PTTE 434 - Lecture 3Quality Organization & Management Ch 5 & 6

Quality Control

Process Management

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Lecture Objectives - Quality Control

Learn the definitions of control Understand Quality Control Understand what is meant by “statistically

significant.” Understand “Self-Control”

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Definition of Control

The process employed to consistently meet standards.

The control process is in the nature of a “feedback loop.”

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The Control Process

Choose the control subject, i.e., choose what is to be regulated.

Establish measurement. Establish standards of

performance: product/process goals.

Measure actual performance. Compare actual to standards. Take action on the difference.

PLAN

DO

CHECK

ACT

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Control Feedback Loop

Process Sensor Goal

ComparisonActuator

1

2 3

4

5

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RUMBA - Establishing Measures

Reasonable: Can you meet the requirements?

Understandable: Do you understand the requirements? Verify with the customer.

Measurable: Can it be determined if, and when you have met the requirement?

Believable: Do you and your employees agree with the requirement and that it can be met?

Achievable: Can the process meet the requirement? Is it realistic? If not, renegotiate with the customer.

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Measurement

Measurement is central to the process of quality control.

Effective measurement depends on a clearly defined process.

Effective measurement must be based on company objectives.

Don’t overlook the “cost of quality.”

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Measurement Process1 of 3 Define the purpose. Emphasize customer-related measurements. Focus on measurements that are useful -- not

just easy to collect. Provide for making measurements as close

as possible to activities they impact.

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Measurement Process2 of 3

Provide for participation from all levels in both planning and implementation.

Provide not only concurrent, also include leading and lagging indicators

Define, in advance, for data storage, collection, analysis and presentation of the measurements.

Seek simplicity

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Measurement Process3 of 3 Periodically evaluate the accuracy, integrity,

and usefulness of the measurements. Measurements alone cannot achieve

improvement - they only indicate whether, or not you have a problem and where the problems might exist.

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Self-Control

Ideally, quality should be controlled by the employee creating the product.

Examples: Rolls Royce Gear - Park City, UT O. C. Tanner, Co. - SLC, UT Woodland Furniture Co.- Idaho Falls, ID

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Deming’s Cycle

Act

A

P

D

C

Plan

Do

Check

A

P

D

C

Plan

Do

Check

A

P

D

C

Figure 5.3

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Control Subjects1 of 2 Should be aligned and linked to customer

parameters. Define work processes in terms of objectives,

process steps, process customers, and customer needs.

Recognize both the components of quality, i.e., freedom from defects, and product features.

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Control Subjects2 of 2 Potential subjects can be identified by

obtaining ideas from both customers and employees.

Quality control subjects must be viewed as being valid.

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Quality Control

Establish measurements Establish standards of performance Measure Actual Performance’ Compare to standards Take action on the difference

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Establish Measurement

A unit of measure: the unit used to report the value of the control subject, e.g., pounds, seconds, dollars

A sensor: a method or instrument that can carry out the evaluation and state the findings in terms of the unit of measure.

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Establish Standards of Performance

Legitimate: have official status Customer focused: external and internal Measurable: numbers. Understandable: clear to all In alignment: integrated with higher levels. Equitable: fair for all individuals

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Establish Standards of Performance

Insure each control subject has a quality goal.

Control subjects and goals

Control Subject Goals

Mean time between failures Minimum 5000 hours

Solder temperature of soldering process 500 degree F.

Overnight delivery 99.5% delivered prior to 10:30 a.m. next morning

Relative quality rating At least equal in quality to competitors A and B

Customer retention 95% of key customers from year to year

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Quality Responsibility Spreadsheet

Process Controlfeatures

ControlSubject

Unit ofMeasure

Type ofSensor

Frequency ofMeasurement

Sample Size Criteria formakingdecision

Responsibilityfor decision

making

Wave solderconditionsSolder Temp.

Degree F(oF)

Thermocouple Continuous N/A 510 oFreduce heat500 oFincrease heat

Operator

Conveyor Speed Feet per minute(Ft./min)

4.5 ft/min 1/hour N/A 5 ft/minreduce speed4 ft/minincrease speed

Operator

Alloy purity % totalcontaminates

Lab chemicalanalysis

1.5% max 15 grams At 1.5% drainbath, replacesolder

Processengineer

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Quality Score Card 1st quarter

MeasurementCategory

CustomerSpecifications

ActualPerformance

Actual

EvaluationExcellent Poor

Underwriting

Turnaround time 4 hours 99.9% 4.6 5 4 3 2 1

Accessibility 100% 99.5% 4.2 5 4 3 2 1

KnowledgeableConsistentapplication ofguidelines

95.5% 3.2 5 4 3 2 1

Billing

Timeliness 3rd - 5th of month 99.9% 4.6 5 4 3 2 1

Completeness 100% 98.9% 3.8 5 4 3 2 1

Claims

Timely Payments 30 days 84% 2.5 5 4 3 2 1

Work out cycletime

To guidelines100%

95% 3.1 5 4 3 2 1

Sales

Meeting frequencyMonthly /quarterly 100% 6+ 5 4 3 2 1

KnowledgeAnswer questionswhen asked

86% 2.6 5 4 3 2 1

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Compare to Standards

Sometimes comparison is simple - if solder temp. exceed 510o F, decrease heat, if between 500o F and 510o F, do nothing, if less than 500o F, increase heat.

Other times, must determine whether it is an apparent difference, or real “statistical” difference in variation.

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Process CapabilitySlide 1 of 4

Process Stability and Capability Once a process is stable, the next emphasis is

to ensure that the process is capable. Process capability refers to the ability of a

process to produce a product that meets specifications.

Six-sigma program such as those pioneered by Motorola Corporation result in highly capable processes.

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Process CapabilitySlide 2 of 4

Six-Sigma Quality

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Process CapabilitySlide 3 of 4

Process Versus Sampling Distribution To understand process capability we must first

understand the differences between population and sampling distributions.

Population distributions are distributions with all the items or observations of interest to a decision maker.

A population is defined as a collection of all the items or observations of interest to a decision maker.

A sample is subset of the population. Sampling distributions are distributions that reflect the distributions of sample means.

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Process Capability

The Difference Between Capability and Stability? Once again, a process is capable if individual

products consistently meet specifications. A process is stable if only common variation is

present in the process.

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Process Control Charts

Implications of a Process Out of Control If a process loses control and becomes

nonrandom, the process should be stopped immediately.

In many modern process industries where just-in-time is used, this will result in the stoppage of several work stations.

The team of workers who are to address the problem should use a structured problem solving process.

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Control Charts

Each point representsdata that are plotted

sequentially

Upper ControlLimit (UCL)

Lower ControlLimit (LCL)

CenterLine (CL)

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Process Control Charts

Interpreting Control Charts The figures in the next several slides show different

signals for concern that are sent by a control chart, as in the second and third boxes. When a point is found to be outside of the control limits, we call this an “out of control” situation. When a process is out of control, the variation is probably not longer random.

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Process Control Charts

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Process Control Charts

Control Chart Evidence for Investigation

improved performance.

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Process Control Charts

Control Chart Evidence for Investigation

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Process Control Charts

Control Chart Evidence for Investigation

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Ch 6: Lecture Objectives - Process Control Understand “functional” versus “process”

management Understand how to analyze process data. Learn the benefits to process analysis and

control. Learn about “Value Stream” mapping

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Functional and Process Management

Billing

Product Development

Distribution

Dev

elop

men

tM

anuf

actu

ring

Mar

ketin

gSe

rvic

e

Supp

ort

Functional Objectives

Pro

cess

Ob j

e ct i

v es

Customer

Customer

Customer

Mission/Vision

Strategic Plan

Key business objectivesBoard of

Directors

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Value Stream Mapping

• A simple, visual approach to:

Focusing on a “product family”

Creating a clear picture of current material and information flow associated with that product family

Identifying Lean tools and techniques that can improve flow and eliminate waste

Incorporating those ideas in a new picture of how material and information “should” flow for that product group

Creating an action plan that makes the new picture a reality for that product family

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Value Stream Mapping

Value stream mapping is a paper and pencil tool that helps you to see and understand the flow of material and information as a product or service makes its way through the value stream. Value stream mapping is typically used in Lean, it differs from the process mapping of Six Sigma in four ways:

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Value Stream Mapping

It gathers and displays a far broader range of information than a typical process map.

It tends to be at a higher level (5-10 boxes) than many process maps.

It tends to be used at a broader level, i.e. from receiving of raw material to delivery of finished goods.

It tends to be used to identify where to focus future projects, subprojects, and/or kaizen events.

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Value Stream Mapping

A value stream map (AKA end-to-end system map) takes into account not only the activity of the product, but the management and information systems that support the basic process. This is especially helpful when working to reduce cycle time, because you gain insight into the decision making flow in addition to the process flow. It is actually a Lean tool.

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Value Stream Mapping It helps you visualize more than just the single-process level, i.e.

assembly, welding, etc. it helps you see more than waste

It helps you see the sources of waste in your value stream it provides a common language for talking about manufacturing processes it makes decisions about the flow apparent, so you can discuss them

It ties together lean concepts and techniques helps you avoid "cherry picking"

It forms the basis of an implementation plan it shows the linkage between the information flow and the material flow

It is much more useful than quantitative tools and layout diagrams that produce a tally of non-value added steps, lead time, distance traveled, the amount of inventory, and so on.

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Current State Map

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Future State Map

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Value Stream Mapping Movie