Hot-melt glue is pretty cool. It has many packaging applications, including carton and case closing, labeling, and more. Instead of messy liquid glues, it uses glue pellets that are solid until melted. It can be applied with rollers. More commonly, it is sprayed.
Here’s how it works.
The typical hot-melt glue system has three main components: melter, hose, and nozzle. While the overall system may seem complex, it’s quite simple when broken down.
Like most adhesives, hot-melt glue comes in a couple hundred formulations, depending on the application. Using the right glue is the first step to making the system a success. Unlike other adhesives, hot-melt glue is provided as solid pellets.
Glue pellets are melted in a heated tank. Controls maintain the melted glue at the optimal temperature. Too cool and the glue will solidify as it is sprayed, preventing good adhesion. Too hot, and it will char, clogging the nozzle. Optimal temperatures will vary depending on the type and purpose of the glue.
The melter also includes a pump to force the glue into the nozzle.
The melted glue is pumped through a heated hose to the spray nozzle. The hose maintains the right temperature and prevents congealing when no glue is used.
The spray nozzle applies the glue in an appropriate pattern and quantity. This picture shows continuous strips for maximum strength, dots to minimize glue use, and stitches for other applications.
A single melt tank can supply four or more nozzles. Sensors detect the position of the product and trigger the nozzle.
It’s easy when you know.
Find out more about hot melt glue and how it works. It’s all in Chapter 2 of John Henry’s Packaging Machinery Handbook. Other chapters cover inspection, flexible packaging, coding, and all commonly used packaging machinery. The complete table of contents and chapter samples can be found at http://www.packmachbook.com/handbooksample.pdf.
Purchase the Handbook on Amazon at https://amzn.to/3kr4qj7.