Issue link: https://iconnect007.uberflip.com/i/1513227
82 PCB007 MAGAZINE I DECEMBER 2023 day, the etcher was slow to heat up and when the pumps were turned on there was virtually no spray pressure even though the pump valves were wide open. A few questions established that the color of the cupric was a bright green with an oxi- dation/reduction potential of over 900 mv but no chlorine odor. is was a bit of a surprise. I was expecting to hear that the color was almost black and the ORP down around the lower 500s, indicating a problem with the etchant regeneration, and accounting for the slow- ing etch rate. Also, with the ORP in the 900s, there should have been at least a strong chlo- rine smell around the etcher even if it wasn't enough to cause the room to be evacuated. I had a sneaking suspicion about the prob- lem and asked if they had the capability do a free acid titration. ey did and their chemist reported that the titration showed almost no We all understand that day-to-day mainte- nance and long-term preventive maintenance of etching equipment is a good thing. However, the pressing need to get product out the door in the face of tough production schedules can sometimes cause us to delay necessary mainte- nance for long periods of time. In some cases, we become fixated on short-term production and forget about long-term stability. is can end up costing a fair amount of money in terms of repairs and lost production, most of which could have been prevented by taking the time to do some simple checks on equipment oper- ation and chemistry conditions. For example, I received a call from a cus- tomer some years ago complaining that his cupric chloride etcher had stopped etching. e Friday before the call, the etch rate started to drop off rapidly so they had to slow the con- veyor speed continually. e following Mon- The High Cost of Etcher Non-maintenance The Chemical Connection by Don Ball, CHEMCUT