THE QUICK ANSWER
Component substitution is a change-control problem, and every useful move in it is a question you ask before the order runs. Ask which document production follows when the approved sample and the written wording disagree. Ask how each bought-in component is named, when it is bought, and who at the supplier may approve a swap. Ask which parts may carry a pre-approved alternate, what a substitution notice must contain and when it arrives, and what the options are for units already built.
Which document does production follow?
Put it in the RFQ in these words: when the approved sample and the written specification disagree, which one does production follow, and who decides? There are four answers you can get. The approved sample governs. The written specification governs. The specification governs and the sample is a reference for appearance only. Both govern, with a stated order of precedence. The difference matters because words describe a category and a sample is one part. A closure line reading nylon zipper, black, top and side entry can be satisfied by a part you have never handled, so where the wording governs, a substitution can be correct on paper and wrong in the carton. A good answer names one document, says how the other is used, and quotes the revision number it is answering about. A deflection says the two will never disagree. Record the answer on the cover page of the specification and confirm it in the written quotation.
How will each bought-in component be named?
Ask it this way: for every bought-in component, what exactly will the specification say, and what would you buy against that line? The answers available are a material and a colour; a material with dimensions; a named part with its size, finish and any identifying feature; a supplier's own part reference; or as per approved sample. The looser the line, the larger the set of parts that pass it, and the size of that set is not visible from the line itself. Run one test on your own document before you send it: hand it to someone who has never seen the sample and ask which part they would buy. Where they could buy a different part and still pass their own incoming check, the line is loose. A good answer fills in the missing fields for each component. A deflection repeats same as sample. This belongs in the specification, one line per component, each line carrying the sample revision it was copied from.
When is each component bought, and who may approve a swap?
Four questions, one page, asked of every shortlisted supplier. Which components are held at the factory and which are ordered for your order. Which are bought against the cutting plan and which against a piece count. What is the part reference or component supplier for each. Who at the supplier may approve a substitution when a part is short, and who do they notify. We publish no purchasing schedule of our own, and you should not accept a general one from any supplier either, because a generalisation about carriers tells you nothing about where the risk sits on your order. A good answer is specific per component and names a role, not a department. A deflection says everything is arranged in advance, or promises to inform you of anything unusual without saying who decides what counts as unusual. Put the four answers in the written quotation, where they can be compared supplier against supplier.
Which components may carry a pre-approved alternate?
Ask which components may run with a pre-approved alternate and which must stop for your written approval. Three answers are possible: none, all, or a split by a rule you set. If you want a rule, one question sorts a list quickly. Would the substitution change something you publish to your customer, or something you approved by eye? For a soft-sided carrier our own development sheet publishes external length, width and height, opening size, ventilation area and maximum stated pet weight, and shell colour and branding artwork are approved by eye. Decide which route each component takes and write both routes into your order, including the condition that production stops until you approve in writing. Where you do pre-approve an alternate, ask for it as a physical part first and check it against the same criteria as the original. An alternate you have never handled is a second guess, not a control.
What will a substitution notice contain, and when?
Ask: if a component goes short, what will you send me, in what form, and how long before the part is used? The form can be a phone call, a message naming the part, or a completed record. The timing can be before the alternate is cut, before it is used in production, at the next production report, or with the shipment. The difference is mechanical. Notice that arrives after the part is sewn in converts an approval decision into a disposal question. Ask for a record carrying the SKU and specification revision, the component named as the specification names it, the proposed part, the reason, the quantity the approval covers, photographs of the proposed part beside the same part on the approved sample, the dated decision with the name of the person who made it, and what happens to units already built. Name the notice window in hours in your own order terms rather than accepting promptly.
What can an incoming check actually see?
Ask, component by component: what would an inspector have to do to tell the specified part from a substitute? The answers fall into four kinds. Read a feature by eye. Take a measurement. Handle or load the part. Or nothing visible without dismantling the product. Sort your own component list into those four before you agree an inspection scope, because the fourth kind is where a substitution can pass every check you have written. On our development sheet for a soft-sided carrier, the three named checks are handling checks: zip strength under load, frame recovery after collapse, base rigidity. A part can photograph correctly and still fail all three. A good answer names the feature and where to look for it. A deflection says quality control checks everything. Add one line to the inspection scope: for every component with a named alternate, record which part was used and against which approval.
The units already exist. What are the options?
Ask: how many units are affected, which cartons, and what do you propose? Then ask what the alternatives are, because there are at least five and they are not equivalent. Accept as built. Accept with a recorded deviation and an updated specification. Rework. Segregate and hold pending your decision. Reject. They differ in cost, in days, and in who carries the decision, so a proposal naming only one of them is not yet an answer. A good answer gives the quantity affected, identifies the cartons, and states what each route costs in days. A deflection asks you to approve on the grounds that quality is unaffected without saying how many units that covers. Whichever route you take, close it in the document trail: a revised specification revision, a new approved sample kept in your own office, the alternate added by name, and the quantity recorded against the order.
A useful comparison
| Question to ask | Answers you may get | What it changes | Where it belongs |
|---|---|---|---|
| When the sample and the specification disagree, which governs? | Sample governs; specification governs; specification with the sample as an appearance reference; both, with a stated precedence | Whether a part that satisfies the wording but not the sample is a substitution at all | Specification cover page, confirmed in the written quotation |
| What exactly will the specification say for this component? | A material and colour; material with dimensions; a named part with size, finish and identifying feature; a supplier part reference; as per approved sample | How many different parts can pass the line without anyone noticing | The specification, one line per bought-in component |
| Which components are held, and which are bought for my order? | Held at the factory; ordered per order; bought against the cutting plan; bought against a piece count | Where on your order a shortage can appear, and how early it is visible | The written quotation |
| Who may approve a substitution, and who do they notify? | A merchandiser; a production manager; the factory's own quality function; you only | Whether the decision reaches you before the part is used | The written quotation and your order terms |
| Which components may run on a pre-approved alternate? | None; all; a split you set by rule | Whether production pauses for your approval or continues on a part you have already handled | Your order terms, listed component by component |
| What will the substitution notice contain, and how many hours before use? | A phone call; a message naming the part; a completed record. Before cutting; before use; at the next report; with the shipment | Whether you are approving a part or disposing of finished units | Your order terms; the completed record joins the order record |
| What would an inspector do to tell the specified part from a substitute? | Read a feature by eye; measure it; handle or load it; nothing visible without dismantling | Which substitutions your agreed inspection can actually catch | The inspection scope, plus a line recording which part was used |
| How many units are affected, and what do you propose for them? | Accept as built; accept with recorded deviation; rework; segregate and hold; reject | Cost, days, and who carries the decision | The order record, then a revised specification and a new approved sample |
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This guide sets out our own product development practice rather than external research. It makes no market, clinical or comparative-performance claim, and every figure named here is confirmed per order in the written quotation and specification.
How we research and writeTURN THE ANSWER INTO AN OEM BRIEF
