# Cutting Force and Cutting Quality during Tapered Milling of Glass Magnesium Board
## 1 Introduction  
Glass magnesium (MGO) board is a new kind of engineering material. It is mainly made of magnesium oxide, magnesium chloride, and alkali-resistant glass fiber [1]. Glass MGO board has been used in a wide range of applications, such as packaging, flooring, and decoration, because of its fireproof, environmentally friendly, and durable properties [2, 3].  
Glass MGO board is a difficult-to-cut material due to its high hardness, which easily increases the wear rate of cutters. In practical production, common cutter materials, such as high-speed steel [4], tungsten carbide [5], and ceramic [6], cannot meet the requirements of glass MGO board machining. Considering the circumstances, diamond cutters appear to be the best choice to deal with this problem [7]. Diamond cutters have many outstanding advantages, including high hardness [8], low friction coefficient [9], high modulus of elasticity [10], and a low thermal expansion coefficient [11]; thereby, they have been widely used in the practical machining of glass MGO board.  
Based on relevant studies, cutting force and cutting quality are important research objects in material processing theories [12] as they affect the tool design, product quality, and the cost of machine power directly [13]. Meanwhile, studies have shown that cutting force and cutting quality are affected by many factors including cutting speed, cutting depth, tool geometry, and so on [14, 15]. Cutting force was investigated by [PERSON] et al. [16] during the turning of glass fiber reinforced polyamide material.  
They found that the feed rate had a more profound effect on the cutting force than the cutting speed, and the cutting force increased with the increase of feed rate but decreased with increased cutting speed. In related studies on cutting force, [PERSON] et al. [17] explored the cutting force during the steel AISI 1040 turning process, and their results showed that the cutting force decreased with the increase of the rake angles of the cutters. In a study on the quality of machined surfaces, [PERSON] et al. [18] determined that the cutting parameters, including the cutting speed, feed rate, and cutting depth, had a great influence on the roughness of the machined surface when milling aluminum alloy. The trend of surface roughness during finishing turning by cemented carbide cutters with different tool angles was researched by [PERSON] et al. [19], who found that the surface roughness was sensitive to tool angles, which was negatively related to the wedge angle.  
Tapered milling is a cutting method where the cutting edge forms a tapered surface at a special angle dependent on the rotation of the spindle. Compared with traditional cylindrical milling, tapered milling has better cutting stability and higher cutting efficiency, and has thus been applied in various materials processing. However, there has been little research conducted on the performance of tapered milling, especially in the machining of glass MGO board.  
Thus, the present work examines the performance of tapered milling during glass MGO board machining with diamond cutters, and the main attention is given to the effects of the tool angle, spindle speed, and cutting depth on the cutting force and cutting quality. Meanwhile, the optimal cutting conditions were obtained by optimizing the tool angle and cutting parameters, so as to offer scientific theoretical guidance for industrial glass MGO board machining.