The main body of the pin screw is a regular screw, and the pin can be set inside the groove of the melting or measuring section of the screw, or on a smooth cylindrical surface without a groove at the end of the measuring section. Pins are arranged in a certain way, with varying degrees of density and quantity. A cylindrical pin is formed by assembling the pin into the hole of the screw; A square or diamond pin is formed by milling the pin directly onto the screw.

If these pins are set in the melting zone, they can break the solid bed, disrupt the two-phase flow, mix the solid and liquid phases together, increase the contact area between the final dissolved solid fragments and the already contained material, and promote melting. If the pin is set in the melt conveying area, its main function is to divide the material flow, increase the interface, change the direction of the material flow, and rearrange the flow beam. Multiple diversion and convergence, changing the flow direction to homogenize the composition and temperature of the melt.

The mixing section is an inward slotted structure set at the end of the ordinary screw homogenization section, with an outer diameter equal to the outer diameter of the screw. The trench is divided into several groups, and between each group is the convergence area of materials. The material is divided by grooves, converged in the convergence area, and then divided and converged. The principle is similar to the pin type.

The characteristic of a separated screw is that in addition to the original screw thread (called the main screw), there is also an additional thread (called the additional thread) on the melting section, whose outer diameter is slightly smaller than the outer diameter of the main thread. The lead of the main and auxiliary threads is different. The auxiliary thread starts from the end of the feeding section (and is connected to the feeding section), passes through several threads, and gradually intersects with the main thread of the homogenization section.

The depth of the screw groove and the thread lead of this screw gradually change from the feeding section to the homogenization end. The thread lead gradually narrows from width, and the depth of the screw groove gradually shallows from depth, which can result in greater compression of the material.