The short answer
Prototype CNC quotes and production CNC quotes answer different questions. A prototype RFQ usually prices a few parts with flexible setups, light inspection, and finishes that prove form and fit. A production RFQ amortizes fixtures and CAM, locks a process plan, adds inspection depth, and often includes finishes and certifications that must repeat lot after lot. Unit price, lead time shape, and what “firm” means all change when you cross that line—so treat them as related but separate quote events, not one number stretched across quantities.
When you are ready with STEP, PDF, material, finish, quantity, and need date, upload on the 3DWK quote page (quote-new.php). This guide is practical buyer framing only—typical shop practice, not a price list.
What buyers actually see on the two quotes
On a prototype quote you often see:
- Higher unit price at low quantity (1–10 or similar bands)
- Relatively short calendar if stock and machine time are available
- Setup and programming called out as a large share of the total
- Inspection limited to critical dimensions or a short checklist
- Finish options kept simple (as-machined, bead blast, common anodize)
On a production quote you typically see:
- Lower unit price once quantity and process stability justify fixtures or dedicated tooling
- A process plan: stock strategy, setup sequence, in-process checks, secondary ops
- Inspection depth that matches drawing criticals (and sometimes FAI on first lot)
- Finish and cosmetic standards written so they can be repeated
- Explicit assumptions about reorder windows, revision control, and scrap risk
Neither quote is “wrong.” They price different risk and different fixed-cost recovery. For what drives cost in general, see the CNC machining cost drivers guide; for calendar shape, see CNC machining lead time.
Setup amortization: why qty 1 and qty 200 feel different
CNC fixed costs—CAM programming, fixture design or soft jaws, first-article prove-out, tool selection—do not vanish at quantity one. They are simply paid by fewer pieces. At prototype quantity those costs sit heavily on each unit. At production quantity the same fixed work is spread, and shops may invest in better workholding because the payback is clear.
What that means for RFQs:
- State the quantity you need *now* and, if known, a realistic next-buy band. “Quote 5 and also 200” is clearer than “5 now, maybe more later.”
- Do not expect the prototype unit rate to apply unchanged at 200 without a re-plan. Fixtures, stock nesting, and cycle time targets change.
- Soft jaws or modular fixtures may appear on a mid-volume quote even when the first five parts were machined in a vise with manual indicating.
Amortization is not a secret multiplier; it is whether the shop can justify non-recurring work against the order you actually place. For how quantity language shows up on preliminary ranges, see reading a preliminary online quote (min / mid / max).
Process plan: from “make it once” to “make it the same”
A prototype plan prioritizes getting geometry and fits right with flexible setups. A production plan prioritizes repeatability: datum strategy that survives every lot, cutter paths that leave consistent stock for finishing passes, and clear ownership of secondary operations (heat treat, anodize, insert installation).
Buyers should ask, in plain language:
1. Will production use the same datums and workholding approach as the prototype, or a redesigned setup?
2. Which faces are cosmetic versus functional, and are they protected the same way every lot?
3. Are threads, inserts, and press fits done in-house or by a named secondary process?
4. What stock size and blank strategy is assumed (saw cut billet vs near-net vs cast/print preform)?
If the prototype was 3-axis vise work and production needs 5-axis or dedicated fixtures for multi-face accuracy, say so early. The 3-axis vs 5-axis buyer guide helps frame that conversation; this article focuses on quote scope, not machine selection alone.
Inspection depth changes the quote more than many buyers expect
Prototype inspection often means verifying the handful of dimensions that affect assembly this week. Production inspection may add:
- Full ballooned drawing checks on first article
- Sampling plans for ongoing lots
- Surface roughness or coating thickness where the drawing calls them
- Material certs and lot traceability when your industry requires them
Call out what you need on the RFQ. “Inspect all dimensions” on a dense drawing at quantity 500 is a different job from “check the six criticals circled on the PDF.” First article inspection reports explains what FAI proves; GD&T basics for buyers helps you mark only the features that earn that cost.
If you skip inspection language, shops quote their default—often lighter than aerospace/medical expectations and heavier than a one-off fit check. Align the note with the real use of the part.
Finishes: prototype cosmetics vs production standards
Prototype finishes prove appearance and basic corrosion protection. Production finishes must be specified so a second lot matches the first: anodize type, dye, mask map, passivation, bead-blast media class, paint thickness targets, and which faces stay as-machined for grounding or sealing.
Practical RFQ habits:
- Name the finish system (for example Type II anodize) rather than “black coat” alone
- Mark mask and keep-out zones on the drawing revision you are quoting
- Say whether color match to a prior lot or sample chip is required
- Separate “prototype OK with shop-standard blast + anodize” from “production must match approved sample”
Anodize choice and RFQ cost interactions are covered in how anodize choice changes CNC RFQ cost. Passivation, powder coat, and chem film guides on 3DWK apply the same rule: production needs a repeatable callout, not a mood.
When to re-quote (do not stretch the old number)
Re-quote when any of these move:
- Quantity band (prototype five → production two hundred)
- Revision that changes stock size, setups, or critical tolerances
- Material or temper
- Finish system or cosmetic standard
- Inspection / FAI / cert depth
- Lead-time commitment (flexible prototype slot → locked production week)
A fair pattern many buyers use: place a small CNC run to validate fit, then issue a production RFQ with the frozen revision, target quantity, finish standard, and inspection note. Upload that pack on quote-new.php rather than asking the shop to “just multiply” the prototype line.
Also re-quote if the first run revealed DFM changes—thicker walls, opened corner radii, relaxed non-criticals—because those changes alter cycle time and scrap risk. The DFM checklist before an online CNC quote is a useful gate before the production RFQ.
How to phrase the two RFQs so they stay comparable
Keep geometry revision letters aligned, then vary only the commercial and quality scope:
| Field | Prototype RFQ | Production RFQ |
|---|---|---|
| --- | --- | --- |
| Quantity | Actual pieces for fit/function | Lot size + likely reorder band |
| Need date | Near-term calendar date | Production window / first ship date |
| Inspection | Criticals / assembly fits | FAI or sampling + drawing criticals |
| Finish | Acceptable prototype finish | Locked standard + mask map |
| Process notes | “Prove geometry; soft jaws OK” | “Repeatable plan; fixture assumptions” |
| Revision | Current experimental rev if needed | Frozen release rev |
Attach the same core file pack both times: STEP, PDF with datums, material/temper, finish, qty, need date. What files to send for a CNC quote lists that pack in detail.
Common mistakes
- Using a prototype unit price as a PO rate at 10× quantity without a new process plan
- Asking for production FAI depth on a still-moving revision
- Changing finish between lots without updating the drawing note
- Omitting reorder expectations, then expecting the shop to hold fixture capacity indefinitely
- Mixing “budgetary” prototype language with a hard production ship date on the same line
- Sending production quantity on a model-only pack with no PDF datums
Illustration 1 compares typical quote-scope differences. Illustration 2 is a buyer decision map for when to keep the prototype quote versus when to open a production RFQ.
What “firm” means in each context
A firm prototype quote usually means the shop can machine the stated revision at the stated qty with the stated finish and light inspection, given stock. A firm production quote usually means those plus a defined process plan and quality plan that the shop is willing to repeat. If either side still has open DFM or unfinished drawings, label the number budgetary and say what must freeze before release.
For online preliminary ranges that flag manual review, see what needs_manual means on a preliminary quote. File completeness and clear prototype-versus-production intent are what move you from range to release.
What to do next
1. Decide whether this upload is a prototype prove-out or a production lot.
2. Freeze the revision and finish/inspection notes that match that intent.
3. State now-qty and, if known, the next quantity band.
4. Upload via quote-new.php with STEP + PDF + material/finish/qty/date.
Related reading on 3DWK: CNC machining service, CNC machining cost drivers, CNC machining lead time, 3-axis vs 5-axis for buyers, DFM checklist, files for CNC quote, first article inspection, and reading preliminary online quotes. One clear intent per RFQ beats one ambiguous number stretched across both worlds.
Common questions
Can one quote cover both prototype and production?
You can ask for two quantity lines on one RFQ, but treat them as two scopes if inspection, finish, or fixtures differ. Separate notes prevent mixing soft-jaw prove-out assumptions with production FAI.
Will my prototype fixtures carry into production?
Sometimes soft jaws or modular plates reuse; often production redesigns workholding for cycle time and repeatability. Ask explicitly rather than assuming carry-over.
Does higher quantity always lower unit price?
Usually fixed costs spread, but tighter tolerances, harder alloys, or heavier inspection can offset that. Quantity helps most when the process plan stays similar.
When should I freeze the revision?
Before the production RFQ you want a firm date on. Prototype quotes can tolerate a labeled experimental rev if you say so; production should not.