Ibrahim Kocaalioglu   posted here about 3D printing materials yesterday.

@Ibrahim_Kocaalioglu posted here about 3D printing materials yesterday. The thread contained a link to this which I call “Lost Wax Investment Casting” Which I have singled out for this thread. (See Below)

Basically you substitute PLA for the Wax

It had occurred to me to try and develop a method of printing an object with wax for just such an eventuality, never even considered the idea of using the PLA directly as a substitute for the wax! It really pays to be a member of such a group as this…

Also linking this back to a recent thread on printing components for radio controlled vehicles, https://plus.google.com/u/0/104012815742569035024/posts/ge1hbZvyu9d

I note the floor pan of some radio controlled racing cars is made from aluminium. This method of “lost wax investment casting” would lend itself to printing that RC component I reckon.

I NOTE: >>>> I made the plastic part perfectly fit the extrusion, then printed it again at 102%. The extra 2% is precisely how much the aluminium shrunk as it cooled.<<<<<

I was wondering about the shrinkage…

@Sebastian_Kuzminsky has been involved with PLA-based lost investment casting; it seemed to work pretty well. Foundries regularly use (and you can buy) margin rulers that are calibrated to account for material shrinkage for mold-making – although presumably you’ll be working from CAD and need to scale in software rather than in hardware. Typically metals were cast with a slight machining tolerance and then machined down to fit the application with precision surfaces.

Aluminum 1.0–1.3% 1⁄8–5⁄32 in/ft shrinkage allowance depending on the alloy content. Overall, I have found the lost ABS/Foam/PLA/Wax casting processes quite useful.

Over the last three months or so I’ve been experimenting with using ABS to do the same thing, and it worked out really well for me: http://jason-webb.info/2012/11/lost-abs-experiment-with-3d-printed-objects-and-aluminum-casting/

I used the process to create an aluminum two-part mold (seen in that post), and three bronze supershapes that I printed in ABS on a Replicator: http://jason-webb.info/2012/12/cast-bronze-supershapes-from-3d-printed-forms-using-the-lost-abs-process-with-cast-aluminum-cradle/

Just for fun, you can actually cast other materials directly into ABS molds (if the investment casting process isn’t a possibility for you). I’ve tried gelatin, resin, silicone and even wax! So much more to explore, but I thought you’d like to see whats possible :slight_smile: http://jason-webb.info/2012/11/wax-casting-with-3d-printed-two-part-molds/

I can’t wait to try this…