Exoskeleton suit replica from the movie Elysium in Autodesk Inventor, 3D printed and investment cast out of Aluminum
I designed and printed all of the parts, machined pistons on a metal lathe, and sewed a harness. Now I am working on casting all of the plastic parts out of Aluminum using the investment casting process.
The printable STLs are available here and on GitHub. See the assembly instructions if you want to put together one of your own.
I often post videos of the metal casting process. Here's the latest one, shot with a virtual reality camera:
I have some mixed news from my attempt this weekend. I got all the data, but the act of observing the temperature and filming combined with more trouble from my regulator caused a decline in casting quality. I suspect it mostly came down to metal that got too hot, thus absorbing more gas from the atmosphere. I also had to move the camera and take laser temp readings, so I didn't remove the mold from the kiln as quickly as last time, and didn't pour as quickly.
First three attempts on the graph was me messing with camera and lights to try and raise "production values" so I left the crucible in the kiln for too long. The last attempt the crucible was in the kiln for about the right amount of time, but the kiln was over-fed by propane.
This week I am sick, so next week I will retry all of this and hopefully have some video worth publishing. I took some time to setup lights, and the video quality was significantly better - next time I will already have that experience so I can setup lighting quickly and before doing anything important to the casting process.
I got a USB temperature logger that works with my K-type thermocouple, so I can overlay a live temperature feed on my next metal casting video.
Here's what the output text file looks like when opened in the app that comes with the logger:
...and this is the raw output. CSV with sample ordinal, date/time, temperature in F, high alarm, and serial number
Today I nailed down the shell casting process (with a great amount of help from The Home Foundry) I can use to finish off remaining parts.
...without pre-heating:
...with pre-heating:
I followed advice on building more shell layers, pre-steaming the pressure cooker before putting in the shell, steaming for a short time (30 mins instead of 2 hours) and repairing cracks /adding another shell layer after vitrification. I have one final problem with a frozen surface in parts of the cast. Here's the video of this attempt:
Here's the frozen effect. I poured at 950-970 and I skimmed a film of metal off the top, but it filmed over just as I was pouring.
Another iteration of sprue planning for the chest pieces: https://github.com/01binary/sprue-planning/blob/master/chest-sprues.stl
The first attempt at shell casting with the two chest plates has started. Sprued wax model:
First dip
Already developing cracks in the fist layer - most likely because the slurry needs more water
Second dip
Sprue planning for models to be cast using the shell casting process is more serious than with vacuum-assist casting, so I am performing at least two rounds of review with metal casting experts before proceeding:
https://github.com/01binary/sprue-planning/blob/master/chest-sprues.stl
https://github.com/01binary/sprue-planning/blob/master/hip-sprues.stl
The last 7 parts cannot be cast using the jewelry process due to geometry that requires a very heavy custom flask and tons of investment. The weight of the finished piece makes it nearly impossible to manipulate fast enough to insert into a vacuum chamber and pour metal in 20 seconds, before shell-shock.
I am going back to shell casting after some advice from The Home Foundry forums, and I will post a video after the first failed experiments.
Another 360 video of trying out the new vacuum chamber:
I exported my first long 360 video with immersive effects, transitions and composited 3D renders:
Assembly Instructions in PDF format: Hackaday (Dark) | Default (Light)
What grade Aluminium did you cast it from? I'm intending to make my own exoskeleton design. However, I'm not sure on the best choice of Aluminium from the extensive variety available.
I am using this right here (closest to 356 alloy):
http://www.ebay.com/itm/ALUMINUM-INGOTS-43-lbs-26-to-30-ingots-Casting-alloy/182166261652
The quality is a lot better than you would expect - I originally bought this as practice stock, but then realized it's actually top-shelf casting stock sold cheaply :) I get as-cast surfaces that are literally polished with no further work required.
Lastly, I did consult with two mechanical engineers here at the hackerspace (one who works at Intel and one who works in a local machine shop), and they both pointed me to 356.
You are casting, right? The alloy is completely different for CNC/machining, 6061.
See https://www.metalsupermarkets.com/7-things-consider-choosing-aluminum-grade/
Ah right. No I haven't decided yet on whether I would cast or CNC/machine it out, while CNC is much more expensive I don't really have the appropriate tools/location to cast.
I've also been looking around for months but can't seem to find those type of pistons/hydraulics used in the joins of your exoskeleton. Is there a specific name or site I've missed? Or did you get those custom manufactured?
I manufactured the pistons, see page 6 of my RPF build thread:
https://www.therpf.com/showthread.php?t=212832&page=6
...through middle of page 7:
https://www.therpf.com/showthread.php?t=212832&page=7
I don't regret learning how to use a metal lathe, but in retrospect this was the wrong decision for the project. Lathe was $500, tube stock I ordered was around $500 as well, and I spent 2.5 months, about 45 hours per week, machining until late night and coming home each day looking like a coal miner. Then I spent another $100 taking them to a painting plant not to mention I had to wake up in the middle of the night to make it back in time for work.
Knowing what I know now, I would say either low-tech them if you are going for appearance and use a convenient size of pipe (2 diff. diameters cut & inserted into each other), or post for help on a CAD forum to learn how to make drawings and submit them to a machine shop (and have them do high-detail matte/gloss indoor electro-coating). Price will likely be the same for machine shop as doing it yourself, BUT you get to spend all that time hanging out with friends instead of machining and crying :)
So with these files being online. I want to ask first. Is this design an open source design. I think it is amazing looking and would like to make one myself. I don't think i can come close to getting this level of detail. Also this suit looks amazing!
Prop replicas are never completely open source, since Sony owns the right to the movie and all props (you are always a voicemail away from Cease and Desist). However, all the files have been created from scratch and a few parts differ from on-screen appearance (thus it's not an exact copy) so as long as nobody's crazy enough to sell it they will likely let it slide.
The build was split between Viper for SLA (http://www.agile-manufacturing.com/product/used-3d-printers/viper-sla.html) and sPro for SLS (http://www.agile-manufacturing.com/product/production-3d-printers/spro-sls-series/spro-140-230-sls-center.html). Parts ordered from ProtoLabs (https://www.protolabs.com/3d-printing/).
Valeriy Novytskyy
Julia Longtin
jupdyke
rawe
Very interesting project. I really enjoyed that film. Interesting to see that you are casting your own parts from aluminium. The actual casting part is really difficult, I know because I have tried it. Since you are putting in so much effort into making it from metal, are you not tempted to make some of mechanisms function like a real robotic exoskeleton? With assistive actuation and motors? great project, will follow with interest.