Transcript of Introduction to process control 2015
- 1. 2010 Colt Technology Services Group Limited. All rights
reserved. For internal use only Introduction to Process Control The
What and the Why Author: Ray McGlew
- 2. Managing by the Monthly Report Managing a company by means
of the monthly report is like trying to drive a car by watching the
central line in the rear-view mirror Myron Tribus
- 3. Limitations of Typical Monthly Reports Retrospective &
delayed data Difficult to interpret Impossible to explore
relationships between data elements Difficult to understand
variation
- 4. Variation Exists In Every Process Process Results Every
process shows variation in performance due to a combination of
factors People Offices Equipment Environment Process/Procedures
Systems/Applications
- 5. What is Process Control? Process Control is the routine
activity of monitoring a process to identify when action should be
taken and what type of action is required The type of action
required depends on whether the process is broken or unbroken
- 6. Unbroken Process Exhibits only natural variation Is stable
and results are predictable, based on the laws of probability
However, the process may not be capable of consistently delivering
the required results Variation predictable A Process that is
unbroken:
- 7. Broken Process Exhibits unnatural variation Is unstable and
results are unpredictable A Process that is broken: Variation?
- 8. What is natural and unnatural variation?
- 9. Natural Variation Also referred to as Random or Common Cause
variation Occurs due to the design & management of the process
itself Pointless trying to determine the cause of individual data
points Requires Management intervention to instigate process
analysis to identify and remove causes
- 10. Unnatural Variation Also referred to as Attributable or
Special Cause variation Occurs due to specific circumstances These
data points must be investigated immediately they occur These can
normally be resolved by the people operating the process
themselves, but not always
- 11. How Do We Determine What To Do? If a process is broken If a
process is capable of meeting its customers requirements The type
of action required to improve the performance of a process The
gains achieved by process improvement action Use Process Control
Charts to enable you to determine...
- 12. What is a Process Control Chart? It is a time plot that
indicates the range of variation built into the process The
boundaries of this variation are marked by Upper and Lower Control
Limits (UCL & LCL) These control limits.. are calculated
according to statistical formulas, using data collected on the
process enable you to quickly identify signals of unnatural
variation are not related to targets or budgets, they only indicate
what the process is capable of achieving
- 13. Parts of a Control Chart Upper Control Limit (UCL) Lower
Control Limit (LCL) Average Control Limits are calculated as 3
standard deviations from the average 302520151050 5 6 7 8 9 10 11
12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33
34 35 36
- 14. Basic Parts of a Process Control Chart 302520151050 5 6 7 8
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
32 33 34 35 36 The vertical axis is the unit of measurement e.g.
Days to Deliver The horizontal axis represents time e.g. Week
Number (data must be plotted in time order) The scale allows for
the level of variation inherent in the process
- 15. Basic Parts of a Process Control Chart A centre line is
calculated as the average of the data points collected 302520151050
5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28
29 30 31 32 33 34 35 36 Average
- 16. Basic Parts of a Control Chart Upper Control Limit (UCL)
Lower Control Limit (LCL) Average Control Limits are calculated as
3 standard deviations from the average
- 17. Basic Parts of a Control Chart Upper Control Limit (UCL)
Lower Control Limit (LCL) Average Warning Levels are calculated as
1 and 2 standard deviations from the average Zone A Zone B Zone C
Zone A Zone B Zone C
- 18. Signals of Variation How do you determine if the variation
is natural or unnatural? Look for the following signals
- 19. Natural Variation Data points fall randomly between the
upper and lower control limits and either side of the average line
UCL LCL Average
- 20. Signals of Unnatural Variation UCL LCL Data point falls
outside the upper or lower control limit Average These must be
investigated as soon as they occur
- 21. Signals of Unnatural Variation UCL LCL 8 consecutive data
points above or below the average line Average
- 22. Signals of Unnatural Variation UCL LCL Average 8
consecutive data points rising or falling
- 23. Zone A Zone B Zone C Zone A Zone B Zone C Signals of
Unnatural Variation UCL LCL Average 4 out of 5 consecutive data
points within Zones B and C
- 24. Signals of Unnatural Variation UCL LCL Average 2 out of 3
consecutive data points within Zone C Zone A Zone B Zone C Zone A
Zone B Zone C
- 25. Process Targets Targets for performance are determined by
the expectations of customers or business differentiators Process
Control Charts determine the actual level of performance a process
is capable of achieving Process Control Charts help to determine
the gap between target performance and actual performance
- 26. How to Identify Gaps in Performance The following slides
show how Process Control Charts are used to determine if there is a
gap between the performance its customers require it to deliver and
the performance the process is capable of delivering The first step
would normally be to identify the needs of the customers of the
process referred to as Voice of the Customer
- 27. Voice of the Customer 302520151050 Process OutputsInputs
Voice of the Customer Days to Deliver For this process, customers
have defined their expectation of service as no more than 10 days
to deliver
- 28. Voice of the Process Voice of the Customer Customer expects
10 days Process delivers between 5-25 days, average 15 days UCL
needs to be reduced to 10 days, gap is 15 days Process is out of
control Remove special causes first, then reduce common causes Gap
302520151050 Days to Deliver Voice of the Process
- 29. Voice of the Process Voice of the Customer 302520151050
Days to Deliver Voice of the Process Gap Process improved UCL
reduced to 18 days Average to 10 days Gap now 8 days Further
improvement required
- 30. Voice of the Process Voice of the Customer 302520151050
Days to Deliver Voice of the Process Process improved UCL reduced
to 10 days Target time can be guaranteed
- 31. Voice of the Process Voice of the Customer 302520151050
Days to Deliver Voice of the Process UCL reduced to 5 days Best of
Breed Competitive advantage
- 32. Key Messages Variation exists in every process Management
are accountable for reducing the variation inherent in a process
they have to instigate process improvement activities Staff are
responsible for investigating the variation that occurs in a
process Process Control Charts enable you to determine the level of
natural and unnatural variation within a process Process Control
Charts enable you to determine the gap between actual performance
and target performance
- 33. Interpreting the Control Chart Most of the points will
occur near the average line Few points will be near the upper and
lower control limits Rarely will a point fall beyond the control
limits The points should appear as a random distribution on the
chart, without cycles or trends As long as the process is operating
under a stable system, you can expect: