Re: Thick section casting (CNC Router Drop Plate)
Posted: Sun Aug 28, 2011 9:43 am
Hi David, yes I used a longer flask so I could feed from each end. At the pouring end I had the sprue feed a bob (blind riser) and at the far end added a second bob. I am still getting a very small depression of less than a couple hundredths but this is well within the waste material that is milled off the part.
I think a lot of the more drastic deformation was mold collapse rather than shrink though. The pattern took up so much of the flask that there was not a lot to support the sand in the cope left and once weighted it simply settled. Using the block molding they way I do the pressure from the mold weights is directed through the sand rather than supported by the flask itself.
I think a lot of the more drastic deformation was mold collapse rather than shrink though. The pattern took up so much of the flask that there was not a lot to support the sand in the cope left and once weighted it simply settled. Using the block molding they way I do the pressure from the mold weights is directed through the sand rather than supported by the flask itself.