An acrylic processing technology

Poly (methyl methacrylate can be used in a casting, injection molding, extrusion and thermoforming. 1. Casting molding casting molding to the molding plexiglass sheet, rod profiles, such as molding material with bulk polymerization method. After molding, casting products require reprocessing, post-processing conditions is under 60 ℃ temperature 2 h, 2 h2 under 120 ℃ heat preservation. Injection molding by the suspension polymerization of granular material, molding in ordinary plunger or screw injection molding machine. Table 1 is the epitome of polymethyl methacrylate injection molding process conditions. Process parameters of the screw plunger cylinder injection molding machine ℃ temperature of 180 - in the back 200, 180 - The central 190-200 The front 180-230 210, 210 - Nozzle temperature 240 ℃, 180 - 210, 210 - Mold temperature 40 ℃ - 240 40-80 Injection pressure 80 MPa - 80 120, 80 - The holding pressure MPa 40-130 40-60 The screw rotation speed rp 60. m - 1 20 - 30 injection molding products also need post-processing to eliminate internal stress, handling - in 70 Within 80 ℃ hot air circulation drying oven, processing acrylic bar time depending on the product thickness, generally require about 4 h. 3. Extrusion polymethyl methacrylate also can be used for extrusion molding, using suspension polymerization to produce granular material preparation of plexiglass plate, bar, pipe, sheet, etc. , but such preparation section, especially the plate, because the polymer molecular weight is small, mechanical properties, heat resistance and solvent resistance are not as good as pouring shape profile, its advantage is high production efficiency, especially for steel tubes and other mould by casting method. Difficult to make profiles. Extrusion can be used for ChanJie or dual exhaust type extruder, twin screw length to diameter ratio in 20 - commonly 25. Table 2 is a representative of the extrusion molding process conditions. Process parameter sheet bar 2 cylinder screw compression ratio 2 ℃ temperature of 150 - in the back 180, 150 - The central 170-180 200, 170 - The front 170-200 230, 170 - 8 - 7 - Inlet temperature of 4 ℃ - 50 50-80 Mold temperature of 80 ℃, 180 - 200, 170 - 1904. Thermoforming thermoforming is organic glass plate or sheet made of various size shape products, the process of cutting into required size of the blank clamped on the mold frame, heating to soften it, the compression moulding surface to make it stick close again, be the same as the profile shape, after cooling to finalize the design the trim edge for a quick products. Pressure can use vacuum draft or use the type with the punch direct compression method. Hot forming temperature can be reference table 3 the recommended temperature range. Using rapid vacuum low draft molding products, appropriate is used close to lower limit temperature, molding shape complex deep drawing products be used close to the limit temperature, generally USES the normal temperature.