The Shapeways Store Buyer's Checklist: CO2 vs Fiber Laser, 3D Printer Size, and CNC Tool Details

For the last six years—actually, five if I don't count the first messy year—I've managed procurement for a 34-person hardware company. Our team designs enclosures, brackets, and small sheet-metal assemblies. Some parts go through Shapeways. Others go to laser cutting or CNC shops. The mistakes I've made along the way are why I now keep a checklist.

When I first started approving custom-part orders, I assumed the lowest quote was the right call. Then a $90 part ended up costing $520 after support removal, grinding, and a rush finish fee. Not a lesson you forget.

Here's the checklist I run now. It's written from a buyer's perspective, but if you're running a Shapeways store, the same questions work in reverse. The focus is on total cost, build size, process type, and the details that don't show up in a spec sheet.

The seven checks I run before approving a custom part order

This is a practical list. If you're comparing Shapeways with another service, or trying to decide if a direct factory quote is worth the risk, these are the checks that catch the expensive problems.

1. Define the part before you define the process

Before you compare platforms, write down what the part actually does. Does it see heat? Does it need to flex? Is it cosmetic? That changes material and process more than any quote line.

Five items: use case, max operating temperature, likely loads, surface finish, color. If two people can't agree on those, don't upload the file yet.

2. Compare total cost, not the first number

Shapeways has an instant-quote system, which makes it easy to compare materials. But an instant quote is not a total-cost statement. Look past the first number for setup, support removal, plating, dyeing, tapping, and shipping.

We put every quote in a spreadsheet. The name on the tab is 'TCO sheet.' Once, a $28 part with a $46 setup fee beat a $31 part with no setup only after I ordered 30 units. The $31 option was the right call for our quantity. The $28 quote only looked better at first.

The real cost of a part is never the first number on the quote.

Shipping matters too. According to USPS pricing effective January 2025, a First-Class Mail large envelope (1 oz) is $1.50. That's cheap. But the moment your part is too thick, oversize, or heavier, parcel rates apply. A low part price plus slow shipping can have a higher total cost than a slightly higher part price with tracking and three-day delivery.

3. Check build size, not '3d printers size'

People search '3d printers size' the way I did: looking for one number that tells you if something will fit. There is no single answer. A desktop printer's machine footprint is not its build volume. On Shapeways, each material page lists a maximum part size. That's the real number to check.

Take the longest axis of your part and compare it to the material's maximum build envelope. Then think about supports and orientation. A part may fit by length but not by overhang. The software won't flag that as a problem—it will simply add support material to the quote.

Build size isn't the only size limit. Check minimum wall thickness and minimum feature size, too. A 0.3 mm rib may look correct on your screen, but the printer may not be able to produce it. If you don't know the material's minimum wall, ask before you approve anything.

4. Ask whether the laser quote is CO2 or fiber

The question 'what is the difference between CO2 and fiber laser?' comes up on almost every sheet-metal project. Short answer: wavelength.

CO2 lasers operate around 10.6 μm. Fiber lasers operate around 1.07 μm. That matters because materials absorb the energy differently. CO2 is usually the practical choice for wood, acrylic, paper, and many plastics. Fiber is generally better for metal, and it uses less electricity, which can show up in the operating cost.

If a quote says 'laser cutting' and the part is aluminum, ask whether the shop uses fiber or CO2. If it's an acrylic prototype, CO2 is normal. Neither is better globally. It's about matching the beam to the material.

The same logic applies elsewhere. A supplier quoting a one-off printed bracket and a supplier quoting 1,000 machined brackets are not in competition. Compare the process, not just the final file name.

5. For CNC parts, ask about the tool before you ask about the price

CNC quotes get expensive when the tool and the geometry don't match. If a pocket has an inside corner, the corner radius can't be smaller than the cutter radius. A square-corner spec with a 6 mm end mill is a red flag.

For 3D-contoured surfaces, a long ball nose end mill is a common choice, but it leaves scallop lines. The finish depends on stepover, so ask the shop what stepover they planned into the quote. Smaller stepover means more time and more cost.

Also, don't confuse a tooling quote with a part quote. People searching for a long ball nose end mill factory in China are usually looking for cutting tools. If you actually need a machined part, a tool factory can't compete with a machine shop—they make the tool, not the bracket. I made that mistake once, so now I list what the supplier sells before I compare.

Another detail: if you don't ask, the shop will choose the tool they always use. That tool may leave a larger radius than your design allows. Your options are: add inside fillets that match the cutter, use a smaller cutter, or pay for EDM. We had an aluminum bracket quote increase by $58 because the default tool couldn't hold a 1 mm inside radius. It was worth it. But it changed the lead time, and I only caught it because I asked.

6. If you're buying from a Shapeways store, qualify the store

'Shapeways store' is not one thing. It's a storefront, and behind it is either a designer who outsources production, a shop with their own printers, or a reseller. All of those can be fine. But you need to know which one you're buying from before you send money.

Ask three questions before ordering from a store. Are you making this in-house? What post-processing is included? Do you test components before shipping? A good seller will answer in one message. A vague answer is a warning.

Per FTC advertising guidelines, sellers have to substantiate the claims they make about products. That doesn't guarantee quality, but it's a reason to keep records if a store claims 'made in USA' or 'weatherproof' and the part fails.

If you run a Shapeways store, use the same discipline on your side. Small orders are how buyers test you. The vendors who treated our $180 trial order seriously are the ones who later got a $24,000 production order. Don't treat small buyers like a nuisance.

7. Define pass/fail before you pay

What does 'good enough' look like? If your only answer is 'it should work,' make that concrete. For dimensions, choose which features you'll measure and what tolerance you expect. For color, use a standard reference if you have one.

Pantone is the usual starting point for brand color. The industry standard close-match tolerance is Delta E < 2. In 3D printing, that's hard to hit, especially across different materials. A filament print and an injection-molded part will not look the same. If color matters, get a printed sample in the actual material first.

For threaded holes, test with a real screw. For press-fit inserts, test with the mating part. This sounds obvious, but we had parts approved on paper that failed when someone put a screw in them.

Layer lines are not defects. If you don't like layer lines, pay for post-processing or pick a different material. If you don't tell the vendor this upfront, you'll get exactly what the process produces.

Final notes and the mistakes that still happen

Rework isn't always the factory's fault. I only fully believed that after our design team changed a mounting hole after the file was approved. That cost us $750 and a week. Now the checklist includes 'design frozen?' before I click accept.

The same checklist won't work for everyone. I can only speak to mid-size B2B product work with fairly standard requirements. If you're doing certified aerospace parts, you need a lot more than a checklist. But for prototyping and low-to-mid volume custom parts, this stops the expensive surprises.

Also worth remembering: small doesn't mean unimportant. The suppliers who treated our $250 trial order seriously are the ones I trust now with larger jobs. We all start somewhere. I'd rather work with a vendor who asks questions about a small part than one who ignores it because the order is small.

That's the whole checklist. Seven checks, one spreadsheet, a lot fewer overruns.