Frequently Asked Questions

The ideal package is a 3D file (STEP or IGES), a 2D drawing with critical dimensions and tolerances marked, your estimated annual volume, and the material if you've already chosen one. With that, you get a quote and DFM feedback within one business day.

Missing some of it? Send what you have. A photo and a rough sketch is enough to start a conversation, and we'll tell you exactly what we still need and why.

Yes. Mail us the sample and we measure it and rebuild it in SolidWorks. You review and approve the drawing before we cut any steel, so the part that comes back is the part you signed off on, not our guess at it. Many of our ODM projects start exactly this way, with a worn part and no documentation.

On existing molds there is no fixed minimum. We run prototype batches of a few hundred parts and scale to over a million units a year on the same tooling.

One honest limit: we don't open a new mold for a project worth less than about USD 2,000 in total. Below that, the math doesn't work for either side, and we'd rather tell you now than quote high and waste your week.

Quote within one business day. If you sent CAD files, DFM comments come with it: wall thickness, draft angles, gate position, anything we'd change before tooling. Questions during a running project usually get answered the same day, because the person reading your email also runs the workshop.

We're usually 10 to 20 percent above low-cost workshops, and we won't negotiate down to match them. What the difference buys: mold steel and coatings we don't cut corners on (the first mold my father made in December 1996 is still in production), inspection that actually happens, and direct engineering answers instead of a week of translated email.

If your project is a one-off prototype where price is everything, a cheaper shop may genuinely be the right choice, and we'll say so. Our pricing makes sense for programs that will run for years, where the cost of a failed mold or a bad batch is much bigger than the per-part difference.

Weilin itself holds ISO 9001, recertified in April 2026, covering our Ningbo production.

What we do not hold, so you don't find out late: ISO 13485, FDA registration, and CE marking. We are a component-level supplier. Our customers integrate our parts into their products and handle device registration themselves, which is how our dental and medical gas programs have worked for decades.

For parts that need more press tonnage than our own machines provide, we work with a partner facility in Hefei that holds its own ISO 9001 and IATF 16949. Those certificates belong to the partner, not to us, and we say so up front whenever a project routes through them.

±0.05 mm standard, ±0.02 mm on critical features, verified with CMM on critical parts. If your drawing asks for tighter than ±0.02 mm, we'll tell you before quoting whether we can hold it on your specific geometry and material, or whether you should be talking to someone else. Shrinkage behaves differently on every resin, and a tolerance that's easy in POM can be a fight in PA66.

Each new mold gets a First Article Inspection. Each batch ships with a material certificate (COA) traceable to the resin lot. We keep retain samples from production runs, and critical dimensions are checked on CMM. For one European medical gas customer we work under a signed quality agreement covering change control, raw material traceability, retained samples, and CAPA procedures, and we can discuss the same arrangement for your program.

The number we watch hardest: our medical gas program runs at 4 to 5 defective pieces per month across the whole product family, and neither of our two anchor OEM programs, 29 years and 17 years, has ever had a batch returned.

Yes. We regularly process medical-grade PP, PC, PEI, medical silicone, LSR, and TPE. Biocompatibility data (ISO 10993) comes through our resin suppliers and ships with the material documentation on request, along with the batch COA.

A few, and it's better you know now:

• Class II and III medical devices, and complete medical devices of any class. We don't hold ISO 13485, and we won't pretend a Class I workshop is the right home for an implant or a syringe assembly.
• Optical lenses and precision optics. We don't have the polishing capability, and faking it would show up in your parts.
• Parts over roughly 2 kg or needing more than 1,000 tons of clamping force. That's past our equipment ceiling even with our large-tonnage partner.

When a project falls outside our depth, we say so in the first reply and, where we can, point you toward the kind of supplier who fits. Wasting your evaluation cycle helps nobody.

Small and medium parts, which is most of what we do, run on our own five presses (100 to 150 tons) in Ningbo. Projects that need bigger machines, roughly 200 tons and up, run at a partner facility in Hefei with eleven presses from 126 to 1,000 tons. It's a long-standing family connection, their certifications are their own, and if your project would run there, we tell you in the quote, not after the fact.

Frank Lai, the second-generation owner. He reads every inquiry, opens every CAD file himself in SolidWorks, and signs off on every quote. There is no account manager layer and no sales team, which is easy for us to promise because there are only 10 to 30 of us in total.

Email gets answered within one business day. For urgent things during a running project, WhatsApp and WeChat (+86 139 6838 7151) are faster.

We sign an NDA before receiving any CAD files. Your mold is dedicated to your project, stored securely, and never used for anyone else. One more data point on discretion: we've supplied some customers for 29 years and you won't find their names anywhere on this site, because they haven't given written permission. The same rule will protect you.

STEP, IGES, STL, Parasolid, SolidWorks (SLDPRT), Creo, and AutoCAD. We review SolidWorks files directly, so DFM feedback comes from the person who will mold the part, without a translation layer in between.

Quote within one business day. New mold in four to six weeks. Production ships 15 to 25 days after you approve T1 samples, depending on quantity and secondary operations. Repeat orders on existing molds skip straight to the production step.

One planning note worth knowing: Chinese New Year closes every factory in China for roughly two weeks, ours included. If your order needs to ship in late January or February, tell us early and we'll schedule around it.

Yes, it's most of what we do: dental consumables to the USA for 29 years, medical gas components to Europe for 17. We ship FOB, CIF, or DDP and handle the export documentation, including material certificates and country-of-origin paperwork.

Yes. In-house secondary operations include ultrasonic welding, heat staking, silk-screen printing, hot stamping, and assembly. For private label programs we mold in your colors, print your logo, and pack in your retail boxes, so what leaves our dock is ready for your warehouse shelf.

Yes, and we'd rather you did. We're in Xiangshan, Ningbo, about three hours from Shanghai. It's a 2,000 square meter family workshop, not a showcase campus. You'll see the presses, the mold racks including the 1996 tool, and meet the people who would actually make your parts. Customers who prefer to start remotely can get a live video walkthrough first, and our batch records are auditable either way.