How do you make cheap enclosures (for production) - Page 1
Forum section: electronics / general

author: Saimoun
author_rank: Frequent Contributor
timestamp: September 23, 2020, 12:25:55 pm
content: HiShort version:How do companies manage to manufacture a custom metal case so cheap? (Example:https://www.thomann.de/gb/behringer_ha400.htm- nice metal U-shape case, the whole products sells for about $25!!)How do you guys choose your enclosure for manufacturing/selling products?Long version w/ background:I am trying to launch a product and we are still at the developping phase. We would like to have a prototype that is as close as possible to the final product. Obviously there will be changes but the idea is to take the price (price per unit for let's say 1000 units, not the price of the prototype itself) into consideration from the start to avoid realizing too late it will cost way too much to manufacture to be sold at a decent price.Ideally we want to sell the product about $100 max (so about $20 manufacturing price).I have already cut down a lot the price by trying to optimize the PCB, the manufacturing, the components, and the plastic knobs. For 1000 units, we can get all components+knobs for about $5. To that we need to add PCB+Assembly+Shipping: PCB is a small 2-layer PCB and the assembly is one-side SMD + very few TH on both sides. So just to have an idea let's say the budget for the case is about $5-10 per piece.So far it seems the cheapest option would be a pre-made plastic case (from Davies Molding f.x.) which we can give to a manufacturing house to drill holes and assemble. I guess the same can be done with metal cases, we are investigating now.We also tried the custom case way, and got a really nice quote from Protocase at 50$ per unit (for 1000 quantity) - even though it was a simple L-shape based on their models.Hence my questions aboveAny comments/remarks or questions even are more than welcome!Thank you!

author: tszaboo
author_rank: Super Contributor
timestamp: September 23, 2020, 12:36:19 pm
content: 1.) Steel is cheap in china. So cheap, that depending on the product, shipping could cost more.2.) You invest in an injection molding tool. That will set you back a few thousand EUR, depending on size, and mold material.Making competitive price at 1000 pieces is really hard, at least that is what I think. At larger quantities, you can create custom parts, and the NRE cost amortizes. At smaller quantities, you can buy as expensive parts as you want. At 1000 pieces, the NRE and tooling cost could easily be higher than the product target price. Obvious solution is to select a market, that is not price sensitive. And leave the "race to bottom" for places like east Asia.

author: ar__systems
author_rank: Frequent Contributor
timestamp: September 23, 2020, 12:39:15 pm
content: This is cut and bent sheet metal, then powder coated. Probably cost $1-2 to makes.

author: Saimoun
author_rank: Frequent Contributor
timestamp: September 23, 2020, 01:21:37 pm
content: Thanks for the repliesFair enough, 1000 units is not much, that is also why we thought we should remove tooling as an option.@ar_systems -> we asked from Protocase precisely this, two pieces case with a few bends and a few holes. At 1000 units their price was $50/unit.

author: SMTech
author_rank: Frequent Contributor
timestamp: September 23, 2020, 01:42:23 pm
content: Quote from: simonlasnier on September 23, 2020, 01:21:37 pmLolz, once you are out of the really low volume qtys, I'd stay away from anyone with "proto" in the name, they often aren't setup for volume. We make some (rather more expensive) HiFi bits in 1/2 size chassis and those cases come in @ 1/2 that in batches <100. The machined & anodized aluminum fronts is another matter of course. Go direct to China with the right volume and design and the cheap options will be there. Much like with PCBs there a good chance your local fabricator also has a volume from China pricing structure too.

author: nali
author_rank: Frequent Contributor
timestamp: September 23, 2020, 01:49:41 pm
content: There was a thread about Chinese CNC cases a little while ago...https://www.eevblog.com/forum/manufacture/custom-aluminium-anodized-cncd-enclosure/msg2759686/#msg2759686You could also go the extrusion / end panel approach which is a sort of halfway house. If you can find a suitable extrusion it's then just a case of getting the end panels laser cut. Don't forget you'll presumably want silk screening which will be an extra process (cost).Finally some choose to use PCBs as panels, although I personally think that looks a bit amateurish. Depends on the product and the market I guess.

author: Saimoun
author_rank: Frequent Contributor
timestamp: September 23, 2020, 05:09:24 pm
content: Thanks so much that helps a lot! I'll look into those chinese manufacturers then

author: ar__systems
author_rank: Frequent Contributor
timestamp: September 24, 2020, 01:17:07 am
content: Quote from: simonlasnier on September 23, 2020, 05:09:24 pm$50 for a stamped metal part @ 1000 pcs is ridiculously expensive even for first world manufacturers. Shop around, and yes 1000 pcs is already large enough volume to talk with Chinese suppliers

author: Alti
author_rank: Frequent Contributor
timestamp: September 24, 2020, 09:21:09 am
content: Another option is to try the other way around: buy a standard case and adapt your PCB and knob layout to it.Have you colsulted the subject withBernic?I am sure you can go cheaper in PRC but with 1000 units the added transportation cost, delivery delays and communication problems have to be included in the budget.

author: phil from seattle
author_rank: Super Contributor
timestamp: September 24, 2020, 02:56:24 pm
content: Quote from: Alti on September 24, 2020, 09:21:09 amYup. All the case manufacturers are willing to do a lot of customization on their standard offerings.When designing a product, it is best to start from the outside and work inward. Design (or at least rough out) the case, figure out the external controls and connections and then start designing the insides. You may have iterate if there isn't enough room for what you need. The case should never be an afterthought but an integral part of the design process.

author: Saimoun
author_rank: Frequent Contributor
timestamp: September 25, 2020, 05:11:52 pm
content: Thanks for the replies again - and yes I fully agree about working from the outside: case -> knobs, displays and connectors -> component placing & PCB design.Our problem has been it is really hard to find a decent cheap case to start with - Davies has some decent options but we are now pretty convinced we want a metal case. There should be pre-made U-shape or L-shape cases, which we can customize, but we have not found any so far. The few metal cases we found are usually the same format at the plastic cases: one rectangular box with a lid.

author: The Soulman
author_rank: Super Contributor
timestamp: September 25, 2020, 05:43:22 pm
content: Have you checked with TEKO and Hammond?Both have what you describe and both can do custom machining.

author: Alti
author_rank: Frequent Contributor
timestamp: September 25, 2020, 05:56:00 pm
content: Quote from: simonlasnier on September 25, 2020, 05:11:52 pmIf you want metal fancy shape then I really doubt you could find sth generic and cheap.

author: Saimoun
author_rank: Frequent Contributor
timestamp: September 26, 2020, 09:38:15 am
content: We looked at Hammond, we will check again, as well as Teko then, thanks.

author: ucanel
author_rank: Regular Contributor
timestamp: September 26, 2020, 11:01:33 am
content: Would you like to do it yourself if soyou may try plaster molding for resin ormaybe vacuum forming orsheet metal forming:this guy has some good videos on sheet metal formingmaybe some youtuber may made it for you.Youtube channel: Stuff made herehttps://youtu.be/8cNeAOpR-Ws

author: Yansi
author_rank: Super Contributor
timestamp: September 26, 2020, 11:09:30 am
content: Quote from: simonlasnier on September 23, 2020, 12:25:55 pmBecause it is cheap these days? Even in our shitty post USSR country, I can have such an simple enclosure manufactured under $10 likely even in single quantity.Laser cut steel is extremely cheap these days. Computer controlled bending presses are also abundant in modern metal workshops.That two pieces laser cut will be well under $4 in single quantity, and then you need what, like 6 bends? costing maybe another $4.Go ask local companies. I was myself quite baffled when I have learnt this.//btw, no special cad modelling skills required, the company I have worked with recently just wanted DXF files for the cutting and bending drawing was just a piece of hand drawn sketch I have scanned and sent them with final outer dimensions of the bends.//

author: Saimoun
author_rank: Frequent Contributor
timestamp: September 28, 2020, 11:23:54 pm
content: Thanks for the reply. We actually contacted a local firm to make a small metal plate - we paid about $100 for two pieces, and that was clearly black work since the guy asked to be paid in cash. Their original price was about $150. It fits the other prices we got from a few other local companies. But that was for a small amount, I am thinking for 1000 pieces it might be much easier.

author: Alti
author_rank: Frequent Contributor
timestamp: September 29, 2020, 05:14:57 pm
content: Quote from: simonlasnier on September 28, 2020, 11:23:54 pmI cannot see the difference.It is a fixed setup/design price + 1000*manufacturing cost.It might be 98€+k*1€ or it might be 20€+k*40€. Both would have resulted in 100€ for k=2.Do not forget to agree the details of surface finish and shipping/packaging.Painted/zinc coated/stamp-pressed/deburred etc.BTW, "local firm", do you have USD in DK?

author: Kasper
author_rank: Frequent Contributor
timestamp: September 30, 2020, 03:41:26 am
content: 3D hubs has a great website with automated DFM review and quoting. Lots of options to explore there. Recently added sheet metal. I've only tried their 3D printing.They use distributed manufacturing so they might have someone local to you.

author: Berni
author_rank: Super Contributor
timestamp: September 30, 2020, 05:29:19 am
content: That Behringer box with bent sheet metal is the cheapest solution for low volume. If you look well enough you should be able to find a local sheet metal place that will do it for <10 USD a piece at a 100 quantity.You just need to draw up a flattened blueprint of the box in a friendly vector format so that they can load the outline into a laser cutter, then they use a press to bend the flat shape into a box. They will also probably be able to get them painted for you, either painting it themselves or having someone else do it for them. With luck they can also silkscreen or laser engrave text for you too.You can also find a Chinese company that will do the same, but do budget a good bit of extra time for that. The first company you find might not do a good job and there are communication barriers as well as slow shipping. But once you do find the right guy and manage to correctly explain to them what you want, then you have decent quality custom made boxes for really cheap.

author: Fire Doger
author_rank: Regular Contributor
timestamp: October 01, 2020, 06:45:40 am
content: If you don't feel comfortable getting them from China you can search at east EU countries.It's just laser cutted metal sheet.Olymex is selling some enclosures exactly as yours (for their boards) for ~15$, so it's definitely feasible sub 10$Companies that do a lot of products with sheets they even import low grade steel from Turkey and use it for spots that are not visible. You can find great prices if you search.

author: Saimoun
author_rank: Frequent Contributor
timestamp: October 02, 2020, 12:32:56 pm
content: Thank you all for the replies, it helps a lot!!We are checking Olymex and 3D Hub.@Alti -> yes prices were in DKK - just converting to USD for simplicityAnd yes that was what I meant, if the price is $98+k*$1, then it means we paid $50 per unit for 2, and will therefore be $1.1 per unit for 1000. But we do not know the details of the price.Based on all your comments, we decided to go with the following:1) Custom design our own enclosure for stainless steel - 2 pieces assembled in U-shape or L-shape2) We will try to follow the usual guidelines about tolerances, bends, etc., hoping it will fit most of the manufacturers without any extra costs3) Once we have the files we will ask a couple of manufacturers to have a price for 1000, both locally in Denmark, in EU, and also in China.Our problem with China is to find the manufacturers, for some reason it is really easy to find PCB manufacturers/assemblers from China, but quite hard to find enclosure manufacturers. We were thinking of using alibaba to find them - any thoughts on that?ThanksSimon

author: Yansi
author_rank: Super Contributor
timestamp: October 02, 2020, 02:49:55 pm
content: If you want a cheap enclosure, do not use stainless steel. Stainless is not a cheap material and is harder to work with (for any manual mechanical finishing jobs).

author: Alti
author_rank: Frequent Contributor
timestamp: October 03, 2020, 09:37:46 am
content: Quote from: simonlasnier on October 02, 2020, 12:32:56 pmWhat, where? Is it the same topic?Not my comments apparently.Custom, stainless & cheap? No kidding.

author: Saimoun
author_rank: Frequent Contributor
timestamp: October 03, 2020, 11:24:35 am
content: Fair enough, you guys kept speaking about bent sheet metal - I thought the material was stainless steel, it is what most of the manufacturers we looked at suggested for bent sheet metal. What is the material, then?And so you think custom cannot be cheap? I got the impression that it should not be that expensive to get a factory to make a few holes and a few bend, for a 1000 enclosures.

author: Yansi
author_rank: Super Contributor
timestamp: October 03, 2020, 09:38:14 pm
content: Jeezus... absolutely none of the cheap enclosures are from stainless steel. Stainless is expensive. There is no need for it (unless designing stuff for specific corrosive or food handling enviroments).They are the most basic DC01 grade steel sheets. Mostly powder coated fully, or just one side, rest of the surface being zinc plated.

author: Saimoun
author_rank: Frequent Contributor
timestamp: October 04, 2020, 12:57:40 pm
content: Ok thanks.

author: Fire Doger
author_rank: Regular Contributor
timestamp: October 04, 2020, 09:40:02 pm
content: Stainless steel doesn't "stain". As you can see in most of gear teardown on EEVblog Dave is looking for rust (and usually finds a little), no-one is using stainless for enclosure.You can avoid rust if they don't have sharp edges (ask manufacturer for it).Sharp edges will take more time / material to cover and usually have none or very thin layer of protecting coating that's why they rust.

author: Cerebus
author_rank: Super Contributor
timestamp: October 04, 2020, 10:57:12 pm
content: Quote from: simonlasnier on October 03, 2020, 11:24:35 amI think they saw you coming.I'd avoid anybody who blindly suggested stainless to you without you having given them a good reason to suggest it and I suspect you didn't. It's an inherently more expensive material and harder to work with than plain old mild steel which is what is probably most appropriate for your use. Kind of smells of 'sharp' business practices to me.If something like the Behringer case you linked to is what you want, then you're looking for simple mild steel, perhaps a passivated version of mild steel such as Zintec, finished by powder coating.The cheapest way to manufacture cases like this, once you get beyond a certain minimum quantity, is for someone to create a set of stamping dies that will cut, out of cheap flat sheet metal, the outline of your flat case parts, including punching any connector, control, ventilation, and even screw holes in one operation. That's followed by a few simple bending operations, optionally some spot welds where corners fold over and then powder coating. Probably followed by silk screening to get any labelling you need. That will get you the minimum per case material and manufacturing costs, but with the NRE cost of the dies as an upfront cost. The exact quantity breakpoint where this becomes the cheapest option is going to depend on the complexity of the case (number and type of holes etc.).At the other end, quantity wise, any competent machine shop that does sheet metal work will be able to fabricate individual cases by cutting out sheet metal stock, drilling and punching out individual holes, and folding the flat parts on a box and pan folder. Your cost per case will be much higher, but there aren't any NRE costs.Cases made from die stamped parts are likely to be more consistent than individually fabricated cases.Powder coating costs will roughly be the same at both ends of the scale. Screen printing costs will also be similar at both ends of the scale with the caveat that there's some setup costs to any screen printing run, which makes long runs cheaper per unit.Anything that involves 'proper' machining operations such as drilling or milling individual holes and openings, to modify existing stock cases is going to be more expensive because those operations have to happen toeachandeverycase you have made. It's cheaper overall below a certain minimum number, but once you get to a certain number then it's better to invest all that 'proper' machining into manufacturing dies rather than individual cases.The same logic applies to the dies for making custom aluminium die cast or extruded cases. Those are an inherently more expensive option, both for dies and basic manufacturing, and for the fact that you're unlikely to get a finished case without doing some further machining to the, already custom, case for those processes. If you start with stock cast or extruded cases, then the per case machining costs are all unavoidable and therefore higher still.

author: Saimoun
author_rank: Frequent Contributor
timestamp: October 07, 2020, 09:47:22 am
content: Thank you Cerebus that really helps a lotAnd @Fire Dodger thanks that's a good tip we will try avoiding sharp edges, sounds difficult though to avoid it where the metal plate ends (for ex where the two pieces of a U-shape case meet)?We are definitely a lot smarter than we were before this topic - so that's good. And also convinced custom is the way forward then - it is also a lot more fun than spending hours trying to find an already existing box to modifyI have a lot of audio devices similar to the one we want to make at home which we looked at - and to be honest that's all we saw: L-shape or U-shape metal case, or extruded aluminium. The aluminium ones are usually made of one round aluminium piece covering top, bottom and two of the sides, leaving the front and back side for connectors/pots, these often covered by a flat metal plate.This one f.x. :https://www.thomann.de/gb/art_headamp_4.htm- the round metal is one aluminium piece which has a way for the 2 PCBs to slide into (no screws needed) and has built-in thread for screws for the front and back panels, as well as a way for these nice rubber sides (clearly custom as well) to slide onto it. The front and back plates seem a lot heavier so I would definitely guess there are steel.