Parts Injection molded at home - Silicone Plaster 3dPrinted

[CustomJoe_MD]

Hi folks, so for a while now I've been thinking of ways to make small custom runs of parts (200 or so) without expensive material or machines and I've found some videos and tutorials that give you a couple of different ways you can make something like a minifig gun as small as a PPK or a helmet or hairpiece, an aquaman harpoon hand, you know the usual normal stuff everyone likes. :)

WARNING: it's a bit long winded.

This is to make abs parts not Cast in resin type stuff (same principle different end process - there are tutorials on wargames miniature casting its the same process more or less)

I've selected a few processes some with 3dprinting at the core other with more arts and crafts available materials (silicone molds clays ets).

I won't go in depth about mold making since the information is in the links and you can watch videos of that kind of thing all over YT.

1- Reinforced Plaster mold + 3d printed 2part mold

---video with process except plaster mold was printed not cast.

This requires a 3d printer for more than one reason. you'll need it to print the prototype of the part or the mold of the part (this would be a negative shape that would surround the part you want to create) and you will, once you have the final die aka "2part mold" use the printer head to fill said mold with plastic directly (since its only small parts and prototypes you don't need much pressure at this scale - a Makerbot works great but its like a 2000usd machine - but if you have access to one your set)

Okay thats the basic setup lets go to the steps:

1a- Print the prototype parts directly (this requieres cad software if you are using a 3d model) see if its at the scale you want make any modifications and finalize the design, once thats done print a negative 2 part mold shape (for how to do this search thingiverse for casting metal molds)

(see video

and

)

make sure to clean any imperfections, smooth or sand the mold pieces until you have it as good as you want it acetone polishing is a good idea too.

**If cloning a part or making a mold from a sculpted or custom piece skip to the silicone step or 3d scan it and process in a cad software.

1b- Now you have a part that you are either casting or you have the plastic negative 2part mold, this is where I'm adding my two cents, in the metal casting video you cast metal with the plastic forms, what I suggest is make a silicone mold (using whatever process works for you - silicone for duplication, caulk method or sugru) OF EACH of your negatives.

Once you have a mold in silicone for each of the parts you can cast it in plaster of paris, you end up with duplicates of your plastic negatives.

NOW the tricky thing RESIN, using 2part epoxy resin brush a thin coat on the inside and after it dries on the outside two. The plaster will suck it up so make it thin layers and make sure you use a resin that can withstand some Temperature. You want the inside to be as non pourous as you can make it without losing final part size (you'll have to trial an error this step).

On the outside you can make it a bit thicker 4 coats maybe, or use a frame (wood aluminum etc around the plaster mold halfs)

Clamp the mold together using blue tape and...

1c- Using the method here

http://www.instructables.com/id/Making-Extremely-Small-Objects-With-Your-3D-Printe/?ALLSTEPS

inject plastic into the cavity using the extruder end on the 3d Printer (using the free flow or fill option - the hot end head is still in parked position for this of course)

That instructable uses the silicone mold instead of plaster I recommend the plaster option with the epoxy resin because it will last longer and you can keep the mold for injection on a machine like this also

(for making multiple parts and if the plaster breaks use the silicone mold of the mold to make a new one, easy peasy and feel free to recycle plastic from bottle caps, etc for prototypes)

http://www.thingiverse.com/thing:26500

Original tutorial for the first video

You can use the same ideas to cast the final mastermold in aluminum instead of plaster/resin --you would need foundry equipment and tools or a melting pot and low melting metals, check the following for this:

http://www.thingiverse.com/thing:20186

As you can see there are several combinations you can use for each step (I'll improve on this later just wanted to put it out there fast so people know)

If someone wants to build a injection machine here is a little instructional you can DL (based on gingery - the one on the video above is better and simpler - gives better injection pressure control):

http://rick.sparber.org/Articles/gpi.pdf

For turning 3dfiles into negative mold parts see here

http://www.thingiverse.com/thing:31581

http://www.thingiverse.com/thing:42827 ---using Rhino CAD

-------------------------------------

This one is just a simple mold you can print and try to cast from it.

http://www.thingiverse.com/thing:109160

Have fun, happy customs ho ho ho!

Edited February 18, 2014 by CustomJoe_MD

[CustomJoe_MD]

UPDATED with the original tutorials and a bit more organized, more to come...

[bond]

very informative video i must say related to plastic moulding but my question is can you cast iron in them? if yes please elaborate it bit more thanks

bond