An injection molding machine injects molten plastic into a mold, and after cooling, it becomes the product. It has a very wide range of uses. Depending on the type of plastic, it is used in different places. Injection molding machines are the most widely used processing machinery in the plastic processing industry. Not only can a large number of products be directly produced by injection molding machines, but they are also the key equipment that constitutes the injection stretch blow molding process.
An injection molding machine injects molten plastic into a mold, and after cooling, it becomes the product. It has a very wide range of uses. Depending on the type of plastic, it is used in different places. Injection molding machines are the most widely used processing machinery in the plastic processing industry. Not only can a large number of products be directly produced by injection molding machines, but they are also the key equipment that constitutes the injection stretch blow molding process. So, what is the force condition and strength of the screw in an injection molding machine like?
A screw-type injection molding machine consists of four parts: the injection device, the clamping device, the hydraulic transmission and the electrical control system. The injection device is composed of components such as the barrel, injection molding machine screw, nozzle, hopper, metering device, screw drive device, injection molding cylinder and injection seat moving cylinder. Its main function is to melt and plasticize the plastic evenly, and then inject a certain amount of molten material into the injection mold under the action of certain pressure and temperature. The clamping device, also known as the mold locking device. It is composed of a clamping cylinder, a moving template, a fixed template, a clamping mechanism, a pull rod, a demolding device, a safety gate, etc. Its main function is to ensure that the mold opens and closes in accordance with the prescribed procedures and speeds, and to guarantee that there is sufficient clamping force to make the mold close tightly. Mold closing devices are classified into three major categories: hydraulic type, mechanical type, and hydraulic/mechanical hybrid type. The hydraulic transmission and electrical control systems ensure that the injection molding machine operates accurately and without error in accordance with the pressure, speed, temperature and time specified by the injection molding process. The hydraulic transmission system is composed of a power oil pump, directional valves, throttle valves, pressure valves and an oil tank, etc. The electrical control system is composed of systems such as power control, action process control and heating control.
An injection molding machine injects molten plastic into a mold, and after cooling, it becomes the product. It has a very wide range of uses. Depending on the type of plastic, it is used in different places. Injection molding machines are the most widely used processing machinery in the plastic processing industry. Not only can a large number of products be directly produced by injection molding machines, but they are also the key equipment that constitutes the injection stretch blow molding process. So, what is the force condition and strength of the screw in an injection molding machine like?
When the screw of the injection molding machine and the main shaft of the reducer are fitted with a longer cylindrical surface, the screw of the injection molding machine can be used as a cantilever beam with one end fixed. The force state of the injection molding machine screw during the extrusion process can simplify the force condition of the screw: self-weight G; The torque M required to overcome material resistance; Axial force P generated by material pressure. Screws are generally scrapped due to long-term wear and excessive gap between the screw and the barrel, which prevents normal extrusion. However, there are also cases where they are damaged due to working stress exceeding the strength limit caused by improper design or operation. Therefore, the screw should also meet certain strength requirements. The dangerous section of the injection molding machine screw is generally located at the point where the root diameter of the thread in the feeding section is the smallest.
For the case where the tail of the screw is in a floating connection with the main shaft of the reducer, since the injection molding machine screw floats in the barrel, the bending stress caused by the self-weight of the screw is equal to zero. Therefore, only the compressive stress and shear stress of the screw are calculated. Since the bending stress caused by the self-weight of the screw is very small (the screw is surrounded by material), it can be ignored even in the former case. Therefore, these two methods are actually the same. There are also cases where the diameter of the screw is estimated based on pure torsion