Tank Leaks
Leaks in a tank can be caused by many things. This story shows how to find the root cause and fix it.
Issue
Argon tank connecting to a wine preservation appliance leaked during EVT.
Tank pressure was good at IQC, but shows leaking after assembling, and causes low FPY at line and delay the schedule.
Root Cause Process
Using gas indicator to find the leaking point first, target the leaking components is at the connection between tank and appliance.
Inspecting the leaking tank and the unit, especially the connecting part. Found the sealing o-ring was damaged by the sharp threads of the regulator. But not all leaking tank with the damaged o-ring.
After further investigation, found the burrs at the thread of the regulator and the tank. The burrs were caused by the poor process control at supplier.
1. Deburring process added in SOP at supplier for the regulator threads
2. Discuss with supplier to find out where the burrs are coming from, which is causing the valve cannot seal.
3. Revise the IQC SIP. Adding inspection of the regulator threads
4. Revise the IQC SIP and sample size. Tank should be operated with test unit before testing. Test is conducted 15 days after that operation.
5. Suggest client that EC of the connection method between tank and appliance.
Those burrs from the tank caused other components leaking. And it cost a lot of time and resource to root cause with other suppliers.
We should collect the burrs to find out what the material of these burrs is.
That could identify the source components earlier.
Anyway, make sure add the deburring process in SOP at supplier and tell them how big damage it would cause. That works.