How to reduce the replacement frequecy of twin screw extruder cylinder for less costs

Polymer Modified Enterprises want to make satisfy products, can do nothing without a good twin screw extruder. 

But in fact, after the material is fully mixed and mixed in the barrel cylinder, the wear of the barrel cylinder and screw components is often serious, and the enterprise has to replace these two parts frequently, which not only affects the production efficiency of the enterprise, but also increases the cost of operation and maintenance. 

How to effectively reduce the replacement frequency of barrel and screw components of twin-screw extruder, the solution is to prolong its service life. 

Five major factors affecting the service life of twin screw extruder barrel cylinder and screw components

Ordinary mechanical wear

When the plastic matrix, auxiliary materials are mixed into the twin screw extruder, there is bound to be friction, which leads to the wear of the barrel cylinder and screw elements. 

In particular, fillers such as calcium carbonate and fiberglass tend to have much more greater friction on metal materials than molten plastics. 

Corrosion wear

The the plastic matrix and auxiliary materials may be corrosive and directly corrode the inner wall of the barrel cylinder and screw components, resulting in a decrease in the life of barrel and screw. 

High strength wear (heavy wear area)  

• Feeding area

In order to increase the conveying capacity of the material, the root of the mandrel is usually used in the SK type screw element, Here is the place of the first section of the barrel cylinder, which is usually the feeding area, and the mechanical wear is relatively severe. 

In the first section, adding plastic matrix, calcium carbonate, talcum powder and so on, these materials have not been melted and are basically in a solid state. The inner wall of the barrel cylinder is rubbed directly with these solids, which makes the inner wall wear severely. This is the first heavy wear area. 

• Fiber glass added  area

In the area of the 5th, 6th and 7^th barrel sections, the glass fiber is usually added. The glass fiber is the filament, and the sharp corner of the eight-shaped hole will be strangled at the inlet, where the barrel cylinder will be made a deep groove; in addition, the glass fiber will be cut at high rotational speed to produce more torn fibers, and these torn fiber has a sharp head, which greatly increases the wear force and wears the inner wall of the barrel cylinder. 

• Middle area

The die side of the twin screw is under pressure, so that the screw in the middle area is in a state of bending during high-speed operation, and the deflection (bending) is very large, the chamber sweeping is very severe, and the wear to the barrel cylinder is very obvious. 

• Screw head area

The screw in the head area is in a cantilever state and hangs down under the influence of gravity. 

After the material enters, it will hold up the head of the screw, resulting in a small gap below, a large gap above, friction between the outer diameter of the screw and the inner wall of the barrel cylinder, and the lower part of the inner wall of the barrel cylinder is badly scraped, which is not changed for a long time. 

• Melt area

Between the second barrel and the first exhaust barrel (or the first mesh block to the exhaust port mesh block), because part of the plastic or small particles of the material melt first, while the calcium carbonate and other fillers do not melt, thus the material forms a “sea-island” structure in the closed chamber of the barrel body, this structure has greater wear on the barrel and screw components. As a result, the life of the barrels and screw components are greatly shortened.

Operating conditions

When twin screw extruder is working,  the melting temperature of plastics is generally high. For example, the melting temperature of polycarbonate, nylon and PPS are about 240 ℃, 280 ℃ and 290 ℃ respectively. 

In the case of high temperature, the physical properties of the metal decrease, resulting in a decrease in the life of the barrel cylinder and screw components for twin screw extruder. 

Moisture, air, oxygen and other gases in the  barrel cylinder

When the machine is mixed with oxygen and water vapor, the wear of the barrel cylinder is more serious. 

But The working condition of temperature, pressure, moisture and air in twin screw extruder are difficult to change. at present, the cylinder of barrel for twin screw extruder can only be made by using more wear-resistant and corrosion-resistant materials to prolong the life of the twin screw extruder barrel cylinder and screw components.

Professional Twin screw extruder Manufacturer- GRANUWEL

Nanjing Granuwel Machinery CO., LTD is specializing in R&D design and manufacture of high polymer extruders, our team of top-level extrusion professionals provides the right extruder for your exact application.

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