32 Preparation of cutting tools and work piece321 WorkpieceAISI 12L

3.2 Preparation of cutting tools and work piece

3.2.1 Workpiece

AISI 12L 14 free cutting steel was used as the workpiece for the turning process in this experiment. The chemical composition for the AISI 12L 14 are stated in Table 3.1.

Table 3.1: Chemical composition for AISI 12L14

Free cutting steel Chemical Composition

C Mn P S Pb

AISI 12L 14 0.15 0.85-1.15 0.04-0.09 0.26-0.35 0.15-0.35

AISI 12L 14 will be in the form of bar with the dimension of 2500m length and 50mm diameter. The bar will be machined and cut with the length of 230mm and 30mm diameter in order to ease the process for turning operation especially on the space of the lathe machine to locate the workpiece.

The dimension of the machined AISI 12L 14 are stated in the figure below

Figure 3.1: The drawing of 3D and 2D with dimension of the machined AISI 12L14 for testing.

3.2.2 Cutting Tool

Tungsten Carbide is selected as the main material for the cutting tools. The cutting tools will be brought and then shaped based on the selected geometry design which is called dual point cutting tool.

The brand new geometry design will be used for this experiment and the geometry parameter are stated inside the Table 3.2.

Table 3.2: The geometric parameter of the cutting tools.

First major cutting angle (Kr1-1°) First minor tool cutting edge angle (Kr2-1°) Second major cutting angle (Kr2-2°) First minor tool cutting edge angle (Kr2-2°) Rake angle (°) Inclination angle (°)

90 3 60 +10 10 3

Front view of new developed tool geometry

Side view of new developed tool geometry (Rake angle: 10°)

Cross section of tool geometry (Inclination angle: 3°)

Figure 3.2: Cutting tools geometry from different angle.

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For this experiment, Physical Vapor Deposition (PVD) coating technique are selected and used to for the coating. Then 3 types of multilayer coated cutting tools are used as a test on the workpiece. The outer resistance layer of the cutting tools will be coated with the different type of materials which is Titanium Nitrate (TiN) Coating, Titanium Carbonitride (TiCN) Coating, Titanium-aluminium-nitride coating (TiAIN) Coating and Sulphur Chromium Nitrade (S-CrN). While at the intermediate layer, same material will be used which is Nitrogen (N) and finally the layer of coating thickness for the outer layer, intermediate and adhesive sub layer are set to 2?m, 3?m and 5?m.

Figure 3.3: Schematic structure of 3 multilayer cutting tool.

3.4 Mechanical Testing

3.4.1 Surface Roughness Measurement

To measure the surface roughness on the workpiece AISI 12L 14, Mitutoyo Surftest SV-400 portable tester are selected and used with the dimension of 0.8mm cut off length and 4.0mm cut off length. The tip of the portable tester will be placed on 6 locations and the mean is calculated from the results.

. Figure 3.4: Mitutoyo Surftest SV-400 portable tester.

3.4.2 Tool Wear Measurement

To measure the tool wear after the machining process, the optical microscope which is Olympus BX51M is used. The test is focused on the flank wear on the workpiece. Then the surface of the workpiece will be monitored and observed by using the optical microscope at 5x and 10x magnification. The Figure X is the set-up of the Olympus BX51M optical microscope.

Figure 3.5: Olympus BX51M optical microscope

The results from the optical microscope will be saved and analyzed. 4 reading will be taken from the workpiece and it will be from different position of the flank wear. Finally the average value will be recorded.

3.4.3 Cutting Force Measurement

To measure the cutting force on the workpiece, a 9257B model Kistler dynamometer is used. The dynamometer is linked with and 5011B type amplifier along with the data acquisition system. The dynamometer are also attached with the mechanical sensing unit or tool holder. Once the data are obtained from the cutting forced, it will be analyzed by tool breakage system which are collected from the different cutting force by a three-dimensional force dynamometer. The Figure X show the 9257B model Kistler dynamometer.

Figure 3.6: 9257B model Kistler dynamometer

3.5 Blank Data Sheet

The data sheet will be filled in order to collect the data from the software or manual when experiment is conducted.

3.5.1 Surface Roughness

Table 3.3: Blank Data Sheet for Surface Roughness

Type of Cutting Tool Feed rate (mm/rev) Cutting Speed (m/min) Cutting depth (mm) Surface roughness (Ra) S/N Ratio

Ti-CN/Ti

0.15 253 1.15

Ti-CN/C 0.15 253 1.15

Ti-CN/N 0.15 253 1.15

3.5.2 Tool Wear

Table 3.4: Blank Data Sheet Tool Wear

Type of Cutting Tool Reading Of Flank Wear From Different Position

Reading 1 Reading 2 Reading 3 Reading 4 Average Reading

Ti-CN/Ti

Ti-CN/C

Ti-CN/N

3.5.3 Cutting Force

Type Of Cutting Tool Feed Rate (Mm/Rev) Cutting Speed (M/Min) Cutting Depth (Mm) Diameter (Mm) Cutting Force

Tangential Cutting Force (Fx), Radial Force (Fy) Feed Force (Fz)

Ti-CN/Ti 0.15 253 1.15

Ti-CN/C 0.15 253 1.15

Ti-CN/N 0.15 253 1.15

Table 3.5: Blank Data Sheet for Cutting Force

3.6 Expected result

From the experiment, the estimated results should be achieved once the experiment is conducted. The data are collected from the surface toughness test, tool wear and cutting force for 4 different multilayer cutting tools based on the new cutting tools design. Once the data has been collected and achieved, it will be analysed and compared with the cutting tool in order to see the performance of turning process when outer resistance layer is changed with the various type of coating materials.