The reason and solution for the abnormal discharge of blow molding machine screw is the subject of this post.
The phenomenon that the screw of blow molding machine is abnormally discharged is mainly caused by the excessive clearance of the screw and barrel of the extruder. We all know that the screw and barrel gap is too large, the flow of the extruded material is unstable, and the surface of the blown product is prone to horizontal wrinkles. The screw and barrel gap is too large, and the extrusion material pressure is unstable so that the geometric shape and size error of the product section changes greatly. The gap between the screw and barrel is too large, and the backflow phenomenon generated when the raw material moves forward in the barrel increases so that the raw material stays in the barrel for too long and the paste turns yellow, which causes the surface of the product to discolor or have burnt spots. The gap between the screw and barrel is too large, which makes the output of extruded products unstable or decreased.
The second reason for the abnormal discharge of blow molding machine screw is caused by the unstable working speed of the extruder screw. If the working speed of the extruder screw is unstable, it will not only cause a large error in the longitudinal geometric shape and size of the product, but also cause the product to appear horizontal wrinkles, making the surface of the product rough, brittle, or partially hard. The product is unstable in quality, poor in strength, and brittle when used.
To avoid this phenomenon, it is necessary to pay attention to the influence of the following factors on the working speed of the extruder screw: The first is to avoid serious wear of the transmission belt and slippage of work; once the center distance of the transmission pulley is too small, the belt transmission will be inclined. It cannot work with the trapezoidal slope of the belt pulley by friction transmission; secondly, the temperature of the heating material in the barrel is low and the raw material is not uniformly plasticized, which causes the increase of the working load torque of the screw rotation and the unstable rotation of the screw.
The third point is that the damage to the thrust shaft of the screw leads to an abnormal discharge of the screw of the blow molding machine. Generally, the screw discharge is too fast or too slow or the discharge length is different. This is a fault caused by the electromagnetic interference of the servo valve and electronic ruler of the blow molding machine, which affects the stable feeding process of the screw. If the electronic ruler is contaminated, it will also affect the stability of the blanking.
The last point is that the heating temperature control of the barrel is unstable, which leads to an abnormal discharge of the screw of the blow molding machine. If the heating temperature of the barrel is controlled too low so that the raw materials cannot be melted, the plasticization quality of the raw materials in the barrel will be uneven, resulting in the rough surface of the product, frequent water lines, unstable cross-sectional dimensions of the product, and geometric shape and size errors. The fluctuation is relatively large, the surface of the product will also appear the phenomenon of hard lumps.
The above content is a variety of factors why the blow molding machine screw discharge is abnormal. In the actual operation process, we must find out the specific reasons and treat them differently according to different situations. Based on the failures encountered in the actual production process, analyze and determine where the problem lies, and take maintenance and troubleshooting measures.