2K Paint Application Equipment Nozzle Issues

What's the problem?

Are guns getting clogged? HVLP? Conventional air? Spray pattern getting messed up by paint build up? Can you set up the line and the gun to cycle simultaneously? Can you set up two guns to cycle on and off?

More questions than answers at this point.

Guns are mounted on two different Robot's and can not be cycled off or on, once the operations start. I use many different types of guns on this line. Some are conventional and the others are air assisted airless. Nozzles sizes range from .3 MM to 2.0 MM.

If you were to look down onto the nozzle (with air cap on) the paint is forming a dry area right at the boundary layer between fluid nozzle and air cap at atomizing air discharge lip.

I have a feeling that the issue is going to be the pressurized air. I may need to go to Nitrogen or other inert gas?

I've done a lot of spraying, but I was the robot.

So that dried paint is messing up the spray pattern I'd guess.

Any chance of boosting the paint pressure, using a fine finish tip and going straight airless, (no air assist)?

Switching to inert gas sounds a little extreme, I don't know how much fine tuning you have on your guns, but it sounds like that build up is a result of blow back from either over atomizing your paint or too much air pressure at air cap.

If your getting the right amount of paint on the substrate, can you try dialing back the air pressure in tiny increments until all paint is going forward? I think the air at the cap is creating a little vortex back there that's causing the build up.

Kramarat; I the 40 years I have been doing this type of work this is a 1st time I have seen this. Now having said that, when spraying with a hand gun and or most automatic units, they are cycled on and off. This cycle has a way of clearing the tips of such build up.

As far as guns go, we have to use the gun that best fits the overall requirement for the job. In this application I have the three major types (in automatic form) in use on this material. We achieve what the customer is looking for using the materials at hand. Now to fix the issue of producing the scrap caused by tip build up. I am sure we will find a solution in the very near future. The inert gas seems to making a difference, but too soon to really tell.

Let me know if it works out. That is definitely one that I wouldn't have thought of.

Good luck!