Severity Reduction by Product or Process Design Change? Seeking Good Example

B

brutas

#1
Please help, I need a good example of Severity reduction by product or process design change. It would be great to see examples for both cases.

My filed is microelectronics. Our processes are focused on testing (probing of wafers and final test of assembled devices).

My coleagues always ask for good examples and I cannot explain correctly.
What do you think about this case:
Process Function/ Requirements: Assure reliable recognition of the probed dice (legible and centered ink dots)
Potential Failure Mode: Recognition is not reliable (some ink dots are illegible)
Potential Effect of Failure: Rejected dice processed at Assembly house
Severity=8
Cause: Equipment malfunction (inker defect)
O=3
Prevention: Preventive maintenace
Detection: During WAK (visual)
D=7
Action: Switch to inkless probing

This is a change in a process: switching from ink probing to inkless (software marking) but I think this reducess the Occurrence not Severity...

Can you give me an examples for common processes like Packagin, Storage, Shipping?
I urgently need both cases - reduction of Severity through product or process design change

Thank you!
 
Last edited by a moderator:
Elsmar Forum Sponsor
M

mariav_66

#2
Re: Good example for Severity reduction by product or process design change?

Hi Brutas,

If you can reduce the occurrence or detection level that will reduce your RPN number and it is OK, the severity level in most of the cases can't be reduced.
Your current RPN number is:
8 * 3 * 7 = 168

If you reduce your occurrence level to 1 your RPN number will be:
8 * 1 * 7 = 56

This is a good improvement but for example if you reduce your detection level to 2 then your RPN number is:

8 * 1 * 2 = 16 Excellent!
 
J

jeffrey_Chang

#3
Hi Brutas,
In your case, you have replace the inking process by using the wafer map (inkless) and thus you have actually designed out the failure mode, a redesign of the process. Hence, the severity of the failure has been eliminated, inkless means no more ink dot illegible problem.
As such, I think you have already provided an excellent example of severity reduction. However, with wafer map, you've other sets of problem and risk that you will need to address.
thks.
jeffrey.
 
Thread starter Similar threads Forum Replies Date
M Severity Reduction in a Design FMEA (DFMEA) FMEA and Control Plans 26
C FMEA Severity Rating for aggravating failures IATF 16949 - Automotive Quality Systems Standard 6
M Inconsistency of VDA-AIAG severity table for DFMEA with the manual text FMEA and Control Plans 0
K PFMEA Severity (9-1) mitigation needed? FMEA and Control Plans 20
R DFMEA/PFMEA mitigation of high severity (9-10) in low volume products IATF 16949 - Automotive Quality Systems Standard 1
silentmonkey How to measure severity if my product is designed for emergency use and failure would result in death? ISO 14971 - Medical Device Risk Management 9
J On PFMEA for danger labels - Label always should be assigned severity 10 ? FMEA and Control Plans 3
S The Severity of a Medical Device Hazard - Risk Analysis Clarification ISO 14971 - Medical Device Risk Management 6
MrTetris Informational Risk Register - Same hazardous situation, different severity of harms ISO 14971 - Medical Device Risk Management 7
A PFMEA severity score different applications FMEA and Control Plans 11
X Customer Service FMEA - Specifically Customer Care / Severity Rankings Service Industry Specific Topics 3
D How to fill a Process FMEA - Three columns - Severity, occurrence and Detection FMEA and Control Plans 16
R DFMEA Severity 9-10 with Occurrence 3 and Detection 3 - Actions FMEA and Control Plans 3
S What should the FMEA Severity for SC & CC Characteristics be? FMEA and Control Plans 5
N AIAG 4th ed. FMEA Manual "Fit" Changed to "Appearance" - Fit severity? FMEA and Control Plans 2
G Severity in Process FMEA for Rework Process FMEA and Control Plans 1
O PFMEA - Reducing Severity (S) Ranking - Manufacturing Process Design Changes FMEA and Control Plans 4
S FMEA's - Severity and Classification of Print Characteristics FMEA and Control Plans 1
N Risk Severity Estimation for Medical Devices as per ISO 14971 ISO 14971 - Medical Device Risk Management 12
C Determining PFMEA Severity for Armored Parts FMEA and Control Plans 5
C FMEA DOGMA about Severity - Am I right or Wrong? FMEA and Control Plans 2
K 4th Edition AIAG FMEA Occurrence, Severity and Detection Criteria for Plastics FMEA and Control Plans 1
F Risk = Likelihood * Severity - Can we mitigate the Severity? Occupational Health & Safety Management Standards 44
E Risk Management selection Probability of Occurrence and Severity ISO 14971 - Medical Device Risk Management 24
S Severity of 9 or 10 should be identified as Special characteristic? FMEA and Control Plans 10
G Internal vs. External PFMEA Severity Rankings FMEA and Control Plans 12
R Risks which must be Distinctly Identified - Harm, Hazard, Severity ISO 14971 - Medical Device Risk Management 7
C Severity of Effect on Process (Manufacturing/Assembly Effect) Scrap or Reworking FMEA and Control Plans 3
W Severity Rating CORRECTIVE ACTIONS - Opinions Wanted Please Nonconformance and Corrective Action 15
H DFMEA Severity Ranking of Non-Compliance to EMC Standards FMEA and Control Plans 2
P Chemical Purity Testing - FMEA Severity Scale FMEA and Control Plans 2
T FMEA Severity 9 &10 - Example of "with warning?" FMEA and Control Plans 6
E Harms Severity Scoring - Combination of Hazards ISO 14971 - Medical Device Risk Management 4
B The Distribution that represents the Severity of Nonconformances Nonconformance and Corrective Action 2
A AIAG Design FMEA Severity Rankings - Noncompliance Government Regulation? FMEA and Control Plans 9
D Severity or Occurrence? Performing an FMEA on Motorcycle Operation FMEA and Control Plans 9
L FMEA Occurrence, Severity and Detection Criteria FMEA and Control Plans 3
I Ford FMEA requirements for Severity and Occurrence Rankings Customer and Company Specific Requirements 1
G FMEA Severity Ranking for an Automotive Audio System FMEA and Control Plans 9
Chennaiite FMEA Severity Rating for Potential Manufacturing Effect mentioned in the FMEA manual FMEA and Control Plans 9
kedarg6500 FMEA Severity Scale - Higher for Failure at Customer's or End-Customer's place? FMEA and Control Plans 19
M FMEA Severity Ratings for Health Care Information System FMEA and Control Plans 10
C Does the PFMEA Severity have to match the DFMEA Severity? FMEA and Control Plans 3
P Measuring Severity of Construction Nonconformance Report Nonconformance and Corrective Action 3
L Standard for process control level depending on gravity (severity)? FMEA and Control Plans 7
I Defining a Severity Level of a non-conformance Nonconformance and Corrective Action 13
Y Severity, Occurrence and Detection FMEA Ranking Tables - Guidelines? FMEA and Control Plans 8
L FMEA - Should a severity of 9 or 10 be always followed by recommended actions? FMEA and Control Plans 2
J Severity of Finding for "Past Due Gage" found on the shop floor General Measurement Device and Calibration Topics 40
S FMEA Severity of 9 or 10 - Shower does not operate FMEA and Control Plans 13

Similar threads

Top Bottom