Processing technology of acrylic

Processing technology of acrylic

Polymethylmethacrylate (Acrylic) can be cast, injection molded, extruded, thermoformed and other processes.

Casting molding

Casting molding is used to form profiles such as plexiglass plates and bars, that is, profiles are formed by bulk polymerization. The cast products need post-treatment. The post-treatment conditions are heat preservation for 2h at 60 ℃ and heat preservation for 2h at 120 ℃.

Injection molding

Injection molding adopts the granular material prepared by suspension polymerization and is formed on an ordinary plunger or screw injection molding machine.

Injection molded products also need post-treatment to eliminate internal stress. The treatment is carried out in a 70-80 ℃ hot air circulation drying oven. The treatment time generally takes about 4H depending on the product thickness.

Extrusion molding

Polymethylmethacrylate can also be extruded to prepare plexiglass plate, bar, pipe, sheet, etc. with the granular material produced by suspension polymerization. However, due to the small molecular weight of the polymer, the mechanical properties, heat resistance and solvent resistance of the profile prepared in this way, especially the plate, are not as good as those formed by pouring, which has the advantage of high production efficiency, Especially for pipes and other profiles that are difficult to manufacture by casting method. Single stage or double stage exhaust extruder can be used for extrusion, and the length diameter ratio of screw is generally 20-25.

Thermoforming

Thermoforming is the process of making plexiglass plate or sheet into products of various sizes and shapes. The blank cut into required sizes is clamped on the mold frame, heated to soften it, and then pressurized to make it close to the mold surface to obtain the same shape as the mold surface. After cooling and shaping, the edge is trimmed to obtain the product. The method of vacuum drawing or direct pressure on the punch with profile can be used for pressurization. The thermoforming temperature can refer to the temperature range recommended in Table 3. When using rapid vacuum low draft forming products, it is appropriate to use the temperature close to the lower limit. When forming deep draft products with complex shape, it is appropriate to use the temperature close to the upper limit. Generally, the normal temperature is used.

Engraving and cutting

It is mainly used for hollowing and carving of formed acrylic or colored acrylic materials. Ordinary laser engraving and cutting machine can meet the engraving and hollowing needs of most acrylic products.