3D Print Into a Solid Aluminum Metal Casting, (Lost-PLA Casting)

In this Instructable I have experimented the first time with lost PLA metal casting, I used as always recycled aluminum scrap for this project, I created in the past two 3D printings using photogrammetry method of two statues, since then I created various sizes of the statues 3d printings but always wanted to have them made from a more solid material such as metal.

I will provide below some summery of the steps in the making but feel free to view my video with the metal casting creation from start to finish ;-).

As always just to highlight this project was conducted with full PPE adequate with metal casting work.

I started by using photogrammetry method taking around 80 images of each of the objects that I planned to turn into metal the main software I worked with was Autodesk ReCap Photo, once the stage of meshing and texturing was complete I did the final touches of removing additional backgrounds and cosmetic fixing's to the object surface. The next step was to upload the files to Ultimaker Cura 3d printing software and test some real 3d prints.

In the images you can see the stages of the Photogrammetry preparation, both for the owl statue and for the crying statue (AKA - The Legend of the Yogi Man - "Orang Malu").

I decided to make an experiment with four hollow 3d printed patterns, x2 in 2mm shell thickness and x2 in 1mm shell thickness. I wanted to experiment if there will be any difference in the aluminum casting details and my assumption was correct where the two 2mm aluminum casting failed while the other two in 1mm turned out much more successful, both not perfect but looking great for the first lost PLA test. I also learned that with lost PLA casting its important to extend the 3D printing and add an additional 1cm base to the object as the PLA rise up once the molten aluminum is poured and in my casting I lost 1cm in height vs the original 3D printing.

I was not sure if the 1mm thickness printing would have turned-out without inner filament support but to my surprise it turned out very well, I have changed the setting in Cura for the thickness of the external shell and 0% infill for all of the four printings.

I used my very old but still usable Petrobond (Oil bonded sand) and buried the four 3D printings in the sand, next I used my mini soldering torch to start the hole at the base where the molten aluminum was to be poured into, the idea was to try and remove some of the PLA hoping it would reduce some of the casting defects as the PLA floats up once the molten aluminum is poured into it.

I used my good old furnace and melted some recycled scarp aluminum, after degassing and removing the impurities I have poured the molten aluminium into the four sand mould cavities. After it cooled down a bit I removed the fresh aluminum castings from the sand and was surprised that my assumption was correct and the 1mm in thickness 3D printing's turned out well while the 2mm thickness failed. In the images you can see the difference before I did a bit of metal cleanup and light polish.

I use a saber saw to cut off the extra aluminum base and an angle grinder to clean and flat the base. After I gave the aluminum casting some light clean up and buffing.

I hope you enjoyed this Instructable, here are just images of the final project result, I will probably try at some point in the future to create a large lost PLA printing of the Yogi man ;-).