit if it’s missed; it made the porosity/yield math concrete and moved our break-even by about 4k/yr… Minor caveat: we paid a few cents/pc more for extra vent cleaning and leak checks, but it beat guessing.
Agree with @noah1492 on controlling air; the single TCO win for us was ditching anodize on A360 and going chem-film + powder — scrap from blisters fell from about 5% to <1%, and the savings easily offset a light post-cast skim on three cast-in pads to hit 0.05 mm. If anodize is non‑negotiable, budget for selective impregnation just on the sealing land.