Pencil Sharpener Report#4 Assembly Workstation Analysis November 21, 2001 Hernan Joglar John Sharkey

1. 2.875 Mechanical Assembly and its Role in Product Development Pencil Sharpener Report#4 Assembly Workstation Analysis November 21, 2001 Hernan Joglar John Sharkey

2. Report Contents • Introduction • Cycle Time Analysis • Candidate Assembly Process Flow • Part And Subassembly Inflow and Outflow • Workstation Layout • Motion Analysis for People and Equipment • Inspection and Test Requirements • Gannt Chart Analysis of Assembly Process • Estimated Cost for Workstation Purchase and Installation • Estimated Cost of Unit Assembly 11. Appendices • Pencil Sharpener Exploded View • Pencil Sharpener Structural Decomposition • Pencil Sharpener Disassembly Photo • Pencil Sharpener Indentured Part List • Pencil Sharpener Parts & Material List

3. Introduction • Purpose is to analyze assembly workflow and workstation requirements • Approach was to modify the assembly flow presented in the Project Report#3 as the baseline for analyzing workflow, workstation and timing requirements • Added an additional final functional test of completed assembly • No attempt made at optimized work flow • Alternate variations considered for inspection and test analysis, but not presented in this report • Method assumes manual assembly process throughout • Approach assumes all electrical contacts are pre-formed by manufacturing, or supplier, prior to assembly operations

4. Cycle Time Analysis • Throughput requirement based on production volume • 250,000 units/year @ 250 workdays/year = 1000 units/day • 1000 units/day @ 8 hours/day = 125 units/hour = 2.08 mins/unit • Assembly time per Boothroyd Handling and Insertion Times • Handling Time per unit = 106.98 (sec/unit) • Location Time per unit = 47.50 (sec/unit) • Reversible Fastening Time per unit = 54.20 (sec/unit) • Irreversible Fastening Time per unit = 121.00 (sec/unit) • Total predicted assembly time = 329.68 (sec/unit) Note: does not include inspection and test time • Measured Times for Handling, Location and Reversible Fasteners (does not include soldering, riveting, lubrication, or other irreversible fasteners) • Test#1 309 sec - Test#4 169 sec • Test#2 222 sec - Test#5 153 sec • Test#3 198 sec 207.18 (sec)

5. Baseline Assembly Process Flow SA 7 Cutter Unit Assy SA 7 Cutter Unit Inspect SA5 Motor/Gearbox Assy 18.25 sec 5 sec SA5a Gearbox Assy SA5b Gearbox Solder SA5c Gearbox Test SA6 Gearbox Cover Assy SA 6 Gearbox Cover Inspect 87.30 + 30 sec 48.06 sec 5 sec SA4 Battery Comp. Assy SA 4 Battery Comp. Inspect SA1 Final Assy SA1 Final Test 30 sec 19.62 sec 5 sec SA1 Final Test 101.83 sec SA3 Battery Cover Assy SA 3 Battery Cover Inspect SA2 Base Assy 20 sec 19.62 sec Package & Ship 5 sec 33.5 sec 30 sec Note: Test, inspection and packaging times are SWAGS

6. Part And Subassembly Inflow and Outflow

7. Workstation Layout

8. Layout Explanation • For layout design, this team has sought to group functions in such a way that floor space is saved without loosing flexibility. Functions that require similar activities and/or tooling have been grouped. Flexibility is accomplished by grouping activities that have similar duration and may be performed in parallel with those being carried out in other workstations. Estimated floor space is 4000 square ft (80’ x 50’). • In workstation A, for instance, functions functions that imply riveting have been grouped, so that workers can help each other if one of them is too slow. • Workstation B groups gluing activities and workstation E groups packaging activities. • The way tasks have been grouped gives management the possibility of changing the number of workers in each station as transitory situations may require it. This variations should not affect the assembly process • The layout has also been designed in such a way that there is a minimum of handlers and they stay at a certain distance of the workers assembling the product, that’s why both storage areas are at the extremes.

9. Motion Analysis for People and Equipment • Every worker has the parts, fixtures and tools he/she needs at an arm length distance or so. • Every worker sits on a wheeled spinning chair for ease of movement. • Parts are moved by a handler from the storage area to the distribution belt in trays. • Part trays are picked up from distribution belt by workers at stations and stored in shelves. • When necessary parts and/or subassemblies are passed on directly between workers (station C). • Subassemblies are moved from station to station on by means of transportation belt. • Tools, fixtures, and materials are moved by handler from storage area to the distribution belt in buckets. These buckets are picked up by workers in stations. • Finished products are moved from packaging station (Station E) to finished product storage in carrying carts by a handler.

10. Inspection and Test Requirements • Unaided Visual Inspection Requirements • Cutter Unit (SA7) inspection to confirm blade installation and alignment • Gearbox Cover (SA6) inspection to confirm proper installation and heat staking of of electrical contacts, and correct soldering, location and orientation of red and blue wires • Battery Compartment (SA4) inspection to confirm proper installation and riveting of electrical contacts • Battery Compartment Cover (SA3) inspection to confirm proper installation and riveting of electrical contacts • Final assembly (SA1) inspection to confirm aesthetic appearance (lack of nicks, scratches, smudges), mechanical integrity (no loose parts) • Baseline Electrical and Functional Tests • Motor/Gearbox mechanical function test, and electrical continuity tests, to confirm proper operation (full range of motion w/out binding) of safety lever switch, motor actuation switch, and ability to manually back-drive the geartrain • Final electrical function test required additional special equipment: • Re-chargeable battery-pack unit • Plastic pencil “simulator” tool which rotates freely inside of a handheld bearing unit • Assembly and test flow requires removal and re-installation of battery compartment cover, to verify proper end-to-end operation

11. Gant Chart of Baseline Assembly Process Time (sec) 30 60 90 120 150 180 210 240 300 330 360 390 0 270 Cutter Unit Assy 18.25 Cutter Unit Inspect 5 Gearbox Cover Assy 48.06 Gearbox Cover Inspect 5 Battery Compartment Assy 19.62 Battery Compartment Inspect 5 Motor/Gearbox Assy 87.30 Motor/Gearbox Test & Inspect 30 Battery Comp Cover Assy 19.62 Battery Comp Cover Inspect 5 Base Assembly 33.5 Final Assy 101.83 Final Test 30 Final Inspect 20 30 Package & Ship 0:00 1:00 2:00 3:00 4:00 5:00 6:00 7:00 Time (min)

12. Estimated Cost for Workstation Purchase and Installation • Overall Cost Summary $20,955 • Workstation equipment $16,660 • Assembly fixtures $2200 • Standard tools and special tooling $2095 • Workstation Equipment $16,660 • Work tables 12 ea @ $250 = $3000 • Part bins 12 ea @ $50 = $600 • Spinning seats 12 ea @ $150 = $1800 • Transportation buckets 2 ea @ $50 = $100 • Part transportation trays 5 ea @ $50 = $250 • Packaged product carry carts 2 ea @ $250 $500 • Finished sharpener trays 4 ea @ $50 = $200 • Trash buckets 7 ea @ $30 = $210 • Conveyor belt ( 30’ x 6 ‘) 1 ea @ $10,000 = $10,000

13. Fixtures and Special Tooling Fixtures$2200 • Riveting fixture for battery compartment $750 • Riveting fixture, or special tooling, for gearbox cover $750 • Soldering station and fixture for electric motor (black and blue leads) $350 • Soldering station and fixture for battery compartment (black and red leads) $350 Standard Tools and Special Tooling $2095 • Heat stake tooling for battery compartment electrical contacts $350 • Magnetic Phillips head screwdriver (4” length) $25 • Small wrench, or pliers, for blade screw and nut $10 • Wire strippers (22 gage) $10 • Wire tinning and pre-form bending $10 • Soldering station for gearbox cover $350 • Electrical test station for operation of motor/gearbox sub-assembly $500 • Lubrication dispenser gun $150 • Electrical test station for final functional test $500 • Plastic pencil simulator with bearing holder $200 • Hand rivet tool $75 • Re-chargeable battery pack $50

14. Estimated Cost of Unit Assembly • Labor rates for assembly in China based on average CY200 hourly compensation cost for production workers, as reported by the U.S. Bureau of Labor Statistics (see Chart 1 below) • Using 405 seconds for total labor ( 330 sec assembly time plus 75 sec test and inspection) per completed unit, assembly costs for various countries are shown in the table below:

15. Appendices • Pencil Sharpener Exploded View • Pencil Sharpener Structural Decomposition • Pencil Sharpener Disassembly Photo • Pencil Sharpener Indentured Parts List • Pencil Sharpener Parts & Material List

16. CAD Exploded View [ Model developed using Autodesk Inventer Version 3.0 ]

17. General Assembly Sub- Assembly Part Product Structural Decomposition Complete Assembly Pencil guide Base screws Motor Gearbox Bat. Comp. screws Shavings receptacle Battery Compartment Sharpener case Base Sharpener base Bat. Comp. housing Black wire Gearbox cover screw Rubber foot Gearbox housing Electric motor Bat. Comp. contacts Output gear Safety lever Battery Comp. cover Bat. install. guide Intermediate gear Lubrication Contacts battery Comp. cover Driven gear Gearbox cover Battery Comp. cover Cutter Unit Gearbox cover contacts Rubber foot Red wire Blade nut and bolt Blue wire Blade Gearbox cover Blade holder

18. Photo of Product Disassembly 9 14 24 15 25 5 8 4 12 11 23 2 7 21 11 20 27 17 26 3 18 19 1 28 29 16 Pencil sharpener parts numbered as in the Part List

19. Parts and Material List

20. Pencil Sharpener Indentured Parts List

21. Part Handling: Gross Motion

22. Part Handling: Gross Motion (con’t)

23. Part Insertion: Fine Motion

24. Part Insertion: Fine Motion (con’t)