How To Wash The Extruder Screw And Barrel?

Date:2022-5-18 Author:hcscrew

Extruders are used to make plastic items. Our extruder screw and barrel must be maintained with care. Similarly, when we change the plastic raw material for our extruded items and the screw, we must wash our screw barrel. So how to wash our old screws and barrel?

How to wash the extruder screw correctly.

01. Using the correct heating device

The use of fire or fire to remove the plastic fixed in the screw, is the most common and effective way to plastic processing units, but never use acetylene flame to wash the screw. Acetylene flames can reach temperatures of up to 3000°C. Washing screws with acetylene flames will not only damage the metal properties of the screw, but will also significantly affect the mechanical tolerances of the screw.

If the acetylene flame turns persistently blue during baking a section of the screw, it implies that the metal structure of that area of the screw has been changed, which can result in a drop in wear resistance or even the peeling of the anti-wear coating off the base metal. Furthermore, partial heating with an acetylene flame might result in overheating on one side of the screw, resulting in screw bending. The majority of screws are manufactured of 38CrMoAlA nitriding steel with very fine tolerances, often within 0.03mm.

The screw’s straightness is normally within 0.01mm, and when baked and cooled by an acetylene flame, it is frequently difficult to return to its previous straightness. Use a flame to wash screw immediately after use. Because the screw is still hot from the machining at this point, the heat distribution of the screw remains uniform.

02. use the correct cleaning agent

The commodities economy is highly developed nowadays, and there is no shortage of screw washers (screw cleaning material) on the market, most of which are expensive, with varying degrees of excellent and terrible effects. Whether or not to use commercial cleaning solutions depends on the manufacturer and manufacturing. Plastic processing enterprises may also be based on their own manufacturing, with the use of different resins to do screw cleaning material, which can save a large amount of money.

03. the choice of the correct cleaning method

To begin cleaning the screw, switch off the filling insert by sealing the bottom of the hopper. Then lower the screw speed to 15 – 25 r/min and maintain this speed until the melt flow stops at the front of the die head. The temperature of the barrel’s heating zones should be adjusted at 200 °C. Cleaning occurs as soon as the barrel reaches this temperature.

Depending on the extrusion process (it may be necessary to remove the die head to reduce the risk of excessive pressure at the front end of the extruder), cleaning must be done by one person: the operator monitors the screw speed and torque from the control panel while also monitoring the extrusion pressure to ensure that the system pressure is not too high. Throughout the procedure, the screw speed should be controlled at or below 20 r/min. The die should never be removed for cleaning in low pressure die applications. When the extrudate has been entirely converted from process resin to clean resin, stop and remove the die head, then resume the screw (within 10r/min) to enable the leftover clean resin to escape.

04. use the correct cleaning tools

Heat resistant gloves, goggles, a copper scraper, a copper brush, a copper wire mesh, stearic acid, an electric drill, a barrel ruler, and a cotton cloth are all necessary equipment and cleaning supplies.

Once the cleaning resin has stopped extruding, the screw can be withdrawn from the machine. Remove the hose lines and rotating connections from screws with cooling systems before beginning the screw extraction unit (which may be attached to the gearbox). The screw is pulled forward using the screw extraction mechanism, exposing 4 – 5 screw blocks for cleaning.

A brass scraper or brush can be used to clean the cleaning resin on the screw. After washing the exposed screw with cleaning resin, the screw extraction equipment is used to drive the screw block forward 4-5 times to continue cleaning. This process is continued until the bulk of the screw has been forced out of the barrel.

After removing the majority of the cleaning resin, the screw is sprayed with stearic acid. The residual residue is then cleaned using a brass wire mesh, and after cleaning the whole screw with the mesh, a cotton towel is used for the last wiping process. This is to guarantee that the screw does not contain any impurities in its next production run. After thoroughly cleaning the screw, leave it aside until the remainder of the machine has been thoroughly cleaned. If the screw is to be kept, a coating of lubricant should be put to the surface to prevent corrosion.

Steel tools, such as screwdrivers, scrapers, or pry bars, should never be used to remove plastic attached on a screw since they might damage the screw and barrel’s surface.

How to clean the extruder barrel correctly

Washing the barrel is much easier than washing the screw, but it is also very important.

1. When preparing the barrel for cleaning, the temperature is likewise adjusted to 200 °C.

2. To make the cleaning tool, a circular steel brush is fastened onto the drill bar and the drill. Then the brush is covered in copper wire mesh.

3. Before inserting the cleaning tool into the barrel, sprinkle some stearic acid into the barrel or spread the stearic acid on the copper wire mesh of the cleaning tool.

4. as soon as the copper wire mesh enters the barrel, start the drill to rotate it while artificially moving it back and forth until this back and forth movement becomes free of resistance.

5. After removing the wire mesh from the barrel, a cotton towel is rubbed across the barrel to remove any cleaning resin or fatty acid residue. The barrel is now clean after numerous such back-and-forth wiping. The freshly cleaned screw and barrel are now ready for the next manufacturing run!

Summary

So, it is an extruder screw and barrel wash procedure. To gain a better experience with the barrel screw, our clients need to know how to maintain or wash self-own screw barrel. Please request a quote or contact HUACHEN Screw Barrel Factory for more information on extruder screws and barrels.

TAGS

screw barrel knowledge

RELATED CONTENTS ABOUT SCREW AND BARREL

;

Solutions