Views: 59 Author: Site Editor Publish Time: 2023-04-24 Origin: Site
Injection molding machine is a common thermoplastic molding equipment. During the production process, due to changes in process conditions and materials, the inside of the machine needs to be cleaned. Common things such as switching the color of the material, or switching between different materials, may also accumulate impurities and black spots and carbon deposits inside the machine. So, how to clean the screw of the injection molding machine?
1. Select the correct heating device
It is the most common and effective method for plastic processing units to remove the plastic fixed on the screw by burning or roasting, but the screw cannot be cleaned with an acetylene flame. The temperature of the acetylene flame can reach 3000°C. Cleaning the screw with the acetylene flame will not only destroy the metal properties of the screw, but also significantly affect the mechanical tolerance of the screw.
If the acetylene flame turns to a persistent blue color when baking a certain part of the screw, it means that the metal structure of this part of the screw has changed, this will reduce the wear resistance of this part, and even peel off the wear-resistant layer and the base metal. In addition, local heating with an acetylene flame will also cause overheating on one side of the screw, which will cause the screw to bend. Most screws are manufactured from 4140.H.T. steel with very tight tolerances, typically within 0.03mm.
The straightness of the screw is mostly within 0.01 mm. When the screw is baked and cooled by the acetylene flame, it is usually difficult to return to the original straightness. The correct and effective way: Clean the screw with a blowtorch immediately after use. Because the screw has heat during processing at this time, the heat distribution of the screw is still uniform.
2. Choose the correct cleaning agent
Plastic raw materials cannot be used to clean the machine, let alone replace the screw cleaning agent. Cleaning the screw with new plastic or recycled material is time-consuming and wasteful, and does not do a good job of removing pigment and carbonation contamination.
3. Use the correct machine settings when cleaning
In order for the screw to be thoroughly cleaned, during the entire cleaning process, follow the machine settings recommended by the screw cleaning agent supplier, so that the cleaning agent can exert its maximum effect.
Taking a certain brand of screw cleaning agent as an example, it is required to use the maximum safe screw speed and maximum safe back pressure during the cleaning process, so that the screw is always kept in the forward position during cleaning and replacement with new plastic raw materials.
4. Make sure the machine is sealed when it is shut down
In addition to regular and preventative maintenance cleaning, shutdown storage seals should be done with a heat-stable screw cleaning agent, especially on weekends or holidays. During downtime, oxygen in the barrel can cause residual polymer to degrade and carbonize, leading to prolonged machine downtime and even scrapping the machine. Screw cleaning agents are good at protecting the screw and barrel from contamination during downtime, and can quickly put the injection molding machine into production mode after the holidays.
Haisi Extrusion is a professional manufacturer of twin screw extruder machine. We design and produce screw elements by our own.
Please feel free to contact us if you are interested.
