Monitor Static Levels for Product Quality
- Published: June 1, 2026, By Trevor
By Kelly Robinson, Professional Engineer and Founder of Electrostatic Answers
Quality products meet or exceed customer expectations by complying with established specifications, standards, and requirements. Producing quality products requires consistent processes and final inspection to ensure reliability, functionality, and performance. I marvel at the dedication and great skill needed to produce quality products. This operational know-how is a competitive advantage.
Static charges must be maintained within acceptable limits to produce quality products. Static charges can cause sparks that damage sensitive products such as silicone release liners. Charges on finished products can cause sticking and jamming problems with labels, cut sheets, bags, and pouches in customer operations.
Figure 1: Readings verify static control and monitor static levels on the unwinding roll. Graphic Courtesy of Electrostatic Answers
Static Control System
Our static control system maintains static levels within established limits. Static readings ensure that the static control system is working properly. For example, the two powered static dissipaters in Figure 1 dissipate static charges on the unwinding roll. Static charge separate at the unwinding nip often with negative charges on the outside surface of the unwinding roll and positive charges on the web exiting the unwinding roll. Powered static bar SBRoll responds to charges inside control volume CVSB Roll and neutralizes the charges on the outside surface of the unwinding roll. The second powered static bar SBSpan responds to charges inside control volume CVSB Span and dissipates static charges on the inside surface of the web exiting the unwinding roll.
Three static readings verify that these two static dissipaters are operating normally. Electrostatic fieldmeter (ESFM) reading ERoll verifies the operation of SBRoll. This reading, which is usually a handheld reading, should not exceed ±5 KV/in. Note that ERoll is taken after SBRoll. ESFM reading ESpan verifies the operation of SBSpan and ensures that the Exiting Web has an acceptably low level of net charge. ESpan is commonly an online sensor and should not exceed ±2 KV/in. Electrostatic voltmeter (ESVM) reading VUnwind verifies that both SBRoll and SBSpan are working together to dissipate balanced charges on the exiting web. VUnwind is commonly an online monitor and should not exceed ±0.5 V/um of web thickness. For example, when running 48 gauge (0.48 mil, 12 um) polypropylene web, VUnwind should not exceed ±6 V.
Static Levels on Incoming Materials
Two additional readings monitor static levels on incoming materials. ESFM reading ERoll In taken upstream of SBRoll is commonly a handheld reading and responds to charges in control volume CVRoll In. This reading detects charges that separated at the Unwinding Nip. If ERoll In exceeds ±20 KV/in, work with the supplier of the Unwinding Roll to better control static in their operation. Similarly, ESFM reading ERoll Out detects charges separated at the Unwinding Nip. If ERoll Out exceeds ±20 KV/in, work with the supplier of the Unwinding Roll to lower static on their products.
Figure 2: ENip Out detects static charges from the Driven Roller. Graphic Courtesy of Electrostatic Answers
The Nip Roller in Figure 2 can deposit a large amount of static charges on the web. Powered static dissipater SBNip responds to the charges in control volume CVSB and dissipates static charges on the web from touching the Driven Roller. ESFM reading ESB Out that is commonly an online sensor, responds to the charges in control volume CVSB Out to verify the operation of SBNip. ESB Out should not exceed ±2 KV/in.
Verify Driven Roller is Working Normally
Two additional readings help verify that the Driven Roller is working normally. ESFM reading ENip In taken upstream of the Driven Roller is commonly a handheld reading. This reading responds to the charges inside control volume CVNip In and detects charges on the web entering the Driven Roller. ENip In verifies that our upstream static control elements are working properly. ESFM reading ENip Out that is commonly a handheld reading, responds to the charges inside control volume CVNip Out. This reading, normally larger than ENip In, detects the increase in field caused by charges deposited on the web from touching the Driven Roller. This reading helps verify that the Driven Roller is operating normally. The charges from the Driven Roller depend on the nip pressure, Driven Roller hardness, Driven Roller surface contaminates, and alignment. In normal operation, ENip Out should be consistent and uniform across the web. Take several baseline readings when the nipped Driven Roller is operating normally. Periodically measure ENip Out to ensure normal operation. If ENip Out is higher than normal, check the nip pressure, Driven Roller wear, and perhaps clean the Driven Roller. If the reading varies from side to side, check the alignment of the Driven Roller.
Reliable operation depends on verifying that our system is running normally. Online static sensors are commonly used to verify the operation of our static control system. Additional handheld static measurements help verify that our production system is running normally.
If you have any questions or comments, please contact me. My email address is This email address is being protected from spambots. You need JavaScript enabled to view it..
About the Author
Kelly Robinson, PE, PhD is a regular Paper, Film & Foil Converter contributor, specializing in static issues occurring in converting processes. Robinson is the founder of Electrostatic Answers, has 40+ years of experience in industrial problem-solving, is an IEEE Life Fellow, and was named Top Manufacturing Consulting Services Provider in 2023.
