Design And Simulation Of Dpm & Ergonomic Analysis In Automated Deburring Section [1]

Transcription

1 Design And Simulation Of Dpm & Ergonomic Analysis In Automated Deburring Section [1] Sreebalajinarayanan R, [2] Azhagar S, [3] Ashok Nandah R, [4] Gowtham Kumar R, [5] Mr.Vinoth Kumar P [1] Student, B.E(Mechatronics), [2] Student, B.E(Mechatronics), [3] Student, B.E(Mechatronics), [4] Student, B.E(Mechatronics), [5] Asst. Prof., B.E(Mechatronics) [1][2][3][4][5] Chennai Institute of Technology Abstract Digital Process Manufacturing (DPM) is applied in this virtual proposal to verify the viability of conversion of manual deburring process to automatic, using articulated robots. As an advanced stage, simulation technology is applied in the DPM concept to enhance the accuracy and precision in the deburring process also the errors and rejection of the component could be reduced. Currently the work is being carried out manually in the existing deburring section of the industry, which involves high human labor, high human body Musculoskeletal Disorders (MSD) and also results in routine economic investments. Postural analysis tool using Rapid Upper Limb Assessment (RULA) is applied for assessment which indicates that the workers are working within the secure limit of the MSD. So, by automating this section using robots, the high human labor is reduced and also the virtual ergonomic analysis carried out in software reduces the human MSD and direct implementation economy wastage.. Index Terms Anthropometry, CATIA, DELMIA, DPM, MSD, Postural Analysis, RULA I. INTRODUCTION For productivity improvement in manufacturing industries, industrial automation and efficiency of worker plays an important role. Initially the purpose of automation was to increase productivity, since automated systems can work uninterrupted for 24 hours a day, and to reduce the cost associated with human operators (i.e. wages & benefits). However, in this project the focus of automation is extended to increasing quality and flexibility in deburring process. Productivity of worker greatly depends upon ergonomic design of workstation. Efficient ergonomics in workstation design shows better interaction between man-machine systems. Lot of research has been done on analyzing, implementing automation solution, improving ergonomics of workstation, facility layout and tool & fixture design. Workstation may function with less efficiency, if anthropometry data mismatches with workstation design. Effect of workstation design, process design, fixture design and working postures on operation shows industrial automation have most significant effect on the deburring process. Study of discomfort experienced by operators during process has been studied and analysis of working postures has been done in DELMIA V5 software to find out awkward postures. The study is conducted on existing manual deburring operation cell which has large human labour and high cycle time. Objective of this study includes performance evaluation of workers during deburring process. In primary phase study regarding workstation layout, process design been carried out. Further motion study is done for the articulated robot and human ergonomic study by capturing motion film of automated deburring process in DELMIA software itself. Robot motion for each position of the robot was analyzed for each element of the robot axes. Human simulation was analyzed for each motion element of worker s body postures and movement of other body members. Results of human simulation revealed various fatigue causing and time consuming factors related to worker and workstation layout. II. LITERATURE REVIEW A. Digital Process Manufacturing A series of research works have already been done on the DPM process, the available literature reveals that DPM is the use of an integrated, computer-based system comprised of simulation, three-dimensional (3D) visualization, analytics and various collaboration tools to create product and manufacturing process definitions simultaneously. Many of the long-term benefits from product lifecycle management (PLM) cannot be achieved without a comprehensive digital manufacturing strategy. Wolfgang Kühn proposed a work on Digital Factory Simulation Enhancing the Product and Production Engineering Process which emphasizes that the digital factory concept offers an integrated approach to enhance the product and production engineering processes and simulation is a key technology within this concept. Different types of simulation, such as discrete event or 3Dmotion simulation can be applied in virtual models on various planning levels and stages to improve the product and process planning on all levels. The focus and key factor is the integration of the various planning and simulation processes. In an advanced stage simulation technology can be applied in the digital factory concept to enhance the operative production planning and control as an integrated process from the top level to the factory floor control. B. Ergonomic Analysis Based on the work of Mr. Gurunath V Shinde Ergonomics plays an important role in workers productivity. Workstation layout and work design are two major factors of ergonomics of worker s efficiency. Now, manufacturers found that instead of investing lots of money on man, machine, material, method (4m), improving ergonomics of workplaces is cost saving. Ergonomics found great need when market demand is high and manufacturers need more output within short period. His study was conducted on assembly workstation of welding shop. Ergonomic study of ISSN: Page 22

2 this assembly workstation was done by using motion study. Observations were made by studying each element of motion film recorded by video recorder. Results from this study reveal that there is need to modify workstation layout according to ergonomic principles. C. Anthropometric Dimensions The anthropometric dimensions of the Indian Man were inculcated from the work of Chakrabarti, D.,1997: Indian Anthropometric Dimensions for Ergonomic Design Practice which focuses that the compiled data (with relevant descriptions of population) forms in the sequence of illustrative anthropometric terminology and illustrative measurement land marks, brief of dimensions! measurements descriptions with the respective measurement and the data table. Dimensional reference numbers as 'R. No.' landmarks) are presented herewith as INDIAN shown in illustrations and referred both in definitions and in ANTHROPOMETRIC DIMENSIONS separately for data tables simultaneously. All dimensions (except body Males, Females and Combined (males and females weight in Kg) are in millimeters (mm). both considering a single study D. Rapid Upper Limb Assessment The ergonomic analysis is based on the working postures of the human in the shop floor. The analysis method used is RULA analysis since in this proposed work the man works with a maximum stress in his upper body portion with the mid line on his arms. Hence the work Ergonomic Evaluation of Industrial Tasks in Indian Electronics Industries proposed by Tarwinder Singh is added as a reference for the analysis which states that Rapid Upper Limb Assessment (RULA) is used for ergonomic investigations of workplaces where work related injuries are reported. RULA is a simple diagnostic tool that allows surveying various tasks involving the upper limbs at workplace with focuses on use of arms, wrists, position of the head and the posture of the upper body. Mc Atamney and Corlett (1993) introduce RULA, or Rapid Upper Limb Assessment. It is developed to observe the operators who suffered upper limb disorders due to the musculoskeletal loading. The RULA is used without need for advanced and expensive equipment that s why it is one of the most popular ergonomic investigation tools in industry. E. Fixture Design The fixture required for this proposed work was designed with reference to the work done by Dr.Yadavalli Basavaraj in Modeling and Analysis of Support Pin for Brake Spider Fixture by Fem Using Ansys Software in which he states that A fixture is designed and built to hold, support and locate every component to ensure that each is drilled or machined with accuracy and manufactured individually. A fixture can be designed for a particular job. A brake spider includes a spider body with a central opening and a slot for receiving a camshaft and bracket assembly. The brake spider is attached to axle housing via the central opening. The form to be used depends on the shape and requirement of the work piece to be machined. In the existing fixture, used for modeling brake spider component, only five components were machined per hour. In the present work, detailed study of brake spider component is carried out and design is modified to increase the productivity. The new fixture design is carried out by using CATIA V5 modeling software and it is critically evaluated for the failure of support pin component, by finite element method (FEM) using ANSYS software. This modified design is adapted in the fabrication of fixture and is tested for its productivity. It is found that there is a considerable enhancement in the productivity to seven components per hour with required accuracy F. Industrial Automation The design and analysis approach of the articulated robots in the DPM simulation is done with reference to the base work of S.Pachaiyappan in the field of Design And Analysis Of An Articulated Robot Arm For Various Industrial Applications. His work is based on design & analysis of a Generic articulated robot Arm. Articulated robot has been noted for application in traversing and performing manipulation in nuclear reactor facilities. Some aspects of the articulated Robot that are anticipated as useful are its small cross section and its projected ability to change elevation and maneuver over obstacle. The small cross section and the loads associated with suspension of the Robot while changing elevation or maneuvering over obstacles require large joint torque to weight rations for joint actuation. A novel joint actions actuation scheme is described and its implementation detailed in this project. III. EXISTING SYSTEM Work cell area : 875m 2 No. of human labours : 8 per shift No. of work shifts : 3 per day Total working labor : 24 per day Component to deburr : Royal Enfield 500CC Flywheel. Weight of component : 3.7Kg Existing RULA score : 8 Existing Job Hazard Score : 64 Tool used : Hand File Tool Life : 7 10 Days Timing cycle : seconds per component Errors : Scratches, cracks, improper Deburr, job rejection. B. Methodology The following is the procedure used in the Ergonomic analysis of the existing work cell. The existing work cell was measured for the area availability. The human posture of the existing work cell for a single human during the process was captured using Digital camera. The ergonomic RULA score was analyzed for the existing work cell. The Job hazard score of the existing cell was calculated manually using a formulated excel sheet which is explained in the further sections. IV. PROPOSED WORK METHODOLOGY A. Process Flow The process flow of the proposed work is as follows, 1. DPM Simulation ISSN: Page 23

3 2. Ergonomic Simulation B. DPM Simulation The available area for the automation layout was measured manually from the existing work cell. Then the virtual work environment was developed with the robotic work cell environment using CATIA V5R20 Software. All robotic safety accessories such as fence, controller, pedestal, Fork lift layout base were modeled in 3D using CATIA V5R20 Software. Fig. 1 Process flow of the DPM & Ergonomic analysis The work table, the pneumatic actuator, the fixture, the component under consideration were created virtually using CATIA V5R20 Software. The Kawasaki RS10N robot, Kawasaki E01 robot controller used in this application were also created using CATIA V5R20 Software. Then the layout was simulated virtually in DELMIA V5R20 Software to determine the following reasons, a) To ensure the incorporation of the all the necessary robotic safety equipment s. b) To determine the reach envelope and the accessible area of the robot with in the work cell. c) To identify the working viability of the cell. d) To determine the timing cycle for the operation. e) To exhibit virtually developed automated deburring work cell. C. Ergonomic Analysis The main tool used for the Human ergonomic analysis was DELMIA V5R20. There 4 main modules in this software as follows, that are used to perform ergonomic analysis. a) Human Measurements Editor b) Human Task Simulation c) Human Activity Analysis d) Human Posture Analysis In this proposed work, the ergonomic analysis is performed on 50 th percentile male of Indian Anthropometric Dimensions. The manikin is created in the Human Measurements Editor module and the dimensions are modified to Indian Anthropometry. Then the manikin is simulated for his activity such as pick, place, walk, climb up & climb down stairs in the Human Activity Analysis module. This created human activity are then merged with human postures like bending, twisting, stretching, etc., in Human Postural Analysis module. Finally, the created human activity and the postures are simulated in the Human Task Simulation module for the identification of the following, a) RULA Score of each posture of manikin b) Reach Envelope analysis of the manikin c) Job Hazard Score analysis of the manikin. Fig. 3 Rendered view of the Ergonomic simulation layout V. RULA SCORE CALCULATION The RULA Score, Reach Envelope analysis and the Vision analysis of the manikin was performed in this proposed work cell using the DELMIA V5R20 Software. B. RULA Analysis Fig. 2 Rendered view of the DPM simulation layout Fig. 4 Rula Score for PICK operation. ISSN: Page 24

4 binocular vision is used to avoid the obstacles in the work envelope. Fig. 5 RULA Score for PLACE operation Fig. 8 Vision Analysis VI. JOB HAZARD SCORE CALCULATION Fig. 6 DELMIA V5 RULA Score Window C. Reach Envelope Analysis In this analysis, the manikin is analyzed for his distance of access from his position to the component and accessories in the layout. The aspects like easy reach, reach path with no obstacles are the main consideration. The Job Hazard Score was calculated for both the existing and the proposed cell using the below procedures. B. Procedure 1. First step is to calculate the Transfer brief score of the human labor for different parts of the body such as, a) Left & Right hand b) Left & Right wrist c) Left & Right Elbow d) Left & Right Shoulder e) Neck f) Back g) Legs Transfer BRIEF Scores Transfer scores (0-4) from a completed BRIEF Survey. Hands and Elbows Shoulders Wrists Left Right Left Right Left Right Neck Back Legs Fig. 9 Transfer score table 2. Then the corresponding conversion factor for each Transfer score is replaced for each above-mentioned part of the body the data table below. Determine Conversion Factors Find each BRIEF Score in + the table at right and determine the conversion Fig. 10 Conversion Factor replacement table Fig. 7 Reach Envelope Analysis D. Vision Analysis This is a software analysis method using DEMIA V5R20. In this method, the vision window of the manikin with a Fig. 11 Transfer score and Conversion Factor Data Table. 3. The cumulative conversion factor for the Transfer score is calculated by summing the above replaced values. ISSN: Page 25

5 Add Conversion Factors 19 Fig.12 Cumulative Conversion Factor 4. Then the physical stress based on transfer score is determined for the following stresses, a) Vibration b) Low Temperature c) Soft Tissue compression d) Impact stress e) Glow issues. The value for the physical stress is the determined by substituting a value of 2 for all stresses mentioned above. In case of absence of that stress the value is substituted to be 0. Determine Time 21 Exposure Multiplier Fig. 17 Time exposure for a factor of 1.25 Calculate 21 Job Hazard Score Fig. 18 Job Hazard Score. Job Hazard Score 0 to 9 Priority Low Summarize Physical Vibration Low Temperature Soft Tissue Compression Impact Stress Glove Issues 10 to to 49 Medium High Place a 2 in the box for each physical stresso the BRIEF, and a 0 for each physical stressor Fig. 13 Physical Stress Substitute Very High Fig. 19 Standard Job Hazard Score Table. VII. FIXTURE DESIGN 5. The cumulative physical stress value is calculated. Add Physical Stressor Fig. 14 Cumulative Physical Stress 6. Calculate Job risk factor is the sum of Cumulative Physical stress and Cumulative Conversion factor. 2 Initially the components were hand held and the operation was carried over with the component in hands. For this automation work cell the job cannot be hand held, hence a fixture was designed using CATIA V5R20 software, that can hold two components simultaneously, the components are held up in the fixture by the Toggle clamp mechanism. The fixture is designed in such a way with POKA YOKE which helps even the unskilled labour to work with full efficiency. Calculate Job Risk Factor Score 21 Fig. 15 Job Risk Factor 7. The time exposure multiplier is the Job Hazard score to be determined, it is calculated by multiplying the Job Risk Factor with the Multiplier factor from the below data table based on the working time of operation per week. Time on Task Per week > 40 hours hours 4-19 hours Multiplier Fig. 20 Isometric view of Fixture with component < 4 hours 0.4 Fig. 16 Time Risk Multiplier Data table. 8. The Standard Hazard Score table is used to identify the fatigue issues in the work posture. ISSN: Page 26

6 Fig. 21 Isometric view of Fixture with component Fig. 22 Isometric view of Fixture Fig. 22 Isometric view of Fixture Fig. 22 Fixture Drafting CONCLUSION Simulation is a very important key technology in the overall concept and can be applied in virtual models on various planning levels and stages to improve the product and process planning. In the first phase the focus is on integrated product engineering. The second phase includes the work cell design and optimization in a collaborative environment concurrently with the product engineering. The third phase in this concept is focusing on operative production planning and control down to the factory floor. The fourth phase emphasizes on the generation of virtual manikin with Indian anthropometric dimensions. The fifth phase involves the integration of the virtual manikin in the virtual work cell. The final phase involves the ergonomic analysis using software. This approach requires an extremely high effort and future research is needed to developed methods and tools for this approach. The benefits of this approach, The approach is more cost effective. Improves economy Provides necessary comfort requirements for the workman. Induces automation Improves accuracy in operation Reduces timing cycle for the operation Increases productivity As a conclusion of this work the following deliverables were obtained, Work cell area : 3.30 x 2.50 x 2.90 m No. of human labours : 1 per shift No. of work shifts : 3 per day Total working labor : 3 per day Component to deburr : Royal Enfield 500CC Flywheel. Weight of component : 3.7Kg Existing RULA score : 3 Existing Job Hazard Score : 21 Tool used : Automatic Robotic Deburring Tool Tool Life : Days Timing cycle : 32 seconds per component Errors : Zero The RULA score value and the Job Hazard Score value proves that the layout is highly safe and comfortable for the worker to handle the components. REFERENCES [1] Chakrabarti, D.,1997, Indian Anthropometric Dimensions for Ergonomic design Practice, NID, Ahmedabad, India [2] Mr. Gurunath V Shinde, Prof.V.S.Jadhav, Ergonomic analysis of an assembly workstation to identify time consuming and fatigue causing factors using application of motion study, International Journal of Engineering and Technology (IJET) [3] N. A. Ansari, Dr. M. J. Sheikh, Evaluation of work Posture by RULA and REBA: A Case Study, IOSR Journal of Mechanical and Civil Engineering (IOSR-JMCE) e-issn: , p-issn: X, Volume 11, Issue 4 Ver. III (Jul- Aug. 2014), PP [4] Tarwinder Singh, Jaswinder Singh, Ergonomic Evaluation of Industrial Tasks in Indian Electronics Industries, International Journal of Science and Research (IJSR), ISSN (Online): , Impact Factor (2012): [5] Wolfgang Kühn, DIGITAL FACTORY SIMULATION ENHANCING THE PRODUCT AND PRODUCTION ISSN: Page 27

7 ENGINEERING PROCESS, Proceedings of the 2006 Winter Simulation Conference L. F. Perrone, F. P. Wieland, J. Liu, B. G. Lawson, D. M. Nicol, and R. M. Fujimoto, eds. [6] Shailesh S.Pachbhai, Laukik P.Raut, A Review on Design of Fixtures, International Journal of Engineering Research and General Science Volume 2, Issue 2, Feb-Mar 2014 ISSN [7] S.Pachaiyappan, M.Micheal Balraj, T.Sridhar, DESIGN AND ANALYSIS OF AN ARTICULATED ROBOT ARM FOR VARIOUS INDUSTRIAL APPLICATIONS, IOSR Journal of Mechanical and Civil Engineering (IOSR-JMCE) e- ISSN: , p-issn : X PP ISSN: Page 28