Careful maintenance of small screw extruders extends their service life

Extruder is an important equipment for plastic molding processing and granulation. The normal use of extruder can fully exert the efficiency of the machine and maintain good working condition. Persistently and meticulously maintain the machine to extend its service life. The main faults of the extruder are abnormal noise and vibration caused by abnormal wear and tear, wear or damage of transmission components, poor lubrication, as well as foreign object jamming, material blockage in the process, etc.

1、 Extruder screw wear
Reason for wear and tear
The normal wear of the screw and barrel of the screw extruder mainly occurs in the feeding area and metering area. The main cause of wear is the dry friction between the sliced particles and the metal surface. When the sliced material is heated and softened, the wear decreases.

Abnormal wear and tear between the screw and the barrel can occur when the screw ring knot and foreign objects get stuck. Ring knot refers to the screw being trapped by the condensed material. If the screw extruder lacks a good protective device, the strong driving force may twist the screw, causing abnormal resistance and serious damage to the surface of the screw and the barrel. Scratches on the barrel are difficult to repair. The design principle of the barrel ensures a longer service life than the screw. For normal wear and tear of the barrel, it is generally not repaired. The method of repairing the screw thread is often used to restore the radial clearance between the inner hole of the barrel and the outer diameter of the screw.

Solution to screw wear
The local damage of screw threads is repaired by welding special wear-resistant and corrosion-resistant alloys. Generally, inert gas shielded welding and plasma argon arc welding are used, and metal spraying technology can also be used for repair. Firstly, grind the worn outer surface of the screw to a depth of about 1.5mm, then weld the alloy layer to a sufficient size to ensure sufficient machining allowance, and finally grind the outer surface and threaded side of the screw to the original size.

2、 Abnormal noise
(1) If it occurs inside the gearbox, it may be caused by bearing damage or poor lubrication, or by gear wear, improper installation and adjustment, or poor meshing. This can be solved by replacing bearings, improving lubrication, replacing gears, or adjusting gear meshing conditions.
(2) If the noise is a sharp scraping sound, consideration should be given to the possibility of misalignment of the machine barrel, which may cause scraping between the shaft head and the transmission shaft sleeve. It can be solved by adjusting the barrel.
(3) If there is noise from the barrel, it may be caused by the bending of the screw sweeping the chamber or excessive friction of solid particles due to the set temperature being too low. It can be processed by straightening the screw or increasing the set temperature.

3、 Abnormal vibration
If this situation occurs at the gearbox, it is caused by the wear of the bearings and gears, which can be solved by replacing the bearings or gears; If it occurs at the barrel, it is due to the mixing of hard foreign objects in the material, and the cleanliness of the material needs to be checked. If necessary, a strong magnetic device should be installed in the hopper to adsorb iron filings.

4、 Ring blockage material at the entrance of the screw
This type of malfunction is mainly caused by the interruption or insufficient flow of cooling water. It is necessary to check the cooling system and adjust the cooling water flow and pressure to the specified requirements. It is also possible that large recycled blocks in the raw materials are blocking the feed inlet, and the feed inlet needs to be cleaned.

Dongguan Zhenggong Electromechanical Equipment Technology Co., Ltd. is a professional manufacturer of single and double screw granulators and single and double screw extruders. Its core products include plastic granulators such as EVA, PVC, TPU, TPR, PP, PE, as well as a complete granulator production line. The granulator equipment produced is affordable and the granulation is uniform. Zhenggong has always maintained a leading advantage in the industry with humanized service, continuous innovation ability and speed. The purpose of the enterprise is to create and retain customers, and has always established long-term partnerships with customers with integrity.

The granulator produced by Zhenggong has uniform granulation and high cost-effectiveness. It is a well-known granulator manufacturer in the industry. For many years, we have been focusing on the research and production of rubber equipment granulators, internal mixers, open mixers, and granulator extruders. We will serve you with the most sincere and enthusiastic heart.