Factory visits should reduce uncertainty. Too often, they don’t.
Buyers come in, get a tour, see some machines running, collect catalogs, and leave with the same fundamental questions they had before: Can this factory actually deliver what I need? At the quality level I require? On a timeline I can build a business around?
The issue is usually not the factory. It’s the questions buyers ask — or more accurately, the questions they don’t.
Here is a practical framework for evaluating an eyewear manufacturer during the 2026 Wenzhou Expo period, whether you’re visiting us or anyone else.
Production Capacity: Ask for Numbers, Not Descriptions
When a factory says “we have high capacity,” that tells you nothing. What you need are actual numbers.
Ask: How many units per day does this production line produce for this specific product type? For context, our three production lines at Wenzhouframe produce a combined daily output that can support both standard wholesale orders and custom OEM projects running simultaneously. But don’t take our word for it — ask us to show you the line running and ask the production manager directly.
Ask: What is your current utilization rate? A factory running at 100% capacity for the next six months is a problematic supplier for a new customer who needs a May delivery. A factory with available capacity can take your order and start immediately. This matters more than the theoretical maximum output number.
Ask: What percentage of your current production is OEM versus standard wholesale? A factory that primarily does OEM has different process discipline than one that mostly ships generic stock. If you’re an OEM buyer, you want to work with a factory that is set up for that kind of work, not one where your custom project will be handled as an exception.
Quality Control: Where Exactly Does It Happen?
Every factory will tell you they have quality control. The question is where in the process it happens.
Pre-production QC — inspection of raw materials before they go into the production line — is a sign of a mature process. Ask to see the raw material inspection records. Ask what happens when a batch of acetate or titanium fails inspection. Factories that have never had a raw material failure have either never looked or are not being honest with you.
In-line QC — checks that happen during production rather than only at the end — is what separates manufacturers who catch defects early from those who ship you a box of problems. Ask what the in-line rejection rate looks like on a typical run. A zero rejection rate is a red flag, not a reassurance.
Final inspection before shipment is table stakes. Any factory will tell you they do this. The more useful question is whether they welcome third-party inspection. If a factory is comfortable with buyers sending their own inspector or using an agency like SGS or Bureau Veritas, that’s a meaningful signal. If they’re resistant, ask why.
At our facility, third-party inspection is welcomed and coordinated at the buyer’s request. We’ve found that buyers who use third-party inspection tend to become long-term customers, because the process removes the uncertainty that otherwise slows down the relationship.
Sampling: Speed Tells You More Than Claims
Ask any factory what their sample turnaround is and they’ll give you a number. Ask them how that number changes if you show up today and ask for a sample of a style they haven’t produced before.
The answer tells you how much of that quoted turnaround time is real process capability and how much is optimistic calendar math. A factory with genuine in-house 3D printing can produce a first prototype in days. A factory that outsources its prototyping will take longer regardless of what they tell you upfront.
We run 3D prototyping in-house. Standard turnaround for a new prototype is seven to fourteen days. For styles that use existing molds — which covers the majority of popular frame shapes in the market — we can have physical samples ready in three to seven days. If you’re at the expo and you find a style you want to reproduce, message us with a photo. We can usually give you a realistic timeline before you leave Wenzhou.
Ask also about revision rounds. Sampling is rarely a single iteration. How does the factory handle the second and third round of revisions? Are they included in the sample fee, or do they charge separately? At Wenzhouframe, revisions are included. The sample fee covers the process, not a single attempt.
NDA and IP Protection: Read the Agreement, Not the Reassurance
Every OEM buyer should be asking about IP protection, and every factory will tell you your designs are safe. The only thing that matters is the written agreement.
Ask to see the factory’s standard NDA before you discuss any design specifics. Read it. Understand what it covers and what it doesn’t. Specifically, check whether it includes a clause about exclusivity — meaning the factory commits not to produce your design for another buyer. Some factories’ standard agreements cover confidentiality but not exclusivity, which is a meaningful gap.
Our standard NDA covers both confidentiality and production exclusivity for custom molds. If you have your own NDA template you prefer to use, we’re willing to work from that as a starting point. What we won’t do is discuss your design before the agreement is in place.
Communication: Test It Before You Commit
One of the most underrated factors in a supplier relationship is communication quality. Not friendliness — actual ability to give you accurate, timely information in English, handle problems when they arise, and escalate appropriately when something is outside their control.
During your factory visit, notice a few things. How quickly did they respond to your initial inquiry? How clear were the directions they sent you? When you ask a question the sales rep isn’t sure about, do they say “I’ll find out and get back to you” or do they guess? These are small signals, but they compound significantly over the course of a sourcing relationship.
Our foreign trade team responds within 24 hours regardless of time zone. Our sales contact for international buyers is Mimi, who is fluent in English and has been working with international OEM clients for years. The communication quality you experience during the evaluation process is representative of what you’ll get during production.
The Evaluation Visit at Our Factory
When OEM buyers visit us during expo week, we specifically structure the visit to address the questions above. You’ll see the relevant production lines. You’ll meet the QC lead and can ask direct questions about the inspection process. You’ll see the prototyping area. And we’ll walk through the NDA and OEM process in detail so you understand exactly what working with us looks like before you commit to anything.
Visits are available May 8, 9, and 10. Book in advance — OEM evaluation visits take longer than standard wholesale visits, and we want to make sure we have adequate time for each one.
- WhatsApp: +86 152 5809 0639 (Mimi)
- Email: mimi@wenzhouframe.com
Wenzhouframe — OEM/ODM eyewear manufacturer since 2015. Wenzhou, China. NDA signed before any project. 3D prototyping in-house. Third-party inspection welcome.
FAQ
What materials do you work with for OEM orders?
Pure titanium, beta-titanium, stainless steel, monel alloy, aluminum-magnesium alloy, handcrafted acetate (including ISCC-certified eco options), TR90 nylon, and ULTEM (PEI). We can advise on the best material choice based on your target market and price point during the factory visit.
How do you handle IP protection for designs we develop together?
We sign an NDA covering both confidentiality and production exclusivity before any design discussion. Custom molds are registered to your account and not shared with other buyers.
What is the minimum order for a custom OEM project?
This varies depending on the complexity of the design and the material. We can discuss the specifics during your factory visit — there’s no single answer that applies to all situations.
