# Investigation of Roller Press Surface and Stud Based on FEM Simulation
## 1 Introduction
The smooth rolls to weld the wear-resistant layer on the surface of the rolls surface, and increase the wear-resistant performance of the rolls surface by using different high-performance wear-resistant materials. However, the later maintenance of the smooth rolls is more difficult. The machine needs to be shut down during maintenance, which affects production efficiency. The composite rolls are mainly used to enhance the wear resistance of the rolls surface by using bimetallic and metal-based ceramic materials, but the wear of the composite rolls surface is also fast. At present, the service life of the composite rolls used by the enterprise is longer than that of the smooth rolls, but it is not obvious. The later maintenance of the composite rolls is the same as that of the smooth rolls. All need to be maintained during shutdown, affecting production. The studded rolls mainly consist of three parts, the roller shaft, the stud-lining and the stud. [PERSON] [21] discovering some benefits of using stud embedded surfaces in HPGR. [PERSON] [22] actually processes cement materials by embedding cylindrical studs into the rolls surface. By processing the materials, it was found that studs can effectively protect the rolls surface of studded rolls. At the same time, the geometry of the studs and the arrangement of the studs will affect the service life of the studded rolls. After the studded rolls has been running for more than 10,000 h, no studs have fallen off. Moreover, replacement of studs does not require downtime, which improves production efficiency. The studded rolls are to drill holes on the surface in a certain arrangement on the rolls surface, and install the stud with good wear resistance on the rolls surface. Two main types of the stud-linings are applied in studded rolls: studded and hexagonal [9; 23], which show varied characteristics of operation and have different lifetime of service. Cylindrical pins being composed of wear resistant cemented carbides, so-called studs, which are pressed or glued into holes drilled into a base material. Hexagonal tiles made of a wear resistant material get fixed to the rolls surface by the hot isostatic pressing (HIP) technology (HEXADURs). These two types of stud-linings are suitable for different processing occasions and increase the service life of the roller press. [PERSON] [24] studied the wear of rolls surface embedded with cylindrical studs. In the interstices between the studs an autogenous wear protection layer from compacted feed material builds up. This layer of fine material prevents the base material from further wear. Which will play a certain protective role on the rolls surface, thus greatly extending the service life of the rolls surface, and the later maintenance only needs to replace a small number of broken and fallen studs. It is easy to maintain without affecting continuous production. Through designed experiments, some scholars [25] installed fixed perforated metal strips on the roller of the studded rolls as the starting position for measuring the wear height of the studs. The wear patterns of studs on studded rolls were studied. When the HPGR operates without the formation of a protective layer, the wear rate of the rolls surface is more than the stud wear. In this case, stud projection and consequently stud breakage increase. [PERSON] [26] investigated the effect of the stud diameter on the capacity of a stud-type HPGR using the DEM with a breakage model. Through this method can contribute to the investigation of the effect of roll design in an efficient HPGR grinding. Results show that the working roll gap increased when a smaller stud was used. [PERSON] [27] utilizes FEM simulation to predict where breakage will occur on the roll according to ASME code standards. Finite element simulation was performed on workbench to predict the fracture position of the roller shaft to determine safe working conditions. It provides theoretical support for the design of the roller shaft and extends the service life of the roller press.