Got chewed out by a retired patternmaker for my sprue placement on a 50-lb aluminum job last month.

He said my gates were causing turbulence and feeding cold metal, so now I always angle them to hit the side wall first, not the bottom of the cavity.

2 comments

2 Comments

rubybarnes1mo ago

That old school patternmaker was right about turbulence. I saw a 30% drop in scrap parts after switching to angled gates on our permanent mold work. The metal needs to glide along the wall to fill smoothly from the bottom up. Straight shots into the deep end just trap air and cool too fast. It’s one of those simple fixes that makes you feel dumb for not seeing it sooner.

claire_grant161mo ago

Wait, isn't that more about reducing turbulence than just cooling? The angled gate lets the metal flow in calmly so it doesn't trap air from the start. Getting the fill right seems like the main win, with less cooling issues as a bonus.