Non-Disclosure Agreements (NDAs) When Sharing CAD for Proprietary Silicone Molds

An NDA does not lock a cavity. It defines who may see the CAD, for what purpose, for how long, and what they must return. A shop that intends to copy you will still be able to mill steel. A shop that is merely sloppy will still drop your STEP into a WeChat group of “partners” unless the NDA and your file habits make that an obvious breach.

This is a practical protocol for sharing CAD on proprietary silicone tools (LSR, HCR, extrusion dies). It is not legal advice, not a form, and not a substitute for counsel in the jurisdictions where the files sit and where the steel will sit. Get that advice on the actual paper. Use this memo to stop sending native CAD to four bidders with a smiley face.

What the NDA can do, and what it cannot

Can do: mark the files confidential; limit use to quoting or to manufacturing part XXX; forbid sharing with unnamed subcontractors; require return or destruction; create a paper trail you can point to; support a contract claim if you later find your cavity in a catalog.

Cannot do: make reverse-engineering from a finished gasket impossible; police a night-shift CNC; replace tool ownership, no-duplicate, and no-export clauses; replace patents or design registrations where those matter; make a bad factory honest.

If the geometry is a standard lip and a catalog 50A LSR, spend proportionally. If the geometry *is* the product (medical profile, branded consumer, custom overmold), treat the NDA as layer one of a stack, not as the stack.

Paper that a factory can actually obey

Mutual NDA, before the first STEP. Purpose: “evaluation and quotation of custom silicone part [code]” and, after award, a manufacturing agreement that *replaces* the quote-purpose with a build-purpose.

Define the confidential items: CAD, 2D, compound recipes you supplied, DFM, photos of steel, process windows. “All discussions” without an exhibit list is how nobody knows what to return.

Name subcontractors or forbid them. Toolrooms, sister plants, color houses. If the molder must send CAD to a cutter, the cutter is either named and bound, or the molder is in breach when they forward the file. Trading companies that will not name the cutter cannot sign a meaningful NDA.

Term and return. A survival period after the quote dies. Return or destroy files, including from personal phones. You will not get a forensic wipe. You *will* get a clause that makes casual forwarding stupid.

Governing law and venue belong to counsel. Do not copy a U.S. template onto a coastal toolroom and assume it is theatre-proof. Also do not skip the NDA because enforcement is imperfect. Imperfect paper is still better than a cheerful email trail that says “feel free to share with your partners.”

The NDA is not the tooling contract. Ownership of steel, electrodes, and generated files lives in the PO. People who think the NDA transferred title will lose a crate.

File hygiene that does more than the PDF

Watermark 2D PDFs and screenshots: vendor name, date, “quote only.” Native CAD for quoting can be a dumb STEP with a decoy only if you will pay to correct it honestly after award. Tricking a shop and freezing is how you get a quiet extra tool.

Stage the files. Quote: STEP + a 2D that omits brand artwork if artwork is a later insert. Award: full 3D, ballooned FAI drawing, shrink notes. Electrode files and cold-runner know-how: after PO, or never if *you* will own that design and the shop only cuts cavities.

Insert strategy. Logo and distinctive ribs on a small insert. The quote CAD can live without them. This is DFM and IP, not paranoia.

Do not email a complete cold-deck design to three bidders if that manifold is your know-how. Ask each shop to propose a runner. Compare. Lock after award.

Channel. A named file portal or email thread, not a personal WeChat. You want a log. You will not get one from a sticker pack.

Version. One revision letter per release. A shop quoting Rev B from a Rev A STEP is a future mixed-steel event.

Factory behaviors that matter more than clause 12

Watch what they do with the first PDF.

• They name the toolroom. Good.
• They ask for shrink, gate faces, and flash spec instead of asking for your entire native assembly. Good.
• They forward your file to “a friend who quotes faster” in the same afternoon. The NDA already failed as a control. Believe the behavior.
• They want the production compound recipe “just to quote.” For a catalog LSR, a grade code is enough. For a custom healthcare kit, a spec sheet you control is enough. Your mill’s confidential formulation is not required to estimate cavitation.

A competent shop can quote from STEP, 2D, annual quantity, grade family, and flash spec. If they demand every electrode and the full device assembly to “see if it fits,” they are collecting.

A proportional protocol

Low uniqueness (standard gasket): one-way or mutual NDA, watermarked 2D, STEP, ownership clause later. Do not delay the RFQ for a ten-page treaty.

Medium (branded consumer, custom lip): mutual NDA with named-subcontractor rule, staged files, logo on insert, no-duplicate in the PO, steel-complete photos.

High (device-critical, custom compound, expensive multi-cavity): above, plus counsel on both ends, file portal, split inserts vs base if warranted, electrode escrow with you, audit of who can open the folder.

RFQ cover line: “CAD is confidential, quote-only, watermarked. No forward to unnamed toolrooms. NDA required before STEP. Award files are separate. Tool and generated design are buyer property on PO.”

If a shop will not sign even a short NDA to see a gasket, they are telling you how they treat the next customer’s files too. That is useful data. It is not a dare to send the native CAD anyway.

FAQ

Do I need an NDA before sending a STEP file for a silicone quote?

Yes if the geometry or compound is proprietary, and it is still cheap hygiene if it is not. The NDA should exist before the file, not as a PDF you remember after three bidders have it. For a truly generic washer, speed may win; mark the file quote-only anyway.

Is a mutual NDA better than a one-way NDA?

Usually for factories: they have process know-how too, and they will sign faster if you are not grabbing it. Mutual does not mean they own your CAD. Purpose limitation still points at your part number. Have counsel tune the form. This is not a form kit.

Can an NDA stop a factory from copying my part from a sample?

No: A sample is a reverse-engineering kit. NDAs cover *your disclosed information*. Physical parts in the market are a different problem (design rights, patents, contracts on the tool). Make copying expensive with inserts, ownership, and traceable steel. Do not ask a PDF to do steel’s job.

Should I send native CAD or a dumb STEP for bidding?

Dumb STEP (and a 2D) for bidding. Native files and electrodes after PO, if the shop needs them to cut. Native assemblies teach how you build the device, not just the gasket. Shops that refuse to quote without the full native tree are collecting or they cannot read a STEP. Both are data.

Does a signed NDA replace a tooling ownership clause?

No: NDA = confidentiality and use limit on information. Ownership = title in steel, inserts, and generated files. You need both, plus no-duplicate and no-export. An NDA with no PO language is how you have a confidential tool that the shop still claims to own.