Differences between extrusion and injection
There is a huge variety of methods for plastic creation. Everyone has their own particular and different process. The main methods are injection, extrusion, thermoforming, and blow or compression.
The extrusion model is thoroughly used in the manufacturing of long plastics like straws, tubes, sticks, profiles, seals, etc.
The primary difference between the injection process and the extrusion process is mainly the mold. During injection, the material is directly introduced into the mold, filling all the holes by the executed pression and giving form to the piece inside the closed mold.
Instead, the way to give form to the piece during the extrusion comes from the die, while the dragger keeps the pulling strain at the long end of the tray of cold, consolidating the geometry of the profile while it is calibrated.
In extrusion is possible to obtain complex transversal sections while injection is used for all type of closed pieces, gaps, or variable geometries in his sections.
The extrusion method has several advantages over injection, including lower die costs and higher productivity because there is no need to open the mold and recollect the piece after each cycle, as in injection.