When I review a die casting part drawing, the first thing I check is wall thickness uniformity. In aluminum die casting, nominal walls typically run 2.0–3.0 mm for small-to-medium parts; anything below 1.5 mm starts demanding high-speed injection and tight thermal control, while thick sections above 4–5 mm invite shrinkage porosity that no amount of die spotting will fix. The practical rule is to transition between wall sections gradually — a 3:1 taper over the length of the change is a reasonable target — because abrupt steps create isolated hot spots. On the tooling side, this translates directly into gate placement and die cooling layout: uneven walls force us to add baffles or bubblers in the thick zones, and if the part design leaves no room for them, we end up fighting cycle time and porosity simultaneously. I have seen more projects delayed by a 6 mm boss sitting next to a 2 mm wall than by any machining tolerance callout.
Draft angle is the other item I refuse to negotiate. For aluminum die casting, 1–2° per side on cored features and 0.5–1° on outside walls is standard practice; textured surfaces need more, roughly 1.5° extra per 0.025 mm of texture depth. Under-drafted cores mean the ejector system has to work harder, and that shows up as drag marks, galling, and eventually cracked cores after a few tens of thousands of shots. I also look at fillets: internal corner radii should be at least equal to the wall thickness, and external corners get a radius equal to the wall plus the internal radius. Sharp internal corners act as stress risers in the casting and as heat concentration points in the die steel — both shorten tool life. Ejector pin locations, parting line position, and slide direction all need to be settled at the design stage, not after the die block is cut.
Finally, don't forget the features that keep the tool simple: avoid undercuts that force slides unless the volume justifies it, keep cored holes with a depth-to-diameter ratio under about 3:1, and specify machining allowance only where it's genuinely needed. Every extra slide or lift adds cost, maintenance, and cycle time. Getting these structural details right early is what keeps a die casting program on schedule. For more mold sourcing and tooling information, visit MoldSo at www.moldso.com.