EEVblog Electronics Community Forum
Electronics => Projects, Designs, and Technical Stuff => Topic started by: dan3460 on February 23, 2017, 01:55:32 pm
-
A week or two ago I posted a topic about finding enclosures for a project. I got a few ideas but after more that a week of trolling the net I'm more frustrated than before. One of the websites offered a design tool and in a exchange of emails they told me that they pricing was the best I could find. After a few hours of installing and learning the tool, which had many restrictions in terms that the width needed to be more than the length etc, came up with something that resemble what I needed. Press the button for "quick quote" and gave me that quote at $360 plus another $40 for tooling.
Most of the stuff that I can find are for "hobbyists", and will look find if I just wanted this for me but I want to be able to eventually sell this. I saw a couple of beautiful enclosures, but the cost was too high. The enclosure that I envision is similar to this one: http://www.ebay.com/itm/30V-5A-Variable-Adjustable-DC-Power-Supply-Switchable-Lab-Grade-w-Cable-110-220V-/311804478685?hash=item4898fec4dd:g:1dYAAOSwHsRYEXDm (http://www.ebay.com/itm/30V-5A-Variable-Adjustable-DC-Power-Supply-Switchable-Lab-Grade-w-Cable-110-220V-/311804478685?hash=item4898fec4dd:g:1dYAAOSwHsRYEXDm) If they are selling this supply for $40, which includes shipping, I would assume that they are not investing more than $5 on the enclosure. Where do they get this enclosure?
-
They stamp them out by the thousands.
I tooled-up a complete CNC machine shop in my basement in order to make cases for electrical equipment my company was designing. Actually, we made the prototypes with the plan to have them farmed out. Prototypes are expensive and it isn't a rip off when you see the amount of time that goes into designing something and then creating the machine programs. The cases you are pointing out are very specific to the purpose which adds much, much more to the price. Look around the surplus stores and see what you can re-purpose.
If that case fits your design for $40, it is 1/10th the cost of a custom box, buy it and rip the guts out.
-
My guess is it's folded sheet metal in 2 or 3 parts with the front, back, and any holes for mounting or handles, etc, stamped out. It's folder into an enclosure and screwed together. Controls are on a PCB that mounts to the front side, and a molded plastic bezel/front sits on top of that. These things are extremely cheap to make in volume, but not really viable in small batches.
-
I use a company called protocase (though I have not used there web tools to build the box, I have a 3D CAD program) there price might be little better but not much for something like that in low quantity. I get 1U chassis made fairly often in low 10s of units and pay about ~$500 unit. which sound expensive but it much cheaper than doing it in house and very competitive with most machine shops. Unfortunately in low volumes things like this are very expensive. The $40 PSU probably has a 2-5$ case but I bet they pay $10K NRE and tooling charges to make them, not bad if your making 5K-50K units though. I doubt you could get a case like that custom made for less than $50 till you are in the 500+ unit range. If you use a extruded Aluminum enclosure though you could get the cost down faster since all you really have make is the end plates.
-
Thanks for the comments, it seems that there is no way to get what I want cheaply. Protocase was the website that I used.
Don't know what to do. I thought that getting a decent box to put my design, which is no more than $15 in parts including the PCB, would have been the easiest part. Don't really know what to do.
-
do you NEED metal?
metal is nice but its not as easy to work with, for many of us.
if you have a hacker space nearby - meaning, a laser cutter - you can make 'tabbed boxes' easily with 2d design programs or even a website like this:
http://boxmaker.connectionlab.org/ (http://boxmaker.connectionlab.org/)
the boxes I make look like this:
(https://c2.staticflickr.com/6/5826/31288166375_5c0a42325f_z.jpg)
its glue-less (so I can replace or change panels at will; especially if it drops and breaks!) and its very service-friendly (those acorn nuts are hand tightened and you can easily get into the box, even at a trade show or similar - with no tools). cost is very cheap since the plastic is about $20 for an 18"x24" sheet of 1/8" acrylic. and since its just 2d objects, learning curve is simpler than cnc or 3d stuff.
I started in the hobby when I was a kid in the 1970's and we had to 'machine' our own boxes using hand tools, drills, reamers, etc. they always looked BAD. hand made never looks great when you compare to machine accuracy. I converted over to doing custom boxes to-size using the laser and unfortunately, I have a stock pile of LMB, BUD (etc) metal boxes that I'll probably never use since its easier and cheaper to make a box to-size than to use a premade one and have to tool the damned thing ;)
and labelling with plastic is super easy. you etch the lettering in, and what I do is to in-fill with white acrylic paint (leaving the plastic mask on; you laser etch thru the mask), use the mask to keep paint out of the voids and press the paint in until it dries (half an hour). peel off the paper backing, scrape off the overflow paint with soft plastic or even fingernail since the paint does not stick well to shiny plexiglass but it just hangs out in the voids and pretty much stays there. with laser etching you can do graphics and much more than just simple lettering.
best part is: you try various sizes and do a dry-test fit while at the shop. I found a secret that speeds things up: you do your first few print runs on cardboard (like office folders). they lase faster than plastic, they cost almost nothing and they let you get the spacing right without wasting good plastic. once I do some test runs with the cardboard stock and all the parts line up the way I want (external jacks and buttons), THEN I put plastic in the cutter and do the real thing.
again, metal would be better almost always, but I can leave my local techshop that nite and walk out of there with a fully done chassis that I know will fit the board and parts. sending things out means waiting and you cant 'iterate' over the design. if you measured something wrong, you have to pay to redo it and wait again. much better to have access to the machines yourself, if you are designing new stuff.
HTH
-
Another option is to create/debug the design in wood using a laser cutter, and then use a local service bureau to cut it from metal.
-
do you NEED metal?
metal is nice but its not as easy to work with, for many of us.
if you have a hacker space nearby - meaning, a laser cutter - you can make 'tabbed boxes' easily with 2d design programs or even a website like this:
http://boxmaker.connectionlab.org/ (http://boxmaker.connectionlab.org/)
the boxes I make look like this:
(https://c2.staticflickr.com/6/5826/31288166375_5c0a42325f_z.jpg)
HTH
That is a nice box. My box doesn't need to be made of metal, plastic will be fine. I checked with a couple of people around me for laser cut (I have a piece of plastic that I want to make square cuts and either not getting answers or they telling me that their laser is not too powerful).
Do you have information that you can share about the people that are you using?
-
I joined tech shop, myself, so I do my own work. I'm lucky that there are 3 TS's near me and they all have decent laser cutters.
they allow 2 hour slots to reserve, which is about the time it takes to develop (from scratch) one of those boxes and iterate thru a few trys before going home with the final version. if I have my design all done and its just a matter of making more, I can make about 4 of those boxes in the 2 hour slot we're allowed. etching takes the most time, so I hold off doing any graphics or text until at least a dry-fit passes.
if you can't find anyone who can do the work for you, PM me and we'll see if something can be worked out. I'm just a hobbiest, though; not a pro.
-
I'm not a fan of of the hobbyist level prototyping tools (laser/fdm) because they produce geometries/finishes that are very distinctive.
FR4 can look really good in certain situations ( https://www.eevblog.com/forum/projects/make-a-cool-case-out-of-pcb-only/ (https://www.eevblog.com/forum/projects/make-a-cool-case-out-of-pcb-only/) http://hackaday.com/2015/06/03/how-to-build-beautiful-enclosures-from-fr4-aka-pcbs/ (http://hackaday.com/2015/06/03/how-to-build-beautiful-enclosures-from-fr4-aka-pcbs/) )
You can prototype relatively cheaply in sheet metal but need to design for the process. For small parts I'd just get someone to waterjet/laser a sheet of metal and do the bending myself.
-
I know that for prototyping you can use anything, I even have a couple of prototypes done on tin cans, that is the reason that I never worried about enclosures until I decided to start selling some of the things that I do.
I'm not sure that FR4 would look good. The thing that I will probably do is to have the PCB fabricator to make some "faces" once I find the box that I will be using, I think that is a cheap way to have nice cuts and the silk screen on the different knobs and plugs.
-
\ Where do they get this enclosure?
It's probably the sort of thing you can buy from several market vendors in Shenzen no problem, but just doesn't get exported as units on thier own.
Maybe try searching taobao.com or 1168.com in Chinese