I'm glad to see that the laser training system has reached commercial status. >From my work in this area many years ago, I still believe that operator training is the number one way to minimize waste and emissions. I was also very interested in the USEPA studies regarding HVLP guns.
I was hoping to see an accurate assessment of conventional versus HVLP methods, but these studies still fall short in their assessment of total impacts. The USEPA bases their study results on the two criteria of transfer efficiency and finish quality. The inclusion of finish quality is very important and they are absolutely correct in stating that a high TE is of no value if it results in an unacceptable finish. Based on these two criteria, the results and conclusions of the USEPA reports are accurate.
However, you cannot use TE alone to calculate emissions from a given painting operation or method. You must also include the DFT that is required to produce the acceptable finish. While HVLP demonstrated a 37% improvement in TE over conventional air spray, it also applied a DFT that was 17% thicker (overall average). In one case, the added coating was as much as 43%, offsetting any savings in increased TE.
This effect would be obvious if one were to calculate the pounds of VOC emitted per square foot of surface painted (assuming that the same paint was being applied). I have yet to find a major benefit of HVLP over conventional air spray when one includes the applied DFT data. Why is it we worry about paint overspray and not about the excess paint that leaves on the part?
Oh well, enough soapbox for a Friday afternoon. Just wanted to say that I found the laser training system to be right "on target." Keep up the good work.
Mike Callahan, PE