The reason for the broken screen of the rotary screen printing machine

The deformation of the rotary screen printing machine is mainly manifested as broken screen, which generally occurs in the printing process of the printing machine, which seriously affects the production efficiency, printing quality and production cost of the printing machine.

The reason for the disconnection

1. Improper matching of nickel mesh material and installation

(1) The nickel mesh should be made of hard and tough material. Due to its excellent hardness and flexibility, it has good resistance to mechanical rotation, stretching, compression, friction, etc., and is not easy to be damaged in the production process. In addition, for the nickel mesh of the same material, because the high-mesh rotary mesh has higher strength, it is not easy to be damaged. However, due to the high mesh size and high price, the selection of nickel mesh mesh should be comprehensively considered according to the thickness of the fabric, the pattern structure and the fineness of the printed pattern.

(2) During production, both ends of the rotary screen are fixed by chucks, and although there is a range of movement in the weft direction, it is very small. If the rotary screen is improperly operated during the preparation process, the re-rounding of the flower net is not accurate, the upper bulky head is skewed, the end faces are not parallel, etc., the pre-stressing of the rotary screen has been generated after the rotary screen is machined, and the rotary screen will jump during operation and withstand uneven pressure Compressive and tensile stress, resulting in twisting or breaking of the net. It can be seen that in the process of making the screen, not only the printing effect of the pattern should be guaranteed, but also the quality of the rotary screen itself. It is required that when preparing the flower net, it should be well rounded, clean, glued evenly, stuffed flat, and tightly bonded.

(3) For the transmission bearing of the rotary screen, due to the tight fit between the dust ring and the outer casing, the performance of water blocking and slurry resistance is good, but the transmission flexibility of the bearing is poor, and even the phenomenon of jamming occurs; the chuck for fixing the rotary screen Insufficient maintenance, especially passive chucks, if the operation is not flexible or does not rotate during normal production, it is easy to disconnect the network.

(4) During normal production, if the cloth feeding tension is not adjusted properly, too tight or too loose will cause the resistance of the rotary screen to increase during the rotation process, resulting in the deformation of the flower net and damage in severe cases.

2. The formation of network disconnection by Liyin is determined by the shape of the street

(1) The shape of the fracture is neat, the inner wall has obvious friction marks, and the fracture is within the effective printing width of the printing machine. This is caused by a chipped blade, a sharp angle in the blade and impurities in the color paste, which can be solved by replacing or repairing the blade and re-filtering the color paste.

(2) The fracture is irregular zigzag near the connection between the circular mesh and the bulkhead. This is caused by the wrong gap between the guide belt and the rotary screen. Because the support roller is too high or too low, the rotary screen is deformed under the action of the guide belt and the scraper, and the rotary screen located at the connection of the bulkhead will be bent and deformed every time it turns to the bottom. Once, when the fatigue strength of the circular mesh is reached, it will crack, causing the mesh to break.

(3) The adjustment of the gap between the rotary screen and the guide belt is very important. When printing general fabrics, the gap should be adjusted to 0.3mm. If printing thick fabrics, the gap should be appropriately increased. If the gap is too large or too small, not only the printing effect is not good, but also it is extremely unfavorable for the use of the rotary screen. If the gap is too large, the net will not be supported, and will be directly subjected to the pressure of the scraper; if the gap is too small, the net will be squeezed by the rubber blanket, which will easily cause the net to break after a long time.

(4) The fracture is in the middle of the circular mesh, and the fracture shape is irregular. This is due to the disconnection of the net caused by the long-term work of the rotary net in the state of slight twisting of the net.

(5) Whether the tension of the rotary screen and the pressing action of the scraper are smooth and without impact have a great influence on the service life of the rotary screen. Since the rotary screen is only a flexible part with a thickness of 0.1mm, the transmission depends on the tension at both ends to obtain the stiffness. If the axial tension is too large or the speed of the scraper is too fast, the bottom of the screen will often have traces of knife edge impact, and over time , the circular mesh becomes scarred and breaks itself. Therefore, it is very effective to adjust the tension of the net tension and the flow rate of the one-way throttle valve on the lift gas path of the scraper, which is very effective to improve the impact of the scraper on the circular net. Also pay attention to the grinding of the arcs at both ends of the blade to avoid sharp corners stabbing the net. wall.

(6) After driving on the circle net, the height must be adjusted before driving. The height of the flower net and the relative position adjustment between the slurry pipe and the magnetic rod are not suitable. The angle cannot hold the magnetic rod. When the magnetic force increases, the force of the magnetic rod on the circular net increases accordingly, and the flower net is easily deformed or damaged.

(7) The choice of magnetic bar and magnetic force should be comprehensively determined according to the printing effect of the pattern and the thickness of the fabric. If the magnetic bar and the magnetic force are too large, the friction force between the magnetic bar and the flower net will increase, and the flower net will be easily deformed, resulting in a bad net. In addition, too much color paste in the flower net will increase the load of the flower net and cause the broken net due to the failure of the pulp detector rod and other reasons.

3. Coordinated operation of the ring net and the ridge guide belt

(1) During the printing process, the transmission line speed of the rotary screen should be consistent with the feed speed of the rubber guide belt. If the speed difference between the two is too large, the rotary network will be subject to certain resistance during operation, which will easily cause network disconnection over time. Therefore, it is crucial to prevent the rubber guide belt from slipping during operation.

(2) The rubber blanket automatically adjusts the deviation. If the control is not in place, the printing rubber blanket will swim left and right during operation, which will increase the friction force of the rubber blanket on the rotary screen, causing the rotary screen to bear left and right stress. As a result, the network is twisted and disconnected.