Does anyone know of a good company for short production runs of plastic products? I want to make a custom shaped plastic enclosure to fit some electronics and battery into (nothing to do with Arduino).
Can anyone recommend some please?
Thanks,
Mike
Good question. You can dig through pactecs offerings and see if one is close:
http://www.pactecenclosures.com/Plastic-Enclosures.html
I think mouser has a few also.
No I don't mean ready made stuff. This would be a bespoke job and a weird shape.
Well, if you're not willing to spend thousands of dollars on a soft mold, you'd probably be best off with a prototype house. Someone like these guys (no idea who they are):
If you do find someone I'd be interested to find out about them too. 
--Phil.
if you look into the usual process of making plastic parts, you will see there are some large setup costs involved. for small numbers i would say that does not make sense.
3d printing or cnc routing processes are more likely to fit your needs.
I think that you can find something interesting visiting the following website http://www.impa-togno.com/, this is an italian company that is very active in the international field of the plastic items production. Let's try, it can be the solution you were looking for.
I mold my own,
You will want to look into the rigid and semi-rigid plastics.
Can you have flat pieces laser-cut and glue them together?
Jassper - Can that Smooth-On produce enclosures? i.e. a hollow inside for placing a circuit board, etc. ?
Oracle - No as parts of the item have curved surfaces.
Can you have flat pieces laser-cut and glue them together?
What I suggest for that is to simply use 1/16 or 1/8 ABS sheet, score and snap with a utility knife and use ABC cement to glue them together
Jassper - Can that Smooth-On produce enclosures? i.e. a hollow inside for placing a circuit board, etc. ?
Yes, If you want I can post a pic of one I recently did.
Yes please !!
Well I don't have any boxes handy, but I have a tray I fabed for a custom dash. It is approx 6"x4"x2"
Here you can see the inside corners are rounded,
and some air bubbles, but no big deal, they sand right out.
In liquid form, it will run into ever crevice, here you can see the grain from the mold.
Basically;
Get some cheap 1/8" paneling that has a smooth side and something you can glue together with regular wood glue. Use it to create your outer shell. Don't worry about rounded corners on the exterior at this point, make them all squared, you can use a file or sand paper to round it off after words.
Next create the inside chuck, I use pine wooden blocks or you can use balsa blocks also. Shape your inside chuck just how you want it, rounded corners and everything. Remember to make the chuck allowing for wall thickness.
The tricky part is to keep the chuck from dropping to far into the shell, making your bottom wall too thin. So, attach the top of the chuck to a plate that is larger than your outer shell. You can also attach centering guides to this plate so the chuck stays the same distance from the interior walls of the shell. Also, because the check is attached to the plate, it can only be lowered into the shell so far.
Here is a drawing of a box a did a while ago, it shows the top view of the shell with the chuck inside it, the top view of the chuck, and the resulting box shape. Later I can round the exterior corners.
Here is a side view drawing of the chuck being lowered into the shell with the center jig and guide rails.
Once you are ready, mix your plastic and pour it into the shell so it fill about half way, then force your chuck into the shell allowing the plastic to ooz out the top. This also forces most of the air out.
Note: Make sure you use the Smooth-on sealer and mold release as directed!!! or your plastic will stick to the material. A trick I use is to cover the entire chuck and shell with clear packing tape. This makes a nice smooth surface, seals the chuck, and acts as a mold release, as the plastic won't stick to the tape. It does however leave a mold line where the Tape edges come together, but those are easy to sand out.
If I get the time, and anyone is interested, I will try to do a step by step procces with pictures and post it.
I'm interested! Very cool process and it seems you can achieve very nice results.
Yep, I have had good results with it, the hard part is thinking "negative" when making the shell and chuck.
Depending on the complexity of the box, it can become time consuming, but it sure beets $3,000.00 - $5,000.00 for a single run from a fabricator. Plus if it is a proto-type, it gives a fabricator an actual part for them to duplicate. It saves them a little bit of time, and you a little bit of money.
That is nice. Any pics of eat post-sanding?
I would love a step by step guide please.
Roughly how much would it cost to make a box that size?
Cheers,
Mike
I buy it by the trial size, that box took less than a half bottle so about $20.00 +/-.
I'll see if I can get a detailed step-by-step done this weekend.
Do you have a part number? I wasn't sure which plastic you used.
Do you have a part number? I wasn't sure which plastic you used.
I use the Smooth-Cast 60D, this is a semi-ridgid plastic 50/50 mix. It is still soft after it comes out of the mold, but after 72 hours it is hard like ABS and not brittle at all. I also use the black So-Strong color tint to make it black. The natural color is clear amber.
Here is another thing I like to use it for, this works great for those wet areas. Using the Smooth-on OOMOO-25 liquid rubber, I make a rubber mold that can be used over and over.
Picture of the wood negative mold and resulting rubber mold, in it you can see a bad spot on the rubber - this is from not mixing it good so be sure to stir it well, but it is OK for this application;
Here you can see the circuit board sitting on top of the stand-offs I designed into the mold.
Now, if there is anything you don't want the plastic to flow into, cover it with clear packing tape, like those green connectors.
Then I mix the 60D plastic and mix in some color tint. First I pour some in to make sure it gets completely underneath the board, then I set the board onto the stand offs and finish filling the mold.
De-mold time! it peels right out.
Then I clean up the edges on a sander, drill 2 mounting holes and vola! a water sealed circuit suited for mounting in an engine compartment.
I should have the box demo done this weekend, I got a good start on it.
Thanks for all the info. and pictures it is greatly appreciated.
It can't find any suppliers of Smooth-On in the UK so I would have to order from the US, which would put the costs up (especially if I got stung by Customs for VAT like I have twice lately).