DESIGN OF ADAPTIVE MULTI TOOL ARBOR ATTACHMENT

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1 INTERNATIONAL JOURNAL OF MECHANICAL ENGINEERING AND TECHNOLOGY (IJMET) International Journal of Mechanical Engineering and Technology (IJMET), ISSN (Print), ISSN (Print) ISSN (Online) Volume 6, Issue 2, February (2015), pp IAEME: Journal Impact Factor (2015): (Calculated by GISI) IJMET I A E M E DESIGN OF ADAPTIVE MULTI TOOL ARBOR ATTACHMENT G. Elanchelian 1, A. Ram Kumar 2, G. Ranjeeth Kumar 3, S. Ravutha Kumar 4 1,2,3,4 Final Year, bachelor of Mechanical Engineering, Rathinam Institute of Technology, Coimbatore, Tamilnadu ABSTRACT Machining time plays a pivotal role in the field of manufacturing. Thus increasing the size and shape of the machining tool, will no longer provides solution to meet today's demand. However, CNC helps to meet desired function but not suitable for many small scale industries which serves as a backbone of our country. Our aim is to reduce machining time by providing multiple tool (spindle) to the arbor with a subordinate view of making tools adaptable longitudinally. The longitudinal adaptation is achieved by mating gears (empiricallyscrew rod (worm) & spur gears) which is elucidated below. INTRODUCTION The Main function of this project is to reduce machining time and provide assistance to productivity. By incorporating adaptive multiple arbor tool attachment, we can minimize the machining time in the conventional setup. Imagine that a product should undergo surface finishing to eliminate rough surface on it. The end face milling tool is used in the industry to achieve this process. This process can be automated easily with the help of computer numerical control (CNC), but in case of small scale industries it is difficult to accommodate CNC where it has little scope for its survival. So these types of business firms use conventional milling machine to achieve this process (surface finish). 137

2 The main drawback of conventional milling machine is machining time & Accuracy when compared to Automated milling machine. When it comes to mass production of multiple parts then Machining time plays a very important role in the field of manufacturing. TOOL ATTACHMENT DESCRIPTIONS The tool works similar to that of holding a chuck in lathe. It consists of a circular bearing at the base to hold other peripherals together along with the ring gear coupled with two bevel gears to promote longitudinal variation. The bevel gear is in turn attached to common lead screw through which, the position of the blocks can be adjusted. On the other side it consists of a driving spur gear being mated with the already mated screw rod (worm) (screw rod) through which the two driven spur gears receives power. The brief description of major components were explained below: 1. UPPER ASSEMBLY Unlike the base assembly, the upper assembly consists a driving gear (spur) and an intermediate screw rod(worm) with the connecting shaft. This upper assembly ensures power from the prime mover to the destination. Spur gear (driver): The spur gear is made out of hardened mild steel. This gear enables power from the source to destination and it is also allowed to contact the intermediate gear for power transmission. 138

3 Screw rod-worm (intermediate): This gear, serves the purpose for contacting multiple gears. Screw rod(worm) gear is made up of high carbon steel to withstand high compressive stress and vibration during machining. The screw rod (worm) gear ensures power transmission between driver & driven gears respectively. Connecting shafts: The connecting shafts is a connecting member which provides link between the prime mover and driving gear (or) provides link between driven gear and cutting edge. These shaft are mainly made up of hardened mild steel to have high tensile strength. 2. BLOCK The housing block is a protecting structure made up of delegate Cast Iron. The main function of this housing block is to provide security to the peripherals and to avoid the external factors affecting the efficiency of the tool geometry. The major exertion of this block is that it acts as a provision between adjustment member and power transmission. 3. BASE ASSEMBLY As described above, the base assembly holds Bearing, Ring gear, Bevel gear, Lead screw & 2 Spur gears (driven). The base is made robust to withstand vibration and heat produced during machining. This is also provisioned to screw the upper block and provide a housing to enclose them. 139

4 The base assembly is together made of Cast iron and mild steel i.e., gears were made out of hardened MS, whereas in bearing and lead screw stainless steel and hardened mild steel is used as their materials. Thus base assembly forms backbone of the attachment as it delivers rigid support to the product. Bearing: The bearing is a basic structure to accommodate other peripherals of the attachments. It is made up of stainless steel due to its high compressive strength (due to its complex structure). The main function of the bearing is to provide necessary rigidity to the attachments and hold the selfweight of the product. In addition to this, it also holds the weight of the tool. As shown in the figure, the circular bearing ensures compactness and adds some aesthetic value to the machine. Ring gear (Plain Spur Gear): These are a cluster of gear tooth found near the circular frame of the upper assembly, which is used to drive pair of bevel gears simultaneously. This function makes it more ponderous in adjusting the tool attachment to the product. The ring gear is powered by the lead screw through an intermediate gear known as bevel gear. Bevel gear: These are a pair of mating gears which is used to transmit power between perpendicular axes. This gear is made of Mild steel material to minimize undercutting and slip. This bevel gear provides necessary assistance in adjusting the length of the cutting tool. 140

5 Lead screw: This is a type of cylindrical screw, threaded (square) without head. This enables the user to initiate power between bevel & ring gear. The lead screw is made out of carbon steel due to its high yield strength and ductility. It serves as human-machine interface to do the work. Spur gears (driven): These gears are driven by intermediate screw rod (worm) gear and highly influence the revolution of cutting edge. These spur gears are made of high carbon steel due to its improved hardness and ductility. These spur gears makes direct physical contact with the chuck of the cutting tool. TYPES OF MECHANISMS There are two types of mechanisms are used to adjust the position of the cutting tool they are Self-centering mechanism Variable positioning mechanism WORKING MECHANISM The working of Adaptive multiple tool arbor attachment is based on two mechanism they are (a) Power transmission (b) Linear tool variation. These two mechanism makes this project a complete product. Power transmission: Power developed in the prime mover is transferred to the driving gear, which in turn drives the intermediate screw rod (worm) gear to deliver its power across the multiple spur gear (driven). Linear tool variation: The linear distance between the multiple tools can be varied using the lead screw head. By adjusting the lead screw, it actuates the ring gear coupled with the bevel gears. The bevel gear at both the ends of the ring gear rotates simultaneously that tends to rotate the lead screw which tends to adjust the position of the block subsequently leading to linear variation of the tool. 141

6 SELF-CENTERING MECHANISM 142

7 VARIABLE POSITIONING MECHANISM 143

8 THEORETICAL CALCULATIONS A face milling cutter of 150 mm diameter is used to give a cut on a block 500mm*500mm. The cutting speed is 50 m/main and feed 0.2mm/revolution. Calculate the time required to complete one cut (1) Conventional model. (2) Multiple arbor model. CONVENTIONAL MODEL Tool diameter, (D) =150mm Block Size =500*500mm Cutting speed, (S) =50m/min Feed rate, (F) =0.2mm/rev SOLUTION N = 1000*S/πD = 1000*50/ (π*150) = 106.1rpm Length of the Job, (L) = 500mm Width of the Job, (W) = 500mm Since D < W Approach = 0.50D = 0.5*150=75mm Over travel = 7mm Added Table Travel = Approach + Over travel = 75+7 = 82mm Milling Time/Cut = {Length of the Job + Added table travel} / {(Feed/rev) * rpm} = / (0.2*106.1) = 27.43min MULTIPLE ARBOR MODEL N is similar to conventional, without change in the speed. Length of the job (L) = 500mm Width of the job (W) = 500mm Tool diameter (D) = d + d = 150*2 = 300mm Since, D<W Approach = 0.50D = 0.5*300 = 150mm Over travel = 4mm Added table travel = Approach + Over travel = 154mm Milling Time/Cut = 15.40min = {Length of the Job + Added table travel}/ {2*(Feed/rev) * rpm} = / (2*0.2*106.1) 144

9 Advantage of time over conventional model = Milling Time/Cut (Conventional) - Milling Time/Cut (Improved) = = 12.03min CONCLUSION The Design and fabrication of this adaptive multiple arbor tool attachment is highly flexible and advantageous because of the way of usage of tool. Rather than using a single tool for machining process, this utilizes multiple tool usage at the same time, which in turn increases the productivity, by minimizing machining time. The machining operations such as milling, slotting, drilling, boring, taping and inner thread cutting, those are carried out by modern CNC machines, can be achieved by this attachment. This project concentrates in the usage of 3tools for a machining process simultaneously. The range of operation of this attachment can be further increased in future by using more than 3tools, by implementing the same mechanism. REFERENCES 1. PSG Design Data Book of Engineers, PSG College of Technology, Coimbatore, India. 2. ITM Cutting Tools Catalogue, India. 3. Machine Design, D. K. Agarwal, 10th edn, S. K. Kataria & Sons, Delhi. 4. Mechanical Engineering Design, Shigley, 8th edn., McGraw-Hill. 5. Aquasub engineering pvt ltd, Coimbatore 6. Subasri engineering works, Coimbatore 7. M. Narasimha, R. Reji Kumar, R. Srinivasa Moorthy Design of adjustable multi-spindle attachment, international journal of industrial engineering Research and development (ijierd), Volume 4, issue 2, May - august (2013), pp , ISSN (print), ISSN (online). 8. Jayakrishnan J and Suraj R., Effect of Roller Burnishing Process on Tool Steel Material Using CNC Lathe, International Journal of Design and Manufacturing Technology (IJDMT), Volume 5, Issue 3, 2014, pp , ISSN Print: , ISSN Online: Patel C H, Mohan Kumar G C, Vishwas Puttige, Low Cost Automation For CNC Machining Center International Journal of Mechanical Engineering & Technology (IJMET), Volume 3, Issue 2, 2012, pp , ISSN Print: , ISSN Online: Prof. (Dr). Rachayya.R.Arakerimath and Prof (Dr).V.A.Raikar, Productivity Improvement By Sa and Ga Based Multi-Objective Optimization In CNC Machining International Journal of Mechanical Engineering & Technology (IJMET), Volume 3, Issue 1, 2012, pp , ISSN Print: , ISSN Online: