A second look is worthwhile even with one supplier and one quotation. Is machining missing, the material merely “equivalent”, or the coating unspecified? The attractive price can later lead to a surcharge or a complaint.
Why “feasible” is not yet a commitment
Suppliers often respond to tight tolerances with “no problem”. They usually mean it honestly, but it says nothing about the production step, measuring equipment or intended evidence. Those differences can cost money later.
Five places where assumptions hide
These are the points we check first in every quotation for a part made to a drawing:
- Revision: do the enquiry, drawing and quotation name the same revision?
- Machining: tight tolerances on faces without a machining symbol – is the machining included in the price?
- Material: “equivalent” instead of the standard designation – and no defined evidence per delivery.
- Surface: colour, coating thickness and adhesion without a testable requirement.
- Tooling and packaging: cost, ownership and tool life not stated; loose in a carton instead of protecting sensitive faces.
How to ask
For “0.05 mm flatness”, ask how the supplier will achieve it. Which production step creates the characteristic? Is machining planned and included in the price? Which measuring equipment will the supplier use? What evidence will accompany the first sample? Combine the questions in one written enquiry in English and, where helpful, Chinese. This is more useful than many separate queries.
Promise or evidence: classify every answer
An answer is not yet evidence. If you classify every answer, you see at a glance where you can already decide and where you cannot:
- CLARIFIED – answered unambiguously and recorded in writing, with supporting evidence where needed.
- PROMISED – confirmed, but the evidence is not yet due.
- EVIDENCE MISSING – requested evidence has not been provided.
- YOUR DECISION – the supplier proposes a deviation; your engineering team decides.
- OPEN – not answered, or not answered sufficiently.
An invented example
An aluminium die-cast housing is specified at revision C. The existing supplier’s quotation is below expectations but refers to revision B. It omits machining of the sealing face to 0.05 mm flatness and leaves the coating unspecified. It offers “ADC12, equivalent” instead of EN AC-46000. After one clarification round, the supplier confirms the revision and promises the machining. Your design engineers must decide on the material; the coating remains open. You can now see what the price covers.
Illustrative example – not a client case.
What should be settled before ordering
Not every open question has to be answered before ordering – but you should know which ones they are and who will resolve them by when:
- Revision and document precedence confirmed in writing.
- Machining, material and surface recorded in the quotation or a supplement.
- Required evidence for first samples and deliveries named.
- A few priority characteristics that are checked specifically during sampling.
- Open points with owners and dates.
Where the boundary lies
Your engineering team decides on tolerances, materials and approvals. They can delegate supplier clarification to us. We speak to the supplier in China, in Chinese and during its working hours. For one item and one existing supplier, we agree a manageable assignment at a fixed price. The deliverables belong to you.