Key Differences between Extrusion and Injection Molding Processes

A PET blow molding machine makes bottles using different processes. These include extrusion and injection molding processes. Extrusion is a strategy by which liquid plastic or some other material is pushed through a two-dimensional opening. It is at this point that the preform goes through a progression of shapes or sizes where the liquid frame gets blown to various shapes and then allowed to cool. In the extrusion process, products obtained have continuous lengths and comes with two-dimensional forms.

Both extrusion and injection molding have their favorable circumstances. The extrusion technique has its advantages over different strategies; one is that it helps in making complex cross-areas. Another preferred standpoint is that fragile and hard materials can be framed into any shapes when utilizing this technique. Additionally, the completed materials have a smooth surface when contrasted with different procedures including the injection technique. In the injection technique, the main advantage is that their negligible waste as the PET material can be reused once more.

Unlike the extrusion process, injection molding produces three-dimensional shapes with the help of the die-casting method. It consists of a unit for injection and the other one for clamping. Injection molding was started way back in the 1930s and has since then been incorporated in PET molding machines. On the other hand, the extrusion process came into reality in 1797 but was fully implemented in 1820 due to the invention of the hydraulic powered press. Since then, this method has been widely used including copper and brass industry.

 Key differences

  •    Resultant products

One of the major differences between the two processes is the products that are produced. A typical PET blow molding machine produces single, hollow bottles. Through the injection process, three-dimensional products are usually produced.

  •    Tool used

The tool used in the injection molding is the mold while extrusion process uses die.

  •    Process

The process of making bottles in injection molding is cyclic where mold is filled each time then cooled before the final product is ejected. In extrusion, the process is continuous as the die comes continuously.

During the injection molding, the presence of air alters the manufacturing process. Air creates the bubbles or air pocket in the product causing it to have unusual properties. A product with the presence of air usually has weak spots that make it defective. On the other hand, blow molding requires air to push the mold and expand the product. Air, in this case, is controlled as a limited amount of it is allowed before it is separated.

When making bottles or containers for soft machines, PET material is usually the best. This material is made of long-chain molecules that make it resistant to various aspects. For instance, a PET bottle has extra strength that enables it to resist any impact in the distribution channel. They are also transparent, pure and corrosive-resistant. Always ensure that you buy an excellent PET blow molding machine that features an extensive mechanism for effective production.