Maintaining a safe and efficient work environment in the packaging industry
Maintaining a healthy bottom line and a healthy workforce are top priorities for leaders at most manufacturing facilities. On-the-job injuries can be one of the most detrimental and one of the most preventable factors impacting company profitability.
Many end-of-line packaging applications require hot melt systems to maintain overall efficiencies. To help maintain a safe work environment, it is important to evaluate hot melt equipment and understand whether it might be putting your operators at risk of workplace injuries.
The cost of workplace injuries
- On average, there are 23,000 on-the-job injuries in the US every day, resulting in 8.5 million injuries annually. In the European Union there are 8,703 injuries a day, or 3.2 million a year. 
- It is estimated that employers in the US pay almost £750 million (€850 million) per week in direct workers' compensation costs alone.
- According to the National Safety Council, in the US the average indirect cost for a workplace
- If a particular injury is common or severe enough, the average cost of hiring replacement staff in the US is between £97,000 (€110,000) and £124,000 (€141,000) per year.
According to the Occupational Safety and Health Administration, manual materials handling jobs are the principle source of compensable injuries in the American workforce. Most end-of-line packaging operations today require manual feeding of unmelted adhesive. This means adding pellets to hot melt adhesive in tanks containing molten adhesive at a temperature of 177 °C (350 °F). Each time the tank needs to be refilled, the operator often has direct exposure to a hot tank containing molten adhesive.
The chance of operators being burned is extremely high, as they face a variety of risks:
- Molten adhesive splashing on to operators
- Contact with heated system components such as heated tanks, hoses, and applicators
- Operators reaching into the hot tank to remove dropped objects
- Accidental pattern misfires, spraying molten adhesive on the operator or maintenance worker
- Contact with molten adhesive from required system purging to eliminate charred adhesive
- Contact with molten adhesive due to incorrect personal protection equipment (PPE)
These scenarios often result in severe injuries, as the typical reaction is to immediately try to wipe off or remove the molten adhesive. Given the nature of the material, this reaction spreads the adhesive and increases the surface area of the burn.
Burning is not the only hazard encountered during manual feeding. Spillage is also an issue with manual feeding. When filling small tanks from large bags of adhesive pellets, there is a high likelihood of adhesive spillage on the floor. It’s not uncommon for an operator or other employee to slip on small adhesive granules that are on the floor.
When opening the tank to add the material, the chance of contamination is high and small pieces of cardboard or paper may fall into the tank. When these come into contact with the high-temperature adhesive, a flame could start and lead to a fire.
Adhesive char creates safety issues
For tank-based hot melt systems, adhesives are heated to high temperatures for hours or days at a time. These long heat soaks lead to the overheating and burning of adhesives, known as adhesive charring. When adhesive chars, it results in hard clumps that have lost their thermoplastic nature. These clumps stick to the heated tanks and release toxic fumes that can affect an operator’s breathing.
In addition to safety hazards, char causes constant nozzle blocking and downtime. As a result, equipment maintenance and system purges are often done with molten adhesive in the system, increasing the risk of a major burn.
How to create a safer environment?
Limit adhesive exposure to increase safety
Manufacturers who focus on safety and health can enjoy a healthy bottom line. Improved equipment technologies available today are improving the safety and working conditions of machine operators. The best way to reduce risk and costly workplace injuries is to limit exposure to equipment and adhesive at high temperatures.
Melt on demand
With a true melt-on-demand system, the melter only heats a small part of the material – and only when it’s needed. By not heating more material than needed, the material will never overheat or burn, thereby eliminating charring and nozzle plugging, avoiding the hazards previously described, and reducing constant maintenance requirements.
Over-pressure & over-temperature solutions
Hot melt systems with a depressurizing valve allow operators or maintenance workers to reduce the pressure in a hose or gun, thus rendering it safe to be handled without the risk of hot melt exposure. Some hot melt hoses include a built-in over-temperature safety interlock. The air filter can be changed very easily and safely without the operator facing any risk of coming into contact with hot melt.
Automatic feeding systems
Automatic feeding systems allow operators to fill a separate unheated container with a large amount of unmelted adhesive pellets. The feeding system transfers the pellets into the melter as needed. With no access to hot melt adhesive or a heated metal tank, the chance of burns is greatly decreased, reducing the potential for safety incidents and costly worker compensation claims. Eliminating access to molten glue also reduces the exposure to toxic fumes, providing a better work environment.
Dealing with adhesive bridging
It is common for unmelted adhesive pellets to “bridge” or clump together. Not all automatic feed systems deal with this common scenario and require operators to “kick the can” or carry out other unnecessary repetitive actions to break up clumps of adhesive. When considering a hot melt system purchase, be sure to have the equipment supplier demonstrate how the system deals with adhesive bridging.
In addition to reducing costs from hot melt equipment-related workplace injuries, learn how to improve the performance of your hot melt system.