Paint line managers of electrostatic paint lines are often tasked to provide plastic substrates with an evenly distributed bright and shiny paint coating and with keeping the painting environment safe.
That’s easy, right? Most people think that all they have to do is to make sure the substrate is grounded.
Yes, that is true, but how do you really know if the ground in place provides a consistent low level of resistance?
One way to check the resistance of the plastic substrate is with a multi-meter (after the conductive costing is applied). This will provide an accurate measurement as long as both probes are placed as needed. The problem is that you need 3 hands to hold the two probes plus the meter, while you touch the probes to places that are often far apart. Additionally, the probes are pointed, so caution must be taken to not scratch or damage the plastic substrate which could remove the conductive primer. The process of using a multi-meter to take a consistent reading across the entire plastic substrate can be very cumbersome and time consuming while the line is in full operation.
A much easier and more efficient way to take a measurement of resistance is to use the Ground Analyzer from Mueller Electric. This is a hand- held device that provides the tools to take a quick and easy measurement of the ground effectiveness across the plastic substrate. The Ground Analyzer will take a reading but will also provide a quick go-no go indicator which will allow the paint line manager to know if the substrate is grounded throughout and is ready for base coating. Every paint manager has their own unique requirements for appropriate grounding levels. For some it may be 500Ωs while others may go at 1MΩ or higher. The Ground Analyzer allows for a threshold to be set at various preset levels (one setting is available for user input) and the reading taken will provide a green indicator if the resistance measurement is below the threshold. If the reading is above the threshold the indicator will turn red alerting the operator to the fact that a better ground is needed. For a better understanding of how the Ground Analyzer works you can watch the video or see the PDF here.