Ask the Expert Question-and-Answer Archive

by Ron Joseph

February, 2005

Dust in Paint Finish

Q. For several months now, we have been fighting with yield problems on our robot lines. We seem to be fighting alot of overspray in our booths. We currently use HVLP guns and use 1 primer robot, 2 base robots, and 1 clear robot. The nature of the defects are particles about .7mm in size. No matter what we try to do, we can't get a first-run yield above 45-50%. Velocity at the part is 60-65 fpm. What can we do to reduce the turbulence in our booths?

A. Without actually seeing your operation it is very difficult to give you meaningful advice.

I take it that dust is your problem?

What does your booth look like?
Is it side draft or downdraft?
Do you have natural draft or forced air supply?
How have you set up your robots?
What is the fluid pressure at the HVLP gun?
What is your atomizing air pressure?
Where does your incoming air come from?
How well do you control the cleanliness of your atomizing air?
Many more questions????

Fred, I know that you were hoping for a more definitive reply, but unfortunately this is usually something that takes personal investigation. If you would like us to get involved and visit your facility, we'll be happy to do so on a consulting basis.

Best wishes,

Ron Joseph