Practical Answer — Supplier Control
What Should I Say Before Sending CAD Files to a Chinese Manufacturer?
Last updated: June 2026
Before attaching anything: confirm the NNN is signed, confirm who receives the files, state the purpose, and set the expectation about what they cannot do with the files. Then attach.
In short
Before sending CAD files, STP files, technical drawings, or any detailed product files to a Chinese manufacturer, you should have already: confirmed an NNN agreement is signed by the correct legal entity; verified who is receiving the files; and stated the specific purpose in writing. If the NNN is not yet signed, the right first message is a request to complete that step — not the files themselves.
Why Sending CAD Files Too Early Is Risky
Once a factory has your CAD or STP files, you cannot un-share them. What the factory does with those files depends entirely on what agreements and obligations were in place at the moment of sharing. Without a signed NNN:
The factory may use your design for other customers
Your design becomes useful input for anyone else asking for a similar product. Without a non-use obligation, the factory has no contractual barrier to repurposing your design.
The factory may file IP based on your design
Utility model patents and design registrations in China can be filed quickly. A factory that has your CAD files and no obligation not to file is a factory with the practical means to register IP rights that may later be asserted against you.
The agent or factory may forward your files
Files shared with a sourcing agent often flow to one or more factories the agent works with. Without a non-disclosure clause covering sub-suppliers, your design may be seen by multiple manufacturing entities.
The implied permission problem
Sending files without any stated condition is sometimes interpreted as general permission to use the files for production-related purposes. Stating the scope of the sharing at the time of sending reduces ambiguity.
What to Confirm Before Attaching Files
Before any file is attached to an email, WeChat message, or file-sharing link sent to a Chinese manufacturer:
NNN is signed by the correct entity
The NNN agreement (Non-disclosure, Non-use, Non-circumvention) should be signed and chopped by the factory or supplier legal entity — not just a sales contact or representative. The signing entity should match the entity that will receive and use the files.
You know who is actually receiving the files
Is the recipient the factory directly, or a sourcing agent who will forward the files? Is the factory a manufacturing company or a trading company? Who will the files be shared with next? The NNN should name the correct receiving entity and cover sub-suppliers.
The files are appropriate for this stage
Does the current stage (price quote, capacity check, initial sampling) actually require full CAD files, or would a general product description or reference drawing be sufficient? Sharing less reduces risk at early stages.
Your trademark is registered or filed
If the product has a brand name, logo, or packaging that is visible in the files, a China trademark application should be considered before the files are shared. Filing after disclosure does not eliminate the risk that someone else files first.
A Safer Way to Frame the Message
When you are ready to send files, frame the message to state the purpose and the limit. Examples:
For a price quote
"Please find attached the product drawings for quoting purposes only. These files are shared under the NNN agreement signed on [date] and are not to be shared with sub-suppliers or third parties. Please confirm receipt and let us know if you have questions."
For sampling
"Attached are the CAD files for the initial sample run. These are shared under our signed NNN for the purpose of producing samples for our review. Please do not share with any third parties or use for any other purpose. Confirm receipt and expected timeline."
For production — where a manufacturing agreement is in place
"Attached are the final production files as referenced in Section [X] of our manufacturing agreement. These are to be used for production of our order only. Storage, permitted use, and return obligations are governed by that agreement."
What Not to Send Yet
At early stages — initial inquiry, price quote, or first contact — hold back:
- Full CAD or STP files with all tolerances, assemblies, and finishes — a simplified reference drawing is often enough for a quote
- Manufacturing process notes, BOM, or material callouts in detail
- Packaging artwork and label designs with your brand clearly visible
- Customer information, shipping destinations, or downstream distribution details
- Pricing targets, margin structure, or competitive information
- Prototype or pre-production unit photos that show unreleased design details
What to Do If the Supplier Says "Just Send It" or "Trust Me"
This is one of the most common situations buyers encounter. The supplier's position is: we are busy, we get files all the time, paperwork slows things down, you need to trust us.
The issue is not trust — it is structure. A supplier who genuinely operates professionally will understand that an NNN is standard commercial practice. What to say:
"We work this way with all factories — it's not specific to you. Our internal process requires the NNN to be in place before technical files are shared. It protects both sides. Once we have that signed, we can move quickly. Can you have someone from your side sign today?"
If the supplier continues to resist after a clear, reasonable explanation:
- Do not send the full files yet — share only a general product category description without detailed design information.
- Ask directly: "Is there a reason your company is not willing to sign a standard confidentiality agreement?" — a legitimate answer may exist; an evasive one is a signal.
- Consider whether this supplier is the right one to move forward with — a refusal to sign basic protection terms is not a good indicator for a long-term manufacturing relationship.
What Should Be Confirmed in Writing
Before or at the time of sending files, confirm in writing — at minimum by email:
- The NNN is signed, referencing the agreement date and the signing entity's registered name
- The files are being shared for a specific stated purpose (quoting, sampling, production under a defined order)
- The recipient confirms they will not share the files with sub-suppliers, affiliates, or third parties without your written consent
- The recipient confirms they will not use the files for any purpose other than the stated one
- A request for confirmation of receipt
When to Use an NNN, Manufacturing Agreement, or Supplier Control Review
These are not the same document and they address different stages:
NNN agreement
Before any technical files are shared. Covers non-disclosure, non-use, and non-circumvention. The first document in the protection structure. Should be in place before CAD files, STP files, drawings, or product specifications are shared.
Manufacturing agreement
When moving into sampling, tooling, or production. Addresses quality, delivery, ownership of molds and files, IP non-filing obligations, and what happens when the relationship ends. Should be in place before tooling fees are paid and production-grade files are shared.
China Supplier Control Review
When the current document structure has gaps — NNN unsigned, wrong entity named, no tooling ownership terms, no file return clause — or when you are preparing for a significant scale-up and want an independent assessment of your exposure.
For further detail on what the NNN covers and why it is needed before sending any files, see: Do I Need an NNN Before I Send Drawings to a Chinese Factory? and How Do I Protect CAD Files and STP Files?
Get Help
Need an NNN Before Sending Files?
We can review your current supplier setup, prepare a China-enforceable NNN with the correct entity named, and identify what else needs to be in place before production files are shared.
Frequently Asked Questions
Do I really need to say anything special before sending CAD files — can't I just attach them?
You can, but sending technical files without first confirming the agreement, the entity receiving them, and the purpose creates real risk. Once the factory has your files, they have the design information. Whether they use it appropriately depends on what you have in place. Sending files with no stated conditions is sometimes treated by factories as implied permission to use the design as they see fit.
What is the most important thing to confirm before attaching CAD files?
That an NNN agreement is already signed by the correct legal entity — the actual factory or supplier, not just a sales contact or trading company intermediary. If the NNN is not signed yet, the right message to send is a request to complete that step first — not the files themselves.
What should I say if the supplier says 'just send the files, we'll sort the paperwork later'?
Treat this as a reason to pause. The paperwork is what makes the file sharing safe. A supplier asking you to share first and sort documents later is asking you to give away your design protection before the protection is in place. A reasonable supplier will understand that your process requires the NNN to be signed first.
Is it enough to write 'confidential' on the email or the file?
No. A confidentiality label does not create an enforceable obligation in China. It may be useful context if a dispute arises later, but it is not a substitute for a signed NNN agreement naming the correct legal entity.
What files should I hold back even after the NNN is signed?
Share only what is needed for the current stage. For a price quote, a simplified drawing may be sufficient — detailed tolerances, full CAD, STP files, BOM, and finishing specifications can be held back until a manufacturing agreement is in place. Staged disclosure reduces what the factory can do with your information if the relationship does not proceed.
What should be confirmed in writing before files are sent?
At minimum: that the NNN is signed, the legal entity receiving the files is the one that signed the NNN, the files are being shared for a specific stated purpose, and that the recipient confirms they will not share the files with sub-suppliers or third parties without your consent.
On this page
Related Resources
Further reading on NNN agreements, file protection, and supplier communication.
Do I Need an NNN Before Sending Drawings?
When and why to sign an NNN before any product files leave your hands — and what happens if you send them first.
Read Answer Practical AnswerHow Do I Protect CAD and STP Files When Sharing With a Chinese Factory?
The NNN, identity verification, file scope, and agreement layers that protect your technical files before and during production.
Read Answer ServiceChina Supplier Control Review
Independent buyer-side review of your NNN, supplier identity, and file-sharing structure before production scales.
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