There are different types of the moulding processes is used for forming a plastic to make various products of different size and shapes. The plastic turns liquid and becomes soft when heated. It can be easily formed for various products. The melted plastic is inserted into a mold and after it is cooled the mold is removed and the product is ready. The plastic products are made with different processes like casting, injection molding, blow moulding, compression molding and rotational molding.
Let’s start with the casting process. In this process, the plastic molding is completed with casting. The plastic is heated till it turns liquid and then inserted into a mold. There is no additional pressure is applied to this process. In the casting process the liquid turns into solid by various methods like evaporation, cooling, use chemical or applied external heat. The casting process is completed with less equipment and it is not costly. The products have little to no internal stress. The Nylon type 6 and Polyurethanes have widely used a material for casting. It is mainly used for complex designs.
The next is the Injection Molding. The process contains three steps. First is design the product. After designing and testing the second step is mold design. There are various metals used for mold to give strength and durability. In the third step, the thermoplastic material is fed from a hopper to a heating barrel. The plastic is heated and took to the mold by a large screw. After filling the mold the screw applies pressure for cooling. After cooled, the product is removed from a mold and this cycle is repeating more and more time to make lots of products. The dashboard of a car, bottle caps, plastic cup lids etc is made with injection molding process.
Ahead in the list is Blow Molding Process. As the name stated blow molding, in this process, the plastic is melted and made a hollow tube. This tube is inserted into a mold and blows the air and the tube is inflated to mold size and shape. The cold air is blown to cool down and it is ejected automatically. The blow molding process is mainly used for making hollow products like milk containers, water bottles etc.
The Compression molding is more complicated and required more labors. The compression molding is more complicated, it is used for large-scale production not for mass production. In the process, the molten plastic is poured into the mold and the second mold pressed it with high pressure. These molds compress the molten plastic before cooled. After removing the mold we get a product with maximum strength with desired size and shape. The compression molding is used for making car tires.
The rotational molding process the plastic in powder form is added to a mold. After it, the mold is closed and heated while rotating. When the plastic is melted it coated the wall of the mold. Then it took to the cooling area and cooled with air. After the product turns to solid the mold is opened and ejects the product. Products like water storage tank, containers, crates, traffic dividers, furniture and toys are made with the rotational molding process.