Universal Systems manufactures pneumatic hot melt systems, which means that our equipment operates via air pressure. It is important to understand how air pressure can put stress on equipment and why the correct pressure points are essential to run a consistent, well-maintained hot melt system.

The way that a pneumatic hot melt system works is that an airline goes into the pump, to move the pump shifter, air motor and pump piston up and down to pump the glue from the tank, through the manifold, through the hoses, into the guns and onto the boxes. There is also going to be another air line into the guns to get the module pistons to open, apply the glue, and in some cases there will be an additional air line the air to close the pistons.

Let’s start with the air pressure to the pump. The air pressure to the pump is very important and should always be set between 20 psi – 40 psi, with an ideal setting in the middle at 30 psi. If your technician thinks the pump is running too fast and lowers the psi to under 20, then the pump might not have enough pressure to move the shifter. In most cases, a pump will run at as low as 18 psi. If your technician comes to you and states that the pump was running too slow, so they increased the air pressure to over 40 psi, that could cause damage to the seals inside the pump’s air motor. It is important to note that if the air pressure on the pump is set to 40 and the pump is still not pumping efficiently, then there is another issue at hand. Most likely there is dirty air inside the shifter or a clog in the tank filter. The air pressure should never be increased to fix other issues stopping up your pump.

The second air pressure point in your hot melt system is at the applicator gun. The air going into the gun should be set at a minimum of 60 psi. In most cases, 60 is the perfect setting for the guns. If your technician tells you they need to set the psi higher to get the guns to fire, then there is a clog in the in-line filter and that filter should be replaced. If the psi to the guns is anything higher than 80, you could blow a seal on the module and have issues with application.

If you have any questions about air pressure, please call us at (561) 272-5442 or email sales@ussefl.com.