Plastic Molding
Plastic products such as carry bags, beverage bottles, yoga mats and phone cases are commonly seen in our daily life. However, these products are manufactured by different type of plastic materials and techniques because of the appearance and shape. The common techniques in plastic molding are injection molding, blow molding, extrusion molding, and Inflation molding.
What is Injection Molding?
Injection Molding is a method to obtain molded products by injecting plastic materials molten by heat into a mold, and then cooling and solidifying them. The process of Injection Molding is divided into 6 major steps as shown below. Clamping → Injection → Dwelling → Cooling → Mold opening → Removal of products. The method is suitable for the mass production of products with complicated shapes, such as toothbrushes and cups.
What is Blow Molding?
Blow molding is a molding process used to create hollow objects made of plastic.
First, molten resin is extruded from a die in a tubular form with an extruder. This molten resin in a tubular form is called a parison. This parison is pinched by a mold and air is blown into the parison to press it against the mold. After pressing and solidification for a given period of time, a blow molding can be obtained. Products such as milk bottles, blue drums, Jersey barriers are made out of blow molding.
What is Extrusion Molding?
Extrusion Molding is the molding of plastic or metals into a pre-defined shape. During the process, plastic is melted and pushed through a die to create a linear form. The final shape, commonly called a rod, although it is not necessarily cylindrical, is then cooled and can then be cut to various lengths, depending upon the application. Products such as fishing rods, yoga mats, water pipes, window frames are made out of extrusion molding.
What is Inflation method?
This is a type of Extrusion Molding where a melted resin is inflated into a cylinder to form a film. This method is used to make products such as wrapping films, shopping bags, and trash bags.