Practical Answer — Supplier Control

How to Check Who Can Access Your CAD and STP Files at a Chinese Factory

Last updated: June 2026

The question is not only whether the factory promises confidentiality. The question is who can actually open, copy, forward, store, or reuse the CAD/STP files.

In short

This page is a file-access audit, not a general confidentiality explainer. It helps overseas buyers ask the right questions before they send CAD or STP files to a Chinese factory, especially when multiple people, departments, or outside providers may be able to see the files.

Why CAD/STP File Access Is Different From Ordinary Confidentiality

A supplier can agree not to disclose information and still have very broad internal access to the same files. Once the files are in the system, the risk is often about access, copying, storage, forwarding, and reuse, not just public disclosure.

That is why a file-access audit matters. It tells you how the supplier actually handles the files, not just what the contract says in general terms.

Who May Access the Files

The sales contact who receives the first email
Engineering, tooling, or production staff
A manager at a related factory or sister company
A mold shop, prototype shop, or outside technical provider
Any internal person who can export, forward, or duplicate the files

Questions to Ask Before Sending Files

Who will open the files first?

Can anyone outside the core project team access them?

Are the files stored on a shared drive, on local devices, or in a system with export rights?

Can the factory forward the files to a sister company or outside vendor without asking?

Evidence to Keep

The exact file versions that were sent
Emails or messages confirming receipt and purpose
Any disclosure log showing who received what and when
Written limits on forwarding, copying, or reuse
Any response about storage, backups, or retention

File-Sharing Red Flags

The supplier insists on receiving full files before any written control structure is in place
The supplier will not say who else can access the files
The files are being shared through multiple people or accounts with no clear record
The factory wants to keep copies without any return or destruction obligation
The supplier treats forwarding the files to related entities as normal and unavoidable

What an NNN Can and Cannot Solve

An NNN can help define confidentiality, non-use, and non-circumvention obligations.

An NNN does not automatically tell you who inside the factory can see the files or how broadly they circulate.

That is why file access should be audited alongside the contract, not after the first disclosure.

When to Use Manufacturing Agreement / Tooling Ownership Terms

Once the files move past early quote-stage use and into tooling, sampling, or production, the manufacturing agreement should say more about file custody, return, destruction, ownership, and reuse limits.

A file-access audit can show you where the contract needs to go next. If the files are already widely accessible, tooling and manufacturing terms need to do more work to limit downstream use.

Get Help

Need help checking who can actually see your files?

A Supplier Control Review can help map the file path, the people involved, and the contract terms that may still be missing before the next disclosure.

Request a Supplier Control Review Contact Us

Frequently Asked Questions

Why is CAD/STP access control different from ordinary confidentiality?

Because the issue is not only whether the factory promises secrecy. The real question is who can actually open, copy, forward, store, or reuse the files once they are inside the supplier's system.

What should I ask before sending files?

Ask who will receive the files, which departments can access them, whether any external provider can see them, and how copies are stored, backed up, or forwarded internally.

Can an NNN stop all file misuse?

No. An NNN can help, but it does not tell you who already has access or whether the supplier has internal controls that actually limit access to the files.

What if the supplier says everyone needs the files to do their job?

That may be operationally convenient, but it is also a sign that file access is broad. The buyer should still know who can access the files, for what purpose, and under what controls.

Related Resources

Supplier Control