Hello,
There’s this material used at our location with this datasheet.
Since is a raw material to produce some fixtures… (the fixtures pass the compliance verification), but what about getting the product qual? since this material is used to make different kind of fixtures…
What would be a good approach for this case for product qual?
Santiago,
I assume you are trying to qualify your fixture as a worksurface. If that is correct, you should follow ANSI/ESD STM4.1 to qualify the fixture. You may need to do some modifications to fit the fixture like omitting the center points if your fixture is open in the middle or clamping on metal plates to allow for the 5 lb probe to sit on the fixture properly, but it should be achievable. You would want to document the changes to the test locations in a report if they don’t completely meet the STM. You would also want to remember to do this product qualification testing at the humidity levels in ANSI/ESD STM4.1 or at the facility’s annual minimum relative humidity per ANSI/ESD S20.20.
ANSI/ESD S20.20 also allows you to use compliance verification records for product qualification if you have a year’s worth of data. “Organizations that can verify the use of ESD control items before adopting this standard to certify their ESD control program can use compliance verification records to meet product qualification requirements. These records shall cover a minimum of one year and reflect a timeframe immediately before using as product qualification records. These records shall reflect test results that meet the compliance verification test limits identified in Tables 2, 3, and 4 of this standard.”
Looking at the material, it apears to be metal. In this case, attach the data sheet which shows the electical properties. That should be enough for product qualification. Metal does not vary with temperature and humidity.
Hi
@JohnK
@SantiagoE
As for aluminum, unfortunately an oxide layer appears on the surface and its resistance increases over time. This is a common problem observed in practice. Such a fixture, if not properly cleaned, rubbed - unfortunately, after some time reaches more than 10 E09 ohms. If we measure not with a metal crocodile, as is sometimes the case, but with a 5 lb probe (ANSI/ESD STM4.1).
This is a common problem. Do you ground the alumium? If you do, then the possiblity of an issue will decrease. I would use a sharp tip probe or clip and make a note in the plan that the compliance verification for alumium is done with alternate probes. The explination would be to make good contact with the metal surface.
The 5lb probes are used to make good contact with static dissipitive materials. In this case, metal does not need the contact area and the resistance of the metal should be much less than 10*3 ohms which is the lowest the 5lb probes can measure.
@JohnK
Little confusion because if the anodized (as usual is done by industry for protection against scratches i.e.) surface is used as the pathway for any grounding, the problem becomes. People never think about covering layer, they think straight: metal is metal, must be always conductive.
I really afraid this material, my best choice is to use stainless steel. Or any of kind plastics with proper resistivity provided. But I know, alu is cheapest one.
This would be approprate for a tailoring statement. While you can keep the RTG to less than 10*9 you can ground the metal underneath. This would allow protection from CDM events, plus it will drain charges but slowly. Of course using stainless steel or conductive plastic would also work.