what type of injection molded enclosure is this? - Page 1
Forum section: electronics / beginners

author: VEGETA
author_rank: Super Contributor
timestamp: December 16, 2020, 10:48:22 pm
content: Hello,kindly see attachments, it is this producthere.I wanted to do a teardown on this but couldn't figure out how to open it without using force... can you guys tell?It is very cheap price despite the injection molded enclosure... how is this possible? it looks like some hard translucent plastic.regards,

author: ataradov
author_rank: Super Contributor
timestamp: December 17, 2020, 12:05:11 am
content: There are clear latches around USB connector. Some force will be required. It may be a chap plastic that is good enough for one snap.

author: Renate
author_rank: Super Contributor
timestamp: December 17, 2020, 12:35:08 am
content: Sacre bleu! SCART! (Syndicat des Constructeurs d'Appareils Radiorécepteurs et Téléviseurs)

author: VEGETA
author_rank: Super Contributor
timestamp: December 17, 2020, 12:46:41 am
content: QuoteI increased my courage a bit and took it apart from there, I like how this enclosure is done. rigid enough and can be taken apart (just not so easy).I wonder if injection molding is cheap enough these days... this product costs about 65$. Surely not much inside (100MHz quad opamp + video buffer ic + sync stripper lm1881 + other misc components) but still 65$ is low.where to get info on pricing of such enclosures if you know?Quoteyes dear it is SCART to component converter for my retro consoles. best way to play them.I designed my own circuit though... gonna make it soon.

author: amyk
author_rank: Super Contributor
timestamp: December 17, 2020, 01:03:36 am
content: If it's a low quantity item, most of the price probably goes toward the case --- once the dies are created, each additional part can be produced very cheaply (basically for not much more than the cost of the material) but the dies themselves are not cheap.

author: Yansi
author_rank: Super Contributor
timestamp: December 17, 2020, 01:04:54 am
content: Injection molding is very very cheap. But the tooling and equipment to do it is extremely expensive. If you want just some small custom plastic parts, the tooling required (the mold) can come north of $10,000 - depending of course of the complexity of the form and mechanism and material used (for the required life span of the mold).But sure, after paying for the initial tooling cost, it'll churn parts like crazy for cheap.

author: wizard69
author_rank: Super Contributor
timestamp: December 18, 2020, 06:32:38 pm
content: Injection molding can be very cheap, I'd be surprised if the resin for that box cost more than a cent. The big cost is in the tooling and even that can be cheaper than the "old days" due to the use of CNC and 3D software. If you make enough parts the cost of the tooling is pretty low on a per piece basis.Back in the day when I was into die cast (basically zinc injection molding) you could get a very rough cost of a part simply by weighing it. In fact that was a big factor in pricing. Plastics is much the same, the weight of the part will be significant in pricing from the casting plants point of view.DaveQuote from: VEGETA on December 17, 2020, 12:46:41 am

author: VEGETA
author_rank: Super Contributor
timestamp: December 18, 2020, 07:44:59 pm
content: QuoteSo how much cheap are we talking about? like for 100, 300, and 1000 quantities of such a product in pictures above.I hear like 10000$ minimum for a mold then it is about 1$ or less for each par. this won't be economical unless I am doing 10000 pieces or more.can this type of box be done for about 10$ or so for such small quantities?Also, what about painting and drilling...etc

author: ataradov
author_rank: Super Contributor
timestamp: December 18, 2020, 07:49:31 pm
content: There are definitely services that do low quantity injection molding into silicon molds specifically for small runs. Those molds are cheap to make, but they don't last long.But I really have no clue how to even start looking for them. I'd be interested in finding a manufacturer like this. But they don't advertise well, and rely on you contacting them for a quote, and it is a lot of effort to contact everyone you find though google.You ideally want to eliminate painting and drilling by designing your mold to have all the holes you need and picking the right color of plastic rigt away.

author: Teledog
author_rank: Regular Contributor
timestamp: December 20, 2020, 02:53:53 am
content: Considered 3D prints for short runs?If you don't care to design your own enclosure, there's a lot here;https://www.thingiverse.com/search?q=SCART&type=things&sort=relevant

author: VEGETA
author_rank: Super Contributor
timestamp: December 20, 2020, 09:20:44 am
content: Quote from: Teledog on December 20, 2020, 02:53:53 am3D printing is ok and known but the speech here is about injection molding being cheap.

author: tszaboo
author_rank: Super Contributor
timestamp: December 20, 2020, 10:11:07 am
content: Quote from: VEGETA on December 18, 2020, 07:44:59 pmSmall production runs use Aluminium mold. You can make a mold in Europe for something like 3000 EUR, mold like is like 50-100K depending on... many tings.

author: kosine
author_rank: Regular Contributor
timestamp: December 20, 2020, 12:14:59 pm
content: Since it's clear, it's very probably polysytrene, about $1-2 per kg depending on quantity purchased. Total part weight is maybe 20-30g, so material cost is negligible.Production costs depend on the size of the moulding machine used. This enclosure wouldn't need anything very big, so maybe $30/hr in US/Europe, probably under half that in China. Would cycle in about 15s and they'd probably make both halves of the case on the same mould (a "family mould"). You can work out the costs, but again it's not much.If they needed the quantity they'd have 4 or 8 cavities in the mould. If that's the case, then there may be numbers embossed onto the mouldings to indicate which cavity they came from. (Makes it easier to identify any issues with the moulding process.) For a niche product, it'd likely just be the two halves since the mould would be smaller and cheaper.The case looks like it has been designed so there are no undercuts or side holes, it's therefore a standard job to make a mould. Would have been done by EDM ("spark erosion") which requires copper or graphite electrodes making first. This indicates it would likely be a steel mould. Aluminium is a bit harder to EDM, but quicker to machine. An off-the-shelf blank mould-set for a job like this would be maybe $2000 in the west, less in China I expect. The rest of the cost is paying someone to cut it, but it certainly wouldn't be more than $10,000 if you know the right people. (Again, likely a lot less in China etc.)A small company could actually buy the required equipment to do everything in-house for about the same price. Hire a toolmaker/moulder and the costs for injection moulding becomes pretty cheap. (Since this is an electronics forum, that may sound a little daunting, but then a moulding company would feel the same about setting up a pick-and-place facility. Both are quite doable with the right people involved.)