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8D
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Towards Effective8DsTowards Effective8Ds
8 Discipline Problem Solving Approach D0 - Prepare for the Ford Global 8D Process
D1 - Establish Team
D2 - Describe the Problem
D3 - Develop Interim Containment Action (ICA)
D4 - Define and Verify Root Cause and Escape Point
D5 - Choose and Verify Permanent Corrective Actions (PCAs) for Root Cause and Escape Point
D6 - Implement and Validate Permanent Corrective Actions (PCAs)
D7 - Prevent Recurrence
D8 - Recognize Team and Individual Contributions
8 Discipline Problem Solving Approach D1 - Establish Team• Visteon SDE should be a part of the team.
• Include the actual ‘operating’ personnel in the team
• There should be Champion for the 8D – He questions / not a part of the work-team
D2 – Describe the Problem• Is this a ‘Chronic’ issue (Something changed) or a sporadic issue (never
been there) ?
• What is / is not the problem?
• Is this a mean shift issue or a excessive variation issue?
Off-Target
X XXX
XXXXX
XX
X
VariationX
X
X
X
XX
X
X
XXX
CenterProcess
Reduce Spread
On-Target
X
XXXX
XXXXXX
XXX
Understanding Problems
LSL USL
Off-Target
On-Target
CenterProcess
Reduce Spread
USLLSL
The statistical view of a problem
LSL = Lower spec limit
USL = Upper spec limit
USLLSL
VariationLarge
Understanding Problems
Understanding Problems Problem :
A Question posed for a solution, decision or determination.
A proposition requiring some operation to be performed.
DoNeed Mean off target ?Statistical Problem
Need
Do
Practical Problem Low yield ?
NeedStatistical Solution Find / Isolate Variables
Do
NeedPractical Solution Install Auto Controller
Understanding Problems
•Common Cause Variation–Source of variation which affects all individual values of a process; Random in nature.
•E.g. Ambient temperature; general vibrations in lathe; etc.
•Special Cause Variation–Source of variation that is intermittent, (often unpredictable); Non- random in nature.
•E.g. Tool broken; Change in RM composition etc.
In Control
Over adjustment/Out of control In Control
Inaction / Out of control
Common Cause
Special Cause
Common CauseSpecial CausePerception
Truth
Understanding Problems
2 Dimensions in Solving Problems
Type of Cause
Common Special
6 sigma
tools
SPCAuto
controlsFirst/Last off
SPC
Escape: A control system failure that allowed advancement of sub-standard product or service.
Escape Point: The earliest location in the process, closest to the root cause, where the problem should have been detected, but was not.
Global 8D – Unique concepts
D3 - Develop Interim Containment Action (ICA)
• Let know the total ‘suspect’ stock including those in transit
• Keep record of actual rejections from the 100% sorting done as a part of ICA.
• Clearly identify all the boxes which have been contained with labels detailing the actual characteristics checked.
• If possible also identify on the part itself .e.g absence of thread in a casting, mark on the thread to show that this was actually checked.
D4 - Define and Verify Root Cause and Escape Point
• The key word is ‘ROOT CAUSE’
• Need to ask ‘Why’s repeatedly till we arrive at root cause.
• Clearly differentiate the Process root cause and Escape root cause.
• Process root cause – What caused the part to fail?
• Escape root cause - What caused the bad part to slip past Supplier place to the Customer plant?
• Most important part:
• The ROOT causes have to be verified before we can proceed further. (90% of the 8Ds we see does not do this effectively)
• Proof confirming proper identification of the Root Cause/potential Cause.
• Performed in two steps: Passive, then Active.
• Passive Verification is done by observation. The presence of the cause is looked for without making any changes to the process. • If presence of the Root Cause/potential Root Cause variable cannot
be observed or proven, chances are great that the identified cause is not a Root Cause or potential Root Cause.
• Active Verification is a process where confirmation of proper identification of the Root Cause/potential Root Cause is made by making the effect come and go using the variable identified as the cause. Both coming and going are essential tests of Root Cause/potential Root Cause confirmation.
Verification of Root Cause
Choose PCA• 80% of the 8Ds lack link between root cause and PCA !!
• PCA should address both Process Root Cause and Escape root cause.
• PCA should address the Root cause and not an intermediate cause.
• E.g Molder short shots case study.
• Addressing an intermediate cause can lead to
• Repetition of the initial issue
• Creation of a new issue
Verify PCA• Verification of Actions: Proof developed BEFORE
implementation that the action taken will do what is intended by providing before and after data comparison and does not introduce a new problem.
• Verification activities may include the following: • Tests and demonstrations • Comparing the new action with a similar proven action.• Reviewing newly designed documents before their
release
Validate PCA• Validation of Actions: Ongoing evidence that the
implemented action is doing what was intended without introducing a new problem.
• Validation follows successful Verification.
Validate PCA•Pre-customer Validation is ongoing evidence (data) - before exposure to the customer and following successful Verification - that the implemented action is still doing what was intended without introducing a new problem.
•Validation activities may include tests,inspections, observations and other quality checks performed on production product using the specified production process.
•These tests, etc., are correlated to the customer's symptom and are good indicators of action effectiveness.
•Customer Validation is ongoing evidence (data) - received from the customer - that the action taken to eliminate the customer's symptom is still working.
•Confirmation is obtained by monitoring the same indicator that demonstrated the symptom initially.
•Performance results of the indicator may be tracked using the Paynter Chart.
Prevent Recurrence• This is the toughest part!!• We tend to relax once the problem disappears
momentarily.• Document the corrective actions in FMEA /
Control plans / Operator Instructions.• Read across to similar product / process lines• Redefine Standards based on lessons learnt.
Control plans• Process control
• Product inspection
• Sampling size
• Frequency
• Default is 5 pcs every hour