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May, 2016


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Taking Charge of ESD Caused by Tapes and Labels


By Dave Geneste, Marketing Communications Manager, Polyonics, Inc. E


lectrostatic discharge (ESD) is present in everyday life, and its effects range from mildly unpleasant to extremely dangerous.


From taking static-charged clothes out of the dryer to touching a lamp after shuffling your feet across a rug in dry weather, to storm clouds creating lightning, ESD particularly affects the electronics industry where it has become a critical pain for design and manufacturing engineers. In electronics manufacturing, ESD occurs


when triboelectric charges are released in the form of electrical currents into an ESD-sensitive (ESDS) device. If the charges exceed the device’s specified threshold, it can cause immediate or latent damage that adds to the overall production cost through repair, return or customer dis- satisfaction. The PCB industry esti- mates product losses due to ESD can be up to 7 percent of manufacturing costs, and despite the implementation of an array of antistatic materials and devices (bracelets, booties, mats, ioniz- ers, etc.) the ESD problem continues to grow.


Every aspect of PCB manufac-


turing is susceptible to ESD. Now, greater importance than ever is being


The PCB industry


estimates product losses due to ESD can be up to


7 percent of manufacturing costs, and despite the implementation of an array of antistatic


materials, the problem continues to grow.


given to the creation of rigorous ESD control plans used to qualify PCB manufacturers. In addition, the effects of induced charges generated from process-required insulators, which include labels and tapes, have become a new focus of these plans.


Triboelectric Tribulations Tapes provide protection for


components during the assembly process by covering or masking sensi- tive parts from flux, solder, cleaning agents, and conformal coatings. Barcode labels are used to provide an accurate means of tracking PCBs during their assembly. Most robust manufacturing processes collect data from the PCB during each assembly step and allow for lot tracking by using barcodes. Using print on demand labels at the site of manufac- ture offers a cost-effective and flexi- ble way to track products. Labels and tapes contribute sig-


nificantly to the occurrence of ESD. When required in a manufacturing process that includes ESDS devices, they need careful consideration to guarantee a successful ESD control plan.


Before being applied to PCBs,


both tapes and labels are removed from their release liners. This can be done manually or automatically with an auto-apply mechanism. By design, the pressure-sensitive adhesive (PSA) and liner have a weak bond, which allows for easy release when separated. The weak bond is achieved by using a coating on the liner that is chemically dissimilar to the adhesive. However, the nature of the PSA


PCB with labels and tape dots, which can cause ESD when peeled off.


and liner has the potential to cause a significant tri- boelectric charge when they are separated or pulled apart.


During the application process, the charged


adhesive will then induce a charge in any conduc- tive components in their vicinity, including circuit- ry. The magnitude of the charges generated when non-ESD labels or tapes are removed from their lin- ers can be greater than 5kV. The same charge generation applies when tapes or labels are removed after processing.


Continued on page 57


Page 55


At Mycronic, we are committed to developing solutions that improve effi ciency for your entire operation. We go beyond the assembly line and eliminate bottlenecks throughout the factory. With our 360 degree approach to SMT manufacturing, we help bridge your performance gaps and bring real value to your business.


We call this Mycronic 4.0 – a highly automated, intelligent factory for just-in-time production. Let’s meet and discuss your production challenges, and how we create the factory of the future – already today.


Meet us at booth


7-343 at


SMT Hybrid Packaging 2016


See at NEPCON China, Booth 1H42 and SMT Hybrid Packaging, Booth 7-343


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