Regarding the surface processing of paper making rubber rollers

Paper making rubber rollers are important components of paper making equipment, such as rollers, idlers, pressure rollers, and press rollers. Because the surface of rubber rollers has material properties such as elasticity, toughness, and viscosity that are completely different from those of metals. Moreover, the roller surface often requires turning, grinding, and groove processing, and its processing quality directly affects the quality of papermaking products. Therefore, studying and summarizing the processing technology of rubber roller surface seriously has certain practical significance. Below, the editor will introduce the processing of paper roller surface.
1、 Types and cutting characteristics of adhesive surfaces
1. Types of paper rollers
According to the surface hardness of rubber, it is divided into three categories: soft, medium, and hard. The rubber surface hardness of soft rubber rollers is generally 30~40A; the hardness of medium hard rubber rollers is 75~85A; and the hardness of hard rubber rollers is 85~100A.
2. Cutting characteristics of rubber on the surface of rollers
Rubber cutting is different from metal cutting because it has material properties such as elasticity, toughness, poor heat dissipation, and low cutting force. According to microscopic analysis, metal cutting is actually extrusion shear. And the cutting of the rubber roller is cutting. So the cutting requirements for the paper making rubber roller surface are: (1) the blade should be sharp; (2) The speed should not be too fast, usually around 100r/min or 200m/min; (3) The cutting force is small, and the cutting feed rate and cutting depth can be larger.
2、 Turning of paper-making rubber roller surface
1. Medium hard rubber roller surface: turning. These two types of rollers are mainly extrusion rollers, support rollers, pressure rollers, and light pressure rollers. It has good cutting performance and can only use cutting edge tools with large front and rear angles. To improve the smoothness of the rubber surface after turning, a circular arc wide cutting tool can be used for overlapping cutting (see Figure 1). Due to the viscosity, toughness, and elasticity of rubber, the rubber coming off the car will not be in the form of fragments like metal, but in the form of strips that need to be manually pulled down to prevent entanglement.
2. Rotation of Soft Rubber Roller
This type of roller is mainly used as a backup roller on drum paper machines or long web paper machines. Because the roller surface is too soft and has too much elasticity, it is not suitable for turning into scrap strips.
3、 First cutting of roller surface
It is difficult to achieve good smoothness on the surface of the rubber roller after turning, so grinding is generally required. Flat roller grinding generally uses sanding cloth and wooden core, which can be ground on a lathe. Talc powder can be added to prevent rubber particles from sticking together. Grinding the surface of soft rubber is relatively time-consuming and labor-intensive due to its high elasticity.
The grinding technology of medium and high roll paper rollers is relatively advanced. Among them, the high volume is generally between 0.10-0.60mm, and automatic control of grinding medium high rubber rollers is naturally good, but most paper mills do not have such grinding machines. Even if there are, the cost of grinding medium and high pressure rubber rollers with a grinder is often too high, so usually the medium and high pressure paper rollers and idlers are manually ground on a lathe. The polishing method is to first polish the roller surface flat, and then smoothly transition from the middle to both sides by detecting the broken lines. The smaller the detection interval, the better, usually around 100mm.
4、 Turning of grooves on the roller surface
In order to improve the dewatering effect of the press roller, the roller surface often becomes grooved. Its plow grooves are divided into triangular plow grooves and rectangular plow grooves. Turning slotting tools generally require two blades, which are combined together according to the required groove angle for turning. Experiments have shown that rectangular grooves have better dehydration effects than triangular grooves because the gaps between drainage grooves are smaller and the compression area of the roller surface is not excessively reduced. However, manufacturing cutting tools is more difficult. Alternatively, use two knives with one curved blade or a combination knife with three blades to rotate.
The above is the content about the processing of paper making rubber roller surface. This rubber roller is a large thick walled rubber roller used in various parts of paper machines. According to different functions, it can be divided into press rollers and various auxiliary rollers driven by press rollers.
Editor: Chihiro