ISO 13485 Finding regarding Control of Timer Relays in a Coating Process

[Illuminatus]

We have the following coating process in our ISO13485 registered company:
1 - parts go into an oven for pre-heat
2 - parts come out and are manually dipped in powdered coating
3 - parts go back into the same oven for the coating to flow and cure
4 - parts come out and operator checks the coating
5 - if the operator judges that part needs extra time it goes back in the oven

there is a robotic arm that takes the parts in and out.
There are two adjustable relays that the operator uses to adjust the pre-heat and cure times based on part size/thickness -this tells the arm when to pick and place.

All parts are inspected by the operator when he removes them from the oven.
We have no internal or external complaints resulting from the coating process.

Here is the registrar's finding: "There are several different time settings for controlling the duration of the coating process. These timers are not controlled."

That last part is true... they are not controlled. But I contend that they do not need to be as they are constantly adjusted based on the part mix and it's the operator's call if the parts are finished... it's not up to the relay.

Thoughts on this? Thanks!

 

[somashekar]

Re: 13485 Finding regarding conrtol of timer relays in a coating process

4 - parts come out and operator checks the coating
5 - if the operator judges that part needs extra time it goes back in the oven

What does he check ?
How does he judge ?
To what temperature and how long to pre heat and to what temperature and how long to cure must be optimized and decided in advance based on several samples tested for the coating properties required to be met. Around this optimized points, the margins need to be fixed for the best process performance. Within these margins the operator would have the freedom to adjust. By control it means to have the process parameters validated, as the coating is a special process.
There can be several different temperatures and times, but they need to be decided in advance the best limits under typical conditions and the same must be met. If there happens to be a variation, that necessary stuff needs to be done to fine tune the process to again meet the requirement, and this is called re-validation.
In simple terms the coating process has to within your process validation plan and validation performed and variables constantly monitored for any re-validation requirement.

All parts are inspected by the operator when he removes them from the oven.

What does he inspect? Does it guarentee meeting all the coating process requirement ?
Going further, are there any controlled pre cleaning or preparation process before the coating process ?

We have no internal or external complaints resulting from the coating process.

This does not justify by any means that process validation is not a requirement.

 

[Illuminatus]

Re: 13485 Finding regarding conrtol of timer relays in a coating process

What does he check ?
How does he judge ?
To what temperature and how long to pre heat and to what temperature and how long to cure must be optimized and decided in advance based on several samples tested for the coating properties required to be met. Around this optimized points, the margins need to be fixed for the best process performance. Within these margins the operator would have the freedom to adjust. By control it means to have the process parameters validated, as the coating is a special process.
There can be several different temperatures and times, but they need to be decided in advance the best limits under typical conditions and the same must be met. If there happens to be a variation, that necessary stuff needs to be done to fine tune the process to again meet the requirement, and this is called re-validation.
In simple terms the coating process has to within your process validation plan and validation performed and variables constantly monitored for any re-validation requirement.

This does not justify by any means that process validation is not a requirement.

Let me make another thing clear - while coating may be considered a special process, in this application it's strictly aesthetic. It's not a performance coating. All that matters is that the coating covers the part and that it looks nice. We do not, nor have we ever, measured coating thickness.

Also - the oven temperature is not adjustable.

Criteria for "covers the part" and "looks nice" is documented in work instructions with photos of acceptable and rejectable parts.

 

[somashekar]

Re: 13485 Finding regarding conrtol of timer relays in a coating process

Let me make another thing clear - while coating may be considered a special process, in this application it's strictly aesthetic. It's not a performance coating. All that matters is that the coating covers the part and that it looks nice. We do not, nor have we ever, measured coating thickness.

Also - the oven temperature is not adjustable.

Criteria for "covers the part" and "looks nice" is documented in work instructions with photos of acceptable and rejectable parts.

That is great and makes your validation requirement that much less complex and hence easy ... but still remains a special process.
While you may be doing |<----------------->| , just come about to doing |<--|-->| for every part of yours with some simple batch checks for only the one variable which is the time.
Also back up with a control in the preparation process.
You are not far from meeting what control means in real terms ...

 

[Gert Sorensen]

Re: 13485 Finding regarding control of timer relays in a coating process

All validation should be based on the risk that the process poses to the user, and on whether the output is verifiable by other inspection techniques.

If your process does not pose a risk - and you have of course made a risk analysis of the process and product - then you are free to exclude the process from validation.

I would however suggest that you establish your parameters for the settings, and that you have some sort of training of the operators for the evaluation of Go-No Go of the products. That should satisfy your auditor.