Liquid Application for Mold Release Industry

This glass manufacturer’s process involves placing laminated glass in an injection molding station, where a rubber seal is created around the glass perimeter. Prior to the laminated glass being placed into the mold, a liquid release agent is sprayed onto the mold to facilitate clean, easy removal of the finished product. Once the glass is secured in place, a proprietary Reaction Injection Molding (RIM) process is used, injecting two separate chemical solutions into the mold.

The solutions react with one another and cure in approximately five seconds, producing a rubber seal that completely surrounds the glass. The glass is then removed from the mold and placed in pallets, with high-density foam between each glass product, and shipped to the customer. While the process sounds simple, the customer was looking for ways to make improvements. The company was using a standard, non-electrostatic atomized spraying system to spray the mold release agent. This system resulted in significant material waste as well as numerous product rejects due to rubber sticking in the mold.

According to the customer’s process engineer, the non-electrostatic spraying system also required significant operator training to assure that the operators sprayed the mold release agent accurately, evenly and consistently.

According to the customer’s process engineer, the non-electrostatic spraying systems require significant operator training to assure that the operators sprayed the mold release agent accurately, evenly and consistently.

This system resulted in significant material waste as well as numerous product rejects due to rubber sticking in the mold.

When the company sought a new process solution for its injection molding operation, they turned to Nordson. “The customer originally contacted us to discuss upgrading a hot melt adhesive system used in another area of their plant,” said Brad Syrowski, global marketing manager for Nordson Liquid Systems. “During the con versation, we talked about our other capabilities and the electrostatic spraying system, and how it could be used to solve their glass mold-release, sticking problem.”

The Nordson team demonstrated how an Iso-Flo® manual electrostatic hand gun system could provide a precision spraying solution that would improve efficiency for the customer. Nordson conducted initial testing, then left them with a demo system to continue testing in their actual production environment.

The Iso-Flo unit is a voltage block system that offers an easier, safer and cost-effective way to spray electrostatically charged waterborne coatings. The system supplies charged coating to the spray devices, while preventing the charge from conducting back through the paint-supply system. For single-gun manual operations, the Iso-Flo system includes a single paint reservoir. The reservoir fills from the grounded paint supply when the gun is triggered off between parts. When the gun is triggered on, the reservoir immediately disconnects from the grounded paint supply and connects to the spray gun.

The electrostatic charge is applied within the Iso-Flo HD unit, between the paint reservoir and the spray gun. Throughout the filling and spraying cycles, an air gap is maintained within the system to prevent the electrostatic charge from conducting back through the paint-supply system. Due to the speed of the shuttle, the operation of the Iso-Flo unit is virtually invisible to the operator. In tandem with the Iso-Flo unit, the company uses a Trilogy™ electrostatic spray gun to optimize spraying capability. Trilogy guns provide superior transfer efficiency and paint wrap.

The customer quickly realized the benefits of using electrostatic spraying to apply the mold release agent. They now use the Nordson system three shifts per day, accommodating production to meet all its customer demands and providing many additional benefits.

“The Nordson electrostatic spraying system is much more lenient and forgiving than the customer’s previous non-electrostatic spray system,” says Syrowski. “The mold release agent (supplied by Franklynn USA, Glenview, Illinois) is applied very accurately. Our customer has essentially eliminated overspray and material waste. In addition, by minimizing the sticking issues, product reject rate is now very low.” As a result, the system resulted in a fast return on investment.

“The customer now sees 40 percent less mold release agent than with the old system,” explains Syrowski. “Material savings alone would have given a system payback in 12 to 14 months. When adding in the savings from fewer product rejects, the customer saw a system payback in less than six months.”