20 Questions to Ask an LED Manufacturer Before Placing an Order

Type: Buyer Guide Updated: 2026-07-04

You've shortlisted three LED manufacturers. Quotes are within 8% of each other. Specs look similar on paper. So how do you pick the right one? You ask the questions that separate factories from trading companies, ISO-certified lines from backyard assembly, and reliable partners from the next shipment disaster.

We've compiled the 20 questions that our procurement team uses when vetting LED manufacturers on Compare2Best — questions that have caught misrepresented certifications, inflated capacity claims, and one factory that didn't actually own the UL file they claimed.

Step 1: Company Background & Ownership

Start with the basics. How long has the company been manufacturing LED fixtures specifically — not just "in the lighting industry"? Ask for their business license (营业执照) and verify the registered capital. A manufacturer with 10+ years in LED-specific production and RMB 5M+ registered capital is in a different league than a 3-year-old trading company. Ask: "Can you provide your business license and factory registration number?"

💡 Cross-check the business license on 天眼查 or 企查查. Look for ownership changes in the last 12 months — frequent changes signal instability.

Step 2: Factory Tour & Production Lines

Ask for a video tour of the production floor — not their marketing video, but a live WeChat video call walking the SMT lines, assembly area, and testing stations. Look for: automated SMT placement (Yamaha or Panasonic machines are industry standard), in-house driver production or a named driver supplier, aging test racks with actual fixtures running, and an integrating sphere or goniophotometer for LM-79 testing. A factory without in-house photometric testing equipment is outsourcing quality control.

💡 During the video call, ask them to show you the aging test area and read the labels on fixtures currently being tested. If they hesitate or the area looks staged, that's your first red flag.

Step 3: Certifications — Who Actually Holds the File?

This is the #1 deception in LED sourcing. Many factories show you UL/ETL/DLC certificates that belong to their client — not to them. Ask directly: "Is the UL/ETL file under your company name? Can you provide the UL file number so we can verify on UL Product iQ?" A legitimate manufacturer will give you the file number immediately. If they say "our partner holds the cert" or "we can do UL but it takes 8 weeks," they don't have it. Budget 8-12 weeks and $5,000-$15,000 for new UL certification if starting from scratch.

💡 Go to productiq.ul.com right now and search the file number they give you. Check the "Applicant" field — it must match the company you're talking to.

Step 4: Production Capacity & Current Loading

Don't just ask capacity — everyone says "50,000 units/month." Ask: "What percentage of your production capacity is currently committed? How many lines are running at full capacity vs. available?" A factory at 90%+ capacity means your order joins a queue. Ask about their largest single order in the last 6 months and the delivery performance on it. A factory that's delivered a 20,000-unit order on time is proven; one that claims 100K/month capacity but their largest order was 2,000 units hasn't been tested.

💡 Ask for 3 customer references from the same region you're importing to. Call them. Ask about on-time delivery percentage and defect rate on the first shipment.

Step 5: Quality Control Process

Ask for their QC workflow in writing. What's their incoming material inspection rate? (Should be AQL 1.0 or tighter for critical components like LED chips and drivers.) Do they do 100% burn-in testing? (48-72 hours is standard for commercial fixtures.) What's their outgoing defect rate target? (Below 0.5% is industry benchmark for tier-1 manufacturers.) Request a sample QC report from their last shipment — not a blank template, an actual completed report with numbers.

💡 If they can't produce a real QC report in under 30 minutes, their QC process exists only on paper. Walk away.

Step 6: Component Sourcing Transparency

The LED chips, drivers, and thermal materials determine 80% of fixture performance. Ask: "Which brand and model of LED chips do you use? Can you provide the binning certificate?" For drivers: "Mean Well, Philips, Tridonic, or in-house? If in-house, what's the warranty period and failure rate?" A factory that says "we can use whatever you want" without standard SKUs is a trading company. Tier-1 manufacturers have preferred chip bins and driver partnerships.

💡 Chinese driver brands (Eaglerise, Lifud, Sosen) are perfectly fine for many applications — but ask for the specific model and MTBF data. A factory using named drivers is more transparent than one using generic "custom" drivers.

Step 7: MOQ, Pricing, and Payment Terms

MOQ isn't just a number — it's a signal. A factory with MOQ of 10 units per SKU is set up for small-batch production (good for boutique/luxury buyers). MOQ of 500+ units per SKU means they run volume production lines. Neither is "better" — but they align with different buyer profiles. Ask: "What's your MOQ flexibility? Can we mix SKUs within the MOQ?" On payment: standard is 30% deposit, 70% before shipment (T/T). If they ask for 100% upfront on a first order, that's unusual. If they offer 30/70 with 30-day net on the balance, they're confident in their product.

💡 Always negotiate payment terms that leave leverage: 30% deposit, 70% against the bill of lading copy — not "before shipment." You want to verify the goods exist before releasing final payment.

Step 8: Warranty & After-Sales Support

Ask: "What's your standard warranty period and what exactly does it cover?" Standard is 3-5 years for commercial LED fixtures, 5-7 years for industrial. But coverage varies wildly: some warranties cover the driver only, some cover the full fixture, and almost none cover installation labor. Ask what happens in a warranty claim: do they ship replacement parts? Whole fixtures? Who pays shipping? A good manufacturer will ship replacement drivers or LED modules within 48 hours of a confirmed claim and cover the shipping cost.

💡 Ask for their warranty claim rate as a percentage of shipped units. If they say "zero claims," they're either lying or nobody bothers claiming because the process is impossible. Realistic claim rates are 0.1-0.5% for tier-1 manufacturers.

Step 9: Customization & R&D Capability

If you need custom housing, specific CCT, or unique optics, ask: "Do you have an in-house R&D team? How many engineers? What's your typical custom development timeline?" A factory with 5-10 engineers can handle fixture-level customization (housing, optics, mounting) in 4-8 weeks. PCB-level customization (driver design, new LED layout) takes 8-16 weeks. Ask for examples of custom projects they've delivered — and get the customer contact to verify.

💡 For OEM projects, ask about mold costs upfront. A simple aluminum housing mold might be $2,000-5,000; complex plastic optics can run $8,000-15,000. Know these before you negotiate.

Step 10: Shipping, Packaging & Logistics

Ask about their standard packaging: individual box? Master carton? Pallet configuration? What's the carton drop test standard they use? (ISTA 1A or equivalent.) Verify the shipping port and typical transit times to your destination. Ask: "Do you handle FOB, CIF, or DDP? Which forwarders do you work with regularly?" A manufacturer who can quote DDP to your warehouse door has serious export experience. One who only offers EXW and says "you arrange shipping" may never have exported to your region.

💡 Always specify pallet configuration in your PO: how many units per pallet, max pallet height, and whether you need stretch-wrapping. Missing this leads to crushed cartons and an expensive claim process.

Checklist

✅ Business license verified on 天眼查/企查查
✅ UL/ETL file holder confirmed as the manufacturer (not a client)
✅ Live factory video tour completed — aging racks, SMT lines, testing equipment confirmed
✅ 3 customer references contacted — on-time delivery and defect rate verified
✅ Sample QC report from actual shipment reviewed
✅ Component sourcing disclosed: LED chip brand/model, driver brand/model
✅ MOQ and payment terms negotiated with leverage retained
✅ Warranty coverage and claim process documented in writing
✅ Customization timeline and mold costs quoted if applicable
✅ Packaging spec and pallet config specified in PO

⚠️ Red Flags

Cannot provide UL/ETL file number under their company name within 5 minutes
Hesitates or refuses live video factory tour
Claims "zero defect rate" or "zero warranty claims" — no real factory has zero defects
MOQ below 10 units for industrial fixtures — likely a trading company, not a manufacturer
Cannot name their LED chip supplier or driver brand
Registered capital below RMB 1M for a company claiming 10+ years in business
Changes the subject when you ask for customer references in your region
Pushes for 100% payment upfront on a first order

We've built these 20 questions into Compare2Best's supplier verification workflow. Every manufacturer on our platform has been pre-screened against the first 6 questions — certifications, factory floor, QC process, and component sourcing. Browse verified LED manufacturers and skip the vetting process, or submit an RFQ and get quotes from 3-5 pre-qualified factories within 24 hours.