Plastic frame can be divided into injection frame and plate frame according to different manufacturing processes. Plastic frame is a kind of spectacle frame whose main part is made of plastic or similar polymer material. According to its temperature properties, it can be roughly divided into two categories: thermoplastic and thermosetting resins. Thermoplastic resin can be repeatedly heated and reshaped. Frames made of such materials are easy to adjust and reshape. Thermosetting resins are difficult to reshape after being formed, so they are often mixed with thermoplastics.
So, what's the difference between a sheet spectacle frame and an injection molded spectacle frame? The injection frame is made of resin pellets, which are injection molded by a mold after being heated and melted. The manufacturing process is simple and the production cost is low. The disadvantages are easy deformation, low tensile and compressive strength, and uneven size of the assembled lens. Due to the shrinkage of the material from the heat to the cold process, the different structural dimensions lead to the generation of internal stress. At the same time, the material melts in the cavity of the mold. Directional flow, the bonding strength between the molecules at the fusion is low. These positions are prone to damage and have a great impact on the strength of the frame. The plate frame is made of resin plates, which are processed by a milling machine for more than 100 processes such as inner turning, groove milling, outer turning, turning and milling, shaping, polishing, surface treatment, and printing. The production process is complicated and the cost is high. The lens frame has high strength, is not easy to be deformed, the size of the lens groove is uniform, and the adjustability is good.

The identification of PC injection frame and acetate frame can generally be done by observation. The products of the two processes have the following differences: First, usually the injection frame will produce obvious line marks at the joint gap of the mold, commonly known as the parting line, usually in the mirror and mirror. The center of the edge of the leg.
Second, since the material is in the injection molding process, from hot to cold, sink marks will be generated in places with larger geometric dimensions. Compared with certain angles of light, it is not difficult to find these sink marks.