Sunday, October 1, 2023

What is QA Matrix and PAC-Verification?

QA Matrix & PAC-Verification

QA Matrix is Quality Assurance matrix. Basically QA Matrix is summary sheet of all critical and non critical items and their control in process. QA Matrix contains PAC-V result over measurable and Non measurable items.
PAC-V is Process assurance capability verification. Purpose of PAC-V is to check whether we have to do inspection 100% for any critical items or we have to do inspection on sample base for variable dimensions as well as non variable items. For that we will calculate Cp & Cpk.
Both are part of MQS (Manufacturing Quality Standard) deployment process.
As you can read my previous articles on Honda QAV audits. I explained details what is Honda QAV audits and as well as what is purpose of Honda QAV audits?
Click Here to read following article on QAV-Audits of Honda and other OEMs.
Here is photo which explain steps of Honda QAV audits. See below picture-
HONDA QAV Audits Types
Here MQS (Manufacturing Quality Standard) & MCP (Manufacturing Control Plan) are prepared before QAV 2 (Step-2) audit.
QAV-2 step 2 is planned before tool Go-ahead. So supplier will prepared MQS/PAC-V Deployment measures. Purpose of MQS/PAC-V deployment measures is to identify and deploy important control items with control standards in manufacturing process to ensure the prevention of critical problem in CBU (Complete build unit).
So Honda QAD Engineer will ask supplier to submit 4 set of documents.

Following are 4 sets of documents:-

  1. MCP
  2. PQCT-1 (Process Flow Diagram)
  3. PQCT-2 (Process Quality Control Table-Control Plan)
  4. QA-Matrix
To reach up to QA matrix, we have to first make MQS in which we have to identify top symptoms, control items & standards identified. Then we will prepared MCP in which we will reflect important control items. Then we will prepared QA matrix in which we check existing process assurance capability. Now in last we prepared PQCT-1, 2 in which we will reflect those control item in process.
In short we have to understand that for MQS, QA Matrix to be prepared after MCP.
To prepared QA Matrix, we have to understand component drawing & accordingly we have to decide category of measurable & Non measurable items from drawing. In sheet we have to check Process assurance capability -Verification (PAC-V).
PAC-V result to be check OK* and NG* for measurable as well as non measurable items. (Here items could be dimensions, drawing Note, Customer specific requirement).
Entire QA Matrix sheet can be understood by 4 major columns. Horizontal understanding of each column.
First Horizontal Column we have to decide if there is any change in process.  As well in this column we have to do comparison of base process flow and new process flow. So we have to write operation name for base process as well as for new one.
In second column we have to check if there any change in 4M situation for process flow. Here we will check change at each operation of a process.
In 3rd Column there is PAC-V OK & NG conditions.

What are PAC-V conditions? 

(PAC-V) will be OK if:-
  1. Process Assurance (Type a, & b) result are OK for Critical items.
  2. Critical items included in PQCS and Operation Std.
  3. Operator aware about Critical item’s importance.
Type (a) Measurable items (Examples):-
  1. Variable Dimensions
  2. Torques
  3. Hardness tests
  4. Weld penetration
  5. Cross Section dimension for which part cut is must
  6. Breaking toque / load etc.
Condition for Type (a) Measurable items is as below:- 
1. If Cp & Cpk is less than 1.33 then we have to do 100% of that dimension
2. If Cp & Cpk is more than 1.33 then we will follow inspection based on sampling.
Type b. Non Measurable items (Examples)
  1. Assembly (Coupler, Bullet terminal. etc.)
  2. Visual Inspection
  3. Grease / Oil /Adhesive applications
  4. Manufacturing process parameters
  5. Specification test (e.g. – Leakage test, Electrical Functions checks etc.)
  6. Material
  7. Salt Spray / CASS tests, Paint adhesion (100/100 etc.) Offline tests [Double check exempted]
  8. Specification test (e.g. – Durability/ Endurance tests, Destructive tests etc. ) [Double check exempted]
Condition for Type (b) Non- Measurable items is as below:- 
If minimum 200% inspection required for non measurable items then we will follow sample based inspection.
In 4th Column we will list out all critical items and their control values & inspection process over those critical items. In right hand side of same column there will be PAC-V result , which mainly depends upon Cp & Cpk.
If measurable item we have to calculate Cp & Cpk, if non measurable ,we will decide no of inspection (Which should be double or more in entire manufacturing process).
Below is MQS deployment Procedure for Honda QAV, PAC-V & QA-Matrix.
Following step are adopted for MQS deployment for Honda 
  1. MQS Issue to supplier
  2. Add MQS deployment plan in MCP
  3. Identify control method in QA Matrix
  4. Simulate PAC-V in similar past model and similar part
  5. Input control item in PQCT, ops
  6. Conduct PAC-V during events
Hope you found this article useful, please write to me for any feedback and suggestions.

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