IE 420 Presentation
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The document discusses optimization of an ATV erector set assembly line. It describes implementing line balancing techniques to distribute work evenly among workers, analyzing workstations for ergonomics, and using 5S principles. Through several iterations, a kitting system and workstation layout were developed that allowed simultaneous work, reduced search time, and provided idle time. Overall, average assembly time decreased from 2.53 to 1.16 hours through these improvements.
IE 420 Presentation
- 1. Optimization of ATV Erector Set Thomas Malloy April Bouquard Abdulrahman Mohammed Nuhuli Leonard Arambam
- 2. Agenda ● Time Standards ● Line Balancing ● Workstation Analysis ● Ergonomics ● Part Presentation ● Iterations ● 5S implementation ● Conclusion
- 3. Time Study Part 1: ● Members worked alone on constructing entire ATV. ● Identified steps to be timed (Battery, 1-24) ● Timed each step in seconds Part 2: ● Users’ times were averaged together to identify standard assembly times. Phase Time (hrs) Average 2.53 Final 1.16
- 4. Line Balancing Goal: We want all workers to have the same amount of time spent working. ● Precedence constraints did not allow for optimal usage of Largest Candidate Rule ○ Grouped steps were very restrictive ● Divided steps into 8 blocks to be divided between 4 workers. ○ 4 Long blocks and 4 short blocks Worker # Time (sec) 1 2207 2 1973 3 2217 4 2710
- 5. Line Balancing (cont.) ● We reallocated steps from longer times to shorter times, but as the assembly progressed we could not have all workers actively working on the same product. ● Idle times between blocks allowed for flexibility. ○ Workers could help others when they lagged behind
- 6. Workstation Analysis ● Due to kitting and task analysis, workers needed to be close together. ● Ordered 360 Degree Rotational Vices for each workstation. ● Separated black screws and ¼” nuts into separate containers. ● Kept tools in order ● Materials lay flat on the workstation (nothing above the head) ● No foreign objects permitted
- 7. Workstation Analysis (cont.) ● Seated work aided in fine assembly and allowed for necessary communication ● All materials were within 24 inches of the worker ● Most used materials were within 14 inches ● Adjustable chairs with wheels provide ergonomic benefits for workers of all heights as well as ability to move laterally along workstation ● Elevated tables for larger workers
- 8. Workstation Design Benefits ● Promotes a social atmosphere. ● Task order automatically designates idle times for workers ● Allows for quick passing of assembly ● Provides help from idle workers
- 9. Tooling ● Magnetized Allen Wrench ● Standard C-Frame Wrench (stock with set) ● 360 Degree Rotational Vice ● Spring Clips ● Power tools were bulky and too powerful ○ Stripped screws/nuts ○ Caused hand cramps/aches ● Hand tools allowed for precision and accuracy
- 10. Part Presentation ● Kitted parts rather than binning ○ Reduced time spent searching for parts. ○ Logical order to the steps ● All parts for worker job were within reach ● Kits had picture instructions as well as what to do when a set of steps was finished.
- 11. 5S Implementation ● Sort: Separate the unnecessary from the necessary parts ● Shine: Place for every part - labelling ● Set to order: Clean the workplace before manufacturing start of shift ● Standardize: SOPs ● Sustain : implement and execute
- 12. Ergonomic Evaluation Methods ● ACGIH TLV for Hand Activity ● Lighting Conditions ● Posture and repetitive work ● Mechanical Safety ● Job rotation.
- 13. ACGIH TLV Evaluation Purpose: To asses the risk of hand injury in performing physically continuous demanding jobs Methods: Conducting ACGIH TLV for Hand Activity by accurately observing the steps through videotaping Results: Our results indicated that most of the work done by our right hand needed some modification.
- 15. Implemented Improvements ● Ordered two 360 degree rotational vices to reduce TLV scores ● Magnetic Allen wrenches reduce overall movement during tightening the screws and decreased the number of lost screws due to dropping ● Holding the assembly in with the vice reduced the strain on the dominant hand while increasing nondominant hand usage
- 16. Lighting Conditions OSHA Recommended: ● Illumination needed: >1500-2000 lux(lumen/m^2) ● Installation of overhead florescent lamp in the workstation with > 40 watt ● Incandescent lamp in the room with > 20 watt
- 17. Posture and Repetitive Work ● Total work per day: 8 hours with one hour lunch ● System capability: 16 ATVs ● Height adjustable chairs ● Elevated tables for comfortable leg room
- 18. Job Rotation ● Eliminate monotonous jobs and potentially harmful posture ● Cross functional training leads to a fully flexible workforce ● Isolate worker strengths ● Increase satisfaction and decrease muscle weakening rate ● Motivate employees to deal with new challenges
- 19. Iteration #1: Assembly Line/Binning ● Assembly line with binning at each station ● No change in step order ● Precedence constraints were severe ● No drastic change in time from single worker method
- 20. Iteration #2: Binning/Current Workstation Layout ● Allowed workers to work simultaneously ● Confusion during part selection ● Increased work time/lack of idle time ● Implemented magnetic c-wrenches and allen wrenches
- 21. Iteration #3: Kitting/Current Workstation Layout ● Easy part selection ● Low precedence constraint effect ● Workers had idle time to reorganize workstations ● Provided quickest assembly time ● Removed magnetized c-wrench tool after it was found to be ineffective
- 22. Quality Assurance ● Worker checklist to ensure all steps are performed ● Signoff sheet to link worker with steps performed as well as determine routings ● Standard Operating Procedures were developed to standardize the way steps were performed.
- 23. Workstation Recommendations ● Drawers or overhead hangers for tool storage ● Lightweight automated tools calibrated to output a set pressure/rotation ● Flow racks to allow for kits to roll towards and away from worker ● Cross training workers to better utilize skills
- 24. Idle Time ● Work on wheel assemblies or other small tasks ● Organize workstations ● Restock materials ● Help other workers ● Perform quality checks ● Start on a new kit
- 25. Conclusions ● Average Takt Time of 29 min ● Layout provided a “team” mentality ● Kitting reduced time spent searching for parts ● Magnetized tooling aided in assembly process ● 360 Degree Rotational vice freed non-dominant hand ● Cross training workers allows for flexibility and cost efficiency