What Should a Mold RFQ Include? A Line-by-Line Checklist
Last updated: 2026-09-01 · Reading time: about 11 min
A mold RFQ that gets comparable quotes back contains nine blocks: part data, resin specification, volume and program life, tolerance on critical dimensions, surface finish per surface, mold standards, deliverables, milestone expectations, and commercial terms. Leave any block out and the factory fills the gap with an assumption — and assumptions are where the price spread and the later surprises come from. This checklist walks every block line by line and tells you exactly how each one changes the quote you receive.
Key facts
- Nine blocks: part data · resin · volume · tolerance · finish · mold standards · deliverables · milestones · commercial terms.
- Every missing block becomes a factory assumption, and no two factories assume the same thing.
- Volume decides cavitation and steel grade — it is a cost driver, not an afterthought field.
- Finish and tolerance must be named per surface and per dimension, against a named standard (SPI grade, texture reference, GD&T).
- The RFQ should demand the reply format too: line-item quotation, written DFM, dimensional report at T1.
Why do most RFQs return unusable quotes?
Send ten factories the same incomplete RFQ and you get ten different numbers — not because the factories price differently, but because each one quietly invented its own scope. One assumed a single cavity, another assumed four. One priced a basic polish, another priced an SPI A2. The numbers look comparable on the bottom line; the scopes behind them are not the same tool.
The fix is structural, not persuasive. Instead of asking factories to “quote their best”, hand them a document where every scope decision is already made or explicitly requested. The nine blocks below are that document.
Block 1: What part data has to be in the package?
The part data block is where most RFQs are thinnest, and it is the block the tooling engineer reads first. Three files, one sentence:
- 3D model in STEP format. Native CAD formats are fine as a supplement, but STEP is what every toolroom can open without your software license.
- 2D drawing with critical dimensions marked. Not every dimension — the ones your assembly actually depends on. Marking everything tight prices tolerance you do not need.
- One sentence of function. What the part mates with, what load or environment it sees. This one sentence changes gate placement and steel choices more than buyers expect.
If the part has been molded before, include photos of the current part with its visible problems circled — witness lines, sink, gate vestige. That is free DFM input, and it tells the quoting engineer exactly what your quality bar looks like.
Block 2: Which resin details actually change the mold?
“ABS” is not a resin specification. The mold design changes with what is inside the grade, and the quote should reflect it. Name the family, then the attributes below that matter for tooling:
| Resin attribute | How it moves the mold design | Write it in the RFQ as |
|---|---|---|
| Glass or mineral fill | Abrasive melt wears gates and cores; hardened steel inserts become necessary, not optional. | “PA66 with 30% glass fill” — percentage included. |
| Shrinkage behavior | Semi-crystalline resins shrink more and less predictably; sizing and hold pressure planning change. | Name the resin family; ask the factory to state the shrinkage value they will design to. |
| Processing temperature window | High-temperature resins need hardened inserts and heat-resistant seals; cooling layout changes. | State the resin and the peak processing temperature if your molder already knows it. |
| Corrosive or flame-retardant grades | Corrosion-resistant steel and plated components enter the bill of materials. | Name the grade characteristic; ask which steel the factory proposes in response. |
| Color and appearance grade | Visible-surface resins raise the polish grade and gate vestige sensitivity. | Mark the appearance surfaces on the drawing and name the color system. |
If the exact grade is not selected yet, say so and give the family plus the requirement that drives selection. A factory quoting against a stated requirement is still comparable; a factory guessing the grade is not.
Block 3: Why is volume a cost driver and not a formality?
Volume is the input behind the two biggest structural decisions in the quote: cavitation and steel grade. A tool that must deliver 50,000 parts and one that must deliver 5,000,000 are engineered differently even when the part geometry is identical — and the correct answer for each is a different balance of upfront cost against cost per shot.
- Annual volume. The recurring number your program will consume per year.
- Program life. How many years the part stays in production — this decides the mold life class the steel must support.
- First order size, if it differs. A bridge-tool situation (small first run before the production tool) should be stated as such, not implied.
Ask for the quote to answer volume explicitly: cavitation chosen, the cycle time assumption behind it, and the cost-per-shot arithmetic. If a quote names cavitation without showing the math, the cavitation was chosen to flatter the sticker price, not your production plan. Our breakdown of how the sourcing process reads these quotes covers how to score the answers.
Block 4: How do you specify tolerance so quotes match?
Tolerance pricing is binary: a dimension is either held to a class or it is not, and the class decides machining time, EDM hours and inspection loops. The RFQ rule is simple — mark critical dimensions on the drawing and quote only those to tight tolerance. Everything else falls to the factory’s standard molding tolerance, which the quote should state in writing.
| What to write | Why it matters |
|---|---|
| Which dimensions are critical, marked on the 2D drawing | Scope of tight-tolerance work is unambiguous; nobody prices the whole part as tight. |
| The tolerance class per critical dimension (± value or GD&T callout) | Every factory prices the same target; replies become comparable. |
| How conformance will be proven (dimensional report at T1, CMM method) | The verification method is priced into the trial phase instead of appearing as a surprise extra. |
| Mating relationships, if the part assembles against another molded part | Reveals which tolerances are truly functional and which can relax. |
Block 5: How should surface finish be named?
Finish is hand work, and hand work is where quotes diverge most silently. “Smooth” and “matte” are not specifications; named grades are. The RFQ should name a finish per visible surface, against a standard both sides can point at during acceptance:
- SPI polish grade (A1–A3, B1–B3, C1–C3, D1–D3) for polished surfaces, stated per surface on the drawing.
- Texture reference — the texture system and pattern number — for textured surfaces, with the depth range if your appearance standard defines one.
- Witness line and gate vestige limits on appearance faces: where the gate may sit, what is acceptable at the parting line.
- Which faces are appearance faces at all. A face nobody marks gets standard benching, and that is usually correct — as long as you decided it, not the factory.
One practical coupling to remember: texture demands draft. If your drawing carries a texture reference, the draft angles must be stated or confirmed in the same document, or the DFM will come back asking anyway.
Block 6: Which mold standards must be named?
Standards are the block most often left to the factory’s default, and the one that hurts most when the mold crosses an ocean. Name them explicitly:
- Mold base system — DME-style for North American presses, LKM or HASCO elsewhere. Mixing standards turns first setup into a fitting job.
- Hot runner decision — brand and nozzle count if you require one, or an explicit request to quote both hot and cold runner options with their trade-offs.
- Ejection and connection conventions your press side expects: ejector plate standards, water fitting types, sprue or locating ring dimensions if known.
- Where the mold will run. Country and, if known, press tonnage and platen constraints. A mold built blind to its destination press is a commissioning risk priced at the wrong end of the project.
Block 7: What deliverables should the RFQ demand?
This is the block that turns the RFQ from a price request into an evidence request. Do not only describe the tool — describe what you expect to receive with it. Factories that cannot commit to these items are telling you how the project will run:
- Line-item quotation. Steel, base, actions, finish, hot runner, trials, export packing — each on its own row. A single-number reply fails this requirement by design.
- Written DFM before the deposit. Gate locations, parting line, draft, sink risk, undercuts — on your geometry, in writing.
- Milestone schedule. DFM date, steel start, first trial, sample shipment — dates attached to deliverables, not one umbrella promise.
- T1 evidence pack. Sample parts from consecutive shots, full dimensional report against your drawing, trial video showing the mold number.
- Ownership and documentation. The mold is your property, stated in writing; final drawings, spare parts list and maintenance notes handed over in transferable formats.
Block 8 and 9: Milestones and commercial terms, in writing
The last two blocks close the loop. Milestone expectations tell the factory you will be managing dates, not just the deposit: state that progress updates with photos are expected at agreed intervals, and that slip handling is a documented conversation, not a discovery. Commercial terms put the money structure on paper before any money moves: deposit percentage and what must exist before it is paid, balance trigger (accepted dimensional report, not just “completion”), and the change-order rule — any engineering change after scope freeze is written, with cost and schedule impact, in both directions.
These two blocks read like legal paperwork, but they are engineering risk control: every dispute in mold sourcing traces back to a term that was assumed instead of written.
An RFQ is not a formality before the real conversation — it is the real conversation. Every block the buyer leaves empty, the factory fills with an assumption, and I have never seen two factories assume the same thing. The buyers who get three comparable quotes are the ones who left nothing to assume.
— Arthur, Tooling Engineer at aCatMould
How do you read the quotes that come back?
With a complete RFQ, reading the replies becomes a mechanical job instead of a guessing game:
- Line up identical rows across all quotes. Steel against steel, cavitation against cavitation, trials against trials. Differences on a row are information; differences in the bottom line alone are noise.
- Flag every assumption stated in the reply. A factory that writes “assumed single cavity” is doing you a favor; one that does not state assumptions is hiding them.
- Score the DFM, not just the price. The quote with the sharpest DFM — real risks named on your geometry — is usually the quote that survives T1 without a renegotiation.
- Convert to cost per shot before deciding. Cavitation, cycle time and mold life turn three sticker prices into one comparable number. The sticker price answers what you pay once; cost per shot answers what the tool costs you for years.
Frequently asked questions
Can I send an RFQ without a finished 3D model?
You can, but the quotes will be budget ranges, not prices. Send the best model you have plus the requirement list, and mark the RFQ as a budgeting round. Reissue the real RFQ when the model freezes — two rounds with labeled intent beat one round of false precision.
How many factories should receive the RFQ?
Three to five. Below three there is no comparison; above five you spend engineering hours reading quotes that blur together. Filter the list by evidence — itemized quotes, written DFMs, named engineers — before the RFQ goes out, not after the replies come back.
Should the RFQ include a target price?
Only if the target is grounded in real scope, such as an earlier tool of similar size. A target without scope anchors the factory to a number before the engineering is read. If you must share a budget, share it as a gate for feasibility, not as a price to hit by cutting lines.
What is a reasonable deadline for RFQ replies?
Five to ten working days for a line-item quote plus a written DFM. The deadline itself is diagnostic: factories that treat your date as negotiable before the deposit will treat milestone dates the same way during the build.
Do small buyers get taken seriously with a formal RFQ?
A formal RFQ is exactly what makes a small buyer legible. It replaces purchasing volume with clarity, and clarity is what a tooling engineer prices against. Vague RFQs from small buyers get vague quotes; precise ones get precise ones.
Should the RFQ mention competing quotes?
No. State your requirements and your verification expectations; let the itemized structure do the comparison work. Announcing competition invites price theater — numbers trimmed by cutting invisible lines instead of engineering trade-offs you can see.
Key takeaways
- An RFQ’s job is to force every supplier to price the identical scope — every block you leave empty, each factory fills with its own assumption.
- The nine blocks: part data, resin attributes, volume and program life, critical-dimension tolerance, finish per surface, mold standards, demanded deliverables, milestone expectations, commercial terms.
- Volume is a cost driver: it sets cavitation and steel grade, and the quote must show the cost-per-shot math behind the cavity count.
- Demand the reply format itself — line-item quotation, written DFM before deposit, dimensional report at T1. Factories that refuse the format have answered your question already.
- Read replies row by row, flag every stated assumption, and convert the finalists to cost per shot before choosing.
If your next RFQ deserves answers instead of assumptions, send it to us the same way this checklist describes. You will get a line-item quotation and a written DFM back — scope first, numbers attached, a named engineer on the reply.
Sources
ISO 20457:2018 — Plastics moulded parts: Tolerances and acceptance conditions
DME — global supplier of mold bases, components and hot runner systems
HASCO — the pioneer of mouldmaking: standard mold units and components
MatWeb — material property database for resin and steel datasheets