Tip no. 1: Avoid connecting several devices to the maintenance unit to prevent pressure drop. Set the pressure on the pressure gauge of the maintenance unit to 5 to 6 bar.
Tip no. 2: Make sure that an oil and water separator is integrated into the maintenance unit to ensure that the solenoid valve functions perfectly throughout its service life.
Machine manufacturers like to use angled or multi-hole nozzles – mainly to avoid higher investment costs. With a multi-hole nozzle, for example, two adhesive beads can be applied to the substrate with just one application head. The disadvantage: angled and multi-hole nozzles are difficult to clean, and exact positioning after a nozzle change requires a lot of time and patience.
Added to this are fluctuating application results and more soiling around the application head. This is why many users later switch to tried-and-tested single-hole nozzles during operation. However, this makes it necessary to convert to multiple heads – and ultimately this is more expensive than a well-thought-out nozzle selection right from the specification stage.
Tip no. 3: During the planning phase, check which application nozzles are to be used. Preferably use single-hole nozzles (296 or 296 Diamond). Trust that higher investment costs will quickly pay for themselves.
Nozzle protection provides a minimum distance between the nozzle and the substrate. This is important for a precise hot melt adhesive application. If you use high-viscosity hot melt adhesives at high machine speeds, aluminum nozzle protection is recommended. It improves the heat transfer and thus optimizes the cut-off behavior.
Tip no. 4: Use aluminum nozzle protection when working with high-viscosity hot melt adhesives and high machine speeds to achieve a clean cut-off.
Machine builders design systems to be as compact as possible and use every available centimeter. Therefore, make sure at an early stage that the positioning of the application heads allows a distance of only two to five millimeters between the nozzle and the substrate. Too great a distance leads to stringing and increases the risk of waste production.
Tip no. 5: Keep the distance between the application nozzle and the substrate as short as possible and have the setting checked by one of our experts. There is no other factor that influences the quality of the adhesive application as much as the correct distance.
The melter liquefies the solid hot melt adhesive and feeds it to the application head. To ensure that the defined amount of adhesive is applied precisely and in the correct position on the substrate, the temperatures of the heating zones and the pump pressure on the adhesive melter must be set correctly.
Tip no. 6: Make sure that the compressed air supply to the adhesive melter is 6 bar. Before starting production, check that the pump pressure is between 3.0 and 3.5 bar.
Tip no. 7: Observe the temperature specified by the manufacturer of your hot melt adhesive on the data sheet. As a rule of thumb, the following heating zone temperatures should be set:
Always have the heating zone temperatures confirmed by an expert. They must be adjusted individually according to the adhesive consumption and application type.
We have compiled all the tips in more detail for you in a free guide. In it, you will not only find information on optimizing adhesive application quality, but also recommendations that will help you to reduce maintenance costs in the later stages of operation right from the planning phase.
We provide you with the guide free of charge as a PDF file.