Finally got my pour team to nail a tricky green sand mold

Three weeks ago, we had a repeat job for a complex gear housing in Cincinnati. The first two pours had cold shuts and we had to scrap the parts. I pulled the crew aside and we walked through the gating system step by step, checking the sprue height and vent placement. We mixed the sand a bit tighter and pre-heated the ladle longer than usual. Last Friday, we poured the third set. Just pulled the shakeout this morning and all four castings came out clean, no defects at all. The shop foreman just gave me a nod, which around here is high praise. It's a small thing, but after those first two fails, it feels good to get it right. What's a job that took you a few tries to get the process locked in?

2 comments

2 Comments

elliotc101mo ago

Nice work getting those castings clean. Just a heads up, mixing the sand tighter can sometimes lead to gas defects if the vents aren't perfect. How did you balance that with the vent placement?

xena_anderson1mo ago

Good call on the gas risk. We used extra risers on the thick sections to act as vents too. The pre-heat helped the metal stay fluid longer, so it could push air out through the vents before the sand got too hard. It was a bit of a gamble, but the extra heat seemed to make up for the tighter sand mix.