Effect of Ion Energy on the Microstructure and Properties of Titanium Nitride Thin Films Deposited by High Power Pulsed Magnetron Sputtering

Titanium nitride (Ti-N) thin films are electrically and thermally conductive and have high hardness and corrosion resistance. Dense and defect-free Ti-N thin films have been widely used in the surface modification of cutting tools, wear resistance components, medical implantation devices, and microelectronics. In this study, Ti-N thin films were deposited by high power pulsed magnetron sputtering (HPPMS) and their plasma characteristics were analyzed. The ion energy of Ti species was varied by adjusting the substrate bias voltage, and its effect on the microstructure, residual stress, and adhesion of the thin films were studied. The results show that after the introduction of nitrogen gas, a Ti-N compound layer was formed on the surface of the Ti target, which resulted in an increase in the Ti target discharge peak power. In addition, the total flux of the Ti species decreased, and the ratio of the Ti ions increased. The Ti-N thin film deposited by HPPMS was dense and defect-free. When the energy of the Ti ions was increased, the grain size and surface roughness of the Ti-N film decreased, the residual stress increased, and the adhesion strength of the Ti-N thin film decreased.

The Performance of Polycrystalline Diamond (PCD) Tools Machined by Abrasive Grinding and Electrical Discharge Grinding (EDG) in High-Speed Turning

Polycrystalline diamond (PCD) tools are widely used in industry due to their outstanding physical properties. However, the ultra-high hardness of PCD significantly limits the machining efficiency of conventional abrasive grinding processes, which are utilized to manufacture PCD tools. In contrast, electrical discharge grinding (EDG) has significantly higher machining efficiency because of its unique material removal mechanism. In this study, the quality and performance of PCD tools machined by abrasive grinding and EDG were investigated. The performance of cutting tools consisted of different PCD materials was tested by high-speed turning of titanium alloy Ti6Al4V. Flank wear and crater wear were investigated by analyzing the worn profile, micro morphology, chemical decomposition, and cutting forces. The results showed that an adhesive-abrasive process dominated the processes of flank wear and crater wear. Tool material loss in the wear process was caused by the development of thermal cracks. The development of PCD tools’ wear made of small-sized diamond grains was a steady adhesion-abrasion process without any catastrophic damage. In contrast, a large-scale fracture happened in the wear process of PCD tools made of large-sized diamond grains. Adhesive wear was more severe on the PCD tools machined by EDG.

Cutting performance study of synthetic diamonds tools applied in ultra-precision machining of copper

In this study, type Ib, type IIa, and type IIb synthetic diamonds tools were used for the ultra-precision machining (UPM) of copper. Raman spectroscopy showed that the diamond cutting tools used in these experiments exhibited high-quality sp3 structure and little residual stress in the diamond lattice. Type IIb diamond cutting tools showed higher durability and better UPM performance than the other types of diamond cutting tools. Chemical wear was deemed significant with respect to the cutting tools’ wear in this UPM experiment. Higher durability and enhanced UPM performance could be attributed to the higher thermal and chemical stabilities of the type IIb diamond cutting tool.

Experimental Determination of the Surface Geometrical Structure Parameters and Tool Wear During Turning the Polymer Concrete

The paper presents the results of experimental determination of the Surface Geometrical Structure (SGS) parameters and tool wear during turning the polymer concrete. Until now, all literature reports have shown that the smoothness and roughness of the mineral cast surface was obtained directly from the mold. However, new applications of polymer concrete, even for some parts of the machine tools, forced the producers to carry out machining, which would improve the parameters of the surface layer. The topic of machining ceramic-based composite materials is a new chapter in the field of machining, which has not been sufficiently researched so far. The article describes the process of experimental determination of dependence of surface layer and tools wear parameters from cutting parameters during longitudinal turning of polymer concrete. The turning was carried out using plates made of a cubic boron nitride (CBN). After machining, the surface roughness and the maximum width of the flank wear were measured. On this basis, the mathematical model of the surface layer and tools wear parameters versus cutting parameters were defined. The authors also attempted to explain the phenomena occurring in the machining zone using variable cutting parameters. Microscopic pictures of CBN plates after machining were also performed. After the study, the final conclusions about the machining of mineral cast material were formulated.

Cutting Performance of Bionic Cutting tools Based on Surface Microstructures of Blood Clams in Dry Cutting of CFRP

Carbon fibre reinforced polymer (CFRP) composites are widely used in high-tech industries like the automobile and aerospace sectors, but the wear resistance of tools is one of the most significant restrictions in machining CFRP. In this study, bionic cutting tools based on surface microstructures of blood clams were fabricated to improve the dry cutting performance of CFRP. Three types of bionic cutting tools with different size parameters were applied in dry cutting test. The three-axis cutting forces and the cutting temperature of the processed workpiece were measured. The average friction coefficient between the rake face and the chip was calculated, and the morphology of the tools wear were observed. The results showed that bionic microstructures with appropriate size parameters can extremely improve the cutting performance of CFRP for tool in turning.