SIDDHESHWAR JANGID

Single Point of failure
What it is (SPOF): - Any Person, Facility, Equipment, Software or any other resource for which no redundancy is available and if that goes down, the process or system dependent on that resource will stop totally. In such cases, the daily function of that process or system is hampered. 
 
 
Method to identification of SPOF
Common sense can be used to find such failure modes. Otherwise, detailed risk assessment can be performed to do so.  
Risk assessment tools like PFMEA may help to find such all-failure points in any process.  During the design phase itself DFMEA can be done.   HIRA can be performed to find operation related failure mode.  Hazop is again a widely used tool in risk assessment in process industry.   With all these tools most of the SPOF (Single point of failure) can be found.  
 
 
Methods to Mitigate such risks
Found all SPOFs must be classified in Severity, Detection and Occurrence to priorities to implement Mitigation plan. 
For the mitigation of such failure below action can be taken 
Create a redundancy plan in case of such failure. Support from an internal or external team can be taken for this.  Create a buffer of such part.   Training in hiring of people must be done if SPOF is a person, whose skill is mandated to run day to day operation.  Flexible layout of the system can be done to eliminate the point so in case of failure other available systems can be used.   
 Example: - 
 
Taking a case of manufacturing 
 
Out of all machines some critical machine or part of machine are available 1 or 2 only and if that fails whole manufacturing stops.  Malfunction of Data base system can stop all machine internal working.   Some specific tasks can be done by X person because he is having only training of that task, or one else is interested in same.  Air (Utility) is critical for some Manufactuing operation, failure of which can stop the plant.   
To mitigate the same 
 
Critical machine components must be procured and stored in inventory.  An additional standby server should be available in case of any issues faced.  Hiring or training existing staff must be done critical task.  Standby Air compressor can be installed to mitigate such failure of Air pressure.   Put system such that before occurrence of such failure, it can be found if cannot be implemented.   
 

 
 

Defective % can be calculated by taking a ratio of Total No of defective items with Total observed Items and Yield is not thing but 100 % - Defective %. 
 
So, calculating accurate total no of defective is very critical in Yield % calculation. 
 
Below Is the table for challenge faced and counter measure (solutions) to address these challenge
 
 
 
Challange Faced 
Counter Measure 
Data accuracy and consistency  
Inaccurate data can lead us in wrong direction of analysis 
Data collection system can be automized 
Standard data collection method can be set and operator to be trained on it 
Frequently changing operational definition 
Operation definition of inspection station CTQ has changed many times as per customer criteria. Which creates confusion between operators.  
CTQ definition can set on High standard, single definition can cover all customer requirement 
Operator skill level 
 
Deputing Un-skilled operator on inspection station in always a challenge. New operator many times takes time to understand all defects 
MSA must be done to ensure that data collected is reliable 
Multi skilling of operator can be done to handle such situation. 
AI based systems always make this process easy by auto identifying defects with location as well as defect name. 
All Defects are not visible. 
Sometimes all defects of a product cannot be seen due to eye fatigue or monotonous Job.  
AI based camera system can identify 100% defects. 
Job rotation in 2-3 Hr a shift of the operator on this type of station where eye fatigue is quite possible 
 
 
 
Example:  I am considering a Solar Panel for this Example.  In any solar panel manufacturing process below can be top defects. 
Poor soldering - Soldering not done up to required strength  Ribbon Misalignment – Ribbon wire not on its place  Cell Crack – Solar cell got a crack  Dark Area in cells – Solar cell coming black in testing  Gap Between Cell to Cell and other defects.    
 
 
Here in inspection process of solar module, two images are captured (visual image – to check visual defect & EL image – to check electrical related defects.). Operators need to look on the image and identify defects.  
Challanges faced in this inspection process are below 
Many times all defects cannot be logged due to manual process and data accuracy is not there.  Not able to see because of human incapability of taking right measure by eye.   Wrongly assessed defective as operator is newly deputed or, customer criteria are change and he is not trained.     
To address these challenge  
 
MES (Manufacturing execution system) can be used for fast data logging and data accuracy.  On defined Frequency MSA to be conducted for operator.  AI enabled system can be installed to identify all defects and criteria changes can be assessed by AI software only.