Detailed introduction
06
2018
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08
Design requirements for barrel screw of injection molding machine
Injection Molding Machinebarrel screwDesign principle:
The main part of the pin screw is a common screw, and the pin can be arranged in the melting section or the drop groove of the metering section of the screw or the smooth cylindrical surface without the groove at the end of the metering section. The pins are arranged in a certain arrangement, with varying degrees of density and quantity. The cylindrical pin is formed by fitting the pin into the hole of the screw; the square or diamond pin is formed by milling the pin directly on the screw.
If these pins are set in the melting zone, the pins can break the solid bed, destroy the two-phase flow, stir the solid and liquid phases together, increase the contact area between the final dissolved solid fragments and the contained materials, and promote melting. If the pin is set in the melt conveying zone, its main function is to divide the stream, increase the interface, change the direction of the stream, and rearrange the stream. Multiple diversion, convergence, change the flow direction, so that the melt components and temperature homogenization.
The mixing section is an inward slotted structure arranged at the end of the ordinary screw homogenization section, and its outer diameter is equal to the outer diameter of the screw. The grooves are divided into several groups, and between each group is the confluence area of the material. The material is divided by the groove, to the meeting in the meeting area, and then divided and merged. The principle is similar to the pin type.
The characteristic of the separate screw is that in addition to the original screw pattern (called the main screw), a thread (called the additional thread) is added to the melting section, the outer diameter of which is slightly smaller than the outer diameter of the main thread, and the lead of the main and auxiliary threads is different. The auxiliary thread starts from the end of the feeding section (and is connected with the feeding section here), and gradually intersects with the main thread of the homogenizing section after several threads.
The screw groove depth and thread lead of this screw are gradually changed from the beginning of the feeding section to the end of the homogenization, that is, the thread lead is gradually narrowed from the width, and the depth of the screw groove is gradually shallower from the depth, so that the material can be compressed to the maximum.
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