What is Lamination?
Lamination is to combine two or more acetates in different colors-through using a chemical glue or mechanical friction for adhesion-to create a new distinct acetate color with unique patterns. Please refer to deepward's acetate lamination models Best Fashion Glasses and Custom Acetate Glasses for having an idea how one handmade eyewear looks like after lamination. Each frame can be made with unique patterns.
Why do we use Lamination process?
Sometimes, this process is completed by the acetate suppliers, for example, Mazzucchelli, jinyu or jimei. The designer selects the color, and the factory buys the laminated acetate from acetate supplier for production directly. This is typically the case for large orders where the color requirements are standard and not so complex.
However, normally independent eyewear brands can not meet high MOQ set by acetate suppliers. Furthermore, these eyewear brands often have their unique design elements. They prefer to have specific color combination for maintaining its exclusivity. By processing lamination in-house, brands can mix any colors without being restricted by acetate MOQs.
There is another practical reason for lamination: structural necessity. Eyewears have different thickness requirements across different parts. While the rims are usually symmetrical, the end pieces (where the hinges attach) and nose pads are generally thicker than the rims. This brings a challenge in selecting acetate material thickness for avoiding MOQ from acetate supplier.
End pieces typically come in two structures: curved and flat. Curved end pieces do not require lamination, but flat end pieces and nose pads do. Following principles of cost reduction and low-carbon environmental protection, manufacturers use lamination to achieve the required thickness for specific parts. This method not only saves material but also allows for more three-dimensional, layered, and design-rich aesthetics.
Is Lamination only for Acetate?
No! with the development of technology, lamination is no longer limited to acetate material. It now involves combining different materials such as fabric, leather, wood, and carbon fiber, this enable eyewear to having richer textures and colors.
Lamination Process (mainly described through automatic lamination process)
Material Selection & Preparation: Choose acetate sheets of different colors, thicknesses, and materials (usually thin sheets between 1.5mm-3.0mm).
Cutting: Cut the acetate into appropriate sizes based on the final product size.
Surface Treatment: This is a critical step. The surfaces of the acetate sheets must be sanded or roughened (to remove the smooth finish) and cleaned thoroughly. This increases the bonding area and friction, preventing delamination.
Stack arrangement: Stack the treated acetate in the color sequence specified by the design.
Layering: Cover the layer with breathable Teflon (heat-resistant cloth) or kraft paper to prevent the material from sticking to the mold.
Molding: Place the stacked material into a special steel mold.
Heating & Pressurizing: Transfer to a hydraulic press.
Temperature: Usually between 110°C - 135°C (adjusted based on material hardness).
Pressure: Maintain high pressure (usually several hundred kg/cm²).
Time: Typically 30-60 minutes to soften and fuse the material.
Cooling: While maintaining pressure, allow the mold to cool naturally or with water to room temperature to fix the shape and density.
Demolding: Remove the bonded block (now a single solid piece).
Trimming: Cut off excess burrs and irregular edges.
Inner Cutting: Cut the lens shape.
Outer Cutting: Cut the outline of the frame.
Routing/Grooving: Mill the lens groove (for lens insertion).
Belt Sanding: Remove tool marks.
Polishing: Polish the surface to a mirror finish.
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Production Key Process
01.Delamination Prevention
02.Color Consistency
Acetate colors can vary between batches, and heat pressing can cause slight color changes. So we need to conduct trial production and color matching before mass production; the left and right sides of a pair of glasses must be cut from the same block of material.
03.Color Bleeding
When two different materials are bonded, colors may bleed into one another, it occurs color immigration issues.So we need to monitor the reaction of combined materials during the sampling stage. If severe bleeding occurs, replace with similar alternative colors. Also, carefully control the temperature and pressure for friction automatic lamination, or the time and amount of chemical glue used in chemical lamination.
04.Dimensional Stability
Laminated materials is easy to get shrink after cutting due to material features. We can conduct some production method for avoiding this problem, for example, ensure a slow cooling process after hot pressing; perform an annealing treatment (stress relief) after rough processing; design molds with springback allowances.
