Wear Mechanism of Multilayer Coated Carbide Cutting Tool in the Milling Process of AISI 4340 under Cryogenic Environment

Cryogenic technique is the use of a cryogenic medium as a coolant in machining operations. Commonly used cryogens are liquid nitrogen (LN2) and carbon dioxide (CO2) because of their low cost and non-harmful environmental impact. In this study, the effects of machining conditions and parameters on the wear mechanism were analysed in the milling process of AISI 4340 steel (32 HRC) under cryogenic conditions using a multilayer coated carbide cutting tool (TiAlN/AlCrN). A field emission scanning electron microscope with energy-dispersive X-ray analysis was used to examine the wear mechanisms comprehensively. At low machining parameters, abrasion and adhesion were the major wear mechanisms which occurred on the rake face. Machining at high machining parameters caused the removal of the coating material on the rake face due to the high temperature and cutting force generated during the cutting process. In addition, it was found that continuously adhered material on the rake face would lead to crater wear. Furthermore, the phenomenon of oxidation was also observed when machining at high cutting speed, which resulted in diffusion wear and increase in the crater wear. Based on the relationship between the cutting force and cutting temperature, it can be concluded that these machining outputs are significant in affecting the progression of tool wear rate, and tool wear mechanism in the machining of AISI 4340 alloy steel.

Non traditional cooling technique using Peltier effect for single point boron carbide (B4C) cutting tool doping with titanium carbide (TiC)

A single point cutting tool is modeled out of two different materials having desired thermoelectric properties. The tool material used is B4C doped with different compositions of Titanium Carbide. In the present work, three different compositions of B4C doped on both sides of cutting tool made by tungsten carbide. The range of composition of boron carbide (B4C) was selected randomly with 0-12.5%, 0-25.4% and 12.5 – 25.4% of B4C on first half and second half of the cutting tool respectively. The simulation process is done in ANSYS 2020 R2 software, thermal-electric module (TEM) is used. From these studies it is evident that considerable cooling effect is achieved and found to be the lowest temperature of 14.960C is observed for 0-25.4% B4C, 18.790C is observed for 0- 12.5%B4C and 26.730C for 12.5-25.4% B4C at the junction of the materials which is nearer to the cutting tip respectively. Finally it is concluded that one side of cutting tool without any doping and other side with 25.4% B4C doped showed good results which observed by conducting number of simulations at different levels of iterations for B4C doped titanium carbide cutting tool used in turning operation.

Pulse laser processing of hard-alloy cutting tool with multilayer coating

The influence of pulsed laser treatment (PLT) on the structural parameters and mechanical properties of singlelayer and multilayer coatings is investigated. The contact indicators during cutting, indicators of the thermal and stressed state of the cutting wedge of a tool with multilayer coatings that have passed the PLT are presented. The effectiveness of PLT for multi-coated carbide cutting tool is shown. Keywords: pulsed laser processing, carbide cutting tool, multilayer coating, structural indicators, indicators of mechanical properties, durability period. [email protected], [email protected]

Neural network modeling of the wear process of a carbide cutting tool

A neural network model of the wear process of a carbide cutting tool is proposed. This model is considered influence of the cutting dynamics on the tool. The dependence of the wear rate on the processing modes and properties of the processed and tool material is shown. Keywords cutting tool; neural network model; dynamics of the cutting process; wear

Laser de-coating of hard DLC coatings from tungsten carbide cutting tool

Laser irradiation de-coating is a promising new approach for effective coating removal of cutting tools. While this method has demonstrated feasibility for conventional coatings, its use and efficacy on lubricant coating is however yet to be ascertained. This paper reports on the results of excimer laser de-coating of hard DLC from DLC-coated tungsten carbide (WC) substrates. A range of fluence and pulse was studied to evaluate the effectiveness of the de-coating process. Result shows that laser parameters of 7 J/cm2 fluence, 400 pulse and 25 Hz frequency were found to yield optimum results in removing hard DLC coating of 3.2 μm thickness from WC substrates. The experimental work indicated successful laser de-coating of hard DLC coating without noticeable damage to the WC substrate. The capability of this new de-coating process is significant in the aerospace industry as it could facilitate re-grinding and recoating of drills thereby improving economics of manufacturing. The process windows could also be applied in the removal of DLC from other cutting tools and applications.

Adhesion Behavior of PVD-coated Cutting Tools

Cutting with TiAlN or CrAlN tip PVD-coated tungsten carbide-based inserts manufactured by powder metallurgy, we found no significant difference in the wear behavior of inserts regardless of whether the insert was used in wet or dry conditions. We determined the adhesion properties of the coating layers with a scratch test and by Daimler–Benz test. On the tungsten-based carbide cutting tool, the thinner TiAlN coating showed slightly better adhesion than the thicker CrAlN coating.