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 Boron Carbide (B4C) doped with different compositions of Titanium Carbide (TiC). In the present work, three different compositions of Titanium Carbide doped on both sides of cutting tool made by Boron carbide. The available combinations of Titanium Carbide (TiC) from the work bench in ANSYS was selected with three cases of 0 & 25.4%, 0% &12.5% and 12.5% & 25.4% 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 10.93°C is observed for the combination of 0% &25.4%, 18.79°C is observed for the combination of 0& 12.5% and 26.73°C for 12.5% and 25.4% combination at the junction of the tool material 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% TiC doped showed good results which observed by conducting number of simulations at different levels of iterations for Titanium Carbide doped Boron Carbide cutting tool used in turning operation.


INTRODUCTION
In the machining process by cutting, a part of mechanical energy used to remove material from the workpiece is transformed into thermal energy developing heat sources which causes heating of the cutting tool as well as workpiece. The major quantity of thus generated heat goes away with chips, while a minor part is retained within the workpiece and the cutting tool. From the practical aspect, the heat transferred to the tool and workpiece is of special importance. This primarily reflects the machinability of a workpiece, that is, the accuracy of shapes and dimensions, quality of the machined surface and tool wear. The heat sources on the tool are located on the cutting wedge. Knowledge of the temperature fields in chips, workpiece and, before all, the tool makes it possible to adjust better the cooling conditions and therefore to reduce unfavourable influences of thermic actions. Lowering of the temperature in the cutting tool is of special importance for reduction of wear and improvement of accuracy of machining. The phenomenon of heat generation as well as the methods of reducing it have been studied in detail, in an effort to prolong the periods between regrinds and get more metal removal in a shorter period of time. One of the simplest and most widely used method used is to play a jet of cutting fluid at the point on the tool where the cutting is taking place. However, the fluid would be carried away by the outward flowing chip more rapidly than it was drawn between the interstices between the chip and tool by capillary forces. In order to increase the effectiveness, additives are added to the coolants which have negative effects on job, they are even more costly and toxic to humans. The other technique used was to blow carbon dioxide gas on to the tool chip interference, which is also dangerous. In case of increased requirements for the quality of the machined surface high-speed machining is more increasingly used where it is not possible to apply classical means for cooling and lubrication. In such cases dry machining with no cutting fliud is more economical but due to friction between tool and workpiece surface quality decreases. Such conditions of machining increase heating of the cutting tools which leads to its more intensive wear as well.Thermoelectric modules (TEM) in the cooling system in industry find very broad and diversified use. In order to solve the problem of cooling in dry machining the idea has developed to try with application of thermoelectric cooling of cutting tools. The central topic of this paper is theoretical investigation of the possibility of applying thermoelectric cooling of cutting tools. Using the known mathematical, analytical and numerical models in the temperature fields in the tools as a base of simulation model with the assistance of FEM takes into consideration to cool the tool itself by thermoelectric module.
In the present study, modeling and simulation is performed using solid works and ANSYS 2020 R2 software's and obtained temperatures for three different compositions to the tungsten carbide cutting tool doped with B4C and observed satisfied results (algorithm of present study illustrated using flow chart shown in Fig.1).

BACKGROUND LITERATURE
Research investigators have attempted to measure these cutting temperatures with various techniques. The main techniques used to evaluate the temperature during machining (tool chip thermocouple, embedded thermocouple, and thermal radiation method) have been reviewed by Barrow [1]. Machining without the use of any cutting fluid (dry or green machining) is becoming increasingly more popular due to concern regarding the safety of the environment [2]. Interfacial temperatures in machining play a major role in tool wear and can also result in modifications to the properties of the workpiece and tool materials. As there is a general move towards dry machining, for environmental reasons, it is increasingly important to understand how machining temperatures are affected by the process variables involved. Sullivon et al. [3] conducted initial experiments which involves the simultaneous measurement of forces and temperature. These experiments focused on the use of embedded thermocouples (in the workpiece) and using the infrared thermal camera to monitor the process. Accurate and repeatable heat and temperature prediction remains challenging due to the complexity of the contact phenomena in the cutting process. latest work on estimation of heat generation, heat partition and temperature distribution in metal machining is reviewed by N.A.Abukhshim et al. [4]. Patwari et al. [5] provided a concept of using peltier cooling effects during aluminium milling operation has been presented and adopted with an aim to improve surface roughness of the machined surface. Previously numerous authors used different techniques in measurement of temperature exerted during machining and found thermoelectric methods best suitable techniques conventionally [6]. The effect of the cutting temperature is mostly detrimental to both the tool and the job. The major portion of the heat is taken away by the chips. In shear zone, maximum heat is produced because of the plastic deformation of metal, and all of this heat is carried away by the chip. A very small amount of this heat (5-10%) is conducted to work piece. In friction zone, the heat is produced due to friction between moving chip and tool face and slightly due to secondary deformation of the built up edge. In work-tool contact zone, the heat is produced due to friction between tool and workpiece. It should be noted that the maximum temperature occurs slightly away from the cutting edge and not at the cutting edge [10]. McLachlan et al. [7] stated that by selecting an optimum combination of different materials improve the thermoelectric properties. Chakraborty et al. [8] provide detailed information towards the future of carbon-based thermoelectric in their critical review and also discussed on basic design of various thermo electric materials. Darukhanavala [9] discussed in detail about thermo electric cooling methods especially in lathe cutting tool in his text book. 6. Select the top face of the tool flank for sketching; draw an elongated hole with centre distance 90mm and radius of 2.5 mm. Finish the sketch. Click on Extrude Cut from the features tool bar, select the above sketch and make a slot through the tool body. 7. Draw a rectangle on one leg of the above formed tool body at the centre with 2mm width and make a slot through the leg as in STEP 6. 8. Draw a straight line along the centre of the tool body, on the top face and draw a perpendicular line to it at the tool boy and tip interface.Search for Split command in the search bar, select the above perpendicular lines under Trimming Tool selection and the tool body under Bodies to be Split. Click ok. Now we have a Single Point Cutting Tool, split into four bodies in order to accommodate different material properties and also for the voltage input. A single point cutting tool was designed with tool signature of 0-7-6-8-15-16-0.8, in Solidworks2020 is shown in Fig.2. A slot was provided to the shank to accommodate voltage input and the whole shank was split into two sections as to provide different material properties. The reduced strength in the tool can be compensated by using non-metallic bushes in between the slot. The isometric and top views of the tool are shown below. After obtain the solid model of cutting tool with provision for embedding the thermo couples and doping of B4C using solid works software package then the model exported to ANSYS for further analysis.

ANALYSIS OF A PELTIER COOLING ON CUTTING TOOL ANSYS 2020 R2
The cutting tool is represented by a square cross section with rectangular block shape and is modeled as a rigid body. A fine mesh density is defined with an input size of 2 mm. Thermal boundary conditions are defined keeping in view that it will allow heat transfer from work piece to cutting tool. Heat transfer between the work piece and the tool is dependent on the cutting force developed during turning operation. The cutting tool is modeled as a rigid body using 30000 (polygon) elements with 20000 nodes.
Step by step procedure to simulate the study in ANSYS 2020 R2 and depicted the pictorial information in details (micro level) in following figures or diagrams represented with labels from Fig. 3 to Fig. 10 for case -I, Fig. 11 to Fig. 18 for case-II and Fig. 19 to Fig. 24

RESULTS AND DISCUSSIONS
The thermoelectric module (TEM) using Peltier cooling on single point cutting tool tip during turning operation studied by design, modeling using solid works 2020 software package and simulation using ANSYS 2020 R2 version by choosing p-doping with TiC with three levels of compositions studied under this project. The output values generated by feeding the predefined inputs in to the ANSYS and depicted these readings in the Table 1, Table 2 and Table 3. Finally draw the graphs to identify the variation of temperature with voltage. Apart from temperature distribution intensity of heat flux along the cutting tool surface also plotted against the variation of input voltage. From the graphs (shown in Fig. 25 to Fig. 27), it is evident that considerable cooling effect is achieved and found to be the lowest temperature of 10.93°C is observed for doping combination of 0% &25.4% TiC, 18.79°C is observed for 0% & 12.5% TiC and 26.73°C for 12.5% & 25.4% TiC at the junction of the cutting tool of B4C and work piece which is nearer to the cutting tip respectively. The relation between voltages to temperature is found to be almost linear relationship for lower temperature that means cooling. From the graph shown in Fig. 28, it is revealed that the dissipation of heat produced from electricity per unit area along the cutting tool surface with respect to variation in the applied voltage under the Peltier cooling circuit found to be increasing slope by increasing the voltage for 0% to 25.4% TiC. From the graph shown in Fig. 29, it is observed that the dissipation of heat produced from electricity per unit area along the cutting tool surface with respect to variation in the applied voltage under the Peltier cooling circuit found to be increasing slope by increasing the voltage for 0% to12.5% TiC but very small amount of heat flux may be found under this doping composition. From the graph shown in Fig. 30, it is evident that the dissipation of heat produced from electricity per unit area along the cutting tool surface with respect to variation in the applied voltage under the Peltier cooling circuit found to be raised sudden increasing slope beyond the 30 V input voltage for 12.5% to 25.4% TiC combination at the junction of the materials which is nearer to the cutting tip.
Finally it is concluded that one side of cutting tool made by B4C without any doping and other side with 25.4% TiC showed good results which observed by conducting number of simulations at different levels of iterations for B4C cutting tool doped with titanium carbide used in turning operation.

CONCLUSIONS
In this simulation study using ANSYS conducted on dry machining (without any cutting fluids) of turning operation with single point cutting tool connected by thermo couples and cooling effect created to the tool by peltier effect principle and found the following conclusions. 1. Lowest temperature of 10.93°C is observed for 0&25.4% combination of doping at the junction between the workpiece and the cutting tip respectively. 2. The dissipation of heat produced from electricity per unit area along the cutting tool surface with respect to variation in the applied voltage under the Peltier cooling found to be increasing slope by increasing the voltage for 0% & 25.4% combination doping but very small amount of heat flux to be observed in the case of 0% &12.5% doping and it is raised suddenly beyond the 30V voltage as input under 12.5% &25.4% doping which identified from the simulation results.