Presentation on theme: "1 Problem Solving RI ASQ May 15, 2008 Dinner Meeting Angelo G. Scangas Quality Support Group, Inc. 978-430-7611"— Presentation transcript:
1 Problem Solving RI ASQ May 15, 2008 Dinner Meeting Angelo G. Scangas Quality Support Group, Inc
Step 2: Describe the Problem “A problem well defined is a problem half solved” A complex problem can not be solved or addressed until it is completely understood and documented.
Step 2: Describe the Problem The problem description covers a broad range of criteria: –Who is experiencing the problem? –What is the problem? –When did the problem occur? –Where did it occur? –Why did the problem occur? (preliminary) –How big is the problem? How much? How many? These components are consolidated into the abbreviation 5W’s and 2H’s.
Step 2: 5W2H Who? –Identify the customers (internal or external) that are experiencing the problem or registering the complaint. –Which groups are impacted by the effect of the problem? What? –Classify the problem in terms of an object and the defect. Determine the part or object in question?
Step 2: 5W2H Where? –Where was the defect found? Which plant? Which line? Which state? Which customer location? –If there is a defective part: Where is the defect located? Note: A concentration (“measles”) chart may be very helpful.
Step 2: “Measles Chart” Note: The root cause (s) must fully account for our complete problem description.
Step 2: 5W2H When? –Analyze control charts, run charts and/or shipment records to determine exactly when the problem began. –Ask whether the problem occurs on all shipments or only specific shifts or days of production? –Is the issue seasonal? Has this problem previously occurred during the same time of year? –Or has the problem been present since the start of production?
Step 2: 5W2H Why? –This is meant to capture known explanations or preliminary “gut” feelings. –These preliminary hypotheses should be captured for later analysis. Note: All potential root causes will be examined against the problem description to determine whether it accounts for the problem and jibes with the data.
Step 2: 5W2H How much? How many? –Determine the magnitude of the problem. –How much nonconforming material was sent to the customer? How many parts were defective? –What was the defect count? –What is the percent defective? Compare the magnitude of the problem to prior baseline defect rates. –Did something change in our process or has the problem been present from the start of production?
Step 2: 5W2H
Step 2: Preliminary List of Causes Begin assessment of the potential causes for the defect –Fishbone diagrams will be the predominant tool in this analysis.
Step 2: “Is/Is Not” The most common tool in comparative analysis is called “Is/Is Not.” “Is/Is Not” is based on asking paired questions: –“What is happening?” –“What could be happening but is NOT.
Step 2: “Is/Is Not” Example: –(Q1) “Who is experiencing the problem?” (A1) “Our customers in the Southwest.” –(Q2) “Who could be experiencing the problem – but is not?” (A2) “Our customers in Ireland” –Analysis/Thought process: What accounts for the difference between the Southwest and Ireland? Perhaps climate differences? Are the process flows the same? Is error-proofing used in one stream and not the other? –Get Information and clear-up any missing facts.
Step 2: Problem Statement The problem statement or deviation statement is an expression of the difference between what is expected (customer specification) and what actually happened.
Step 2: Comprehensive Problem Description The problem statement is a dynamic entity. It is modified as the problem is further understood. –The team will revise and update it as the problem solving progresses. Problem Statements must be as specific as possible – avoid generalities. –Do not include your proposed root cause or potential solution. This will be derived later. –Avoid reference to root cause.
Step 4: Identify Root Cause (s) Objective –To identify and test potential causes of the problem using the detailed problem description and data to isolate and validate the true root cause (s). There are many tools that need to be employed in this process. –Problem Solving practitioners should be familiar with the following concepts and methods: Process flows/VSM, Control Plans, FMEA, Standard Operating Procedures, Fishbone/C&E Diagrams, Pareto Analysis & Histograms, Control Charts, Capability and Gage Studies, Scatter Plots, brainstorming etc. Design of Experiments and advanced statistical tools may be required depending on the complexity of the problem. In this case: A LSS black belt should be included on the team.
Step 4: Basic Steps The Basic Steps in Determination of the Root Cause: Generation –Review the problem definition (5W2H) and Is/Is-Not looking for potential occurrence causes. –Ask “What Changed”? –Review the process flow for clues to potential root causes. –Brainstorm potential causes using a “fishbone” diagram. Refinement –Prioritize the list of potential causes and compare them to the problem description for consistency. –Employ the 5Whys. Verification –Test the prioritized list of causes. Consider conducting investigations in parallel to reduce time. –Verify the root cause (s) through experimentation. –Review the cause (s) to insure a full accounting of the problem description.
Step 4: Generation Continuously ask “What Changed”? Unless the problem has existed all along (common cause) – something must have changed. Example: In the case of the LS console – what changed? The plastic? The press? The temperature?
Step 4: Generation Continuously ask “What Changed”? What changed in the process flow? What changed in the equipment? What changed in the supply base? What changed in the mode of transportation? What changed in personnel? What changed in calibration? What changed in terms of process capability? What changed in the weather? Was it unusual? Focus on the distinctions in the Is/Is-Not analysis!
Step 4: Generation -- PF Review Review the process flow for potential clues and potential causes. Review each step along the flow and ask what could cause the effect or problem.
Step 4: Cause and Effects Diagram Brainstorm potential causes using a “fishbone” diagram. The head of the fish is labeled with the problem or the effect. The major bones of the fish are categories of potential causes. There are two primary labeling practices: Mark the major bones with broad categories such as the classic 6M’s – methods, machines, materials, manpower, measurements and mother-nature. Then brainstorm potential causes and mark them on the small bones.
Step 4: Cause and Effects Diagram Key variables from CE diagram from the delamination problem: Dwell time, adhesive exposure, Poron foam thickness (pressure)
Step 4: Refinement (“Funneling”) The fishbone may contain many potential causes. This list will need to be narrowed down to a manageable list of causes to be tested. How? Compare the list of potential causes to the problem definition for consistency. –Eliminate those causes that are inconsistent.
Refinement Employ the 5 Whys The 5 Whys is a tool that assists in moving from the problem statement and effects of the problem to the true root cause. It is used in conjunction with the fishbone diagram analysis in moving from the chosen root cause to the true root cause. Simply ask Why 5 times starting with the effect of the problem. Example: Why did the console delaminate? The glue was stripped from the plastic cover. If you stopped: The cause would seem to be the glue!
Step 4: “5 Whys” As you can see: 5 Whys focuses the investigation toward true root cause and away from mere effects of the problem. Example II: A functional tester lost power. Why? The power cord got pulled out. Corrective Action: Re-insert cord and retrain all operators. Would this be a robust and permanent corrective action?
Step 4: “5 Whys” Would this be a robust and permanent corrective action? No. Simply replacing the cord is attacking a symptom. Why did the cord come loose? It was kicked loose. Why? The cord is long and runs on the floor Why? The nearest available power supply is across the aisle. Corrective Action: Install a power source closer to the tester.
Step 4: “5 Whys” Is there even a more robust answer? Corrective Action: Install a power source under the tester to eliminate contact. 5Whys drives us to a permanent corrective action. At the center is the most robust solution.
Step 7: Prevent Problem Recurrence It is critical to look systematically at the problem and the root cause and to modify our methods and practices at the highest level. –For example: An error-proofing device was turned off on line A for product #1 -- thereby allowing defective material to ship to the customer. –It is critical to look for systemic issues: Why was error proofing turned off? What part of the broad management system -- including policies, procedures, training methods, core processes, etc. - - may be implicated? What actions would you undertake?
Step 7: Prevent Problem Recurrence Addressing the systemic root cause involves: –Asking the question: “What management system failed and allowed the problem to occur and to escape?” –Correcting the management system that failed. Systemic root cause deals with “drilling deep” into why the system failed. –Why did the development and planning process not predict the defect? –Why did the manufacturing process not prevent the defect? –Why did the quality process not protect the customer from the defect? –Note: Use the 5 Whys approach to each of these questions to determine systemic causes.
Step 7: Prevent Problem Recurrence
Steps need to be taken to monitor the product and the process to insure that the problem does not return. Process/System audits should be established to verify all of the controls and SOP’s determined in the 8D. Product and System should be audited on an ongoing basis to insure long-term control of the problem.
Thank You! Angelo G. Scangas Quality Support Group, Inc