# Investigation of Roller Press Surface and Stud Based on FEM Simulation
## 1 Introduction  
In recent years, the application of High-pressure grinding rolls (HPGR) has become one of the hotspots of technological innovation in many mining enterprises. The application of laminated crushing technology in the crushing industry started late, delaying the application of HPGR in the mining industry. Comminution processes, especially grinding, are highly energy-intensive and energy-inefficient. In the mining industry, comminution processes such as semi-autogenous grinding (SAG) and ball milling can be responsiblefor up to 60% of overall process plant energy consumption and have energy efficiency as low as 1% [1]. At the end of the 1970s, [PERSON] [2] put forward a design concept of high-efficiency and energy-saving crushing equipment while deeply studying the principle of laminated crushing. Application of HPGR in very fine feed sizes represented the first successful use of the technology [3] as result of its introduction in the cement industry. [PERSON] [4] highlighted that the cement industry was important to consolidate the HPGR technology as an efficient alternative in fine grinding. With the continuous development of HPGR, the HPGR was quickly applied to the production of cement raw materials and metallurgical mines [5; 6; 7]. The working principle of the roller press, which is composed of a pair of extrusion rolls rotating synchronously in opposite directions. The roller press mainly consists of two rollers and drivers. One roller is the fixed roll and the other roller is the floating roll. The material with a certain particle size enters from the feed opening above the two rollers and is brought into the roller by continuous rotation of the extrusion roll. At this time, it is subject to the direct pressure caused by the contact with the rolls surface, and the pressure caused by the gravity of the material layer. When the two rollers rotate, they will also receive mutual extrusion force from the surrounding materials. Finally, the material becomes a dense cake and is discharged from under the roller press. Figure 1 is a schematic diagram of a studded rolls. The studded rolls are divided into three parts: the roller shaft, the stud-lining, and the stud. The surface of the stud-lining of the studded rolls are composed of several stud holes arranged in a certain pattern. Roller press have been widely used in the cement industry due to their efficient grinding capabilities [8]. The current problem with roller press is that the rolls surface is prone to wear and needs to be replaced regularly. This greatly reduces the service life of the roller press and affects the development of the roller press. Therefore, how to reduce the wear on the surface of the roller press and increase the service life of the roller press is an urgent problem that needs to be solved for the current roller press. Current research mainly focuses on the mechanism research of roller press wear and the optimization of rolls surface structure. The ways to solve the surface wear of roller presses are mainly divided into the following aspects: On the one hand, it is to study the influence mechanism of materials on the rolls surface. Select the appropriate roller press surface material according to the material. Adjust the processing technology of the roller press according to the characteristics of the material. On the other hand, the surface structure of the roller press is optimized to reduce the wear of the rolls surface. The current studded rolls surface is a new structure that effectively reduces surface wear. However, there is currently little research on the studded rolls surface. The size of the studs, the assembly method of the studs, and the distance between the studs are mostly designed using empirical methods. Figure 1: Schematic diagram of studded rolls. Research on the wear mechanism of roller presses mainly focuses on the wear of materials on the surface of roller presses. By studying the wear of the rolls surface, the grinding circuit of the roller press can be optimized.