First, molding

The molding process, as the name implies, is the processing method of pressing molding. The refined sheet rubber rubber embryo is placed in the cavity of the mold, placed in the cavity of the mold, and then the mold is closed and pressurized to form and cure or vulcanize, and then the mold is released.

The molding process is suitable for thermosetting and thermoplastic products. The rubber products made by the molding process are mainly structural connectors, protective seals and electrical insulation parts, such as sealing rings, gaskets, protective sleeves, sealing plugs, edge sleeves, gaskets, oil seals, miscellaneous products. Widely used in industry and agriculture, transportation, electrical and chemical industry, construction machinery, daily supplies and other materials fields.

Advantages:

1, the product size accuracy is high, the shape is flat, the surface is smooth.

2, can be made into any shape according to demand, one molding.

3, low internal stress, small warping deformation, small shrinkage, mechanical properties are more stable.

Cons:

1, the length of the product is limited, usually can only be made of less than 600 mm length;

2, the production process will produce flash, removal of flash workload.

3, the mold production is complicated, the development cycle is long, the efficiency is low, the cost is high.

4, the production process and press have certain technical requirements, only suitable for mass production of small products.

Second, extrusion

Extrusion, also known as extrusion molding, generally according to the type and shape of the processed material, select the extruder, head and mouth die, the rubber material through the extruder cylinder and screw action, while being thermoplasticized, while pushing forward to make a variety of cross-section shape rubber products.

In the extrusion process, the rubber material is generally refined, but also through cooling curing or vulcanization and other styling methods, and the process conditions are more complex, such as screw speed, head pressure, material temperature and molding temperature, traction speed.

Extrusion process is suitable for the processing of thermoplastic rubber, the use of extrusion process can be made into sealing strip, pipe, sheet, sheet, film, a variety of complex section shape of rubber products, as well as hollow, solid, foam and other finished rubber products. Widely used in construction industry, petrochemical industry, machinery manufacturing, electronic equipment, automotive aviation and other fields.

Advantages:

1, the length is unlimited, can be produced according to the need of any length of pipe, strip, bar, profile, etc. 

2, fast production cycle, high production efficiency, large output.

3, the product has no rough edge, less loss. 

4, a multi-purpose machine, through the replacement of different heads and rubber materials, the production and processing of a variety of products. 

Disadvantages:

1, can only be made into tubular, strip, ribbon products. 

2, the accuracy is relatively poor, the product shape is complex and difficult to manufacture.

The difference between extrusion and molding is the length and shape, one can make a wireless extension of the length of the product size, and there is no parting line of this appearance, and molding can make any shape, square, round and shaped, so they each have their own advantages.

In the extrusion process, the quality control problem of the product is focused on bubbles, deformation, appearance quality and material. If the size has a H shape or a relatively thin barb type, the size of the product has no fixed support point, and it is prone to deformation. If the product size is too large or the diameter is large, it is easy to cause the product to be immature and cannot be vulcanized normally.

In the process of molding production, the more troublesome is that the production efficiency of the product is low, and the cost of making the mold is high. And in the production process, the sealing performance of many silicone seals will be affected by the parting line, and the low hardness of the product will cause the parting line to break, which is due to the control method and the quality requirements of the product during the molding production.