Hi jaejay ,
More details required to give more specific feedback ,
- - Is the magnetic trap is a CCP in your process , or it is a control point and there is another point after it is controlling the risk as CCP.
- - The product passing through the magnetic trap is it a raw , semi finished or final product .
- - What is the maximum capacity of the metal dust for the magnetic trap ,Heavily contaminated magnets lose separation ability - pulling and holding power decreased( i mean after this load the trap will not be effective ).
-Normally the magnetic trap is to remove ferrous objectives , so if it is a CCP in the system , the control limits is either the magnetic trap working or not working , or we can set a limit for the metal dust weight as per question 3 above , and then judge the magnetic trap beside assuring it is working ,
I believe that the monitoring records is a important step, use it to decide the frequency of checks , from your record you will know the level of contamination and expect when it should be checked and cleaned .
your historical records could give you
- Heavily contaminated magnets lose separation ability (pulling and holding power decreased).
- Expect complete cleaning and removal of any metallic materials (supplier performance implications , timing for decision making).
- Understand product flow, accumulations.
As per my experience I were checking it at the change over before the cleaning , however it depends on the process , in line placement , how easy to check , can we check during operation or not .
So if you want to set the critical limits if needed you can :
- magnetic trap is working
- metal trapped weight less than the maximum load for the magnetic trap ( you can get it from magnetic trap standard or you can use a lower limit as per your historical records ) .
- As per your historical records , process , availability to check
- Replace the magnetic trap with a lager one or reduce the frequency of cleaning .
hopefully this could help .