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Chapter 11

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1. Check sheets2. Pareto Charts3. Flow charts4. Cause and effect diagram5. Histograms6. Control Charts7. Scatter Diagrams

The 7 Classic Problem Solving Tools

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Project Charter

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Teams should be comprised of key individuals directly involved with the process being addressed. Other functional representatives can be brought in as needed. Each individual brings unique expertise and perspective to the team and melds that with the talents of the other team members.

The team process leads to decisions of higher quality than those arrived at by individuals. Moreover, members of a team are much more willing to take ownership in the resultant decisions and to actively pursue their successful implementation.

 

Teamwork

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Group Activity

Launch #1

Using what you are given baseline the process for shooting the statapult.

Remember: Customer desires a rapid-fire, precise, and accurate launcher that can launch projectiles over mountain ranges.

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Objective: To fire the statapult and record the distance in inches for each of the launches. The measured distance will be from the back base of that launcher to the pointwhere the ball hits the floor. Use the following grid to record the distances inthe order in which they were obtained (to the nearest inch). This will establish

Launch Number Distance (inches)12345678910111213141516171819202122232425

Rules of Engagement:(1) Every shot will be launched from a pull back angle of 177 degrees, with the peg position in the second hole from the top. Each person on the team will perform an equitable number of launches (or as close thereto as possible). "Launching" means pulling back and releasing. Record to the nearest half inch.(2) There will be a time limit of 15 seconds between successive firings. Each group will be required to police themselves. There will be a penalty associated with late firings. One practice shot will be allowed.(3) Plot the distances recorded above as points on the run chart form on the next page. Connect adjacent points with straight lines, and record the longest distance (Max) and the shortest distance (Min) and compute the Range = Max - Min.

Launch 1

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Statapult launch #1

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Brainstorming

1. Clearly state the problem and make sure that all team members understand it2. Allow each team member to present his or her ideas3. Record each suggestion exactly as it was stated. Make no preliminary judgments on ideas4. Decide which ideas should be acted upon first, which ones can wait, and which ones aren't applicable5. Decide how each idea will be acted upon. Determine who is responsible and when those actions will be done by.6. Document all results for use in future meetings, or as evidence that the problem is fixed.7. Create a file somewhere in the department to document what problems have been fixed, and what problems still need to be worked on8. If a project is generated from the Brainstorm session, before leaving the meeting make sure that everyone understands who is Responsible, who is Accountable, who are the key Contacts, and whom we should keep Informed throughout the project.

1. Clearly state the problem and make sure that all team members understand it2. Allow each team member to present his or her ideas3. Record each suggestion exactly as it was stated. Make no preliminary judgments on ideas4. Decide which ideas should be acted upon first, which ones can wait, and which ones aren't applicable5. Decide how each idea will be acted upon. Determine who is responsible and when those actions will be done by.6. Document all results for use in future meetings, or as evidence that the problem is fixed.7. Create a file somewhere in the department to document what problems have been fixed, and what problems still need to be worked on8. If a project is generated from the Brainstorm session, before leaving the meeting make sure that everyone understands who is Responsible, who is Accountable, who are the key Contacts, and whom we should keep Informed throughout the project.

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Defect check sheet

Objective: Develop a check sheet for what you think is causing you problems with accuracy.

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Pareto Chart

Objective: Develop a Pareto Chart from the data you recorded on the check sheet.

30 100%

2890%

26

24 80%

2270%

20

18 60%

1650%

14

12 40%

1030%

8

6 20%

410%

2

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Process Flow Chart

Objective: Develop a process flow diagram that explains how to launch a ball.

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Cause and Effect Diagram Objective: Develop a C&E diagram that explains the variability of the launching process. Label as C/N/X.

METHOD

MOTHERNATURE

MEASUREMENT

MANPOWER MACHINE

MATERIAL

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SOP

Objective: Develop an SOP that accurately defines each controlled step of the launching process.

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Demonstrate the importance of error proofing

Show error proofing is not difficult◦ Simplification and standardization is

key◦ Make everyone’s job easier

Encourage you to recognize the opportunities for error proofing◦ Operator error rarely acceptable as

root cause◦ Operator training rarely acceptable as

corrective action◦ Incorporate into all of your

improvement projects

Why talk about error-proofing?

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Aircraft Accident Causes Last 20 Years

The reliability of the parts themselves have improved dramatically. What has not improved is the ability of humans to adequately comprehend and attend to the process of assembling and maintaining these dramatically more complex machines correctly.

The reliability of the parts themselves have improved dramatically. What has not improved is the ability of humans to adequately comprehend and attend to the process of assembling and maintaining these dramatically more complex machines correctly.

Time

Human Causes

Rel

ativ

e P

ropo

rtio

n o

f Acc

iden

ts

Machine Causes

Fre

quen

cy

Source: FAA Human Factors Guide to Aviation Maintenance

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In response to a sharp increase in air traffic control errors nationwide and the near-collision of two planes over New York's La Guardia Airport, the FAA has:

You make the call…

A. Ordered retraining for 10,000 air traffic controllers.

B. Hired a team of experts to pareto errors, look for trends, and find the root cause for the errors.

C. Base future salary actions on controller’s performance.

D. Rewrite the operating procedures placing messages and warnings in appropriate locations.

Air Traffic Control Errors

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(Matthew L. Wald, New York Times, Oct. 23, 1999). -- CF

After touring the site of last month's nuclear incident in Japan, three Energy Department experts said the plant's managers expected workers to follow safety rules but never explained why the rules were important.

Frank McCoy, deputy manager of the DOE's Savannah River Operations Office, said technicians at the Tokaimura plant were using incorrect equipment to process nuclear fuel.

McCoy: "Using the system in the right way was more difficult than anyone would have desired." The experts said the workers did not understand the reasons behind rules limiting the size of batches and containers.

On Sept. 30, plant workers brought too much uranium together in one spot and created a chain reaction that lasted for 17 hours.

Nuclear Safety:

Experts Blame Japanese Incident On Incorrect Equipment

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Errors are difficult to manage using statistics.

1998, John R. Grout

• Most of our processes are at a relatively high sigma, therefore sampling unlikely to catch abnormalities: sampling aimed at catching process drift not defects

• Want to use error proofing to eliminate the tails of the distribution

Hole diameterSpecial causes

Examples:

1) Misses Hole

2) Worn drill

3) Wrong drill

1

2

3

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Knowledge-based

( Perform theory based

analysis)

Skill-based

(routine actions,

perform on autopilot)

Task Type Mean P(d) s level- Initial problem solving or 0.2

0.85 Troubleshooting- Detection of deviation or 0.07

1.45 inspection- Calculation 0.04

1.75- Dial a 7 Digit phone number 0.021 2.05- Alpha input per character 0.008

2.40- Numeric input per character 0.003 2.75- Control action per demand 0.001 3.10- Assembly per task element 0.00007 3.80

Data from “Human Reliability Data - The State of the Art and the Possibilities”Jeremy C. Williams, 1989 CEGB

• Depending on task and environment humans are typically 2 to 3 sigma

• Errors will occur the trick is preventing them from becoming defects and escaping to the field

Error Probability

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What is “POKA-YOKE”?The concept of poka-yoke has existed for a long time but it was Japanese manufacturing engineer Shiego Shingo who developed the idea into a formidable tool for achieving zero defects. Shingo came up with the term poka-yoke which generally translates as “mistake-proofing” or “fail-safing” – to avoid (yokeru) inadvertent errors (poka).

Generally, any manufacturing or transactional process is dependant on human intervention, look for ways to either minimize the intervention (automation, menu choices, mouse clicks vs. typing), or if human intervention cannot be reduced, look for ways/methods of….

• Mistake proofing the form/process (provide a template or overlay)

• Color coding instructions or the form (certain functions only fill-in a certain color on the form)

• Minimize the writing required (have repetitive or standard info hard printed onto the form)

• If the form is electronic limiting access, blocking certain entries, having the computer verify information, or granting certain permissions may provide some relief.

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Red flags for error proofing

Excerpted from:

Poka-yoke Improving Product Quality by Preventing Defects

TechniqueInadvertent

Willful

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Error Proofing

Excerpted from:

Poka-yoke Improving Product Quality by Preventing Defects

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Demand vigilance

– ask designers and workers to “be more careful!”

– continue the “blame and train cycle”

What can we do?

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Eliminate the chance of making the error

Provide automatic feedback to sense and fix the error

Make incorrect actions correct Make wrong actions more difficult Make it easier to discover the

errors that occur Make it possible to reverse actions

- to “undo” them - or make it harder to do what cannot be reversed◦ Source inspection◦ 100% inspection◦ Immediate feedback and corrective

action.

A New Attitude toward Preventing Errors

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Best I. Error Elimination - Prevention - The opportunity to make the error no longer exists in the process.

II. Automatic Feedback “Poke-Yoke” devices - The error is automatically detected and the process halted prior to making a defect.

III. Defect Detection and process adjustment -”Source Inspection” Defect is discovered at the operation where generated.

Err

or P

roof

ing

Pro

cess

Im

pro

vem

ent IV. Make it easier to do it right. Colors,

color coding, shapes, symbols, kitting, checklists, forms, procedures, process simplification

Subsequent Inspection, Audits,

Perfection Reviews, TPM

Error Proofing - Process Improvement

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Everyday Examples

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Put “Knowledge in the World”

Make it easier to do it right!

Provide clues about what to do through the use of:◦natural mappings◦visibility◦ feedback

Source: The Design of Everyday Things, by D.A. Norman, 1988, Doubleday

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Natural mappings:

Which dial turns on the burner?

Stove A

Stove B

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Visibility means making relevant parts visible(kitting) and effectively displaying system status

Feedback means providing an immediate and obvious effect for each action taken. ◦ This is how you can error proof

anything. If you can provide immediate feedback to the human operating the process, he/she will correct the error before a defect is generated.

Visibility and feedback

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Customer Satisfaction - Process variation hurts customers but it is normally the special causes which cause them the most pain◦ Must detect errors and prevent

defects from escaping Reduces production disruption

along the supply chain and the associated cost and liability

Cost reduction - scrap and rework and fixing downstream problems are reduced dramatically

Benefits of error proofing

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Error proofing is of critical importance internally and at the customer◦ Addresses the outliers and affects

what the customers see Whenever dealing with processes

look for the red flags and excessive operator intervention◦ Process walks are easy to perform

and effective You must error proof in the

control phase Don’t accept operator error as

root cause or operator training as the only corrective action

Takeaways

To achieve zero defect levels you must error

proof

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Objective: To fire the statapult and record the distance in inches for each of the launches. The measured distance will be from the back base of that launcher to the pointwhere the ball hits the floor. Use the following grid to record the distances inthe order in which they were obtained (to the nearest half inch). This will establisha process baseline.

Launch Number Distance (inches)12345678910111213141516171819202122232425

Rules of Engagement:(1) Every shot will be launched from a pull back angle of 177 degrees, with the peg position in the second hole from the top. Each person on the team will perform an equitable number of launches (or as close thereto as possible). "Launching" means pulling back and releasing. Record to the nearest half inch.(2) There will be a time limit of 15 seconds between successive firings. Each group will be required to police themselves. There will be a penalty associated with late firings. Practice shots are not allowed.(3) Plot the distances recorded above as points on the run chart form on the next page. Connect adjacent points with straight lines, and record the longest distance (Max)

Launch 2

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Statapult launch #2

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Histogram

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Scatter plot

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Overview ◦ Why◦ How◦ FMEA Types◦ FMEA Steps

The FMEA Process Severity Table

Failure Mode and Effects Analysis

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Why do it?

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Identifies potential product related process failure modes.

Assesses the potential customer effects of the failures.

Identifies the potential manufacturing or assembly process causes and identifies process variables on which to focus controls for occurrence reduction or detection of the failure conditions.

Develops a ranked list of potential failure modes, thus establishing a priority system for corrective action considerations.

Documents the results of the manufacturing or assembly process.

FMEA overview

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Failure Mode – The manner in which a part or process can fail to meet specification. It is usually associated with a defect or nonconformance.

  Effect – The impact on a customer if a failure

mode is not prevented or corrected. The customer can be an immediate one or one downstream.

  Cause – A deficiency that results in a failure

mode. Causes are sources of variability associated with key process input variables.

A FMEA is best when a team prepares it. The team should be made up of people from all areas impacted by the process.The FMEA is useful in a number of applications: in determining X’s, helping to define process improvements and controls, and others.

FMEA terms

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A System FMEA is used to analyze systems and subsystems in early concept and design stages. It focuses on potential failure modes associated with the functions of a system caused by design.

A Design FMEA is used to analyze products before they are release to production.

A Process FMEA is used to analyze manufacturing, assembly, and transactional processes.

A Product FMEA is used to analyze failure modes that could occur to the product once it gets into the customers hands.

Types of FMEA’s

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Preparation  A FMEA begins with a process map. Identify

the process and map its key steps. List the key process outputs to satisfy customer

requirements. List the key process inputs for each process

step. Define a matrix relating product outputs to

process variables . Rank inputs according to their importance. 

The goal in your preparation is to have a complete understanding of the process you are analyzing. What are its steps? What are its inputs and outputs? How do they relate?

 **Information for this section taken from: GE Six Sigma Playbook and the AIAG

Reference Manual.**

FMEA process steps

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FMEA process

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FMEA Rating table

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FMEA Risk Priority No.

 

 

Calculate the Risk Priority Number (RPN). This is a calculation of the relative risk of a particular failure mode given the ratings assigned for severity, occurrence, and detection. To calculate, apply the following equation: 

RPN = SEV * OCC * DET The higher the RPN, the greater the risk for a failure mode! Careful analysis provides a priority for action. 

ImprovementAvoid analysis paralysis. The object of a FMEA is to initiate action. Select the trouble areas that cause the top few causes. Determine what action will reduce RPN’s and establish time frames for their completion. Assign responsibilities. Once action brings about results, recalculate RPN’s and put controls into place. 

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FMEA form