Example Part - I have some pics I took a while back but never used for anything of the metal casting process... casting magnesium prototype parts. Hope you enjoy
This is an example part that this company used to show the process. First they make a SLA or SLS master
First Mold - A clay negative is made of one half of the part. This is actually a master part which they will reproduce to produce a number of disposable molds.
Second mold (of the first mold) - Then they make a urethane mold ( the yellow one) of the clay negative 'master' . This will be used to mold the disposable sand molds. You can seem my bare parts in the background
Casting the final mold - Then they fill the urethane molds (shown here covered with mud) with liquid clay, producing the other negative " master" half of the mold.
Deep under the clay is the SLA master part, so there is a hollow for molding.
When it dries, this second clay negative 'master' is then molded in the yellow urethane, just like the first side, to produce a template to create the other half of the molds. Getting confusing yet?
Epoxy-Sand Mixture - Now they make the disposable molds... sand is mixed with epoxy right before it goes into the mold. It's like a putty at first
Packed sand in the molds - The molds are filled with the sand-epoxy mixture. This will harden into a material that feels like sandstone
Raw materials - There is lots of raw material on hand.. aluminum and magnesium
Furnace - This is the furnace where they put the raw metal
The pour - carefully pouring the molds
mold details - Waiting for the parts to cool.. you can see the crude sprue pipe
Removing the molds - Breaking the mold off the parts
My raw part - My fresh cast part! now it needs lots of machining to clean it up and cut in the detailed vents...
A more detailed example - example of the more detailed parts they cast.. some kind of turbine