Imperial Journal of Interdisciplinary Research (IJIR) Vol-2, Issue-9, 2016 ISSN: 2454-1362, http://www.onlinejournal.in

Design & Development of Special Purpose Machine for its Cycle Time Optimization

A. H. Rasal1, Prof. (Dr.) V. R. Naik2 & R. A. Mane3 1M.E. (Mech) P.D.D.student, Textile and Engg. Institute, Ichalkaranji, Kolhapur. 2Head of Mechanical Department, Textile and Engg. Institute, Ichalkaranji, Kolhapur. 3Asst. manager, Paranjape Autocast Pvt, Ltd,,Satara.

Abstract - The growth of Indian manufacturing the experience of the shop floor sector depends largely on its productivity & operators for optimal selection of cutting quality. Productivity depends upon many factors, conditions and tools. Considerable efforts are still one of the major factors being manufacturing in progress on the use of hand book-based efficiency with which the operation /activities are conservative cutting conditions and carried out in the organization. Productivity can be selection at the process planning level [8]. improved by reducing the total time, Sawing is a metal cutting process which combining the operations etc. In case of mass makes use of cutting tools such as band , production where variety of jobs is less and . These tools are used on conventional quantity to be produced is huge, it is very essential sawing machines i.e. a worker holds the job on the to produce the job at a faster rate. This is not machining table and slides it further in the direction possible by using general purpose machines. The of rotating saw and the cutting process takes place. best way to improve the production rate In this paper, the component is a cylinder head (productivity) along wit quality is by use of special made of aluminium alloy (IS designation 4223). It purpose machine. The existing manually operated is cut on a band saw machine. The problems while band saw machine will be replaced with a special using this machine are discussed and solution of a purpose machine. This paper deals with such special purpose machine is presented. development undertaken for similar job under consideration. 2. Component information

1. Introduction Metallurgical specification of the In the special purpose machine, a carbide component: tipped circular saw is used which is stationary, Component under investigation and design while the table on which the component is mounted is having the following material specifications, in the is given a hydraulic feed [1]. Due to the automatic feeding system the total cycle time is Name of the component : Cylinder head (Pulsar decreased. Added benefits include less chance for engine) error, less accumulated tolerance error, and Material : Aluminium alloy (IS designation 4223) eliminate changes in the saw[2]. In such a special purpose machine, the component to be machined is Hardness : 160-180 BHN hydraulically clamped in the fixture on the table. It Mass : 3.8 kg is not possible neither to two or more components on the table; nor use two or more Component: tables in the same machine. Thus, in every Pulsar engine: Cylinder head. movement of the feed, only one component can be clamped in the fixture of such a machine. Next Description: component cannot be loaded before the previous The component is a Cylinder head of part is not finished. Once machining of a part is Bajaj Pulsar & its material is aluminium alloy. It is started it cannot be interrupted. manufactured through the casting process. The The customer demands the product of Cylinder head has a gate / riser, which is to be cut- right quality, right quantity, right cost, & at right off. The total thickness of the material to cut is time. Therefore it is necessary to improve about 110 mm. productivity as well as quality. One way to achieve this is by using special purpose machine [3]. The Gate thickness specification: As the Cylinder manufacturing industries depend on the skill and head is manufactured through the casting process,

Imperial Journal of Interdisciplinary Research (IJIR) Page 1659 Imperial Journal of Interdisciplinary Research (IJIR) Vol-2, Issue-9, 2016 ISSN: 2454-1362, http://www.onlinejournal.in the thickness of material to cut can vary upto a few mm. Thickness of the material to cut: 110 mm.

Need: A skilled labour is required for removal of gate, as it is important that, during the cutting of extra material the edge of combustion chamber is not damage. Thus, it is a very intricate and precision work[5]. During the process, the worker has to repeat several cuts of lesser dimensions. This repeatability of cuts increases the cycle time of the process, for a single engine. Also as the number of cuts goes on increasing, the material of the tool, i.e. the band saw gets worn out. This decreases the rate of productivity of band saw. This causes the frequent change of the band saw. Thus it involves additional capital investment Fig. 2: The component. in tooling [4]. 4. Compilation of data of machining When the cutting of gate is in progress, there is time of sawing a possibility of change in the angle of blade. This The data for 30 components under taken causes the bending of the blade and eventually its from machining cycle time inspection on band saw breakage & also there is a possibility of damage to machine, the data found as the engine. follows: All these problems of the process are required MACHINING CYCLE TIME to be eliminated. 1.28 3. Working process & component 1.26 1.24 images 1.22 WORKER 01 WORKER 02 1.2 WORKER 03 1.18 1.16 MACHINING TIME (MIN.) 1.14 1 2 3 4 5 6 7 8 9 10 WORKPIECE NUMBER

Fig. 3: Graphical representation of machining time of the workers.

5. Problems identified by using conventional machine:

The gate cutting is done by conventional band saw machines the difficulties noticed are as, Fig. 1: The manual cutting process of gate of the component. Manual handling of the component results in excess idle time: The process of gate cutting is done by the worker, on a conventional band saw machine. During the cutting process, the worker has to adjust the cut properly, in case the cut is not correctly positioned, the idle time increases.

Band saw & the component requires more setting time : The conventional band saw machine consists of a vertically mounted band saw. This band saw requires accurate tensioning to avoid its

Imperial Journal of Interdisciplinary Research (IJIR) Page 1660 Imperial Journal of Interdisciplinary Research (IJIR) Vol-2, Issue-9, 2016 ISSN: 2454-1362, http://www.onlinejournal.in breakage, thus it requires to be set by tightening at the end screws, at specific intervals. The component is adjusted at regular intervals so as to avoid any damage to the component.

Need of skilled labour & : The process of cutting the gate on the conventional band saw machine is very intricate process. The band saw rotates at a very high speed; the worker has to be very careful while cutting the gate. Thus there is a need of skilled labour which increases the labour wages. If unskilled labour is employed, the surface finish achieved is poor, thus affecting the quality of the component.

Bending of the blade and its breakage: The cutting of the gate is done using a band saw, mounted on the pulleys. Initially the Fig. 4: Conceptual model of the special purpose positioning of band saw is a time consuming machine. process. While cutting the gate, there is a The machine structure is a sheet metal possibility of change in the angle of blade. This work and has rigid supports of M.S. bars as causes the bending of the blade and eventually its well as cross stiffening ribs to ensure adequate breakage. This involves additional capital rigidity and strength. Inside it are housed the investment in toolings & also it is hazardous to the various mechanisms as the carbide tipped circular [7] worker working on the machine. saw , workpeice carriage, speed gear box, electric motor, belt and pulley drive unit, pipes and hoses. Damage to the engine: The workpeice carriage moves to and fro on the The performance of engine depends on the guideways located at the bottom of the slide. accuracy with which it is manufactured. The Hydraulic clamping is used for clamping the bending of the blade might cause inaccuracy in the workpiece rigidly to sustain the cutting forces. part geometry of the engine, thus hampering its Proximity sensors are used to define the distance performance [6]. The surface finish achieved is of travelled by the workpeice carriage. Screw poor quality. This also leads in the increase in the conveyor is used to remove the chips developed rejection quantity of engines. through the sawing process. The hydraulic system consists of a Less productivity: hydraulic power pack which consists of a reservoir Due to the increase in the idle time the tank with fluid stored in it. A FRL unit is used rate of production is affected. Productivity also proper filtration, regulation and lubrication of the decreases, as the setting time required for the fluid throughout the system. The fluid is circulated component & saw is large. In the component, the through the system by a pump associated with the thickness of the material to cut is about 110 mm. At motor. Direction control valve is used to direct the present the cycle time required is about 1.22 min / fluid flow in appropriate direction. The flow rate component. Thus the target completion within the and pressure of fluid is controlled through the flow specified time is not achieved. and pressure control valve. Actuators are used to 6. Solution: conceptual model achieve the linear motion. Coolant is continuously sprayed on the saw and workpeice interface. Taking into considerations the mentioned The hydraulic circuit is designed and problems regarding sawing on the conventional developed in such a way that, first when the worker band saw machine, the solution for this is to design positions the workpeiece on the central locator; the and develop a special purpose machine. A side clamps are activated and hold the workpiece conceptual design is hereby presented along with sideways. Next the top clamp is activated and it its working description [5]. holds the workpiece from the top side. Then the

worker operates the workpiece carriage which is given a faster motion till the approach of the cutter, then after it moves at a defined slower feed and it is kept constant throughout the length of the cut. After the sawing process, workpiece carriage returns to its original position at a faster speed. Thus the total manufacturing cycle time is reduced.

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The performance testing of machine will F = 34.64 N be conducted by manufacturing a number of products and quality specifications will be verified Calculation of cutting forces , with respect to the required standards [8]. The cutting force has three components, PX : Axial force 7. Basic calculations required to drive PY : Radial force the circular saw PZ : Tangential force Therefore, the resultant cutting force, Assuming the following data, R = K - Material Factor = 0.55 Determining tangential force, P = Z- Number Of Cutting Teeth In Contact Of Job Z = 4 = V - Cutting Speed [m/min] = 450 m/min PZ = 480.2 N A - Depth Of Cut [mm] [Below 1.5mm] = 1.4mm Determining axial force, PX = 0.15 to 0.25 PZ S – Feed [mm] [For HSS & Carbide Tipped Tool] Assuming mean value as, 0.20, = 0.12mm PX = 0.20 PZ = β - Machining Exponent = 0.940 PX = 96.05 N Determining radial force, D1 - Max. Diameter Of Cutter = 350 mm PY = 0.45 to 0.55 PZ N - Number Of Revolutions Per Min. = 1158 Assuming mean value as, 0.40, PY = 0.40 PZ Power = P = = PY = 192.08 N = Therefore, the resultant cutting force, R = = =

= R = 526.03 N = Thus, the cutting force required is 526.03 N. P = 3.6 KW 8. Conclusion = According to the conceptual model, the special purpose machine is to be designed and = 4.93 HP developed. This will result in increasing the productivity of the machine as compared to the P = 5 HP present manually operated band saw machine. Another benefit of this machine will be reduced Feed Force = F = manufacturing cost per component.

9. References P - Power [KW] = 3.6 KW [1] Vincent . R. Gingery & David. J. Gingery, D-Diameter of circular saw [mm]= 350 ‘Build a metal cutting band saw.’ David. J. Gingery mm Publishing, Vol. 1, 1995, pg. - 33, 65, 88, 109, 120, 161, 163. N-Number of revolutions circular saw [2] Tilen Thaler, Ivan Bric, Rudi Bric, Primoz [rpm] = 1158 rpm Potocnik, Peter Muzic, Edvard Govekar, ‘Characterization of band sawing based on cutting forces’, Journal of Machine F = Engineering, Vol. 12, No. 1, 2012, pg. - 41-50. [3] John Allen, Dragos Axinte, Paul Roberts, Ralph = Anderson, ‘ A review of recent developments in the design of special purpose machine tools.’, The

Imperial Journal of Interdisciplinary Research (IJIR) Page 1662 Imperial Journal of Interdisciplinary Research (IJIR) Vol-2, Issue-9, 2016 ISSN: 2454-1362, http://www.onlinejournal.in international journal of Advanced Manufacturing Technology, 2010, Vol. 50, pg. - 841 - 857. [4] Aitzol Lamikiz, L. Norbeto Lopez de Lacalle & Ainhoa Celaya, ‘ Machine tool performance and precision.’, Machine tool for high performance machining, 2009, pg.- 219 – 260. [5] Dehong Huo, Kai Cheng & Frank Wardle, ‘Design of precision machines.’, Machining dynamics, Springer series in Advanced Manufacturing, 2009, pg. - 283 – 321. [6] K. Martisen & G. Ringen, ‘ Formation Avoidance for Robust Circular Blade Sawing of Thin Walled Extruded Aluminium Profiles.’, Burr’s Analysis, Control & Removal, 2010, part 1, pg. – 21 – 28. [7] Kristina Ukvalbergienė, Jonas Vobolis, Antanas Baltrušaitis, ‘Impact of Circular Surface Hardness and Thickness on Coefficient of Damping’, ISSN 1392–1320 Materials Science, Vol. 12, No. 2. 2006, pg. - 129 – 133. [8] Rex Miller, Mark Richard Miller, ‘Audel Tools Processes’, Wiley Publishing Inc., Fifth Edition (2004), pg.- 1–25.

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