ITW Chemtronics - The CW2200 Conductive Pens: Tips and Tricks for Best Performance

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By: Michael Watkins, ITW Chemtronics

The CircuitWorks Conductive Pens, part numbers CW2200STP and CW2200MTP, are among Chemtronics most popular products. These pens have a wide range of uses, from drawing traces between components on proto-type circuit boards, coating components and assemblies to shield them from electrical and radio frequency interference, to repairing broken solder traces on PCBs and broken grid lines on automobile rear-windshield defoggers. The silver-filled acrylic polymer in the CW2200 pens provides a quick, easy alternative to building solder traces between components and can effect repairs where conventional soldering techniques are not practical or possible. The nature of the conductive "ink" does lead to issues with regard to shelf-life, flexibility, clogging, conductivity, curing and thinning which I would like to address in this article.

Tip Assembly and Trace Dimensions

The tip of the CW2200 Conductive Pens is really a spring-loaded retractable stopper. As you press the tip of the pen against a hard surface, the tip retracts into the tip assembly, opening a channel through which the conductive ink flows out of the pen. Ejection of the ink is aided by gently squeezing the flexible pen barrel.

The CW2200STP (standard tip pen) has an orifice size of 1 mm and will draw traces that will average 2.0 mm in width. The CW2200MTP (micro-tip pen) has an orifice size of 0.7 mm and will draw traces that average 1.5 mm in width. A skilled technician, with experience in using the CW2200 pen applicators should be able to produce consistent traces that will be narrower than the dimensions cited. If even narrower trace widths are required, the ink can be applied using a fine artist's brush or pen. A stencil can also be prepared to facilitate the drawing of fine pitch traces. The CW2200 Conductive Ink is also available in bulk form in a 100 gram bottle for large-volume brush or pen applications...

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