FDS - Fault Data Spectrum is a simple yet very Effective and Necessary tool to Monitor the effectiveness of corrective actions for Field Problems.

1. 1
Title
Fault Data Spectrum:FDS
an important tool to monitor effectiveness of corrective
actions in Field before it is too late
By K Umesh

2. 2
Manuscript
The Objective is to introduce a tool to monitor the effectiveness of Corrective Actions on a
continuous basis so that the “Faults” cease to appear . If the “Faults” still appear after the
Corrective Actions, it is visible early so that the Organization regroup the teams together to start
another Cycle of “PDCA” with a proper root cause analysis and help with a fully Effective
Corrective Action.
The Corrective Actions may be taken on a Production or a Field Problem where the impact is
External and deep and can cause substantial loss of repute to the Organization at the cost of a
disenchanted Customer.
Brief Definition Of Fault :-
A “Fault” can occur in a Process, Component or a Product if one or more of the parameters
deviate beyond permissible limits of Design Intent. A Process Fault can occur due to high
dispersion and is controllable with control on the Process and Machine Parameters. The outcome
of a Process Fault will be a Faulty Product ultimately.
A “Fault” can also occur if the desired output is not achieved with the intended Design Input. A
Fault due to Design inadequacy will be highly repetitive in nature.

3. 3
All “Faults” are not similar in Impact with few in small nos. having a catastrophic effect on the
Product e.g. Safety Faults. While there may be others in large nos. but not noticed by a Normal
Customer but only by a “Highly Discernible Critical Inspector”. Such Faults do not have any
impact on the Functional or Reliability aspect & If they are overcome through simple Process or
Material change, it is pragmatic.
Thus, Faults need “Classification”. “Acceptance Quality Levels-AQL” can be decided for different
categories of Faults based on the Criticality of the Product. A Critical Healthcare equipment will
have a very rigid AQL.
See example below where the Faults are classified, coded and can be traced in the Field later.
The “Fault Codes F1 ..F13” shown are derived during development stages but will be used in Field
later.
Part Name
Part No
Date
Supplier
Classification
K A B C
1. Safety F1 a) Poor Weld Joints X
F2 b) Missing :Part Missing X
F3 c) Sharp Edges X
F4 d) Tube Crack X
F5 e) Weld Cracks X
2. Functional F6 a) Weld Discontinuity X
F7 b) Uncoverage of Paint /Coating X
F8 c) Paint peel off X
F9 d) Rust formation X
F10 e) Bubbles X
F11 f) Fastening Points - No Thread / Oversize /Undersize X
3. Minor / Appearance F12 a) Poor Surface Finish X
spot, pit marks, streak mark, scratches, flashes, burr
F13 b) Dirty
- Difficult to clean X
- Easily cleanable X
d) Surface Scratches
- Severe X
- Minor X
FAULT CLASSIFICATION
Chassis Frame Assy Document No xx/xxxxxx/001
xxx-xx-xx Revision R0
Fault type Fault Description
DD-MM-YYYY Prepared By----> xxxx/yyyyy
xyz, ABC Approved By----> zzzzzz
Fault
Codes

4. 4
Concept of “Fault Data Spectrum-FDS” :-
In the event of a Field Complaint, PDCA Cycle is used for Corrective Actions. “PDCA Cycle should
be Short & Effective” otherwise it will require another Cycle Causing delays & bad Customer
Perception.
Start Project
Collect Data
Identify Process
&
Set Target
Analyse Problem
&
Determine Cause
Decide On
Corrective
Actions
Implement
Solution
Review &
Assess
Results
Standardise
Solution
Conclude
Project
Plan
Do
Check
Act

5. 5
Customer perception gets affected if the Corrective Actions are not effective and that is
monitored through “Fault Data Spectrum”.
Fault Data Spectrum Tool
“FDS-Fault Data Spectrum” is a tool consisting of “Fault Classifications” with a “Positrol –
Positive Control Plan” in a Grid Structure.
The Tool has an FDS sheet and a Positrol sheet. The FDS sheet contains Faults Codes & Product
Sr.Nos. In each column it has color shades showing the implementation of Actions with reference
to the Manufacturing Month or Product Sr.No. After the implementation of the Corrective
actions the Faults should taper drastically or become zero.

6. 6
FDS of a New Product – an Outdoor Application Vacuum Cleaner with Fault codes & upto 3000
nos. sold.
For Faults F1 and F2, a corrective action was taken after Product No.226 but the action was only
partially effective as it did not eliminate complaints altogether. Only after another PDCA cycle at
Product No.326, the Faults did not recur in 2700 Products sold.
But additional PDCA Cycle has taken time equivalent of 100 Products manufactured and this is a
costly lapse for the company. Faults 3,4,5,7 & 8 have shown first time right corrective actions.
Final Effective
Solution
80 41 13 5 6 3 5 4 3
475 ~ 3000
400 ~ 475
375 - 400
351 - 375
326 - 350 1
301 - 325 1 1
276 - 300 1
251 - 275 1 1
226 - 250 1 3
201 - 225 1 1 1 1
176 - 200 6 1
151 - 175 4 1 2 1 1
126 - 150 7 2 2 2
101 - 125 2 1 1 1
76 - 100 13 2 1 1
51 -75 1 1 1 1
26 - 50 1 2 1 1
0 - 25 5 1
F1-Fault 1 F2-Fault 2 F3-Fault 3 F4-Fault 4 F5-Fault 5 F6-Fault 6 F7-Fault 7 F8-Fault 8
xxxx not
opening
with yyyy
xxxx not
opening
with zzzz
xx/yy not
opening
from inside
xx/yy not
opening
from
outside
xxxx noise
(abcd
loose)
nnnn
failures
xxxx switch
failure
White dot
markTotal
Production
Batch / Fault
Types
Containment Action
Interim Action-not fully
effective
Fault Data Spectrum for XXXX Assy

7. 7
Corrective Actions are described in Positrol sheet :-
Variation in xx Capacity:
Higher
All xxx above 180grams used 259 onwards
Intermittent operation in
rainy condition due to
water entry
-Hot glue application for connectors
-Wrapping of xxxx motor and
connector to avoid water ingress.
315 onwards
Variation in xx Capacity:
Higher
All xxx above 180grams used 259 onwards
Intermittent operation in
rainy condition due to
water entry
-Hot glue application for connectors
-Wrapping of xxxx motor and
connector to avoid water ingress.
315 onwards
F3
xx/yy not
opening from
inside
Bend length of xxx bigger
link is found insufficient to
hold the link even if the
clip is unlocked.
2. The xxx link bend length increased
by 2 mm
259 onwards
F4 to
F9
F2
xxxx not
opening with
zzzz
Similar method
Implemented
On
Status
F1
xxxx not
opening with
yyyy
Fault
Code
Fault
Description
Analysis Corrective Actions

8. 8
Example of a domestic Hair dryer which has 5 Major Faults.
For Fault1 , the corrective action was effective only in 3rd
Cycle.
Final effective solution
Intrim action-Not
fully effective
Intrim action-
Not fully
containment
action
30 24 3 1 1 1
375 - 10000
351 - 375
326 - 350 1
301 - 325
276 - 300 1
251 - 275
226 - 250 2 1
201 - 225 1
176 - 200 1
151 - 175 2
126 - 150 3
101 - 125 3
76 - 100 2 2 1 1
51 -75 5
26 - 50
0 - 25 3 1
Prod. Batch Fault 1 Fault 2 Fault 3.1 Fault 3.2 Fault 3.3
Switch operating
but lever not
moving
Solenoid
driver
failure
Driver fault
in pcb
Reverse lamp
driver failure
Fault Data Spectrum for Hair Dryer
Total
Fault types
Switch not /
intermittently
working
Positrol-Hair Dryer
Fault Code Fault Description Analysis Corrective Actions Implemented OnStatus
Flashes in switch cap assembly
Flashes in switch cap removed 001
Suction cup sticking to the switch bkt
Retainer design modified 314
Switch intermittent due to black
deposition after around 1000 cycles Switch make changed to xyz 384
Detent plate got bend
1.100% hardness checking of detenet
pin and bush.
2.Torque mark on detent plate screw to
be ensured @ incoming stage
347
Solenoid pin touching to PCB
housing
Pokayoke implemented @ supplier end
for complete pressing of solenoid pin
347
F3.1 Solenoid driver failure
Driver Optocoupler failure in xxxxx
PCB
Defective part sent to supplier for analysis
100% diagnostics checking @ supplier
end
347
F3.2 Driver fault in pcb
lead bridging positive signal track
and Dig 1 output pin short
100% diagnostics checking @ supplier
end / FI
347
F3.3 Reverse lamp driver failure Reverse Reed switch damage
100% diagnostics checking @ supplier
end /FI
347
F1
Switch not /
intermittently working
F2
Switch operating but
lever not moving

9. 9
Conclusions :-
“Fault Data Spectrum” is a very effective tool to monitor the effectiveness of corrective actions. It
can detect early and initiate another action without loosing much time and make a solution
permanent.
“Fault Data Spectrum” and “Fault Classification” are linkable and can take the actions upstream
at Tier 1, Tier 2 and Tier 3 supplier level. They can be used during Development Phases and each
Failure encountered in Alpha, Beta or Pilot Production can be seen for Closure effectively.