A factory can be the company named on the purchase order while important parts of the product come from elsewhere. It may buy a motor, zipper, resin, coating, textile, battery cell, printed insert, packaging material, or testing service from another provider. That is normal manufacturing. The buyer’s concern begins when a critical input changes without notice and the factory cannot show which source was used for the affected production.
A China factory approved sub-supplier control process does not require the buyer to run the factory’s entire purchasing department. It identifies the materials, components, outsourced processes, and services that can affect product acceptance. It then defines approved sources or source criteria, evidence requirements, notification rules, and records that connect a critical input to the production order.
This is general sourcing guidance, not regulatory or legal advice. A buyer should obtain qualified technical and compliance support for regulated goods, restricted substances, food, medical devices, chemicals, electrical products, and any product that requires specific supplier approvals or test evidence.
A buyer does not need to approve every screw vendor. It does need to know when a critical input changes the product it agreed to buy.
Define which sub-suppliers matter to the order
Start with impact, not hierarchy. A sub-supplier deserves buyer attention when its product or service affects safety, fit, function, appearance, compliance, customer requirements, delivery continuity, or a hard-to-detect quality characteristic. A carton supplier may be critical for a retailer’s barcode program. A plating supplier may be critical for corrosion performance. A generic cleaning-material vendor may not need buyer approval for a simple product.
| Input or service | Why it may need control |
|---|---|
| Critical component | Affects function, compatibility, reliability, or safety |
| Raw material or formulation | Affects performance, composition, finish, or product claims |
| Surface treatment or coating | Affects appearance, durability, corrosion, or restricted-substance risk |
| Outsourced assembly or special process | Affects process capability and product consistency |
| Test laboratory or test service | Provides evidence used for release or customer requirements |
| Packaging or label source | Affects barcode, artwork, warnings, protection, and receiving accuracy |
| Battery, electronic part, or power component | May affect product function and product-specific compliance requirements |
| Customer-nominated source | Must be controlled because the buyer or customer specified it |
The list should be short enough to manage. A broad rule that says every supplier of every commodity must be approved can create paperwork without reducing the risks that matter. Define the critical inputs in the product specification, bill of materials, quality appendix, or approved-source register.
Create an approved-source register
An approved-source register is a buyer-facing list of critical inputs and the source or evidence that supports their use. It can name a particular manufacturer, a component part number, material grade, qualified process, customer-nominated vendor, or an approval condition. The factory should understand whether the record is a strict source lock, an approved alternative list, or a specification-based requirement.
| Register field | Practical purpose |
|---|---|
| Product and SKU | Limits the approval to the right product family |
| Critical input | Names the component, material, process, or service being controlled |
| Specification | States part number, grade, drawing, test method, or performance requirement |
| Approved source | Identifies the supplier, manufacturer, or qualified process when required |
| Evidence required | Lists data sheet, sample, test record, certificate, or inspection evidence |
| Change rule | States whether the factory needs notice, buyer approval, or first-use verification |
| Traceability record | Defines lot, invoice, production record, or source identifier to retain |
| Effective revision | Connects the source rule to a controlled document version |
| Buyer owner | Identifies who can evaluate a proposed change |
Keep source identity separate from a general description. “Use high-quality resin” is not a source-control rule. “Use resin grade X, approved color masterbatch Y, and notify the buyer before substituting either” is a usable instruction.
FDA purchasing-controls educational material, in a medical-device context, describes evaluation, selection, finalization of responsibilities and controls, monitoring, and communication as typical supplier-control steps.1 Ordinary consumer goods are not automatically subject to that framework. The basic risk-based approach still helps a buyer decide where approval effort is worth spending.
Request evidence that matches the risk
The right evidence depends on the input. A buyer should not request the same certificate for every component and should not assume a document alone proves a product result. Ask for the evidence that helps confirm identity, suitability, or consistency for the particular requirement.
| Controlled input | Evidence to consider |
|---|---|
| Branded or specified component | Part number, source identity, product photo, and approved sample comparison |
| Material grade | Data sheet, material declaration, lot reference, or test evidence where required |
| Coating or finish | Process reference, appearance sample, thickness or performance record if specified |
| Outsourced special process | Process provider identity, defined requirements, and applicable inspection or test record |
| Printed artwork | Approved artwork revision, print proof, and production photo or sample |
| Customer-nominated supplier | Purchase record, part label, and source confirmation consistent with customer instruction |
| Test service | Laboratory or service identity, method, sample identity, and report scope |
The buyer should state whether the factory may use an equivalent source. If equivalency is allowed, define who decides it and which evidence is needed. “Equivalent” is otherwise easy to interpret as “available at a lower cost this week.”
Put source rules into the purchase order and product file
A source-control rule has limited value if it sits only in a separate spreadsheet. Reference it in the purchase order, material specification, bill of materials, quality agreement, or controlled product file. The factory should see it before it orders inputs and before it schedules production.
| Buyer instruction | Factory action |
|---|---|
| “Use approved component number ABC only.” | Purchase and issue the named part for the defined order |
| “Alternative source requires written approval.” | Stop substitution and send proposed source evidence before use |
| “Retain lot reference for each production batch.” | Link material or component identity to the finished-product lot |
| “Use approved packaging artwork Revision D.” | Confirm printer proof and prevent old artwork use |
| “Notify us of outsourced process change.” | Report a new processor, location, or method before implementation |
| “Submit first-use sample.” | Provide sample and evidence before using a new critical source in mass production |
The wording should match the buyer’s actual intent. A source lock is appropriate when a customer specifies a component or when a change could affect critical performance. A specification rule may be better when the buyer only needs material to meet a measurable standard and can accept multiple qualified sources.
Require notice before a critical source changes
Sub-supplier changes may be driven by shortage, lead time, cost, capacity, quality issues, or a factory’s internal purchasing decision. The reason does not remove the buyer’s need to review the effect. Require written notice before the factory substitutes a source, changes material grade, moves an outside process, or uses a different test provider for an evidence-sensitive requirement.
| Proposed change | Buyer review question |
|---|---|
| New component maker | Does the part match the approved design, performance, and documentation requirements? |
| Material substitution | Does the new grade or formulation affect fit, function, appearance, or product claims? |
| New coating or plating source | Does the process change affect finish, durability, or required evidence? |
| New outsourced assembler | Does the factory retain control of work instructions, inspection, and traceability? |
| Different packaging printer | Are artwork, barcode, color, and carton requirements protected? |
| Test laboratory change | Does the report method and scope still answer the buyer’s requirement? |
FDA material on purchasing controls describes the value, in its cited medical-device setting, of purchase documents that include an agreement for suppliers to notify the manufacturer of changes in product or service.1 A commercial buyer can adapt that concept through a product-change notification clause without claiming it is a universal regulatory requirement.
Connect the source to production and inspection records
The most useful source control is one that can be checked after a problem appears. For critical inputs, ask the factory to retain an identifier that connects the source to the finished product or production lot. This might be a component lot label, material batch record, purchase reference, outside-process report, or an internal issue record.
| Record link | What it helps answer |
|---|---|
| Component lot or label | Which component batch entered the finished lot? |
| Material batch reference | Which material was used for the production run? |
| Purchase record | Which approved source supplied the input? |
| Outside-process reference | Which provider and process applied the treatment? |
| Inspection report | Was the changed or critical characteristic checked? |
| Finished-product lot | Which shipment or inventory scope may be affected? |
The buyer does not need confidential pricing or every vendor invoice. It needs enough evidence to confirm the source rule was followed or to identify the affected scope if the input was wrong. Agree on the minimum record before ordering, especially where a supplier treats its sub-supplier identity as commercially sensitive.
Verify first use of a new approved source
Even after the buyer approves a proposed alternative, the first use can merit focused verification. The check might be a new sample, first-article measurement, material record review, product performance test, packaging proof, or targeted inspection of the first production lot. Match the verification to the risk created by the change.
| Source change | First-use verification |
|---|---|
| New critical component | Fit, function, part identity, and traceability check |
| New material grade | Sample comparison and relevant product test or inspection |
| New finish supplier | Appearance and specified performance evidence |
| New packaging supplier | Artwork, barcode, dimensions, protection, and pack-out check |
| New outsourced assembler | First-production evidence and focused inspection plan |
| New test provider | Report review for method, sample identity, and criteria |
Do not approve a source for every future product automatically when the evidence only covered one SKU or configuration. The register should state the scope of the approval and when re-evaluation is needed.
Review performance without turning the list into paperwork
An approved source can change performance over time. Track practical signals such as incoming defects, shortages, delivery disruption, document errors, inspection failures, customer returns, or repeated change requests. Review frequency should reflect the input’s significance and problem history.
| Performance signal | Buyer response |
|---|---|
| Repeated component defect | Increase incoming or pre-shipment checks and request supplier action |
| Frequent substitution request | Review whether the source rule is realistic or needs a qualified alternative |
| Documentation gaps | Require clearer source or lot records before release |
| Delivery disruptions | Identify secondary approved source or stock strategy |
| First-use failure | Hold the alternative source and revisit approval conditions |
| Stable performance | Maintain routine monitoring rather than adding unnecessary checks |
A buyer can use the register to make sourcing more resilient, not only more restrictive. If one source repeatedly causes delays, the buyer may decide to qualify an alternative before an emergency forces a rushed substitution.
Handle a discovered unauthorized substitution
If the buyer discovers that the factory used an unapproved source, first identify the affected product, production dates, lots, inventory, and shipments. Ask for the actual source, reason for the change, supporting evidence, and any remaining stock. Contain unreleased goods while the buyer decides whether to inspect, test, rework, accept under a defined concession, return, or take another action.
Avoid treating the issue only as a communication problem. The buyer should ask whether the source change affected the product baseline and whether the factory’s purchasing or production controls allowed the substitution to escape notice. The answer informs the corrective action and the level of control needed for the next order.
Frequently asked questions
Does a buyer need to approve every sub-supplier used by a China factory?
No. Focus on materials, components, outsourced processes, services, and packaging sources that can affect product acceptance, customer requirements, or meaningful supply risk. Routine noncritical purchases usually do not need buyer approval.
What is the difference between a source lock and a specification requirement?
A source lock requires a named source or part. A specification requirement allows the factory to use a source that meets defined criteria. The buyer should state which model applies and whether alternatives need approval.
What should a factory provide when it wants to change a component source?
Ask for the current and proposed source, product scope, reason, part or material comparison, effect on quality and timing, evidence available, and a request for written buyer approval before use.
Can a buyer require traceability without asking for confidential supplier pricing?
Yes. The buyer can request a lot, component code, purchase reference, or provider identity linked to the finished product. The exact record should be agreed in advance and limited to what is needed for the critical input.
Control the inputs that control the product
A China factory approved sub-supplier control process identifies critical inputs, defines whether their sources are locked or specification based, requires notice before a meaningful change, and keeps enough records to connect an input to production. It gives the factory room to manage ordinary purchasing while protecting the parts of the supply chain that define the buyer’s product.
Before the next order, list the components, materials, processes, and packaging sources that could change product acceptance. Supplier Ally can help buyers build practical approved-source registers, coordinate supplier change notices, review first-use evidence, and maintain traceability across China manufacturing projects.
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