How 5 Rapid Prototyping Companies Work

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  Key takeaways
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  How the five companies work, side by side
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  What rapid prototyping companies work means in practice
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  Tolerance, finish and the machine list behind the quote
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  Lead time, MOQ and what the quote actually includes
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  Certifications: match the scope, not the logo
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  Matching the process to the part, not the brochure
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  How to evaluate a rapid prototyping company in 6 steps

The phrase covers two very different businesses. One owns the machines and controls the schedule. The other owns a website and routes your file to a partner shop. Both can deliver a good part, but the risk sits in different places, and that is what you need to price before you commit.

An in-house shop quotes from a manufacturability review. Someone opens your STEP file, checks wall thickness, tool access and tolerance stack-up, then sends a quote with notes. At GreatLight this happens within 12 hours, and production can start within 24 hours once the drawing is agreed.

A network quotes from a cost model. Upload the file, get a number in minutes. That speed is real. What the number does not tell you is which shop will run the job, on which machine, with which inspection routine. That gets decided after you pay.

Neither model is wrong. But if your part has a 0.4 mm wall, a ±0.005 mm bore, or a cosmetic surface, the difference between the two models shows up in the first article, not in the quote.

Tolerance is where marketing language gets vague. Any shop can say 'precision'. Ask what the machine can hold across the full travel of the part, not in a 20 mm test coupon. GreatLight works to ±0.005 mm (±0.0002 in) and finishes down to Ra 0.2–0.8 μm when the drawing calls for it.

The machine list matters because geometry decides the process. A deep pocket in a 5-axis part needs a tilting head and a short tool. A long shaft needs a mill-turn center so the part is not re-chucked three times. GreatLight runs 127 high-precision CNC machines, including 16 simultaneous 5-axis centers, 12 four-axis mills, 27 three-axis machines and 16 mill-turn centers.

Size is the second filter. Maximum processing size reaches 4,000 mm, with travels of 4,000 × 400 × 150 mm for long parts and 750 × 1,150 × 550 mm for plate work. If your prototype is larger than a benchtop, say so in the RFQ. It changes the shop, not just the price.

Surface finish is often quoted as a single line item. In practice, anodizing hides tool marks, polishing reveals them. On a prototype, ask for the as-machined finish value first (Ra 1.6–3.2 μm is typical), then decide whether the cosmetic step is worth the extra days.

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  ±0.005 mmTolerance to state in the RFQ for mating features.
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  Ra 0.2–0.8 μmFine finish for sealing faces and bearing bores.
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  4,000 mmMaximum processing size for long parts.
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  Ø400 mmRotary table capacity for turned features.

A 3-day lead time means nothing if the clock starts after a two-week DFM thread. Ask when production starts, not when the quote arrives. For a clean file, GreatLight can start cutting within 24 hours and ship in 3–5 days. Historical late-delivery probability sits below 2%.

MOQ is the quiet cost driver. Networks often price one piece aggressively because it wins the account, then the price per part barely moves at 200 pieces. An in-house shop with no minimum order quantity can run one prototype, then scale the same process to 10,000+ parts without re-quoting the tooling.

Read what is inside the price. Material, machining, inspection and basic deburring should be listed. Plating, anodizing, laser marking and bead blasting are usually separate. Laser marking has a minimum character height of 1.5 mm, so a 0.8 mm serial number will not survive the process.

For prototypes that must pass a customer review, 100% inspection before shipment matters more than a low unit price. Ask for raw material certificates, in-process checks and a final dimensional report. Reports are available on request, and that request should be in the first email.

Certificates are a filter, not a score. ISO 9001:2015 covers general quality management. IATF 16949:2016 is the automotive standard and matters if the prototype feeds a PPAP later. ISO 13485:2016 applies to medical devices. ISO 27001:2022 covers information security, which is what protects your CAD files.

A network may hold a certificate at the platform level while the partner shop that runs your job holds none. Ask who is certified and for what scope. If your part is a surgical instrument housing, the answer changes the shortlist immediately.

Confidentiality is part of the same question. Uploads should be encrypted and access-limited. If the project is under NDA, sign it before the first file transfer, not after the first quote. GreatLight offers an NDA on request and treats uploads as confidential by default.

For regulated industries, plan the paper trail from the prototype. Material certificates, inspection records and revision control on the drawing are easier to set up on day one than to reconstruct three months later.

CNC is the right first choice when the prototype must behave like the production part. Metal brackets, housings, manifolds and fixtures with real loads belong on a mill or a lathe. Aluminum 6061-T6, 7075, 304 stainless and 17-4PH cover most of what we see.

3D printing wins when geometry is the question, not strength. SLM handles dense metal parts in stainless steel, aluminum, titanium and mold steel. SLA holds fine features in polymer. SLS makes functional nylon parts that survive a fit check. Use them to answer 'does it fit', then move to CNC for 'does it hold'.

Vacuum casting and sheet metal fill the gap between one-off and production. Vacuum casting gives you 20 to 50 polyurethane parts from a silicone tool, useful for a sales sample run. Sheet metal covers enclosures and brackets where the final part will be stamped or bent anyway.

The mistake we see most often is choosing the process before the tolerance. Decide the critical dimension first. Then pick the process that can hold it, and the finishing step that does not destroy it.