When sourcing custom eyewear, buyers often ask why a standard plastic frame order takes 45 days to complete. If the factory just pours plastic into a mold, shouldn’t it be faster?
The reality is that stable frame production requires a careful 10-step process. Skipping steps to save time directly causes peeling paint, crooked hinges, and broken frames.
As a responsible china sunglasses manufacturer, Jion Eyewear does more than just produce frames. We help you analyze your local market, identify regional hot-selling styles, and build a mature brand. Understanding the manufacturing timeline is the first step in that growth.
Here is exactly what happens during those 45 days and why each step protects your investment.
What Buyers Need to Know First
Fast lead times sound appealing, but they often hide manufacturing shortcuts. When factories rush production, they skip crucial cooling, polishing, or cleaning phases.
For brand owners and wholesalers, receiving a batch of defective eyewear costs far more in retail returns and damaged reputation than waiting an extra 10 days for proper production.
The 10-Step Plastic Sunglasses Production Process
We have broken down the factory floor process to show you where the time goes and what risks we manage at each stage.
1. Mold Making
Before mass production begins, the factory prepares the steel molds. Plastic eyewear requires heavy-duty steel molds with excellent hardness, wear resistance, and corrosion resistance.
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The manufacturing fact: The steel must withstand extreme temperatures and high pressure during injection without warping.
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The commercial benefit: A precise mold ensures exact frame dimensions. This means the lenses will fit securely later without popping out, reducing customer complaints.
2. Raw Material Preparation (Plastic Pellets)
We prepare raw plastic pellets, such as PC or TR90, for injection.
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The potential quality risk: To cut costs, some suppliers mix in unknown recycled plastics or mismatched color batches.
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The commercial benefit: Using pure, traceable raw materials prevents the finished frames from snapping easily under stress. It also eliminates the risk of cheap plastics causing skin allergies for the end consumer.
3. Injection Molding
High-temperature melted plastic is injected into the steel mold. Once cooled, it is removed to form the rough frame front or temples.
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The potential quality risk: If rushed, several defects occur. “Short shots” leave incomplete frame edges. Poor mold closure creates “flash” or sharp burrs. Uneven cooling causes sink marks or complete frame deformation.
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The commercial benefit: Careful temperature control and adequate cooling time ensure the frames sit straight on the wearer’s face, making them ready for immediate retail sale.
4. Vibration Tumbling (Sanding)
The rough plastic parts are placed inside a vibrating machine filled with specific abrasives. The friction removes the mold lines and gate marks.
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The potential quality risk: Insufficient tumbling time leaves noticeable plastic seams and injection points on the frame.
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The commercial benefit: Proper tumbling creates a smooth matte texture. This provides a clean base for polishing and ensures the product doesn’t look like a cheap novelty item.
5. Hand Polishing
Workers manually polish the frames on a spinning wheel to create a completely smooth surface.
The potential quality risk: Inadequate polishing leaves surface pitting and roughness.
The commercial benefit: A perfectly smooth frame allows the final paint layer to adhere evenly. This prevents uneven coloring and gives the sunglasses a refined, retail-ready finish.
6. Hinge Installation
Machines use heat and pressure to embed metal hinges into the plastic frame and temples.
Buyer Concern: The buyer worries about “uneven legs” or hinges falling out.
Manufacturing Fact: If the angle is wrong, the glasses will not sit flat. If the pressure is too high, the plastic cracks. If the hole is too large, the hinge becomes loose.
Commercial Benefit: Taking time to calibrate hinge machinery ensures the frame opens and closes smoothly. This extends the daily wearing life of the sunglasses.
7. Painting Room
The polished picture frames are sent to a semi-automated spray-painting line and then undergo heat curing.
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Buyer Concern: The buyer worries about paint peeling after a few weeks of use.
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Manufacturing Fact: Cheap production uses a single, thin layer of paint. Spraying too heavily causes paint runs. Dust in a poorly managed room causes a gritty texture.
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Commercial Benefit: Controlled environments and proper paint thickness ensure excellent color adhesion. The product maintains its look even after sun exposure and daily handling.
8. Lens Assembly
Workers manually fit the cut lenses into the frame grooves.
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Buyer Concern: The buyer worries about scratched lenses out of the box.
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Manufacturing Fact: If a lens is cut too large, forcing it in can snap the plastic frame. Careless handling causes tool scratches or deep fingernail marks.
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Commercial Benefit: Precise lens fitting guarantees a secure hold and a flawless optical surface. This is critical for buyer satisfaction in both online and offline retail.
9. Ultrasonic Cleaning
The assembled sunglasses are placed into ultrasonic cleaning tanks.
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Buyer Concern: The buyer wants a product that looks completely new upon unboxing.
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Manufacturing Fact: Rushing this step leaves water stains, dust, or harsh cleaning chemicals hidden in the frame crevices.
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Commercial Benefit: Thorough cleaning removes processing dust, fingerprints, and machine oil. This ensures the eyewear looks pristine the moment your customer opens it.
10. Final Packing
Qualified glasses are placed into transparent protective bags and prepared for shipping.
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Buyer Concern: The buyer worries about damage during international shipping.
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Manufacturing Fact: Poor bagging leads to frames rubbing against each other during transit.
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Commercial Benefit: Correct packing protects your inventory, ensuring 100% of the batch is sellable upon arrival.
Quick Buyer Decision Guide
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Best for: Importers, brand owners, and wholesalers who want stable inventory and plan their sourcing 2 months in advance.
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Not ideal for: Buyers looking for a 10-day turnaround on custom molded designs.
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MOQ consideration: Stock plastic frames require lower MOQs. Custom injection colors or OEM mold developments require higher MOQs to offset machine setup costs.
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Customization potential: Logo printing, specific frame pantone colors, lens tinting, and retail packaging can be customized during the 45-day window.
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Key point to confirm before ordering: Ask your supplier if the 45-day lead time includes raw material purchasing and mold adjustment, or only the assembly phase.
Common Mistakes to Avoid
The most common mistake buyers make is pushing a factory to reduce a 45-day lead time to 25 days. When a supplier agrees to this, they usually shorten the cooling time during injection (causing frame warping) or skip the hand-polishing phase (causing peeling paint). Plan your sourcing schedule early to allow for the correct manufacturing physics to take place.
Supplier Checklist
Before placing a bulk plastic eyewear order, confirm these details:
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Do you use pure PC/TR90 pellets or recycled mixed plastics?
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Does your quote include ultrasonic cleaning before packing?
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Can you provide a pre-shipment inspection for hinge alignment and paint adhesion?
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How many days does sample creation take versus bulk production?
Let’s Build Your Local Market
At Jion Eyewear, we want to help you expand your business.
Send us your target market region, your current business stage, and your target price range. We will analyze your local trends and recommend 2–3 suitable plastic frame options to test.
