A study on the development of milling process for silicon nitride using ball end-mill tools by laser-assisted machining

Abstract

Silicon nitride is a non-oxide ceramic that represents strong characteristics in high strength, abrasion resistance, corrosion resistance, and thermal shock resistance at high temperatures and that has been widely used in the industry. However, it also exhibits high levels of hardness and brittleness, and machining of silicon nitride is usually implemented using a diamond grinding process. This presents difficulties in machining due to increased machining cost and time, and a machining method to reduce these is needed. Current studies on an alternative approach to the problem have been focused on laser-assisted machining (LAM) methods that facilitate machining by softening a workpiece using a laser heat source. The advantages of a LAM process are decreases in tool wear and cutting force and reductions in catastrophic tool failures and the occurrence of chatter. In this study, a high-power diode laser (HPDL) is used as a heat source for machining of silicon nitride. Machining experiments were carried out using cubic boron nitride (CBN) tools. The proper laser power for the experiment was determined through thermal analysis. A back-and-forth laser-path preheating method was newly proposed to obtain sufficient temperature for softening the silicon nitride. Machining experiments were performed using back-and-forth method and insulation material for protecting heat. The machining of silicon nitride was performed successfully by a laser-assisted milling (LAMill) process using a CBN ball end-mill tool, which is stable at high temperatures. In the machining with applying three times of a back-and-forth laser-path preheating process, tool breakage and gas marks were not occurred at the 170 W for processing a depth of cut of 0.15 mm. It is expected that the results of machining experiments can be used to process the various shape of silicon nitride material.

Rapid Development of an Injection Mold with High Cooling Performance Using Molding Simulation and Rapid Tooling Technology

“…However, the mechanical properties of the injection molds fabricated by Al-filled epoxy resins are inferior to metallic molds. Thus, some reinforcing fillers such as wollastonite, molybdenum disulfide [ 52 ], glass sphere, zirconia [ 53 , 54 , 55 ], silica sand, glass fibers , or silicon nitride [ 56 , 57 , 58 ] were recommended to add in the matrix materials. Additionally, metal AM technologies such as DB [ 59 ], SLS [ 60 , 61 ], SLM [ 62 ], electron beam melting, or direct metal laser sintering were recommended for manufacturing injection molds with optimum CCCs for mass production of wax patterns.…”

Improving Cooling Performance of Injection Molding Tool with Conformal Cooling Channel by Adding Hybrid Fillers

“…Thus, optimization of CCC is also an important research issue using the Taguchi method [ 62 , 63 , 64 , 65 ]. Further improvements in the mechanical properties of the SRM with CCC by adding fillers or reinforcing additives, such as wollastonite, glass fibers, carbon fibers, glass sphere, molybdenum disulfide [ 66 , 67 , 68 , 69 ], zirconia [ 70 , 71 , 72 ], silica sand, or silicon nitride [ 73 , 74 , 75 ] into the SRB is also an important research issue. In addition, the internal surface of CCC has high surface roughness [ 76 , 77 , 78 ] and result in reduction in mold life due to stress concentration [ 79 , 80 , 81 , 82 ].…”

Laser-Assisted High Speed Machining of 316 Stainless Steel: The Effect of Water-Soluble Sago Starch Based Cutting Fluid on Surface Roughness and Tool Wear

“…In addition, from the Figure 6 c–f, the flank wear reduces gradually for both cases, as the laser power is increased. Thus at low power, a maximum wear is obtained due to the abrasion [ 57 ]. Overall, the flank wear with water-soluble sago starch cutting fluid is considerably 38.41% reduced comparing to conventional cutting fluid (refer to experiment no.…”