Quality ControlAlicia, Nicole & Jason

Outline

ReviewThe Basics

Terms & Concepts Statistical Measure

ExampleHomework

Review

Total Quality Management: An organization-wide effort directed towards the continuous improvement of quality

Quality as… “Excellence” “Conformance to Specifications” “Fitness for Use” “Value for the Price”

Review Quality-Related Product Characteristics:

Reliability, Durability, Serviceability Quality-Related Service Characteristics:

Reliability, Tangibles, Responsiveness, Assurance, Empathy

Design Quality: Inherent value of a product in the marketplace

Conformance Quality: Degree to which the product or service design specifications are met

Review Costs of Quality:

External Failure Costs: Result from defects found after products reach customers

Internal Failure Costs: Result from defects found prior to shipment to customers

Appraisal Costs: Result from inspections to assess quality levels

Prevention Costs: Result from efforts to prevent product defects

Characteristics of OPI Systems: Vision/mission/purpose for quality Focus on supplier/customer linkages Passionate commitment to continuous improvement

Basics –Definitions of Product Quality

Product Quality: A product’s fitness for consumption in terms of meeting customers’ needs and desires.

Design Quality: A measure of how well a product’s designed features match up to the requirements of a given customer group

Conformance Quality: A measure of whether or not a delivered product meets its design specifications

Quality Management: A management approach that establishes an organization-wide focus on quality, merging the development of a quality-oriented corporate culture with intensive use of managerial/statistical tools

Basics –Creating TQM

Process-Oriented Focus on

Prevention & Problem Solving

When managing quality control,

management should focus on the process

as a whole as opposed to each individual entity

Viewing Quality Management as a

Never Ending Quest

Because products and processes are

continually changing, quality

management must be continued (even

if only small improvements are

being made)

(Ongoing Process Improvement)

Building an Organizational Culture Around

Quality

Create a culture within the

organization that supports quality

improvement initiatives

Basics –Inverted View of Management

Direction of Support

Traditional Organizational

StructureTQM

Organizational View

Top Manageme

ntMiddle

Management

Lower Level Management & Front Line Supervisors

Employees

Employees

Lower Level Management & Front Line Supervisors

Middle Management

Top Manageme

nt

Basics –Plan-Do-Check-Act Cycles (Deming Wheel)

Act

Check

Plan

Do

Six Sigma Quality

Definition: A management program that seeks to improve the quality of process outputs by identifying and removing the causes of defects and variation in the various processes

Sigma (σ): Represents the standard deviation of values for the output of a process

“Six”: +/- 3 standard deviations

Six Sigma Quality –DMAIC Cycle

1. Define2. Measure3. Analyze4. Improve

5. Control

Customers & their prioritiesProcess & its performanceCauses of defectsRemove causes of defectsMaintain quality

ISO 9000 A set of internationally accepted standards for

business quality management systems Developed by the International Organization for

Standardization (ISO) to facilitate international trade Original: 1987 Newest Version: ISO 9000:2008

Malcolm Baldrige National Quality Award: A national quality award bestowed by the NIST in recognition of superior quality and performance excellence Given by the US President to strengthen American

competitiveness

X-bar / R Charts X-bar/R Charts are useful when you want to monitor

averages over time but still keep track of the variation between individual results

Note: X-bar Charts: Subgroup Average▪ Shows how much variation there is over time in your average

R Charts: Range▪ Shows how much variation there is within each subgroup

“Statistical Control”: The subgroup average is consistent over time and the variation between a subgroup is consistent over time

X-bar / R ChartsExample

X-bar – Subgroup Average Determines whether a

process has shifted to the point that it is no longer “in control”

R – Range = Maximum – Minimum Evaluates the gap between

the largest & smallest observations in each sample

Ex. Bowling

X-bar / R ChartsStep 1 – Gather the data

1. Select subgroup size (n)2. Select the frequency with which the

data will be collected3. Select the number of subgroups (k) to

be collected before control limits are calculated

4. For each subgroup, calculate the subgroup average (Xbar = SX/n)

5. For each subgroup, calculate the group range (R = Xmax – Xmin)

X-bar / R ChartsStep 2 – Plot the data

1. Select the scales for the x and y axes for both the X & R charts

2. Plot the subgroup ranges on the R chart and connect consecutive points

3. Plot the subgroup averages on the X chart and connect consecutive points

X-bar / R ChartsStep 3 – Calculate the overall process averages and control limits

1. Calculate the average range (Rbar = SR/k); Plot it on range chart

2. Calculate the overall process average (Xdbar = SXbar/k); Plot it on X-bar chart

3. Calculate control limits for R chart; Plot on R chart1. (Upper) UCLr = D4Rbar2. (Lower) LCLr = D3Rbar3. D3/D4 are control chart constants that depend on group size

4. Calculate control limits for X-bar chart; Plot on X-bar chart

1. (Upper) UCLx = Xdbar + A2(Rbar)2. (Lower) LCLx = Xdbar – A2Rbar3. A2 is a control chart constant that depends on subgroup size

X-bar / R ChartsStep 4 – Interpret both charts for statistical control

1. Consider variation 1st

1. If R chart is out of control, the control limits on the X-bar chart are not valid

2. All tests for statistical control apply to the X-bar chart

1. Points beyond the limits, number of runs & length of runs tests apply to the R chart

X-bar / R ChartsStep 5 – Calculate the process standard deviation, if appropriate

1. If the R chart is in statistical control, the process standard deviation (s) is:

1. s = Rbar/d21. d2 is a control chart constant that depends

on subgroup size

Control chart constants

X-bar / R ChartsPatterns suggesting a nonrandom process…

A “Run Test”: Checks for patterns in a sequence of observations

Helps an analyst detect abnormalities and provides insight into correcting an out-of-control process

Other indications: Runs Hugging Cycles are similar to

Periodocity

Quality Control in SimQuick

Example 23: A Quality Control Station Go through together

Example 24: A Machine with Breakdowns Homework for Thursday For “Sheets” buffer, use…▪ Capacity = 200▪ Initial # objects = 200

NOTE! New SimQuick Info Resources: Resources that this Work

Station needs in order to work To find: Main Menu Other Features

Resources Useful in modeling situations where:▪ 1 person is operating several machines▪ A machine has several setup configurations▪ Several other situations

Assigned to Work Stations in the corresponding tables

Examples…

QC @ McDonald’s http://www.youtube.com/watch?v=kPv2ii

JA-ok&feature=related Ikea QC Commercial

http://www.youtube.com/watch?v=kP9PZYjVwUo&feature=related

Toyota QC after recalls http://www.youtube.com/watch?v=2C-w

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