Introduction of Plastic Extrusion Machine Cleaning Methods

1, choose the right heating device

It is the most common and effective way to remove the plastic that is fixed on the screw by fire or fire roasting. However, it is absolutely not possible to clean the screw with acetylene flame. Acetylene flame temperature up to 3000 ° C, Acetylene flame to clean the Please clean the screw will not only destroy the screw metal properties, but will also significantly affect the screw mechanical tolerance.

If the acetylene flame burns a certain part of the flame into a long-lasting blue, then that part of the screw structure of the metal has changed, which will lead to reduced wear resistance of the site, and even wear-resistant layer and the substrate Metal peel off. In addition, the use of acetylene flame local heating can also cause one side of the screw overheating, resulting in screw bending. Most of the screws made of 4140.H.T. steel, tolerances are very close, generally less than 0.03mm.

Most of the flatness of the screw is within 0.01mm. When the screw is baked and cooled by the acetylene flame, it is usually difficult to return to the original flatness. Correct and effective approach: Use the torch immediately after the screw to clean. Because at this time the screw with the heat in the process, so the screw heat distribution is still uniform.

2, choose the right detergent

Today, a highly developed commodity economy, there are many different types of screw cleaners (screw cleaning materials) on the market, most of which are expensive and the results are mixed. Whether the use of commercial cleaning agents, according to different manufacturers and production conditions may be; plastic processing enterprises can also be based on their production, using different resins for screw cleaning materials, save a small unit for a small expenditure.

3, choose the correct method of cleaning

The first step to clean the screw is to turn off the feed flapper, which is to close the discharge opening at the bottom of the hopper; then reduce the screw speed to 15-25 r / min and stop this flow until the melt flow at the tip of the die stops until. All heated areas of the barrel should be set at 200 ° C. Once the barrel reaches this temperature, it starts to clean immediately.

Depending on the extrusion process (which may require removal of the die to reduce the risk of overpressurizing the front end of the extruder), it must be done by one person during cleaning: the operator observes the screw speed and torque from the control panel and observes the squeeze Put pressure on to ensure system pressure will not be too high. Throughout the process, the screw speed should be maintained within 20r / min. In low pressure die applications, do not remove the die for cleaning. Immediately shut down and remove the die as the extrudate is completely converted from the process resin to the cleaning resin, and then restart the screw (at a rate of 10 rpm) to allow residual cleaning resin to flow out.

4, use the correct cleaning tools

Properly appropriate tools and cleaning materials should include:

Heat-resistant gloves; Goggles; Copper scraper; Copper brush; Copper mesh; Stearic acid; Drill;

Once the cleaning resin stops extruding, the screw can be pulled out of the equipment. For screws with a cooling system, remove the hose line and swivel connections before starting the screw extraction device, which may be attached to the gearbox. Use a screw-extraction device to push the screw forward to expose 4-5 screws for cleaning.

The cleaning resin on the screw can be cleaned with copper scraper copper brushes. After the cleaning resin on the exposed screw is cleaned, 4-5 screws will be propelled forward using the screw extraction device and cleaning will continue. So repeatedly, eventually most of the screw is pushed out of the barrel.

Once most of the cleaning resin has been removed, sprinkle some of the stearic acid onto the screw; then use a copper mesh to remove the remaining residue. After the entire screw has been polished by the copper mesh, use a cotton cloth for the final wipe. This is to ensure that the next screw production will not bring any pollutants. After the screw has been completely cleaned, it can be set aside until other equipment is also completely clean. If the screw needs to be stored, apply a layer of grease to the surface to prevent rusting.

Cleaning the screw Never use steel tools, such as steel screwdrivers, scrapers or pry bars, to remove the plastic adhering to the screws because the steel can damage the surfaces of the screws and the barrel.