Ask HN: Small-batch builds of smaller phyiscal objects

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.

I suggest you google "machine shop online"

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.

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

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

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.

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

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)

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.

https://oneoffparts.com/

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.

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.

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

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.

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

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.

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.

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

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