A factory using subcontractors is not automatically unsuitable. You need to know which operations happen elsewhere, who controls them and whether changes require your approval. Check the actual production arrangement before assuming that a visit to one workshop covers the whole order.
A supplier may assemble a product at its own site while buying components or sending parts out for finishing. The important question is whether that arrangement is understood and controlled for your requirements.
This guide focuses on mapping and checking outside operations. It does not treat every traded component as a warning sign or assume all work must happen under one roof.
Map the operations that matter to your product
Ask the supplier to describe the route from material to packed goods. Identify the operations most likely to affect dimensions, function, finish or traceability. Record which are in-house, which are external and which remain unconfirmed.
| Operation | What to establish | Supporting evidence to request |
|---|---|---|
| Materials and components | Specification and source controls. | Purchase requirements, approved references or relevant records. |
| Main manufacturing | Site, equipment and process used. | Relevant production observations and process discussion. |
| External finishing | Who performs it and how requirements are passed on. | Specification, batch identification and incoming checks. |
| Assembly | Who accepts components and manages fit problems. | Assembly instructions and handling of rejected parts. |
| Final packing | Who checks the finished order and variants. | Packing requirements, check records and identified exceptions. |
Connect the company, site and order
Confirm which entity quotes, contracts and receives payment, and how it relates to the production site. The same trading name in messages does not establish every legal or operational relationship.
A supplier can explain an external operation without necessarily disclosing every commercial detail. Agree the evidence and access needed for your decision. If access is restricted, report that restriction rather than presenting the operation as checked.
Our supplier verification support for company and factory checks can help investigate named questions. Remote documents, factory statements and on-site observations should remain clearly distinguished.
Give a factory visit a specific agenda
A visit should examine the operations and controls relevant to your product. Ask to see applicable equipment, material handling, work instructions and examples of current work where access permits.
For outsourced finishing, discuss how parts are identified when they leave, how requirements are communicated and how returned parts are checked. Ask what happens when an outside process creates defects or delays.
Someone attending on the buyer’s side can ask follow-up questions and compare explanations with observations. A tour alone does not establish the performance of an external site that was not visited.
Review certificates within their actual scope
When a supplier provides a certificate, check its named organization, covered activities and sites where stated. ISO’s guidance on certification and accreditation describes ways to check certification claims. Do not assume one factory’s certificate automatically establishes the status of every subcontractor or product.
If the product needs a particular process approval, laboratory test or destination-market assessment, define that requirement explicitly. A general site review and a specialist technical assessment answer different questions.
Agree what can change without approval
The production arrangement may change after a sample is accepted. Set a written rule for changes to critical materials, operations or sites. Specify who must notify the buyer, what evidence is needed and who approves the change.
| Field | What to record |
|---|---|
| Current arrangement | The accepted operation, site or process reference. |
| Proposed change | What will change and why. |
| Effect to assess | Specification, capacity, timing, tests and traceability. |
| Evidence | Sample, document, inspection or specialist review needed. |
| Decision | Approval, rejection or further questions, with a date and owner. |
A statement that “quality will stay the same” does not explain how the requirement will be maintained. Ask how the supplier assessed the change and whether another sample or test is needed.
ASQ’s explanation of quality plans connects quality requirements with responsibilities, inspection activities and change procedures. Use that principle to make your order’s control points explicit rather than relying on informal assurances.
Follow the handovers during production
Ask for updates at the points that matter: material arrival, transfer to an outside process, return for assembly and readiness for final checks. The useful evidence depends on the operation and agreed scope.
Keep quantities and product versions identifiable through the handovers. If parts from different batches can become mixed, discuss how accepted, pending and rejected material will be separated.
With production follow-up for agreed manufacturing milestones, the task should identify what information is sought, how often and how issues are escalated. It should not imply continuous physical supervision unless that has actually been arranged.
Use the findings to decide what to do next
The answer may be to accept the documented arrangement, obtain another sample, investigate an external site or compare another supplier. Tie the next step to the concern that remains open.
If the supplier cannot explain a critical operation or repeatedly changes the story, treat that uncertainty as part of the purchasing decision. Equally, a clearly explained and well-managed outside operation may be workable. Judge the evidence and product requirements together.
Questions buyers often ask
Does subcontracting mean the supplier is a trading company?
No. Manufacturers can outsource particular operations. Establish the actual roles and responsibilities rather than classifying the supplier from one external process.
Must I visit every subcontractor?
Not necessarily. Prioritize operations affecting critical requirements and decide what evidence or specialist work is appropriate. A visit to one site cannot be reported as a visit to all sites.
Can a factory change its finishing supplier after sample approval?
Confirm the change-control terms before ordering. Changes affecting agreed requirements may need notification, review, samples or approval under those terms.
Can GCB investigate a factory I already work with?
We can discuss a defined check of your existing supplier’s arrangement. Share the product, known sites and specific concern so the assignment addresses your decision.
Bryan’s Perspective
I do not expect a factory to perform every operation itself. I do expect a clear answer when we ask where an important process happens and how it is controlled. Visiting the workshop is useful partly because we can keep asking until the explanation matches what can actually be established.
If the arrangement remains unclear, identify the critical process first. Our manufacturer selection support based on production requirements can help compare the arrangement with suitable alternatives.
Global China Bridge supports overseas entrepreneurs and small businesses with sourcing, supplier checks and manufacturing coordination in China. Start with a free introductory conversation at service@globalchinabridge.com. We agree the scope and fee before paid work.
Updated: October 23, 2026