Injection molding machine screw (non-return valve) Details
The barrel structure is simple.
In large extruders, the barrel can be composed by several sections.
Because the barrel consists of several sections, the length of every section is reduced, which makes it easier for processing barrel.
However, the inside dimension and bore concentricity accuracy of these sections are hard to fit completely.
Besides, the sections of the barrel are jointed with the use of flanges, this brings difficulty in arranging heating and cooling equipments, and the temperature control will be uneven.
In order to save costly alloy steels, some large extruders’ barrels adopt adding bush to the bore or casting abrasion-resistant layer methods.
This way, the outer casting of the barrel can be made by common steels, so as to reduce the cost.