Evaluating Prototype-to-Production Scalability with Overseas Silicone Manufacturers

A pretty prototype from an overseas silicone shop is evidence they can copy a shape. It is not evidence they can run your annual quantity, in the production compound, on a tool class you can maintain, with a QMS your device or automotive file will survive.

Scalability is a score you give the *factory system*, not a feeling you get from a 20-piece courier box. Score it before you let them cut production steel. After steel, you are funding their education or funding a transfer.

Unmix the processes while you score: tin-cure RTV jackets, platinum RTV, aluminum LSR bridges, steel LSR, HCR compression, extrusion. A shop that is brilliant at vacuum-cast samples and has two tired LSR presses is not “vertically integrated.” It is two businesses sharing a logo.

Prototype capability is the wrong trophy

Ask how the sample was made. Then ask whether production will use that process.

RTV vacuum-cast samples (platinum jacket around a printed or CNC master) are fast and geometrically honest for undercuts. They lie about LSR shrink, flash, gate vestige, and cycle. If production is LSR, the sample only proved CAD.

Printed or aluminum 1-cavity LSR samples prove fill and vestige. They do not prove multi-cavity balance, cold-deck behavior, or Class 103 life.

Steel 1-cavity “prototype” on a production press is the most honest sample. It is also the one shops resist because it occupies a real machine.

If the shop’s prototype cell is a trading company plus a sample room, and production is “our partner factory,” you have not met the molder. Scalability starts when you can name the press, the toolroom, and the QMS site on the certificate.

Questions a sample cannot answer

Write these into the audit. Samples will still look fine.

Process match. Will production be LSR injection, HCR compression, or extrusion? Does this site run that process every week, not once for your visit? Ask for a similar part’s process sheet, not a brochure.

Tooling ownership and class. Who cuts steel? In-house or a named toolroom? SPI/SPMA class language on quotes? Spare inserts? If they cannot talk class, cavitation, and cold runner, they cannot scale LSR.

Capacity math. Presses in the right clamp range, cold-deck experience, oven space for post-cure, labor for destage. “We can add shifts” is not a number. Hours of similar work on the calendar is a number.

Compound control. Incoming COA, lot hold, platinum vs peroxide segregation, approved mill list. Scaling a unique healthcare LSR is a mill relationship. The sample used a leftover pail.

Change control. How a drawing revision becomes a recut. How a gum substitution is refused. Overseas email culture hides silent changes. You want a procedure you can sample.

Quality system vs product. ISO 9001 vs ISO 13485 vs IATF 16949, *scope matched to the site*. A 13485 trading office in front of a 9001 press hall is a scalability trap for medical.

Export reality. Lead time with ocean, not with a sample courier. HS/docs competence. Ability to crate a tool if you leave.

A scorecard you can reuse (weight what you buy)

Score 0-2 each. Zero is a story. Two is evidence (procedure + floor + a similar SKU).

1. Production process = sample process, or a named bridge plan (RTV → aluminum LSR → steel).
2. Toolroom that can recut lands and add cavities without a mystery sub-tier.
3. QMS scope matches product risk.
4. Material traceability from drum to carton on a live lot.
5. Stated cavitation path (1 to N) with balancing talk, not “we will make an 8-cavity when you are ready.”
6. Post-cure and inspect capacity at production rate, not at sample rate.
7. English (or your language) process sheets that match the press HMI.
8. Ownership, no-duplicate, file-release clauses they will sign *now*.
9. Second-site or second-press story that is real, or honesty that they are single-site.
10. A similar part they still run, with shot history and a PM log.

A shop that scores well on 1-4 and poorly on 5-6 is a prototype house. Keep them for samples; cut production steel elsewhere, or fund a real cell. A shop that scores well on 5-6 and poorly on 1 will “scale” you into a different geometry than you approved.

Do not average a 9/10 sample-room tour with a 3/10 production hall. The hall is the molder.

Capacity is a calendar, not a building

Walk the press list: tonnage, LSR vs thermoplastic (a converted plastic press is a question, not an automatic no), cold-deck plumbing, occupancy. A hall full of plastic tools with one LSR machine is a queue.

Ask what happens at 3× your forecast. Honest answers: a second tool, a night shift with a named technician plan, or “we cannot.” Dishonest: “no problem.” Overseas scalability deaths are usually queue and quality, not missing floor space.

Post-cure ovens, washing, and clean pack are the silent constraints on medical and food. The press is fast. The rack is slow. Count racks.

Change control is scalability

Your CAD will move. The overseas molder who scaled you is the one who can recut an insert in a known number of days, send steel-complete photos, and not ship mixed revisions. Put a revision drill in the kickoff: dummy a small logo change. Time it. If it disappears into a WeChat group, you found the limit.

Also drill *their* change: gum shortage, pigment swap, operator. If the quality agreement does not force a notice, scaling just scales the silent substitution.

RFQ that selects a factory you can grow with

“State sample process vs production process. Quote aluminum 1-cavity LSR and steel N-cavity as separate stacks. Name the production site, QMS scope, press count in range, and toolroom. Sign tool ownership and file release. Provide a similar part’s PM log. Sample courier lead time is not production lead time.”

If they answer with photos of the sample and a single piece price at 10,000, they are not a production system. They are a sample that learned how to invoice.

FAQ

Can the same overseas shop do my RTV prototypes and my steel LSR production?

Yes if both processes exist on the *named site* with people who still run them. Many “full service” shops sample in a prototype cell and outsource steel. That can work if the steel site is named, audited, and bound by the same ownership clauses. An unnamed partner is not scalability. It is a surprise.

How many similar parts should I see before I trust capacity?

Enough to prove the process family: a valve-gated small part if you need that; a compression HCR if you need that. One unrelated consumer gadget in a display case is zero. Ask for a live traveler and a PM log, not a trophy wall.

Is a trading company always a scalability risk?

A trader who names the plant, hosts the audit, and puts ownership clauses on the steel can be a language and logistics layer. A trader who hides the plant cannot scale with you because you cannot find the press when forecast triples. Price the layer; do not pretend it is a factory.

Should I freeze production steel at the prototype vendor to save time?

Only if the scorecard says they are the production system. Saving six weeks of a second FAI is expensive if you then transfer a hostage tool. Parallel: prototype vendor for geometry; production vendor cutting steel from the same CAD, with an aluminum bridge if LSR behavior is still unknown.

What lead-time number belongs in a scalability review?

Production lead time at the stated batch size, including compound procurement and ocean, plus a recut interval. Sample courier days belong in a prototype SOP. Mixing them is how launches plan airfreight as a personality trait.