Set all temperature set points at the suggested operating temperatures.
Apply the proper amount of hotmelt, normally 0.10" non-compressed bead width.
Mate the two surfaces within the proper open time of the hotmelts.
Hold the flaps in intimate contact in compression for the proper amount of time. Even though hotmelts do gap fill, the bead must be totally compressed.
Select the proper adhesive for the end-use pack conditions.
Use dyne pens to test the surface energy and select the proper adhesive for your package. This test will help you identify heavily coated or difficult-to-bond substrates.
Common Glue Failures and How to Correct Them
Glue failures can be very frustrating and time-consuming. To avoid downtime, it is important to identify your glue failure in order to correct it. Here are 5 common glue Failures.
Poor Adhesion
If you have hotmelt on one substrate and not on the other you might have a poor adhesion failure.
Check your hot melt temperatures, and bead sizes, as well as coatings or heavily sized board.
Adhesive Pre-Set/Cold Resistant Failure/Poor Compression
Adhesive Pre-Set
Your hotmelt might be setting before being compressed. Check application temperatures, open time, and bead size. The adhesive might be too cold. Increasing the temperature or bead size might solve this issue.
Cold Resistant Failure
If your bond is being exposed to cold temperatures, using a cold-resistant hotmelt might solve this issue.
Poor Compression
Your compression settings might not be ideal. Check the compression section, and check to be sure the minor flap is not being pushed away from the major flap
If compression can’t be adjusted, try placing the bead closer to the edge. Consult our “Ideal bead placement for hotmelts” video.
Slow Set Speed
If you have hotmelt on both substrates and your bond is coming apart, check hotmelt temperatures and bead size. The adhesive might be too hot. Lowering the temperature and bead size might solve this issue.
Your compression time might be too short. If the compression time can’t be adjusted, using a faster setting hotmelt might solve the issue.
Daily Preventive Maintenance
Keep system filled with adhesive
Keep application tanks covered
Keep reserve adhesive covered
Check air pressure gauge for proper operating pressure
Check temperature set points in all zones
Use a pyrometer to determine the actual temperatures in those zones