Feature Articles - Stack Plastics

Stack Plastics Uses Mold-Vac Vacuum System to Assure Part Quality

Menlo Park, CA-based Stack Plastics is an 11 year old custom plastic injection molding company. Eighty percent of its business involves high-tech, high-end engineering resins for products for the medical device industry. The other 20 percent of its business includes light assembly, sonic welding, and pat printing. The company operates 11 presses ranging from a micro molding machine at three tons to a 150-ton press.

Mark Rackley, president of Stack Plastics, says his organization began experiencing venting issues from the beginning of its establishment 11 years ago. Back then, he was working with the manufacturer of Frisbees for playing Frisbee golf. “Those specific Frisbees are much different in design than the standard Frisbees,” Rackley explains. “They violate many of the practices of good molding and good mold design in order to obtain the geometries to allow them to fly in a specific way. We had a lot of trouble with gas traps, burning, and shorts.”

He realized that a vacuum system would likely eliminate the issues they were experiencing. Initially, Rackley searched the Internet to research vacuum systems and found CAE Services ( Batavia, IL), a leading provider of engineering services and Mold-Vac units.

Mold-Vac systems are standalone, motor and maintenance-free devices that eliminate molding issues as a result of gas and air entrapment. Exclusive to Mold-Vac design is its blowback control that cleans vent pins every cycle. Mold-Vac provides precise microprocessor control for both vacuum and blowback timing functions.

Prior to purchasing the Mold-Vac system, Rackley met with his Frisbee customer to convince him that the vacuum system would benefit production of his product. “I explained to my customer that both parties would benefit in terms of our yield of their product by introducing a Mold-Vac unit to production. “We needed to eliminate a high percentage of reject rates,” Rackley says.

Mold-Vac benefits:

“Since installing the unit, we have definitely realized a significant return on investment.”As a result of installing the Mold-Vac Model 4000, Stack Plastics’ cycle time has decreased by at least 15 percent and its production yield has dramatically improved. Rackley adds, “Since installing the unit, we have definitely realized a significant return on investment.”

The Mold-Vac unit has been used on multiple presses throughout Stack Plastics, depending on need and job. Over time, there have been other tools in the shop that experienced venting issues. The Mold-Vac unit helped address those issues. “We have definitely gotten a lot of use out of the unit and, because of that, I am in a position to purchase an additional Mold-Vac system,” Rackley adds.

Ease of use.

Stack Plastic shop floor technicians say the Mold-Vac system is easy to install and operate. They note that there is a little bit of work to drill in paths and holes to mount the switches and facilitate actuators. However, any maintenance or tooling person can perform those tasks. They move the unit from machine to machine as needed.