I worked with a customer recently who was experiencing a static issue when trying to apply a bar coded label to their cardboard box. The boxes travel down a conveyor then passes by a labeler that uses a mechanical arm with air vacuum to hold the label in place. As the box passes by a sensor, the arm applies the label to the corner (front and side) and then the box passes by an applicator brush that ensures the label is firmly applied.
They were starting to see wrinkles in the label as it passed by the brush and were thinking the label was holding a static charge which was making it be rejected by the box during the process. They were experiencing this about every other box. When it would occur, they would need to stop the line and manually check to make sure the label was seated properly. As a result, this was negatively affecting their production time and increasing wasted labels.
Since they thought it was the label holding the static charge, they wanted to use one of our Ionizing Bars to remove the static from the label as it was attached to the arm. The Ionizing Bar produces a high concentration of positive and negative ions able to dissipate 5 kV in 0.30 seconds, 2” from the object’s surface. It is also UL listed for safety and RoHS compliant.
The customer is local, so they asked if someone from EXAIR could visit their location and take a look at their process. I was able to make the appointment for the next morning and brought a few of our Static Eliminating products and a Static Meter to take some measurements. By measuring within 1” of the surface of the product, the Static Meter measures the voltage and polarity up to +/- 20 kV.
Upon arrival, I was directed to the labeler and took a measurement – I was only getting a reading of about 0.2 kV. I then decided to take a reading on the box itself as it traveled down the conveyor. Now I was getting a reading of 3 – 5 kV, which meant that it was the box and not the label that was holding the static charge.
Since the customer could get within 2” of the surface of the box, they were able to mount a 6” Ionizing Bar vertically to remove the static prior to the labeling process. This helped to greatly reduce the downtime of the line.
If you have a similar issue or would like to discuss your particular application, please contact one of our Application Engineers at 1-800-903-9247.