Sustain Aid

Analyze Stability

Analyze Capability

Processes that are "out of control" need to be stabilized before they can be improved using the problem-solving process. Special causes require immediate cause-effect analysis to eliminate variation.

When Cp, the process capability index, and Cpk, the centering index, are over 1.0, the process is capable, but most manufacturers require Cp>1.33. Lower Spec Limit

The following diagram will help you evaluate stability in any control chart. Unstable conditions can be any of the following:

Upper Spec Limit

Waste

Capable Cp>1 Cpk>1

Rework Target

3σ 2σ 1σ

-1σ -2σ -3σ

SPC Simplified

Cpk 1.0 1.33 1.66 2.0

How to Plug the Leaks In Your Cash Flow! SPC SIMPLIFIED

Sigma 3 4 5 6

Use the problem solving process to identify and prevent the root causes of waste (usually below the lower specification limit) and rework (usually above the upper specification limit). The goal, is to reduce variation so that all of your points fit within the specification limits, clustered around a target.

Time to Install (Before) Any of these conditions suggests that an unstable condition may exist. Consider investigating the special cause of variation. The QI Macros automatically identify these for you. Use the Ishikawa diagram to analyze potential root causes. Once you've eliminated the special causes, you can turn your attention to using the problem solving process to reduce the common causes of variation: BEFORE

Problem Solving AFTER

8 7 6 5 4 3 2 1 0

11 10 9 8 7 6 5 4 3 2 1 0

LSL

SPC Made Easy

USL

SPC Made Easy Quick Reference Card For SPC Video © 2006 Jay Arthur

Time to Install (After) LSL

KnowWare® International, Inc. 2244 S. Olive St. Denver, CO 80224-2518

USL

(888) 468-1537 or (303) 756-9144 (888) 468-1536 or (303) 753-9675 (fax) $3.00

[email protected] www.qimacros.com

Choosing The Right Chart

Sustain the Improvement

QI Macros Sample Data

Sample Size

Purpose: Stabilize and Sustain the Improvement

Defect Data

Key Tools Flowchart: Show the flow of work through a process including all activities, decisions, and measurement points.

Count Defective Items?

X

Defective? Yes/No

Defective

Step Activity

Defects People Events

X

X

How many defects?

X

1 Refine the process

Define Measure

2 Identify the critical to quality indicators (CTQs)

Improve Measure

3 Implement the critical to quality indicators

Sustain Control

4 Check the process for stability and capability

Honor

5 Review, recognize, and refocus

SPC Training Video To learn more about SPC, consider our 1 hr video: www.qimacros.com/sixsig267.html

u Chart

Varies errors/orders components/assemblies Patient falls/days

Count Number of Defects Per Item

More than one defect per item

Rates or Ratios?

Services & Manufacturing

XmR Individuals

Cycle Time

XbarR

(Measured) decimal: 1.3 Time

Length Weight

Variable Data

1 length or weight per item time/project cost/project infections/1000 patient days 2-10 diameters, lengths tensile strength resistance

Variable

Height

Focus

c Chart

Constant injuries/month Patient falls/month

(counted) integer: 1,2

Sustain The Improvement (Control) FISH

p Chart

Varies wrong orders/orders medication errors infections/patient days

Attribute

Control Chart: Help analyze, sustain, and monitor the current levels of process stability and to identify key issues for problem solving or root cause analysis. Histogram: Determine the capability (i.e., the level of performance the customers can consistently expect) of the process and the distribution of measurable data.

Constant defects/100

np Chart

Cost

11-25 diameters, lengths tensile strength resistance

$ XbarS

Samples used to analyze large runs of product

Manufacturing

Download a FREE 30 day evaluation copy To automate these charts, try the QI Macros for Excel. www.qimacros.com/freestuff.html.

Control Chart Wizard The QI Macros can analyze your data and select and run the right control chart for you.