Several Production Processes of Acrylic (PMMA)

The production mode of acrylic plate mainly includes: casting molding, injection molding, extrusion molding, hot molding, we respectively introduce these four different production processes.

1. Casting process

Casting method - Casting requires the use of molds, and the texture, shape and structure of the surface of the processed products are of great complexity, so the production scale is suitable for small batch production.The products produced by pouring method have high toughness and strength, and the ornamental value is also better.Therefore, the way of pouring is often used by handicraft production, decoration and other industries.

After casting, the products need to be post-treated. The post-treated condition is that the temperature is maintained for 2h at 60℃ and for 2h at 120℃.

2. Extrusion production method

The particles produced by suspension polymerization can be used to prepare plexiglass plates, rods, pipes, sheets, etc. However, the profiles prepared in this way, especially the plates, have low polymer molecular weight and are in terms of mechanical properties, heat resistance, and solvent resistance. , Are inferior to cast-shaped profiles, especially for pipes and other profiles that are difficult to manufacture by casting. Single-stage or double-stage exhaust extruder can be used for extrusion molding, and the ratio of screw length to diameter is generally 20-25.

The extrusion method can realize the mass production of large quantities and large pieces.The reason is that the extrusion mode can be completely automated, and this advantage also makes the processing not flexible, the process flow and the product model are not easily changed.

3. Injection molding production method

Injection molding uses pellets made by suspension polymerization, which are molded on a common plunger or screw injection molding machine. Typical process conditions of injection molding: injection molding products also need post-treatment to eliminate internal stress. The treatment is carried out in a 70-80°C hot air circulation drying oven. The processing time depends on the thickness of the product, and generally takes about 4 hours.

Problems that should be paid attention to in the production process

1. Bubble problem

Acrylic production is the same as that of other alloys, and bubbles are the biggest trouble. Every process and process of the production process must prevent the storage of air bubbles in the body of the processed product. Once the bubbles are formed, it will cause great harm to the aesthetics and rigidity of the processed products. Moreover, acrylic products are mostly transparent, and it is difficult to sell them after bubbles are generated, which poses a great threat to processing costs. Regardless of the processing method, care must be taken to clean the gas and ensure the vacuum.

Note: There is also a special material in the market—Bubble Acrylic, which is a new type of bar material that enters uniform air during the extrusion of the bar through a special technology to form bubbles in the middle. The product is beautiful and the bubble shape is uniform and natural. It is a good material for decoration.

2. Transportation problem

Certain protective measures must be taken for transportation. Whether it is the transfer between equipment in the production workshop or the transport on the road, certain protective measures need to be adopted. Acrylic sheets do not have much rigidity and do not have the impact resistance of PC. Once cracks occur, the whole sheet will gradually break. Therefore, the protective film and vacuum device should be used to fix the material in the transportation of acrylic to prevent its irreversible consequences due to collision.