Saturday, April 21, 2012

sand casting mendelmax parts

I decided that, while I'm testing the injected waxes and molds and using the lost wax process, that I should maybe take advantage of sand casting using the original prints as a pattern. This would save us a lot of time in making a lot of parts if we could just ram molds using the original prints, pull the pattern, cut the sprue channel and then pour the mold.

The flask I used was too small, but I thought I should test it anyway. I used the delft clay casting sand from Rio Grande and chopped it finely with a small straight edge and rammed one mold half, then I turned it over, dusted the part and mold face and then rammed the other half. I then separated the mold halves and carefully pulled the part out. This piece has no draft so it was a little tricky getting it out without wrecking the mold, but it worked o.k. You'll also notice that I didn't use core pins for the holes. I figured this was just a test, so no need to worry about these at this point. I proceeded with cutting the sprue channel (no risers/vents). I put the two halves together and started melting the aluminum in our mini-furnace. Once the metal was up to temp, I poured the mold and let it cool. The piece came out decent for literally a 5 minute test, so I'm hopeful that this might work for a fully metal framed rep rap. I just need to make large quantities of sand and dig out my super large flasks in my studio. Can you imagine an entire printer cast in one flask? I think I can......


Have Blue said...

Funny - during my foundry class, I was pondering the possibility of making a Mendel matchplate, which would make mass production in aluminum a breeze!

Have Blue said...

Also, rather than trying to use core pins for all the holes, I figured it would be best to just have divots to mark the hole locations. After casting, just run them over to the drill press (which you'd likely have to do anyhow, even with core pins).