When I review a die casting drawing, the first thing I check is wall thickness. Non-uniform walls create hot spots that cool at different rates, and that means shrinkage porosity, cold shuts, and sink marks you will fight for the life of the tool. The practical target for most aluminum alloys is a nominal 2.0–3.5 mm, with transitions kept gradual rather than stepped. Where a thick section cannot be avoided, core it out or design a rib pattern instead of adding mass. Ribs should run at roughly 0.5–0.7 of the nominal wall thickness and be spaced at least two wall thicknesses apart, otherwise you simply move the hot spot rather than eliminate it.
Fillets and draft are the two items designers most often trim to save space, and both come back as tooling cost. Internal fillets should be at least half the wall thickness, external fillets equal to the wall; sharp internal corners concentrate stress and accelerate heat checking on the die steel, which shortens insert life and shows up as cracking within tens of thousands of shots. Draft angles should be 1–2 degrees on internal surfaces and 2–3 degrees on external surfaces, with more on deep cores and textured faces. Insufficient draft means scuffing, higher ejection force, and bent ejector pins. Gate location deserves the same discipline: place it so the melt fills thick sections first and avoids direct impingement on cores, and confirm flow with a filling simulation before steel is cut.
None of this is exotic, but it is the difference between a tool that runs at a stable yield and one that lives in the tryout press. Tolerance stack-up, ejector pin placement, and slide timing all trace back to these same early decisions, so lock them in at the drawing stage rather than in the mold shop. For more die casting and mold sourcing information, visit MoldSo at www.moldso.com.