Structured Problem Solving

This course develops a systematic approach to investigating and resolving engineering and manufacturing problems. It begins with the common logic shared by structured problem-solving methods, then focuses more deeply on 8D and DMAIC, the tools used during each stage of an investigation, and their application to actual engineering problems.

Core Topics

Common structured problem-solving approaches
8D problem solving
DMAIC methodology
Problem definition, containment, and investigation
Root cause analysis and verification
Corrective action, implementation, control, and follow-up

Detailed Course Outline

Structured Problem Solving in Engineering
- Relationship between engineering design and structured problem solving
- Investigating problems in design, manufacturing, and field operation
- Interactions among design, materials, tooling, equipment, process, and environment
- Replacing trial-and-error troubleshooting with structured investigation
- Using objective data to guide decisions
- Distinguishing symptoms from root causes
- Developing corrective actions that prevent recurrence
Generic Problem-Solving Sequence
- Identify — select the problem to be worked on
- Define — develop the problem statement and investigation scope
- Problem Investigation / Measure — understand and quantify the problem
- Cause / Analyze — identify and verify root cause
- Solution / Improve — develop and verify permanent corrective actions
- Implementation / Improve — put permanent corrective action in place
- Review / Control — measure results and determine next actions
- Follow-Up — document results, standardize improvements, and identify future actions
Deming Cycle
- Plan
- Do
- Check
- Act
- Using the cycle for continuous improvement
- Holding gains and learning from results
Kepner-Tregoe Problem Analysis
- Define the problem
- Describe the problem
- Establish possible causes
- Test the most probable cause
- Verify the true cause
- Implement corrective action
- Using disciplined cause evaluation rather than assumption
7-Step Problem-Solving Process
- Project theme selection
- Customer and success measures
- Grasping the present status
- Process mapping and Pareto analysis
- Root cause analysis
- Corrective action
- Checking the effects
- Standardization and control
- Conclusions, savings, and future plans
8D Problem Solving
- D1 — Form the cross-functional team
- D2 — Describe and quantify the problem
- D3 — Establish containment and temporary corrective action
- D4 — Identify and verify root cause
- D5 — Formulate and verify permanent corrective actions
- D6 — Implement corrective action and confirm its effects
- D7 — Prevent recurrence and distribute lessons learned
- D8 — Recognize the team and close the investigation
- Using the 8D form to structure and document the investigation
- Application of 8D to actual manufacturing problems
DMAIC Problem-Solving Methodology
- Define — customers, project boundaries, problem, and process to improve
- Measure — determine current process performance, defects, and metrics
- Analyze — determine root causes and opportunities for improvement
- Improve — develop and verify solutions
- Control — prevent recurrence and establish ongoing controls
- Relationship between DMAIC and the generic problem-solving sequence
- Relationship between DMAIC and 8D
- Using DMAIC as a structured engineering project
- Management review and project gate considerations
Defining the Problem and Investigation
- Developing a clear and measurable problem statement
- Defining what is occurring, where, when, and under what conditions
- Quantifying occurrences using objective data
- Defining project scope
- Defining what is outside the project scope
- Business case
- Project objectives
- Goals and success measures
- Expected deliverables
- Project schedule and milestones
- Team roles and required resources
- DMAIC project charter
- 8D problem description and team definition
Is / Is-Not Analysis
- Using Is / Is-Not to sharpen the problem definition
- Identifying what exhibits the problem and what does not
- Comparing good and bad assemblies or processes
- Identifying what changed
- Using contrasts to narrow the investigation
Containment and Temporary Corrective Action
- Protecting the customer before permanent root cause is known
- Improving detection of defects
- Quarantining suspect material
- Stopping production when necessary
- Using temporary corrective action while permanent solutions are developed
- Measuring containment effectiveness
- Recognizing the expected effects of successful containment on scrap and rework
Problem Investigation and Measurement
- Reviewing warranty history
- Reviewing scrap and rework data
- Reviewing manufacturing efficiency
- Breaking high-level data into specific failure modes
- Verifying data accuracy before drawing conclusions
- Pareto analysis
- Failure data by date, shift, product, or process condition
- Developing timelines of failures
- Developing timelines of design, material, process, tooling, equipment, and repair changes
- Process mapping
- Mapping defect locations through the manufacturing process
- Identifying knowns and unknowns
Root Cause Identification
- Identifying potential causes
- Selecting key causes for further investigation
- Determining measurements needed to verify suspected causes
- Designing experiments to verify causes
- Separating occurrence from detection
- 5 Why analysis
- Working from the observed failure down toward the root cause or physical failure mechanism
- Cause-and-effect / fishbone diagrams
- Thought-process maps
- Reviewing DFMEA and PFMEA
- Examining design, material, tooling, equipment, process, and environmental contributors
- Connecting observed defects to stresses and failure mechanisms
Process Capability and Variation
- Using process data to evaluate suspected causes
- Process capability
- Cp and Cpk
- Short-term and long-term process capability
- Process centering
- Relationship between process capability and defect rates
- Sigma level and expected fallout
- Process shift and drift
- Comparing previous and current process performance
- Using capability data to distinguish equipment, process, and dimensional causes
Structured Problem-Solving Tools
- DFMEA and Design-for-Failure / Physics-of-Failure analysis
- PFMEA
- Design of Experiments
- Cause-and-effect / fishbone diagrams
- Brainstorming
- Pareto charts
- Maintenance history
- Check sheets
- Scatter charts
- Bar charts and histograms
- Timeline analysis
- Control charts
- X-bar and R charts
- Run charts
- Capability studies
- APQP checklists
- Control plans
- Gage R&R
- Process flow maps
- Is / Is-Not matrix
- 5 Whys
- Thought-process maps
- Selecting tools according to the problem rather than treating the methodology as a cookbook
Developing Permanent Corrective Actions
- Identifying multiple possible solutions
- Selecting solutions for further evaluation
- Evaluating feasibility, cost, and benefit
- Checking related processes for unintended effects
- Designing experiments to verify proposed solutions
- Testing solutions using previously defined success measures
- Reducing occurrence of the defect
- Improving detection where elimination of occurrence is not yet possible
- Applying design, tooling, equipment, process, and assembly changes as appropriate
Solution Verification
- Verifying the performance of the selected solution path
- Production-intent pilot verification
- Confirming that the corrective action addresses the identified root cause
- Confirming that the solution does not create new problems elsewhere
- Comparing post-improvement performance with original measurements
Implementation
- Obtaining authority to implement the permanent corrective action
- Training affected personnel
- Updating engineering and manufacturing documentation
- Confirming the change is implemented as intended
- Measuring actual improvement after implementation
- Monitoring related processes for unintended consequences
Documentation and Control
- Updating PFMEA
- Updating DFMEA
- Updating control plans
- Updating drawings and specifications
- Developing or revising standard operating procedures
- Operator and process training
- Establishing ongoing detection and monitoring methods
- Preventing recurrence through documented controls
Review, Follow-Up, and Sustaining the Improvement
- Reviewing results against project goals
- Determining why expected improvements did or did not occur
- Returning to earlier investigation stages when necessary
- Standardizing successful solutions
- Tracking scrap, rework, warranty, and other performance measures
- Monitoring improvement effectiveness over time
- Driving lessons learned across other products, processes, and production lines
- Documenting the completed investigation
- Identifying additional improvement opportunities
- Closing the project
Worked Engineering Problem-Solving Example
- Defining an actual field-performance problem
- Developing the project charter and scope
- Containment and improved end-of-line detection
- Reviewing warranty and manufacturing data
- Pareto analysis of failure modes
- Timeline analysis
- Process mapping
- Verifying data accuracy
- Root cause investigation
- Process capability analysis
- Identifying failure locations and mechanisms
- Developing corrective actions for multiple root causes
- Verifying solution performance
- Implementing detection and occurrence improvements
- Updating FMEAs, control plans, drawings, training, and procedures
- Tracking improvement effectiveness after implementation

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