I have seen a few questions on here about the SMT room and it sounds like the consensus is making the entire SMT room an EPA. All the machines, personnel, any area where unprotected components and circuit boards would be affected are all grounded. My question is how does this work when there are other items/benches/shelving that are not grounded but still required to be in the area to run the room correctly?
Josh,
Making the whole room an EPA may be a good idea if you have ESD flooring installed and are using a footwear/flooring system for personal grounding or if the entire floor is automated and having the machines grounded.
Your question on how to deal with “other items/benches/shelving that are not grounded but still required to be in the area” is a good one. You could make those areas not be part of the EPA by doing something like taping the area off. You could also consider labeling the bench/shelf something like “Not ESD Safe” so personnel know they cannot safely handle the ESDS items there. These options still run the risk of personnel ignoring the signs and putting the ESDS items on a non-compliant bench/shelf. The only way to ensure this can’t happen is to make all the benches/shelves in the room compliant or remove them entirely. You may also consider having certain areas on the floor where your non-compliant benches/shelves exist and then roping off those areas.
You would also need to make sure your “other items/benches/shelving that are not grounded but still required to be in the area” are not within 300mm (12 in) of ESDS items. This was a concern with the previous revision of ANSI/ESD S20.20 because it said that all non-essential insulators need to be removed from the EPA. The latest revision now states “All nonessential insulators shall be separated from any ESDS item by at least 300 mm. Areas can be designated within the EPA to store static generating items provided the areas do not cause any of the requirements below to be exceeded”
We have non-EPA workbench and non-EPA location labels (stuck on the workbench or location) for certain places within an EPA, with 0.5m clear space around it. This is also stipulated in our ESD policy and within training. In our ESD audits, there are specific questions related to ensuring that these locations are being managed correctly. If we find they have not, we take away that option by making all of the benches/locations an EPA again.
Greetings of the day to all , from India
As our ESDA expert Mr. Andy has mentioned above,
“Making the whole room an EPA may be a good idea if you have ESD flooring installed and are using a footwear/flooring system for personal grounding or if the entire floor is automated and having the machines grounded.”
Also, he has cleared in the last para , “other items/benches/shelving that are not grounded but still required to be in the area” are not within 300mm (12 in) of ESDS items. This was a concern with the previous revision of ANSI/ESD S20.20 because it said that all non-essential insulators need to be removed from the EPA. The latest revision now states “All nonessential insulators shall be separated from any ESDS item by at least 300 mm. Areas can be designated within the EPA to store static generating items provided the areas do not cause any of the requirements below to be exceeded”
Thus, if your non-EPA workbench and non-EPA location labels (stuck on the workbench or location) for certain places within an EPA, with 0.5m clear space around it and if you are not facing any ESD threat by ( field voltage in the vicinity over and above the specified limit per ANSI /ESD S 20 20 ) then it should be okay.
By and large for an exclusive SMT line EPA, I go with and endorse Mr. Andy’s first para.
Thank you.