Manufacturing for hardware startups
What to build at each stage, in what quantity, with which process — and what it costs, what paperwork it needs, and how to choose a partner you will not have to replace at scale.
The four builds, and what each one is for
Hardware programs run EVT → DVT → PVT → production. Each build answers one question; buying more parts than the question needs is the most common early mistake.
| Stage | Question it answers | Units | Mechanical parts | Lead time |
|---|---|---|---|---|
| Proof of concept / works-like | Does the idea function at all? | 1–3 | CNC from stock 6061, 3D-printed housings, off-the-shelf everything else | 2–7 days |
| EVT — engineering validation | Does the design meet the spec? Final materials, near-final geometry. | 5–50 | CNC machining in production materials; laser-cut and bent sheet metal; machined or printed housings | 5–10 days |
| DVT — design validation | Does it pass the tests (drop, thermal, EMC, life)? Production-intent parts. | 50–500 | CNC and sheet metal in final finish; injection molding from an aluminum prototype tool (2–3 weeks) for plastics | 2–4 weeks |
| PVT — production validation | Can the line build it at rate and yield? Production tooling, fixtures, packaging. | 500–2,000 | Steel or P20 production molds (4–12 weeks); stamping or casting tooling if volumes justify; CNC for low-count metal | 6–12 weeks |
| Production | Ship. | 1,000+ / month | Tooled processes; CNC and sheet metal continue for metal parts, brackets, chassis | Per blanket order |
Quantities are industry-typical for consumer and industrial hardware; robotics, medical and aerospace programs often run smaller builds and more of them. FabDigit has no minimum order — an EVT of five parts is quoted the same way as a PVT of two thousand.
Which process at which stage
CNC machining is the default for functional metal and plastic parts until volume pays for a tool. 3D printing is for form studies and geometry a mill cannot reach; it is not the production path.
| Part | EVT (5–50) | DVT (50–500) | PVT → production |
|---|---|---|---|
| Structural metal part, bracket, housing | CNC from 6061 / 7075 / 304 — ±0.025 mm, production material from day one | CNC; heat treatment and anodize / plating as production | CNC to ~2,000 / yr; above that die casting or stamping with CNC finishing |
| Sheet metal chassis, enclosure, panel | Laser cut + bend, PEM hardware, powder coat — from 3 business days | Same process; tab-and-slot seams, hardware finalised | Same process at batch pricing; progressive-die stamping only past several thousand |
| Plastic housing, cosmetic part | CNC from ABS / PC / POM, or SLA / MJF for form checks | Aluminum prototype mold (2–3 weeks) — real material, real gates, 5,000–10,000 shots | P20 bridge tool (4–6 weeks) or hardened steel production tool (6–12 weeks) |
| Gears, bushings, shafts | CNC turning and milling from bar | CNC; case hardening or nitriding if the spec needs it | CNC or powder metal / screw-machine at volume |
| Welded frame, tank, weldment | Laser-cut tube and plate, MIG / TIG, post-weld machined pads | Same with fixture; inspection report | Same; fixture amortised across the blanket order |
| Complex internal channels, lattices | DMLS / SLS print (the one place printing wins) | Print, or redesign for machining and molding | Redesign — printing rarely holds production cost |
Per-piece curves for each process are in the CNC, sheet metal and injection molding cost guides; the crossover points (CNC → rapid tool ≈ 250 units, rapid → steel ≈ 4,000) are there too.
What a build costs — and where the money goes
Budget by stage, not by part: the price of a part falls with every build while the number of parts rises. Three numbers to carry into the plan.
3–5×
EVT part price vs production
A machined bracket at quantity 5 costs three to five times its quantity-500 price; the setup is spread over five parts. Do not optimise EVT pricing — optimise the number of EVT parts.
≈ 250
Units where a plastic tool pays back
Below about 250 pieces a CNC-machined plastic part beats an aluminum prototype mold; above it the mold wins. Most DVT builds sit right at the crossover — quote both.
10–20 %
Of the mechanical BOM in documents and finish
Inspection reports, material certs, plating, anodize and masking are real line items. Choose the inspection level per part, not per program, and the share drops.
- Pay for tolerance only where a fit needs it. Tightening ±0.1 mm to ±0.05 mm on a CNC part raises price 20–40 %; on a bend it is a re-quote. Tolerance the interfaces, default the rest.
- One material family per build. Five parts in five alloys is five material lots and five certs. 6061-T6 and 304 cover most EVT metal.
- Order the DVT finish at EVT. Anodize and powder coat change fits (up to 0.1 mm per face) and appearance; a bare EVT part hides problems the DVT part reveals.
- Combine processes on one order. Brackets, a chassis and machined pads on one PO with one engineering contact means one DFM review across the interfaces — and one delivery.
- Use the price-beat. FabDigit prints a price-beat offer on every quote: send a lower quote for the same part and FabDigit beats it. Get two quotes at DVT and use the second one.
Documents and protections, by stage
The paperwork a hardware company needs grows with each build. Have each item before the stage that needs it, not after the first problem.
| Item | Needed by | What it is | At FabDigit |
|---|---|---|---|
| Confidentiality | Before the first upload | Protection for the CAD, drawings and product plan | Customer-design confidentiality covers every account (Terms §9); a mutual NDA is signed on request; manufacturing partners operate under signed NDAs |
| Drawings with tolerances and finish | EVT | The contract for what “right” means; a STEP alone has no tolerance | The DFM review reads the drawing and flags every risk before the quote is released |
| DFM review | EVT and every revision | An engineer’s check that each part can be made as drawn and at the price | A FabDigit engineer reviews DFM on every quote — not on request, not a flag list |
| Material certificates (MTRs) | DVT | Mill test reports proving the alloy and heat lot | One of 8 certificate types selected per line in the quote form |
| First-article inspection (FAI) | DVT / PVT | Full dimensional report on the first part of a build, AS9102 format for aerospace | Not offered as its own level; a dimensional or CMM report is one of 4 inspection levels selected per line |
| Certificate of conformance | PVT / production | Statement that the lot meets the drawing and PO | Selected per line; issued with the shipment |
| Quality system evidence | Regulated programs | ISO 9001; AS9100 / IATF 16949 / ISO 13485 where the market requires | Production partners hold ISO 9001:2015; AS9100 / IATF programs are placed only with partners certified to that standard, certificate supplied with the order |
| Commercial terms | First PO | Payment, warranty, dispute terms in writing | USD pricing; card or bank transfer before production, or approved net terms (§12); 30-day conformance warranty — remake or refund (§13); California law |
| Revision control | DVT onward | Every part number tied to a revision; every PO to a revision | Quotes, orders and files live in one project workspace with the revision on each line |
Choosing a manufacturing partner that scales
Startups change suppliers at DVT because the EVT shop cannot do the finish, the volume or the paperwork. Ask these eight questions before the first order and you keep one partner through PVT.
- Does an engineer look at every part? Automated DFM catches thin walls; it does not notice that two parts will not assemble. Ask who reviews the quote.
- How many materials, finishes and heat treatments can be quoted? A 45-grade list runs out at DVT. FabDigit quotes 790 grades, 150+ finishes and 30 heat treatments per line.
- Can CNC, sheet metal, molding and welding go on one PO? One contact and one delivery for a sub-assembly, or four suppliers to reconcile.
- What inspection and certificates come with the parts, and at what price? Pick them in the quote (7 levels, 8 certificates at FabDigit) rather than negotiating them after the fact.
- What is the minimum order and the quantity break? No minimum means the EVT of five is on the same account as the PVT of two thousand; batch pricing shows the curve.
- Who is the contracting party and where are parts made? FABDIGIT INC. (Dublin, California) is the contracting party on every order; parts are made in a vetted partner network in the US, Canada, Mexico and Asia, with US engineering review.
- What happens when a part is wrong? A written conformance warranty (30 days at FabDigit — remake or refund) beats a goodwill promise.
- Will the price hold against a competing quote? A price-beat policy printed on the quote removes the re-sourcing exercise at every stage.
How FabDigit answers these against Xometry, Protolabs, Fictiv and others is on the platform comparison pages, on each vendor’s own published facts.
Before the first EVT upload
- NDA or confidentiality terms in place; account created under the company, not a personal address.
- STEP + drawing for every part, tolerances only on interfaces, material and finish on the title block.
- Quantity = the number the test needs, plus two spares; not a round number.
- Production material from EVT (6061-T6, 304, 5052 — not “whatever is cheapest”).
- DVT finish specified at EVT so fits and appearance are real.
- Inspection level chosen per part — visual for brackets, dimensional report for the interfaces.
- Both quotes for plastics near 250 units (CNC and prototype mold).
- One order for the sub-assembly so the DFM review sees the interfaces together.
Manufacturing for hardware startups — FAQ
How many units should an EVT build be?
Enough to run the engineering tests plus two spares — typically 5–50 for consumer and industrial hardware, fewer for robotics, medical and aerospace programs. Parts at this stage cost three to five times their production price because setup is spread over few units, so the saving is in ordering fewer parts, not cheaper ones.
Should EVT parts be 3D printed or CNC machined?
CNC machined in the production material for anything that must function or be tested: ±0.025 mm, full-strength billet, the same alloy and finish as production. 3D printing (SLA, MJF) is right for form and fit studies and for internal geometry a mill cannot reach; it is not the production path and its results do not validate the design.
When does injection molding make sense for a startup?
From roughly 250 units of a plastic part an aluminum prototype mold (2–3 weeks, 5,000–10,000 shots) beats CNC-machined plastic; from roughly 4,000 units a P20 or hardened-steel production tool beats the aluminum one. Most DVT builds sit near the first crossover — quote both and compare the total for the program, not the piece price.
What documents do I need from a manufacturer for a hardware product?
Confidentiality terms or an NDA before uploading, drawings with tolerances and finish, an engineer’s DFM review at each revision, material certificates (MTRs) from DVT, a first-article inspection report at DVT/PVT, certificates of conformance with production lots, and — for regulated markets — the producing partner’s ISO 9001 / AS9100 / IATF certificate. At FabDigit inspection levels and certificates are chosen per line in the quote.
Does FabDigit sign an NDA before I upload CAD?
Customer-design confidentiality covers every account under the Terms & Conditions (§9), manufacturing partners operate under signed NDAs, and a mutual NDA with FABDIGIT INC. is signed on request before any file is shared.
Is there a minimum order or a setup fee?
No minimum order: single prototypes and 10,000-part runs are quoted through the same engine, and the batch pricing shows the quantity curve so the program can plan each build. Setup is inside the per-part price; there is no separate program fee.
How does a startup keep one manufacturing partner from EVT to production?
Choose one at EVT that already has the DVT and PVT capability: an engineer reviewing every part, a material and finish list that will not run out (FabDigit: 790 grades, 150+ finishes, 30 heat treatments), CNC, sheet metal, molding and welding on one PO, inspection and certificates priced in the quote, a written warranty, and a price policy — FabDigit prints a price-beat offer on every quote — that removes re-sourcing at each stage.
Start the EVT build today.
Upload CAD for an instant quote — 790 materials, 150+ finishes, inspection and certificates chosen per line, an engineer’s DFM review on every quote, no minimum order, and a price-beat offer printed on the quote.