The Screw of Twin Screw Extruder Machine’s Disassembly Method

The Screw of Twin Screw Extruder Machine’s Disassembly Method

“Modular Screw Design for Twin Screw Extruder Machine: Enhancing Flexibility and Maintenance Efficiency”

For the twin screw extruder machine, the design of the screw adopts the building block principle, which can be combined and replaced according to the needs of different materials. 

When removing the screw, you should first empty the materials in the main engine as far as possible (especially for high-viscosity plastics such as PC or medium-viscosity plastics such as ABS, POM, etc., you can add HDPE material to clean,or use a special washing machine material cleaning which our company can provide the washing machine material sample before stopping). 

Then stop the operation of the mainframe equipment, but each electric heater section can continue to maintain the normal working state. 

Then, follow the following steps to remove and replace the screw:

For different pelletizng systems, there are different methods to disassemble the head

For the Water-cooling strands Pelletizing system,the method of disassemble the die head as below steps

Water-cooling strands Pelletizing system
  1. Disconnect the heating power supply of the machine head, put on gloves,
  2. Loosen the small screw of the discharge board with a wrench and remove the discharge board.
  3. Loosen the 4 big screws on the head body with a wrench, open the head to the left, then you can see the built-in porous plate, take out the porous plate,
  4. Clean the residual materials in the inner cavity of the machine head. Until you can see the screw head,
  5. Rotate the screw at a low speed, when the remaining little material inside the cylinder is squeezed out to the front, and shut down after cleaning
  6. Clean the perforated plate and discharge plate

Method for removing the die head of hot-cutting air-cooling pelletizing system


as shown in the figure:

Firstly, move the cutting cover around the hot machine head away from the machine head, leaving enough room for operation

  1. Disconnect the heating power supply of the machine head, put on gloves,
  2. Loosen the screws holding the template with a wrench for one week.
  3. Rotate the screw at low speed, at which time a little material remaining in the cylinder is extruded to the front, and the extruded melt will push the hot plate until it is separated from the head body.
  4. Remove the hot plate and clean the residual material in the inner cavity of the machine head
  5. Clean hot plate

The steps to pull out the screw of twin screw extruder machine

Step1-Granuwel twin screw extruder machine

Loosen and remove the fastening nut (left-handed thread), and then install the tool to remove the screw.

Step2-Granuwel twin screw extruder machine

Loosen the two coupling fixing screws near the shaft end of the screw(Spline sleeve for connecting barrel screw and transmission box output shaft), and observe and remember the marks corresponding to the two screw tail splines and sleeve couplings.

Step3-Granuwel twin screw extruder machine

Pull out the two screws synchronously and slowly, use a wire brush or copper shovel to quickly clean the material on the surface of the screw, be sure to clean up when the material is in a hot state. 

Then, apply an appropriate amount of paraffin wax on the surface of the screw, or wipe the surface of the screw with a cotton cloth to achieve good results until all the screws have been cleaned, pull them out and place them flat on the board or sleeper.

Step4-Granuwel twin screw extruder machine

Remove the screw removal tool (left-hand thread) on the screw and remove the screw element in case of heat. 

It is forbidden to strike with sharp and hardened tools. Use wooden hammers, copper rods  rods to gently tap around the screw elements. 

Avoid tapping on the thin wall of the end face of the thread block, which may damage the thread original, if the thread original does not move, it is very likely that there is melt in the mandrel.

If this happens, the screw can be put back into the cylinder for heating, and after the material in the gap is softened, it can generally be removed in a hot state.

Step5-Granuwel twin screw extruder machine

Remove the extruder screw components, clean the end face, inner hole and keyway immediately and place them neatly on the shelf. 

It is strictly forbidden for screw elements to collide with each other, and antirust grease should be applied to screw elements that are not in use for the time being. 

The surface of the mandrel should also thoroughly remove the residual material. If assembly is not needed for the time being, it should be hung vertically to prevent deformation and be smeared with antirust grease.

Step6-Granuwel twin screw extruder machine

For the hole in the extruder barrel, you can use a stick to wrap the cloth to clean it.

Step7-Granuwel twin screw extruder machine

The assembly configuration of the two screws of the twin screw extruder must be exactly the same, and the inner hole of each component and the surface of the mandrel need to be evenly coated with a layer of high temperature resistant grease during assembly. 

When each screw element is assembled on the mandrel, the end face of each screw element must be cleaned, and finally tighten the compression screw. 

Step8-Granuwel twin screw extruder machine

After the two screws are placed side by side according to the working position with a phase of 90 ° and slowly inserted them into the barrel. 

After the position of the spline at the tail of the screw corresponds to the position of the sleeve coupling, the two screws are pushed in at the same time, so that the tail of the screw closely fits with the end face of the output shaft of the transmission box, and a thin layer of grease can be applied evenly on the tail spline before installing the screw. 

Step9-Granuwel twin screw extruder machine

After the screw is installed, you should manually turn the screw for more than two circles . after confirming that there is no interference, scraping and grinding and other abnormal phenomena, you can install the net change and head assembly.  During installation, the surface of each screw thread should be evenly coated with high temperature resistant grease.

Twin screw extruder machine manufacturer- Granuwel

Granuwel is a professional manufacturer specializing in the design and manufacture of co-rotating parallel twin screw extruder machines and spare parts. Building on our own strengths, we have absorbed the essence of many industries and developed new high-torque, high-speed, high-yield GTE series co-rotating twin-screw extruders, GTS series twin-stage extruder pelletizing units, and HSJ series single-screw extruder pelletizing units. These machines are widely used for homogenization, plasticization, coloring, compounding, filling, reinforcement, and recycling of various types of plastics and rubbers.

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