Plastic Container Molding

A method of processing plastic where pre-forms are produced by injection molding. The pre-forms are heated and transferred to the blow molding machinery where it is blown into its final shape.

Plastic parts containing metal inserts are produced using the insert molding method. Inserts made from metal and other material, are placed in the mold prior to the injection of the plastic. The plastic is injected and flows around the insert which is set into place as the plastic cools.

Autoclave molding is a method of forming plastic in which it is possible to create pressure and heat at the same time. Layers of pre-impregnated fibers are piled with varying fiber orientation to the desired thickness above the forming tool. The pre-preg is pressed down to the forming tool by pressure. Heating then hardens the mixture and the laminate takes the desired shape. The process is very versatile and gives a very uniform quality as pressure and heat can be regulated very precisely. Any geometric shape can be produced.

This process is best suited for larger plastic parts since tool investments are low. Also used for high volume production for products such as disposable cups and chocolate packaging. The surface facing the mold has the best quality. Material thickness is often difficult to control. A sheet of thermoplastic material is heated to the softening point. The sheet is then positioned over a mold with small air canales, and a vacuum pulls the sheet into the mold. A vacuum is normally sufficient enough because of the low strength in the material being formed but for a more complex designs additional air or mechanical pressure can be applied.

The sandwich injection molding method allows for unique plastic formation to be constructed. This method sandwiches plastic parts with different types or different colors inside or on the surface of the other plastic. This method allows for parts with low surface quality to be covered with plastic types of higher surface quality. This process works much like injection molding, though instead of air another plastic is injected.

Much like insert molding, here though a large metal part surrounds one or more plastic elements like distance pins, flexible snap locks, buttons, etc. A prepared sheet of metal holes and gripping areas is place in a mold. Then plastic is injected as in conventional injection molding.

A plastic molding process carried out in four steps. This method is good for hollow parts, parts with low residual stress, and thin walled parts. Parts with negative slip angles can be made as well. First the required amount of plastic material is poured into the mold, which is then closed. While rotating around two axes the mold is first heated to the melting point of the plastic and then cooled again. Finally the mold is opened and the finished part is removed. No finishing operations, like removal of runners, are required.

Profiles of all shapes can be produced. In an extruder the plastic material is heated and continuously pushed by a rotating screw through a die with the shape of the profile. After the die, the profile is cooled by air or water and cut into desired lengths. This production method allows for high production rates.