Result of Reconstruction in Parameter in Covering Shagginess - Research Paper Example

Effects of Change in Parameter in Surface Roughness Student University Abstract This report, tries to illustrate the effect of change in parameters in surface turning and milling used in industries. In this case, the parameters considered were; feed rate, depth of cut and the cutting speed of the spindle. With respect to these parameters, the surface roughness of the instrument was compared at different levels of cutting speed and different cutting nose radii while the other parameters were kept constant. From this experiment conducted under the above conditions, it was found that the surface roughness was indirectly proportional to the cutting speed. In addition that, it was found that the larger the cutting nose radius was the smaller optimum cutting speed. Table of Contents Abstract 2 Used abbreviations 5 Effects of Change in Parameter in Surface Roughness 6 Introduction 6 The purpose of the experiment 7 Required Equipment: 7 Needed materials: 7 Procedure 1 (Turning) 7 Procedure 2 (Milling) 8 Calculations 9 Turning 9 Calculating cutting speed, V, 9 Milling 10 Analysis of Experimental Data 11 Discussion 14 Conclusion 15 References 17 Used abbreviations Effects of Change in Parameter in Surface Roughness Introduction Manufacturing industries need to be relevant in the market. This can be enhanced by the qualities of their products. The surface roughness is one of the most important parameters that influence the market as well as the economy of any manufacturing industry. When the surface roughness of a material is very high, then the frictional force developed when in contact with other instrument(s) is also very high. This is causes a lot of heat energy that results to the wear of the instrument. This interferes with the integrity of the instrument and hence its use can be rendered futile. If this happens then it means that the industry has to undergo some losses as well as resultant poor reputation in the market. It is therefore, necessary to ensure that the best surface roughness is obtained that results to an instrument with effective working conditions as well as improved durability. Surface roughness is influenced by a number of factors that may include the cutting speed that is influenced by the work piece diameter and the spindle speed, the feed rate and the depth of cut. These parameters have different effects on the surface roughness and therefore, it is important to determine the effect of each parameter separately by keeping the other parameters constant. In this case, the effect of the feed rate and the cutting speed parameters on the surface roughness is investigated. The purpose of the experiment Investigating the effects of parameter change in resultant surface roughness was the main purpose of the experiment. Required Equipment: Lathe. Surface roughness comparator. Surface-finish measuring instrument. Two sharp single edge carbide cutting tools with suitable nose radii. Vertical milling machine and sharp face milling cutters. Surface roughness instrument Safety equipment Needed materials: One cylindrical carbon steel work piece material of approx Two blocks of Aluminium alloy approx. Procedure 1 (Turning) a. A low cutting speed of 350 rev/min and a high cutting speed of 1500 rev/min was chosen. b. The equation was applied that relates spindle speed (N) in rev/min to cutting speed (v) in m/min and work piece diameter (Do) in mm. For this task Do is 45 mm. c. A feed, f, of 0.24 mm/rev was chosen. d. The length of the rotational work piece material was divided into four sections, each approximately 50 mm long. e. Using a lathe the following tasks were performed keeping the depth of cut maximum 2 mm: i. The work piece was clamped on the chuck such that two sections on the other end could be machined. ii. Using a cutting tool with sharp nose radius (0.2 mm) section 1 was turned with a low cutting speed. iii. Section 2 was turned with a high cutting speed and the same cutting tool. iv. The work piece was clamped from the other end such that two sections on the other end can be machined. v. A larger cutting tool nose radius (1.2 mm) was used and section 3 turned with the same machining parameters used for section 1. vi. Section 4 was turned with the same machining parameters used for section 2 but with the larger cutting tool nose radius. f. The roughness of each surface machined was measured using the Surface Roughness Measuring Instrument. Procedure 2 (Milling) a. A low cutting speed of 350rev/min and a high cutting speed of 1500 rev/min was chosen on the basis of the available spindle speeds. b. The equation was applied that relates spindle speed (N) in rev/min to cutting speed (v) in m/min and cutter diameter (D) in mm. For this task D is 50 mm. c. Values of the machine’s feed rate were chosen from table d. A vertical milling machine was used to perform the following operations with a small cutting depth (about 2mm) i. Face 1 of block 1 (50X50 mm) was machined using low cutting speed and low feed rate. ii. Face 2 of block 1 (opposite to previously machined face) was machined using low cutting speed and high feed rate. iii. Face 1 of block 2 (50X50 mm) was machined using high cutting speed and low feed rate. iv. Face 2 of block 2 (opposite to previously machined face) was machined using high cutting speed and high feed rate. e. The roughnesses of machined surfaces were measured using the Surface Roughness Measurement Instrument. Calculations Turning Calculating cutting speed, V, For low cutting speed Applying the given equation; Rearranging the above equation; Given; Therefore; For high cutting speed Given; Rearranging the above equation; Given; Therefore; Milling Calculating cutting speed, V, For low cutting speed Applying the given equation; Rearranging the above equation; Given; Therefore; For high cutting speed Given; Rearranging the above equation; Given; Therefore; Table 1: experimental results Nose radius Ra1 Ra2 Ra3 Ra average 0.2 L 3.818 4.016 3.771 3.868 0.2 H 3.772 3.618 3.602 3.664 1.2 L 3.300 3.231 3.432 3.321 1.2 H 1.895 1.935 1.948 1.926 Analysis of Experimental Data To analyze the data obtained during the experiment effectively, a better presentation of the data most especially using line graphs. In coming up with the graphs, the feed rate and the depth of cut had to be kept constant so that only the cutting speed is considered as the only factor affecting the surface roughness. The effect of the size of the cutting tool nose radius was also considered when coming up with the graphs. In that regard, a graph of surface roughness, Ra, against the cutting speed, V, was obtained and the trend of the graph closely monitored. Figure 1;surface roughness ,Ra, against cutting speed ,V, when a small cutting nose radius is used Figure 2; Surface roughness , Ra , against cutting speed when a large cutting nose radius is used Discussion Considering figure 1: The value of the surface roughness increases with increase in cutting speed from point P1 to point P2. The value of the surface roughness then decreases with increase in cutting speed from point P2 to point P3 at almost the same rate as it increases from point P1 to point P2, thereafter, the surface roughness continues to decrease with increase in cutting speed from point P3 to point P4 but at a lower rate. The surface roughness then continues to decrease with increase in cutting speed at varying rates from point P4 trough point P5 to the lowest value of the surface roughness at point P6. In figure 2: Surface roughness decreases with the increase in the cutting speed from point P1 to point P2, the surface roughness then increases from point P2 to point P3 then decreases with increase in speed at a higher rate from point P3 to point P4, the surface roughness then increases at a lower rate from point P4 to point P6. Comparing the results obtained when a small cutting nose radius is used and when a large cutting nose radius is used, it was observed that, lower values of surface roughness are obtained when a large cutting nose radius is used than when a small cutting nose radius is used. In addition, it can be noted that the lowest values of surface roughness are obtained at different cutting speeds. The lowest value of surface roughness in figure 1 is obtained at a cutting speed of whereas the lowest value of surface roughness in figure 2 is obtained when the cutting speed is at 169.5 m/min. Therefore, using a large cutting nose radius will result in obtaining the a better cutting speed to achieve the lowest value of surface roughness. Generally, from the two figures, it can be seen that the surface roughness decreases with the increase in speed until the optimum speed is obtained. However, the changes in the surface roughness values and the cutting speed values are not constant throughout the experiment. Hence great care has to be taken in coming up with the best cutting speed in the manufacturing industry. Conclusion Surface roughness decreases with increase in the cutting speed and the optimum cutting speed obtained when using a small cutting nose radius is higher than that obtained when using a large cutting nose radius. Therefore, it is economical to use a large cutting nose radius in the manufacturing industry to come up with the best value of the cutting speed. The surface roughness of an instrument is very important in determining the efficiency as well as the duration of the instrument. An instrument with a very high surface roughness will have a very high friction when in contact with another instrument. Because of the development of a very high frictional force, the instrument experiences wear on its surface, this renders the instrument obsolete and hence fort never used, this will destroy the reputation of the manufacturing industry and thereafter a lot of losses experienced. Therefore, every industry should develop a mechanism of obtaining the best value of the surface roughness by controlling the cutting speed, the feed rate and the depth of cut. References Destefani J. 1994. Tool tackle tough tasks. ,Todd, Robert H.; Allen, Dell K.; Al ting, Leo (1994), Industrial Press Inc., p. 153 Read More