V
vasudev
what is validition of special process (man,M/c or operations) & which processes are called special processes & why not all the processes are under scope of validation
In most situations it is possible to check/verify that a job has been done to the required standard by conducting some sort of inspection activity e.g. you manufacture a simple component and then you check the length and diameter.
On other occasions you may perform a process such as sticking together 2 pieces of paper and the only way to check they are stuck properly is to tear them apart. Therefore, it falls into this category we used to define as 'special processes'. Because we cannot verify that the job is done to the required standard, we emphasise the control aspects of the process such as what type of glue, what temperature/humidity, how much glue, held together for how long, under what pressure, etc.
These parameters would be established beforehand (through trials perhaps) in order to provide as much assurance as possible that the job works as required.
so do we have to validate the process every time before start of the production...
Revalidation only needs to be done 'as applicable'. If the welders need refresher training or 're-coding' periodically then go ahead. If the criticality of the work you are doing is low and the other controls are all in place then the need to do revalidation is less or not required at all.
You can verify the success of the welding process by the number of nonconformaces created, the number of complaints and returns etc. Obviously, if the work is more critical you cannot wait for things to go wrong before acting.
vasudev,
That depends on what the process is.
For example - on our paint line, we perform certain checks on the process at the begining. We check the titration of the wash line chemicals, we verify the temperatures and line speed of the curing oven.
As Colpart said - revalidate as applicable.
what if we are doing 10% of jobs which require pressure testing (critical welding for oil tanks) & 95% are just covers,cabinets... even we checked rejection level of this oil tanks which we supply @750 a year & for last 10 years we are supplying it where in we had 3 rejections so far from customer... that too almost 3 years back than after as on today no rejections so what do you suggest
what if we are doing 10% of jobs which require pressure testing (critical welding for oil tanks) & 95% are just covers,cabinets... even we checked rejection level of this oil tanks which we supply @750 a year & for last 10 years we are supplying it where in we had 3 rejections so far from customer... that too almost 3 years back than after as on today no rejections so what do you suggest
we are in the bussiness of sheet metal fabrication... hence welding is one of the process.... if we weld as per the set perameters like current, wire feed, gas feed than what should be the freqency of validation of process or validatoin of welders....