Custom Plastic Enclosure - Page 1
Forum section: electronics / projects

author: Isaac Newton
author_rank: Contributor
timestamp: May 08, 2013, 09:32:12 pm
content: I know it's really expensive to make plastic extrusion moulds for a first production run, especially for a small batch like 100 or 200. I know there is a big number of ready made plastic enclosures, but I raven't found one that would suit my purposes. Besides, custom plastic enclosures are more atractive for the costumer.I'm making a electronic household product and I'm thinking in using a 3D printr to make a first piece and than reproduce it by silicon mould making and then casting it with some kind of resin... Has anyone tried this method?

author: Baliszoft
author_rank: Frequent Contributor
timestamp: May 08, 2013, 10:36:39 pm
content: It is cheaper to use cnc milled aluminium enclosures for small runs like this.

author: notsob
author_rank: Frequent Contributor
timestamp: May 08, 2013, 11:25:59 pm
content: For a low budget project (ie no BIG$'s up front) I would try and start with getting a suitable box first and then design the board to fit. Free electrons version of 'jim williams' pulse generator is a great example.

author: Isaac Newton
author_rank: Contributor
timestamp: May 09, 2013, 03:02:15 am
content: Does anyone know a box enclosure that can be screwed into a standard wall mounted light switch box?

author: notsob
author_rank: Frequent Contributor
timestamp: May 09, 2013, 03:49:54 am
content: have you looked at the eevblog wikihttp://www.eevblog.com/wiki/index.php?title=Enclosure_Manufacturers

author: pickle9000
author_rank: Super Contributor
timestamp: May 09, 2013, 04:06:33 am
content: If your prototyping buy a lamp dimmer, that's a good place to start. Toss out the guts and magic a box for 3 bucks.

author: Isaac Newton
author_rank: Contributor
timestamp: May 09, 2013, 05:06:22 am
content: Unfortunately i'm not prototyping...I will try the eevblog wiki. Thanks for the tip. Though I think that all these manufacturers will have almost the same kind of enclosures...

author: notsob
author_rank: Frequent Contributor
timestamp: May 09, 2013, 05:40:26 am
content: Here's a couple more to look athttp://www.polycase.com/flanges-surface-mounthttp://www.bahar.asia/en/Cheers

author: Isaac Newton
author_rank: Contributor
timestamp: May 09, 2013, 03:47:03 pm
content: QuoteInteresting, the enclosures from the first site you gave me looks very much like the boxes from BUD Industries...

author: paul23
author_rank: Regular Contributor
timestamp: May 09, 2013, 05:16:07 pm
content: Quote from: Isaac Newton on May 08, 2013, 09:32:12 pmI was going to try the exact same thing, and like you only need a small batch initially. I did get several quotes for companies in china to make them, and they ranged from 30 - 95USD each in 100QTY. That´s too expensive, so I figured I would have a go myself, doing it the way you have suggested. I need to order the resins yet, but i have a local company that does them, so I should be having a go in the next month or so. Let us know how you get on if you do it before me.

author: nctnico
author_rank: Super Contributor
timestamp: May 09, 2013, 07:24:14 pm
content: I recently got a quote around €10k for a very large injection molding. This project seems much smaller. Nowadays they can mill the molds from aluminium as well which reduces the costs considerably. I'd call around to see what you can come up too. Another technique is vacuum forming which is even cheaper. Potting is an option but not something you can do by yourself. Potting without air bubbles is an art in itself.

author: G7PSK
author_rank: Super Contributor
timestamp: May 09, 2013, 08:42:47 pm
content: GRP or vacuum forming. Vacuum forming is easy to do yourself, make a mold from clay or plaster with lots of small holes trough it put it on a table with a vacuum pump and then place a piece of sheet plastic on top and heat that with an infra red lamp and turn the vacuum on. In the 70's I made the steel work and wired all the lights onto street Christmas decorations that then had plastic moldings made in this fashion fixed on them.

author: Isaac Newton
author_rank: Contributor
timestamp: May 09, 2013, 09:34:55 pm
content: QuoteI would like to know what are the resins or some link I could read about those things because I have in mind a poduct that requares some kind of flex in the plastic case so the two halves would snap together without screws.I may be wrong but I think that the PU (poliurethane) resin is not very flexible... I say that because I have a design that will be killed if I have to use screws in the front painel.I think It's a very comon issue for us who are trying to bring a new product to the market and we get stuck with this limitations. If someone know a way or heve already used this method, please let as know.

author: Isaac Newton
author_rank: Contributor
timestamp: May 09, 2013, 09:39:02 pm
content: QuoteAs I said, the case will have a mechanical function so I guess vacuum forming will not be suitable for my purpose, but is a really good sugestion for future projects.

author: tridentsx
author_rank: Regular Contributor
timestamp: May 09, 2013, 10:55:14 pm
content: Maybe this step by step art lie for a diy resin enclosure will help.http://www.wired.com/geekdad/2012/12/diy-mold-making

author: Isaac Newton
author_rank: Contributor
timestamp: May 10, 2013, 05:29:11 pm
content: I think I've found one that suits my purposes:http://www.patola.com.br/index.php?route=product/product&path=59_81&product_id=228Nice thing is that It is local.Anyway, I ask forpaul23to post his photos when he make his castings. Coul be realy useful for mine future reference or anyone else who will have this issue.

author: paul23
author_rank: Regular Contributor
timestamp: May 10, 2013, 06:11:23 pm
content: Quote from: Isaac Newton on May 09, 2013, 09:34:55 pmI´m kind of limited to suppliers that I can use due to where I live. I contacted a local company and this is what they recommended, so I am going to try this first.http://adhesivostnk.es/tienda/es/96-resinas-de-poliuretanoI need to try it really to see what it flexes like. I will post pictures when done, but it wont be for a few weeks yet.

author: Apothus
author_rank: Contributor
timestamp: May 12, 2013, 08:58:38 am
content: The only other thing I would suggest is traditional machining.I do a lot of work with a local machinist and I always find it fascinating what they are able to machine from a block of plastic.With a run of 100-200 items it would even be worth while for them to program a CNC to get the costs down further.