Quotes from different mould suppliers are only comparable if every supplier priced the same written requirements. Write and freeze a Statement of Requirements (SOR) first, then compare suppliers on capability, assumptions and risk, not only on price.
You ask three toolmakers to quote the same part. The quotes come back at three very different prices. The lowest looks like the obvious choice.
Often it is not. In most cases the three suppliers did not price the same mould. Each one filled the gaps in your request with its own assumptions, and those assumptions are where the price difference comes from.
Why quotes for the "same" mould differ
When a request for quotation is thin, every supplier has to guess. Common gaps:
- Number of cavities and expected tool life. A 500,000-shot tool and a 1,000,000-shot tool are different products.
- Steel and heat treatment. The grade, hardness and surface treatment change both cost and durability.
- Hot runner or cold runner. One quote may include a hot runner system while another leaves it out.
- Surface finish and texture. A cosmetic grade needs more polishing and sometimes outside texturing.
- Tolerances and inspection. Without stated tolerances, each supplier assumes a different level of precision.
- Trial scope. How many trials, which machine, which material, and who pays for changes after the trial.
A low quote that leaves these open is not cheap. It is incomplete. The difference shows up later as change requests, delays and disputes.
What a Statement of Requirements (SOR) should contain
A Statement of Requirements is the single document every supplier prices from. It does not need to be long, but it must be specific. At minimum:
- Part and product data. Final part drawings, 3D models, material, colour, and the expected annual volume.
- Mould specification. Cavity count, steel, expected tool life, runner type, ejection and cooling expectations, and any standards you require.
- Quality requirements. Critical dimensions, tolerances, cosmetic grade and how they will be measured.
- Trial and acceptance criteria. What a successful trial means, in numbers, and who signs it off.
- Commercial and schedule terms. Delivery milestones, what triggers each payment, and how changes are handled.
- Ownership. Who owns the mould, the design data and the revision history.
Once this is written, freeze it with a version number and a date. Any supplier who proposes a change must show it as a separate line, not buried in the price.
Compare suppliers on more than price
After the quotes come in against one SOR, compare them on these questions:
- Capability. Has this supplier built a mould of this size, material and finish before? Ask for evidence, not claims.
- Assumptions. List what each supplier assumed. Differences in assumptions explain differences in price.
- Technical response. Did the supplier raise sensible questions or design-for-manufacturing points, or simply return a number?
- Schedule realism. Does the plan show design review, steel, machining, trial and corrections, or only a delivery date?
- Change handling. How does the supplier price and approve changes after the order?
A supplier who asks you good questions before quoting is often showing you how they will behave during the project.
Where supplier checks usually fall short
At the start of a project, most teams run a general check on the supplier. Is the factory in good order? Does the infrastructure look right? Is the experience broadly relevant? Does the team seem competent? The purchase team does this, and often the project manager repeats the same check.
These checks are useful, but they stop one level too early. They tell you the supplier looks capable in general. They do not tell you whether the supplier is capable of building this mould, for this part, to these requirements.
The gap is in the capability questions. In our experience, teams rarely get to the point of knowing exactly which questions to ask. They fall back on a few questions that worked on earlier projects and repeat them every time. That feels efficient, but it has two problems:
- The questions are fixed, while the project is not. Every project has different requirements, a different supplier selection criteria set, a different working structure and a different risk profile. A standard list tests what mattered on the last project, not this one.
- It still consumes time on every project. The same few questions are asked again, and the answers are collected without being tied to a specific risk.
A better way is to derive the capability questions from the SOR itself. For each critical requirement, ask what would have to be true for the supplier to meet it, and ask for evidence:
| If the SOR says | Ask the supplier |
|---|---|
| Tight tolerance on a critical feature | Which comparable features have you held to this tolerance, and how did you measure them? |
| High cosmetic grade or texture | Which parts with this finish have you delivered, and who does the polishing and texturing? |
| Long tool life target | Which steel and heat treatment did you use for similar life targets, and what was the result in production? |
| Hot runner system | Which hot runner makes and configurations have you commissioned for this material? |
| Large or complex mould | What is the largest mould you have built, and which machines and capacity will be used for this one? |
| Specific trial and acceptance criteria | How do you run trials, record results and correct issues before handing over? |
The questions change from project to project because the SOR changes from project to project. That is the point. Capability is judged against what this project needs, not against a generic checklist.
A simple way to close the decision
Before you award the order, check that each of these is true:
- Every supplier priced the same frozen SOR version.
- Each quote lists its assumptions and exclusions in writing.
- You have compared capability evidence, not only prices, using questions drawn from this project's SOR rather than a fixed list.
- One named person on your side owns the supplier decision and can approve changes.
- Trial acceptance criteria and payment milestones are agreed before steel is ordered.
If any item is still open, the risk has not gone away. It has moved further into the project, where it costs more to fix.
For the wider set of decisions to close before you commit to a mould, read the Tooling Risk Checklist.
Common questions
Should I always choose the lowest quote?
No. The lowest quote is only the best value if every supplier priced identical requirements and has comparable capability. Compare assumptions and evidence first.
How detailed should an SOR be?
Detailed enough that two suppliers would build the same mould from it. If a requirement can be read two ways, write it down more precisely.
Who should own the supplier decision?
One named person on the customer side, with authority to approve changes and close open points. Shared ownership usually means no ownership.
When should the SOR be written?
Before you request quotes, and ideally once the product definition and design review are complete enough to freeze the main requirements.
Before you commit to a mould
A short list of the early decisions that most often turn into tooling risk later.
Read the Tooling Risk Checklist →