Quality Tools RCA FMEA Manufacturing Systems Analysis Professor

Quality Tools, RCA, FMEA Manufacturing Systems Analysis Professor: Nour El Kadri e-mail: nelkadri@ site. uottawa. ca

Correlation: Strong positive Positive x Negative * Strong negative Competitive evaluation x = Us A = Comp. A B = Comp. B (5 is best) 1 2 3 4 5 x AB A x. B x A B x x x Acoustic trans. , window Water resistance 6 6 9 2 3 Maintain current level 7 5 3 3 2 Importance weighting Target values Technical evaluation (5 is best) Energy needed to open door Easy to close Stays open on a hill Easy to open Doesn’t leak in rain No road noise Reduce energy to 7. 5 ft/lb me r Check force on level ground sto Reduce force to 9 lb. Customer requirements cu Maintain current level ce to Door seal resistance 10 Engineering characteristics Energy needed to close door Im po rta n x Reduce energy level to 7. 5 ft/lb x 5 4 3 2 1 B A x B x A B x. A Relationships: Strong = 9 Medium = 3 Small = 1 Source: Based on John R. Hauser BA x and Don Clausing, “The House of Quality, ” Harvard Business Review, May-June 1988.

Quality Tools n The Seven Tools – Histograms – Pareto Charts – Cause and Effect Diagrams – Run Charts – Scatter Diagrams – Flow Charts – Control Charts

Ishikawa Democratizing Statistics n Kaoru Ishikawa developed seven basic visual tools of quality so that the average person could analyze and interpret data. n These tools have been used worldwide by companies, managers of all levels and employees.

Histograms – A histogram is a bar graph that shows frequency data. – Histograms provide the easiest way to evaluate the distribution of data. – Histograms suggest the nature of and possible improvements for physical mechanisms at work in progress.

Histograms n Creating a Histogram – – Collect data and sort it into categories. Then label the data as the independent set or the dependent set. § The characteristic you grouped the data by, would be the independent variable. § The frequency of that set would be the dependent variable. – Each mark on either axis should be in equal increments. – For each category, find the related frequency and make the horizontal marks to show that frequency.

Histograms n Examples of How Histograms Can Be Used – Histograms can be used to determine distribution of sales. – Say for instance a company wanted to measure the revenues of other companies and wanted to compare numbers.

Pareto Charts n Pareto Chart: – Pareto charts are used to identify and prioritize problems to be solved. – They are actually histograms aided by the 80/20 rule adapted by Joseph Juran. § Remember the 80/20 rule states that approximately 80% of the problems are created by approximately 20% of the causes.

Pareto Charts n Constructing a Pareto Chart – First, information must be selected based on types or classifications of defects that occur as a result of a process. – The data must be collected and classified into categories. – Then a histogram or frequency chart is constructed showing the number of occurrences.

Pareto Charts n An Example of How a Pareto Chart Can Be Used – Pareto Charts are used when products are suffering from different defects but the defects are occurring at a different frequency, or only a few account for most of the defects present, or different defects incur different costs. What we see from that is a product line may experience a range of defects. The manufacturer could concentrate on reducing the defects which make up a bigger percentage of all the defects or focus on eliminating the defect that causes monetary loss.

Pareto Charts www. yourmba. co. uk/pareto_diagram. htm

Cause and Effect Diagrams n Cause and Effect Diagram: – The cause and effect diagram is also called the Ishikawa diagram or the fishbone diagram. – It is a tool for discovering all the possible causes for a particular effect. – The major purpose of this diagram is to act as a first step in problem solving by creating a list of possible causes.

Cause and Effect Diagrams n Constructing a Cause and Effect Diagram – First, clearly identify and define the problem or effect for which the causes must be identified. Place the problem or effect at the right or the head of the diagram. – Identify all the broad areas of the problem. – Write in all the detailed possible causes in each of the broad areas. – Each cause identified should be looked upon for further more specific causes. – View the diagram and evaluate the main causes. – Set goals and take action on the main causes.

Scatter Diagrams n Scatter Diagrams – Scatter Diagrams are used to study and identify the possible relationship between the changes observed in two different sets of variables.

Scatter Diagrams n Constructing a Scatter Diagram – First, collect two pieces of data and create a summary table of the data. – Draw a diagram labeling the horizontal and vertical axes. § It is common that the “cause” variable be labeled on the X axis and the “effect” variable be labeled on the Y axis. – Plot the data pairs on the diagram. – Interpret the scatter diagram for direction and strength.

Scatter Diagrams n An Example of When a Scatter Diagram Can Be Used – A scatter diagram can be used to identify the relationship between the production speed of an operation and the number of defective parts made.

Scatter Diagrams n An Example of When a Scatter Diagram Can Be Used (cont. ) – Displaying the direction of the relationship will determine whether increasing the assembly line speed will increase or decrease the number of defective parts made. Also, the strength of the relationship between the assembly line speed and the number of defective parts produced is determined.

Flow Charts n Flow Charts: – A flow chart is a pictorial representation showing all of the steps of a process.

Flow Charts n Creating a Flow Chart – First, familiarize the participants with the flow chart symbols. – Draw the process flow chart and fill it out in detail about each element. – Analyze the flow chart. Determine which steps add value and which don’t in the process of simplifying the work.

Flow Charts n Examples of When to Use a Flow Chart – Two separate stages of a process flow chart should be considered: § The making of the product § The finished product Flow charts are used to define, standardize, or find areas for improvement in a process

Run Charts n Run Charts Defined – Run charts are used to analyze processes according to time or order.

Run Charts n Creating a Run Chart – Gathering Data § Some type of process or operation must be available to take measurements for analysis. – Organizing Data § Data must be divided into two sets of values X and Y. X values represent time and values of Y represent the measurements taken from the manufacturing process or operation. – Charting Data § Plot the Y values versus the X values. – Interpreting Data § Interpret the data and draw any conclusions that will be beneficial to the process or operation.

Run Charts n An Example of Using a Run Chart – An organization’s desire is to have their product arrive to their customers on time, but they have noticed that it doesn’t take the same amount of time each day of the week. They decided to monitor the amount of time it takes to deliver their product over the next few weeks.

Control Charts n Control Charts – Control charts are used to determine whether a process will produce a product or service with consistent measurable properties.

Control Charts n Steps Used in Developing Process Control Charts – Identify critical operations in the process where inspection might be needed. – Identify critical product characteristics. – Determine whether the critical product characteristic is a variable or an attribute. – Select the appropriate process control chart. – Establish the control limits and use the chart to monitor and improve. – Update the limits.

Control Charts n An Example of When to Use a Control Chart – Counting the number of defective products or services § Do you count the number of defects in a given product or service? § Is the number of units checked or tested constant?

Root Cause Analysis (RCA) If the severity of a discrepancy, or its repetitive nature demands an in-depth analysis of the root cause of the problem, the we should complete a Root Cause Analysis & Problem Solving. n RCA combines several effective tools for identifying and resolving problems n It forces the user to document the entire process from identifying potential causes, conducting a 5 -Why analysis, determining countermeasures, and establishing an action plan for preventative action n 27

Root Cause Analysis n What is Root Cause Analysis? - Finding the real cause of the problem and dealing with it rather than simply continuing to deal with the symptoms n Reactive method n Goals - Failure identification - Failure analysis - Failure resolution n Iterative Process: - Complete prevention of recurrence by a single intervention is not always possible.

Steps for Root Cause Analysis n Collection of data - Phase I - A fact-finding investigation, and not a fault-finding mission n Event Investigation - Phase II - Objective evaluation of the data collected to identify any causal factor that may have led to the failure n Resolution of occurrence - Phase III - Realistic assessment of the viability of the corrective action that the previous phase revealed. - The phenomenon must then be monitored periodically to verify resolution.

Why do we need it n Benefits of RCA - Real cause of the problem can be found - Problem recurrence will be minimized

Types of RCA n Safety-based RCA n Production-based RCA n Process-based RCA n Systems-based RCA

Types of RCA n Safety-based RCA - Investigating Accident and occupational safety and health. - Root causes: unidentified risks, or inadequate safety engineering, missing safety barriers. n Production-based RCA - Quality control for industrial manufacturing. - Root causes: non-conformance like, malfunctioning steps in production line.

Types of RCA n Process-based RCA - Extension of Production-based RCA. - Includes business processes also. - Root causes: Individual process failures n System-based RCA - Hybrid of the previous types - New concepts includes: change management, systems thinking, and risk management. - Root causes: organizational culture and strategic management

Methods of Root Cause Analysis n Change Analysis n Barrier Analysis n MORT: Management Oversight and Risk Tree n Human Performance Evaluation (HPE)

Kepner-Tregoe Method Developed in 1958 n Fact-based approach to systematically rule out possible causes and identify the true cause. n Composed of fives Steps: n - Define the Problem - Describe the Problem - Establish possible causes - Test the most probable cause - Verify the true cause Kepner-Tregoe is a mature process with decades of proven capabilities. n Kepner-Tregoe Problem Analysis was used by NASA to troubleshoot Apollo XIII. n

Tools for Root Cause Analysis

Failure Mode Effect and Analysis (FMEA) n Methodology for analyzing potential reliability problems early in the development cycle. n Failure modes are any errors or defects in a process, design, or item, especially customer related. n Effects analysis refers to studying the consequences of those failures.

FMEA Example Source: http: //asq. org/learn-about-quality/process-analysistools/overview/fmea. html

FMEA Benefits: Improves the quality, reliability, and safety of products. n Increases customer satisfaction. n Stimulates open communication and collective expertise. n Disadvantages: n Assumes cause of problem is a single event. n Examination of human error overlooked.

Fishbone Analysis n Components : - Head of a Fish : Problem or Effect - Horizontal Branches : Causes - Sub-branches : Reason - Non-service Categories : Machine, Manpower, Method etc. - Service categories : People, Process, Policies, Procedures etc. Measurement Material cause Machine cause reason cause Management Method cause reason Man Power Problem

Fishbone Diagrams n An Example of When a Fishbone diagram can be used – This diagram can be used to detect the problem of incorrect deliveries. § Diagram on next slide – When a production team is about to launch a new product, the factors that will affect the final product must be recognized. The fishbone diagram can depict problems before they have a chance to begin. n Advantages - Helps to discover the most likely ROOT CAUSES of a problem - Teach a team to reach a common understanding of a problem.

Fishbone (Cause and Effect) Diagrams Diagram of the Incorrect Deliveries Example: Source: http: //www. hci. com. au

Fishbone Analysis n 5 WHY’S Didn’t buy WHY this morning WHY Ran out of Gas Car stopped Middle of the road WHY Didn’t have WHY money Lost them in WHY last night’s poker Not very good in “bluffing”

RCA-Goodrich Aerostructures n The first step is to clearly define the problem 44

Root Cause Analysis (RCA) Assemble a multi-disciplined team of people who are involved in the process n List the actions taken to prevent the problem from reaching the customer n 45

Root Cause Analysis (RCA) n Schedule a brainstorming session and use the fishbone diagram to document all possible (not just probable) causes for the problem 46

Root Cause Analysis (RCA) From the fishbone diagram, choose the top 3 probable causes n Use the 5 -Whys and drill down to determine root cause for each of the 3 probable causes n 47

Root Cause Analysis (RCA) n For each of the 3 most probable root causes, establish countermeasures and a plan of action to address each area 48

Root Cause Analysis (RCA) n Finally, verify that all the actions are complete, that similar products have been reviewed as well, and that the team concurs that the countermeasures have been effective 49

References n http: //www. envisionsoftware. com/articles/ Root_Cause_Analysis. html n http: //www. au. af. mil/au/awcgate/nas a/root_cause_analysis. pdf n http: //www. isixsigma. com/library/con tent/c 020610 a. asp n http: //www. quality- one. com/services/fmea. php