Electric screwdriver grounding requirements

Technical Questions
#1

Hello John, Regarding the electric screwdriver in ESD regulation, is it possible to measure the resistance of the tip to ground when the tip is turned on
Less than 1x109Ω is considered qualified. If the tip is measured to ground greater than 1x109 Ω, can an ionizer be used to dissipate the voltage?

#2

First check to see if the screwdriver comes into contact with an ESD sensitive item. Most of the time, they may come into contact with ground or just make a mechanical connection. In this case, there is nothing needed to be done.
If it does come into contact with an ESD sensitive items and the tip to ground resistance is greater than 1x109 ohm and the tip has a resistance of less than 1x104 ohms, then treat it like an isolated conductor. If the tip is less than 35 volts then you are done, if greater then ionization may be the solution but measure again to be sure.

#3

First of all, thank John for your answer
So does the electric screwdriver still need to control the tip -to -ground leakage voltage? Or do you just need to control the ground resistance?

#4

At this point, tip to ground would be the only requirement on screwdrivers or anything except soldering/desoldering irons.

#5

Dear Sir,

Could you please confirm if there is any reference ESD standard for torque driver/screwdriver measurement? Currently, we are referring to the ESD S13.1 Electrical Soldering-Desoldering Hand Tools standard for torque driver/screwdriver measurement.

Thanks in advance.

#6

Using ESD S13.1 as a guideline would be fine. I would first determine if the tip would contact and ESD senstive part. If it is a ground connection then the risk is low as those connections are typically not as sensitive as signal lines.

#7

Thanks a lot Sir…

"According to ESD S13.1, we need to follow the <2 ohms, <20 mV specification for product qualification and the <10 ohms resistance specification for compliance verification. Am I correct?

#8

That is correct, however, it can be treated as the same as a conductor so the upper limit could be 1x10*9 ohms to ground.

#9

Hi John.
just to confirm on soldering/desoldering irons verification of the tip to resistance, it should be <10 Ohms per ESD S13.1… currently our verification plan for this is weekly and the limits we have defined is same that the qualification. <2 Ohms. Should we change the requirements to <10 Ohms…? I appreciate your inputs.

#10

The soldering iron spec was developed with these requirements due to electical overstress issues. The tips would develop voltages and current when the heating element turned on and off. I can’t exactly remember but I think it was back in the 90’s.
For an electric screwdirver, there is no heating element and I don’t think you will find any transiant current or voltage on the tip. In this case, I would treat it as a conductor. If that is the case, then I would measure the tip to ground of the electic screwdriver for less than 1x10*9 ohms and use that as my qualificaiton/compliance limit.
Since there are no hard limits for tools, changing your limit to 10 ohms would be fine.

#11

thanks John for your input.