Introduction to the Engineering Design Process


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  • 1 click = 10 sec, yell left, right, both 10 people, two fists (sandwiches) Cut bread – 10 sec (open fist) Add meat – 10 sec (add stir stick) Add toppings – 20 sec (add penny) Add condiments – 20 sec (add paperclip) Packaging – 10 sec (close fist) Total processing time to make a sandwich: 70 sec How long before first sandwich complete: 20 x 10 sec = 200 sec 20 x 10 = 200 20 x 20 = 400 20 x 20 = 400 1 x 10 = 10 Total = 1210 sec = 20.17 min % of time in process with nothing done to it = (1,210 sec-70 sec)/1,210 sec = 94.2%
  • Football game example: 140 plays x 8 sec/play ≈ 19 minutes, 19 min/3 hr = 11%
  • Introduction to the Engineering Design Process

    1. 1. Process Improvement Methodologies <ul><li>References (sources of graphics): </li></ul><ul><li>Fiore, Clifford, Accelerated Product Development: Combining Lean and Six Sigma for Peak Performance , Productivity Press, NY, NY, 2005. </li></ul><ul><li>Hamilton, Bruce, “Toast Kaizen, An Introduction to Continuous Improvement & Lean Principles,” Greater Boston Manufacturing Partnership, University of Massachusetts, Boston, MA, 2005 (DVD). </li></ul><ul><li>Insights On Implementation-Improved Flow: Collected Practices and Cases , Ralph Bernstein, Editor, Productivity Press, 2006. </li></ul><ul><li>Jacobs, Robert F. and Chase, Richard B., Operations and Supply Management: The Core , McGraw-Hill/Irwin, NY, NY, 2008. </li></ul><ul><li>Nahmias, Steven, Production & Operations Analysis , 5 th Edition, McGraw-Hill/Irwin, NY, NY, 2005. </li></ul><ul><li>Nave, Dave, “How to Compare Six Sigma, Lean, and the Theory of Constraints,” Quality Progress, March 2002, pgs 73 – 78. </li></ul>
    2. 2. Comparison of Three Commonly Adopted Improvement Methodologies <ul><li>See reference, How To Compare Six Sigma, Lean and the Theory of Constraints </li></ul><ul><li>Comparing the main points of the three improvement methodologies: Six Sigma, Lean Thinking, and Theory of Constraints </li></ul>
    3. 3. Six Sigma Approach <ul><li>Define, measure, analyze, improve, control (DMAIC) cycle </li></ul>
    4. 4. Six Sigma Tools <ul><li>Tools common to other quality programs are used in Six Sigma </li></ul><ul><li>Failure mode and effects analysis (FMEA) </li></ul><ul><ul><li>Structured approach to identify, estimate, prioritize, and evaluate risk of possible failure at each stage of a process </li></ul></ul><ul><ul><li>Risk priority number (RPN) is calculated and is based on </li></ul></ul><ul><ul><ul><li>Extent of damage resulting from failure (severity) </li></ul></ul></ul><ul><ul><ul><li>Probability failure takes place (occurrence) </li></ul></ul></ul><ul><ul><ul><li>Probability of detecting the failure (detection) </li></ul></ul></ul><ul><ul><li>High RPN items are designated for improvement first </li></ul></ul><ul><ul><li>Example </li></ul></ul><ul><li>Design of experiments (DOE) </li></ul><ul><ul><li>Statistical approach used for determining the cause-and-effect relationship between process variables and an output variable </li></ul></ul><ul><ul><li>Approach allows for experimentation with many variables simultaneously </li></ul></ul>
    5. 5. Six Sigma Quality <ul><li>To achieve a Six Sigma quality (according to the assumptions used by Motorola and GE) a process must produce no more than 3.4 defects per million opportunities </li></ul><ul><li>Assuming a process follows a normal distribution and given design limits of ± 6 σ there would be 2 defective parts per billion (0.000000002 fraction defective) </li></ul><ul><li>Motorola’s and GE’s value of 3.4 defects per million is due to the fact that a shift of 1.5 σ in the process mean is assumed </li></ul><ul><li>An example process </li></ul><ul><ul><li>spec = 1.250 ± 0.005, μ = 1.250, σ = 0.002, UCL & LCL = 3 σ ( μ and σ estimated from sample parameters) </li></ul></ul><ul><ul><li>Six Sigma process: μ = 1.250 in, σ = 0.000833 in (0.005 in/6) </li></ul></ul><ul><ul><li>Six Sigma process with a 1.5 σ shift to the mean: μ = 1.25125 in, σ = 0.000833 in </li></ul></ul>
    6. 6. Process Capability Index <ul><li>Process capability index (C pk ) </li></ul><ul><li>For (Motorola’s and GE’s) Six Sigma process </li></ul>
    7. 7. Example Problem
    8. 8. Origins of Lean <ul><li>Lean concepts evolved from the JIT philosophy pioneered in Japan by Toyota and embodied in their Toyota Production System </li></ul><ul><li>The emphasis of JIT is the elimination of waste throughout the supply chain </li></ul><ul><li>In the 1990's companies adopted the term lean in place of JIT </li></ul>
    9. 9. The Basis of Lean Thinking <ul><li>Lean means producing </li></ul><ul><ul><li>What is needed </li></ul></ul><ul><ul><li>When it is needed </li></ul></ul><ul><ul><li>With the minimum amount of materials, equipment, labor, and space </li></ul></ul><ul><li>Producing what is required, when it is required, but with minimal investment </li></ul><ul><li>The goal of an enterprise adopting lean </li></ul><ul><ul><li>Make each process as efficient and effective as possible </li></ul></ul><ul><ul><li>Connecting those processes in a stream or continuous chain that is focused on flow and maximizing customer value </li></ul></ul>
    10. 10. Flow <ul><li>Flow is defined as continuous movement of products and information through a value stream </li></ul><ul><li>The goal of a lean enterprise is to minimize idle time in the value stream (idle time equates to inefficiency and waste) </li></ul><ul><li>Winona Sandwich Company example </li></ul><ul><ul><li>Daily special </li></ul></ul><ul><ul><li>Custom order </li></ul></ul><ul><ul><li>Example parameters </li></ul></ul><ul><ul><li>Other factors could potentially influence process time </li></ul></ul><ul><ul><ul><li>Resource levels </li></ul></ul></ul><ul><ul><ul><li>Material availability </li></ul></ul></ul><ul><ul><ul><li>WIP inventory levels </li></ul></ul></ul>
    11. 11. Winona Sandwich Company Daily Special <ul><li>How long before first sandwich ready? </li></ul><ul><li>Majority of time is idle time - no work is being performed on a sandwich </li></ul><ul><li>Batch process </li></ul><ul><ul><li>Push system </li></ul></ul><ul><ul><ul><li>Completes a predetermined quantity of work from an established work queue or forecast </li></ul></ul></ul><ul><ul><ul><li>Typically, the work queue or forecast is offset to the actual customer demand to allow time for production and delivery </li></ul></ul></ul><ul><ul><li>High inventory </li></ul></ul><ul><ul><li>High degree of risk </li></ul></ul><ul><ul><li>Yet a great convenience for customers in a hurry </li></ul></ul><ul><li>No flow </li></ul>
    12. 12. Single-piece Flow Process <ul><li>Winona Sandwich Company Custom order </li></ul><ul><li>Single-piece flow process </li></ul><ul><ul><li>Process of creating a sandwich is triggered only when a customer order initiates the process </li></ul></ul><ul><ul><li>Pull System </li></ul></ul><ul><ul><ul><li>Completes a quantity of work that is directly linked to customer demand </li></ul></ul></ul><ul><ul><ul><li>Materials are staged at the point of consumption </li></ul></ul></ul><ul><ul><ul><li>As materials are consumed, signals (kanban) are sent to previous steps in the process to pull forward sufficient materials to replenish only those that have been consumed </li></ul></ul></ul><ul><li>Total flow </li></ul><ul><li>Ultimately selection of the model to be implemented should be dictated by marketplace demands with the goal of maximizing customer value </li></ul>
    13. 13. Customer Value <ul><li>Customer value refers to specific activities that add value to the products and services customers buy </li></ul><ul><li>Determination of what is value-added is made from the customer’s perspective </li></ul><ul><li>Under lean philosophy for an activity to be value-added it must meet the following three criteria: </li></ul><ul><ul><li>(1) The customer must be willing to pay for the activity </li></ul></ul><ul><ul><li>(2) The part or the object must change (movement?, inspection?) </li></ul></ul><ul><ul><li>(3) It must be done right the first time </li></ul></ul><ul><li>Non-value-added activity -> waste </li></ul><ul><li>Football game illustration </li></ul><ul><li>Viewing a process in the context of what is truly value-added, a different perspective will emerge for the opportunities for improvement </li></ul>
    14. 14. Waste <ul><li>A key tenet under the philosophy of lean and continuous improvement is to minimize non-value-added tasks and eliminate the sources of waste </li></ul><ul><li>Seven sources of waste, DOTWIMP ( ref: Fiore, Clifford ) </li></ul>Types of Waste Factory Waste Example Defects - Part failing functional test - Part feature violating drawing dimensions Over-production - Machining parts with no usage requirement Transportation - Moving parts from one machine to another Waiting - Partially machined parts on the shop floor queued for the next operation Inventory - Completed parts that have not been purchased Motion - Extra process steps Processing - Part inspection
    15. 15. Required Waste vs Pure Waste <ul><li>Waste can be further classified as required waste and pure waste </li></ul><ul><li>Required waste represents activities that do not meet the three criteria for a value-added task but are still necessary to support the creation of a product </li></ul><ul><li>Activities may be mandated by the customer and/or government regulation (i.e. inspections/tests) </li></ul><ul><li>The most obvious examples of pure waste (greatest opportunity for improvement) are associated with the idle time and wait time within a process </li></ul><ul><li>Pure waste activities represent the top priority for elimination </li></ul><ul><li>Video </li></ul>
    16. 16. Single Minute Exchange of Die (SMED) <ul><li>Tool/die changeovers disrupt production – production is stopped while tools/dies are changed </li></ul><ul><li>Idea behind SMED (originated at Toyota around 1970 by Shigeo Shingo) is that a significant portion of the die-changing operation can be done off-line while the previous die is still in place and the line continues to operate </li></ul><ul><li>Die-changing operation is divided into two components: inside exchange of die (IED) and outside exchange of die (OID) </li></ul><ul><li>OID portion is performed while the line is operating in advance of the actual exchange – the goal is to structure die change so that there are as many steps as possible in the OID portion </li></ul><ul><li>Tool/die changeovers typically reduced from hours to minutes </li></ul><ul><li>Additional rules for reducing set-up times (Kodak) </li></ul><ul><ul><li>Eliminate, simplify, automate steps – only in that order </li></ul></ul><ul><ul><li>One way, the right way, the same way – every time </li></ul></ul><ul><ul><li>Build the required level of precision in the system – not the setup (convert adjustments into settings) </li></ul></ul>
    17. 17. Five S (5S) Methodology <ul><li>5S transforms and maintains a work environment that supports lean implementation </li></ul>
    18. 18. Additional Benefits of 5S Methodology <ul><li>5S provides the foundation for creating discipline in the workplace </li></ul><ul><li>It helps cultivate relationships in the company and raises employee morale </li></ul><ul><li>Work areas that are neat and clean will gain credibility with customers, suppliers, and visitors to the company </li></ul>
    19. 19. Value Stream <ul><li>The value stream represents the linkage of all value-added and non-value-added activities associated with the creation of a product or service desired by a customer </li></ul><ul><ul><li>In manufacturing: raw materials -> finished product </li></ul></ul><ul><ul><li>In product development: design concerns -> technical data package (drawings) </li></ul></ul><ul><li>The goal in reviewing/studying the value stream is to maximize customer value </li></ul>
    20. 20. Value Stream Map
    21. 21. Benefits of Developing a Value Stream Map <ul><li>Allows more than just the visualization of the activities in the process </li></ul><ul><li>Helps identify the sources of waste and impediments to flow </li></ul><ul><li>Helps identify the information flows as well as the product and material flows in a process </li></ul><ul><li>Helps reduce “cherry picking” of improvement projects </li></ul>
    22. 22. Five Lean Principles <ul><li>(1) Specify value in the eyes of the customer </li></ul><ul><li>(2) Identify the value stream and eliminate the waste </li></ul><ul><li>(3) Make value flow at the pull of the customer </li></ul><ul><li>(4) Involve and empower employees (there is no better source of insight than the employees who are performing the work) </li></ul><ul><li>(5) Continuously improve (kaizen) in pursuit of perfection </li></ul>