Small-batch builds of smaller phyiscal objects

I've done a bunch of builds like that before.

Typically, machine shops specialize in some form of manufacturing type (milling / lathing metal, for example) or specific niche (metal stamping). If your parts require different manufacturing processes, you may potentially need multiple shops to get that done.

I found that Chinese machine shops are going to be both cheaper (about 8x in my experience) and faster lead time than North American shops. The exception will be that if you need something highly specialized (e.g. super tight tolerances), you may find it easier to get it done locally. I'll assume you'll be going with a Chinese place below. For finding Chinese places, I use Alibaba with MOQ set to 1.

Machine shops are always trying to expand and get bigger contracts with bigger customers. They dislike low order quantities and low volumes, and I found that I need to continuously cycle machine shops every couple of years as they move to larger customers. The other thing is that with manufacturing, there's a setup cost (flat cost per batch) plus a per-part cost. At single and low double-digit volumes, setup cost is going to be a lot. Make your part easy to manufacture - easy to clamp, made from readily available stock, use more readily available machining (e.g. 3 axis and not 5 axis, straight lines doable with a manual mill vs CNC), reduce manufacturing steps.

I found that cheaper machine shops (say, 2x cheaper than others) will tend to have a lower ability to understand what I'm trying to get done (will take a lot more & simpler communication) as well as a higher probability of the part being out of spec.

The more proficient you are at knowing what you want (obsessively defined specs and tolerances on everything you can think of) will get you much cheaper results. The less you spec out, the more they need to think about your design and your needs, and that's quite expensive from their side. My process is to have a drawing PDF that I send to 10 manufacturers for quotes, get 5 quotes back and select from those.

If you send any sort of marketable product to China, expect that it can and will be duplicated and sold in competition with you.

China sells tons of products they cloned from something pre-existing. I know because I own some of it and I've seen lots of western companies making use of it too. Here are a couple of examples of products from Amazon that existed long before China started producing clones.

https://www.amazon.com/BIG-RED-TAM82012-Hydraulic-Carrying/d...

https://www.amazon.com/BILT-HARD-Vertical-4-Stroke-Compliant...

All that being said, my best advice is to refine your design locally first, before farming out mass prooduction. Lots of local machine shops can fabricate simple custom metal parts --- they exist just for this purpose.

You're looking for a "job shop". There are small machine shops all over the world that can do this for you, but don't expect to get mass production prices... it's going to cost A LOT. You're paying for someone to figure out how to make it, set up any jigs, cut materials, etc.

I suggest you google "machine shop online"

My dad has a small machine shop that specializes in producing single run parts like this. Generally speaking you'd be able to find small shops like this around the country, but machinists aren't great at advertising or having websites so you'd probably have to use something like the Yellow Pages or local business listing to find one.

https://oneoffparts.com/

If it's all sheet metal-esque pieces, where you could suffice with just laser cut features and/or simple bends.. then you should take a look at OSH Cut.

They have a fairly powerful platform -- instant quoting from uploaded design files, 2D/3D views, DFM feedback, good turnaround times, etc -- and the pricing isn't half bad for prototyping... but might not be as good for large-scale runs compared to bigger shops where you can nail down volume pricing discounts.

I do this sort of thing, but more on the woodworking side of things. I'd look into your local maker spaces. They are filled with one to three person companies doing lots of projects just like this. I'd recommend have prototypes made using a laser cutter and then final parts machined later.

Another option is to just learn to do it your self. Many of the maker spaces will have have classes on metalworking, welding, aluminum cutting, CNCs, laser cutters. I also TA as a 2.5 day weekend workshop on the central coast that will teach you to woodworking and welding.

Let me know if you have any other questions.

Sheet metal/waterjet cutting: https://sendcutsend.com/

chineese sheetmetal/cnc milling/3d printing (including metal): https://www.pcbway.com/

But if you can find a local fabricator that is probably best as they can help you understand if you design is manufacturable as is or if there are some simple tweaks that would make it cheaper/easier.

It is practical to iterate in other materials. Cardboard would be the simplest to get started on physical form.

Galvanized steel flashings from Home Depot etc. can be hand formed with tin snips, a hammer, and a block of wood. Or you could buy a cheap brake from Harbor Freight, Amazon, etc. Same with a drill press.

Doing it yourself will speed up development and eliminate most if not all of the need for CAD drawings.

Not to mention it will avoid the mental overhead that your question embodies.

Or not, good luck.

https://www.emachineshop.com/

It’s been a bit over a decade but I used this to make small runs of metal parts for a store I worked at. Their basic CAD is good for simply parts and you can easily adjust settings to find the price vs material/finish goals you’re after.

where are you located. i both do this kind of work and know a fair number of small fabrication shops in the bay area.

all you need to do is look for 'machinist' or 'tool and die' or 'metal fabricator' and make sure its a place that takes on small random work and not some high margin specialized manufacturer. probably call them and get used to rude dismissmals.

show up and shop and ask for the guy in charge. for this kind of work its often done under the table, so offer to pay cash. its very likely that the floor manager or a senior fabricator is going to do this in their spare time and not even put it on the books.

you're gonna pay too much. probably a couple to a few hundred depending on complexity.

you also sometimes ask a metal supplier. they have relationships with these kind of people. they often aren't that friendly though

Plenty of comments already cover a lot of this. I'll throw my two recommendations here as well:

- OSHCut for sheet metal cutting and bending.

- 3DHubs (very very recently became Protolabs Network) for aluminum machined parts.

In general, the task you're now on could be considered "design for manufacture" - you have the basic concept, but now need to figure out how to go from general design to manufactured product.

Design for manufacture includes keeping in mind the process/technology that will be used to produce the part: - you can do some amazing things with laser cut and bent metal, but you're limited to a single thickness per component; - lathes are extremely precise and great for making round/concentric items, but the part is limited to rotational symmetry (barring fancy machines and/or moving the part to a mill for further work); - mills are great for all sorts of things but really shine in "2.5d" work - where you have different profiles milled down to different depths, but from a single direction. Mills also can't handle overhangs (without a 5-axis, multiple setups or very special tooling) or features in different directions without multiple setups (which add time/complexity/cost/risk of misalignment of features).

For one-off or small run products, you can get away with being very inefficient in the process - starting with a piece of stock and milling 90% of it away for instance.

For the one part I saw you post a picture of, that could be done through either SLS or similar metal 3D printing (as someone else said), or one of the "official" ways to make a gear is to cut it with a custom single tooth cutter - where you run a special cutter along the length of the gear, rotate the gear one tooth, and repeat, cutting away the space between the teeth each time. Clickspring on Youtube has a bunch of videos covering the topic. I don't know who could do that as a service though.

If you post more pictures / sketches of the project, people here might be able to give better guidance for specific parts and operations.

Last year, I backed a really interesting project on Kickstarter called Powercore. The simplest idea is that you take a cheap 3D printer (like a refurbished Ender 3), swap out the print head module for an EDM module that can disintegrate metal the way a CNC machine mills wood.

https://www.rackrobo.io/

They appear to be between versions right now, but to their credit, they are the only KS project I've ever backed that has shipped a high quality product on time and on budget. I anticipate big things from this team.

If you're near a university, check if they have a machine shop that accepts external jobs. They're used to one-off manufacturing for student projects or research lab tooling.

I used to use SunPe: https://sunpe.com

They were relatively cheap and fast (I haven’t done any prototyping in five years though)

There's a Youtube channel I watch, a machining/welding shop in Australia that makes and repairs parts for construction equipment. What amazes me is the work he gets because fabricating a new part, or substantially replacing much of an old worn part, can be like 1/2 the OEM price of a replacement part.

https://www.youtube.com/@CuttingEdgeEngineering

We've used SunPe before.

https://www.sunpe.com/

They have about a 10% full-rejection rate; so order at least 10% more than you need

Also sometimes they just mess up and get the part out of spec. Then just complain and they'll make it right

After getting more funding we switched to US based rapid proto shops that charge 3-4x, but have a better experience.

(DISCLAIMER: I only spoke to the ME guys talking about SunPe. I never used them myself)

Clough42 (YouTube machining mainly, plus CAD, 3D printing, electronics) recently said he hasn't really used sheet metal tools since discovering sendcutsend.com (I haven't used them, don't think he has any affiliation/sponsorship either).

For machined/moulded parts there's shapeways.com (I haven't used them beyond quoting).

I'm sure there's plenty of alternatives for both too, if you search 'x vs' or whatever.

A cheaper alternative to SendCutSend is Fabworks: https://www.fabworks.com/

They do stainless from .048" to .120" thick: https://www.fabworks.com/resources/materials/stainless-steel

You can try Ponoko or Shapeways - both are online services for prototyping / 3d printing

https://www.ponoko.com/ https://www.shapeways.com/

There's good advice in this thread but also you can call around to small product design/mechanical engineering shops and find out who they use for prototyping.

Otherwise yeah find a local machinist and if you're only doing a single one-off it shouldn't be too spendy.

Shapeways metal prining? Can do steel. Kinda expensive but also not when you think about it.

https://www.shapeways.com/business/metal-3d-printing

https://www.protolabs.com/ does this all day every day, but your iterations for fine-tuning you should probably try to do by finding a local 3d printer.

https://www.pcbway.com/rapid-prototyping/manufacture/

Does the initial prototype have to be made of metal? Can you work out the initial kinks with something 3D printed before moving to a expensive and laborious material?

Find a local machine shop or two and ask them to machine them.

An expensive machining job that finds problems early will save lots of money.

Where I live in Canada here it's like a mini-china when it comes to shops and manufacturing. You can speak to someone that speaks English and won't steal your product. As well as USD is worth more than CAD, you will get a decent deal. I know of one shop that does custom fabrication that I've done IT work for: https://www.acmetalfabricating.com/

Xometry will fabricate pretty much anything from anything and it's easy to use - but not cheap.