The screw barrel of an injection screw barrel for injection machine
has a number of functions. It serves as the main feed and delivery mechanism for the molten plastic. It has three parts: the feed zone, the compression zone, and the metering zone. The feed section consists of a deep uniform channel that preheats the polymer granules and forces them downward. The compression zone compresses the granules while the metering section pulls them forward. The metering section of the screw is approximately 25 percent long and acts as a pump to develop shot sizes.Another important function of the injection screw barrel is to control the pressure. It is essential that the injection pressure is controlled to maintain consistency in quality and production. High pressures can degrade the material, so it is important to use a barrel with a lower pressure. The rpm speed of the screw also affects its output.Extruder screw barrel for plastic recycling granulation
Ratio of length to diameter:L/D=20-50
Ratio of length to diameter:L/D=8-20
The L/D ratio is another important factor to consider when choosing an injection screw barrel for your machine. It affects the amount of material you can inject and the melt uniformity. Generally, a screw with an L/D ratio of 20:1 is recommended, but some manufacturers offer screws with L/D ratios as high as 28:1. Another important factor to consider when choosing a screw barrel is the compression ratio. The compression ratio is important because it influences mixing and shear heating of the material. A typical compression ratio is between 2:1 and 3:1. However, the real difference is between a semicrystalline and an amorphous material. Semicrystalline materials have higher density than amorphous materials and require a lower compression ratio.The screw in an injection machine will wear over time. This is a slow process that has a minimal impact on the overall performance of the machine.
When it becomes too worn, you should consider replacing the screw and barrel. While a minor amount of wear may not seem like much, it can greatly reduce your production rates. In addition, your finished product quality may suffer, and your customers will notice. This wear will be noticeable as soon as the diameter of the screw has gotten smaller than the barrel's diameter.Regular inspection of the screw and barrel is essential in order to ensure its performance. Several tools can be used for this purpose. You can use portable electronic bore gauges or extension rods to measure the interior of the barrel. Digital micrometers can also be used to measure the screw flights. A visual inspection can also reveal a lot of information about the wear of the screw and barrel.Injection machine wear is caused by metal-to-metal contact. The contact can occur due to mechanical conditions or it can be the result of larger problems. Temperature and pressure are two of the most common factors that lead to increased friction.
The transition section and the last few turns of the metering section are typically subjected to high temperatures and pressure. This is where most of the OD wear occurs.If you want to maintain the performance of your injection machine, you should pay attention to the maintenance of your injection screw barrel. A proper PM program will help you determine when it is time to replace the barrel or screw. It is also important to know how long your screw lasts and what you can do to extend its life. This can help you avoid unnecessary downtime and reduce costs.The performance of your injection screw barrel is dependent on the design of the feed screw. The design and the surface treatment of the screw affects its ability to feed material. If the screw wears out, it can result in lower performance and increased energy consumption. While minor wear will not affect the machine's overall performance, a large amount of wear can lead to increased energy costs and longer cycle times. This wear pattern can be avoided by changing the barrel.