Orlando, Fla. — Kuhne Group's Mo-Con modular concept blown film die gives plastics processors what the company says is "flexibility without limits."
The stackable die, which was launched at K2016 and introduced in North America at NPE2018, is expandable from five to 17 layers and can be used on any type of blown film line, including triple bubble, water-quenched or conventional air-cooled lines.
Kuhne Group, based in Sankt Augustin, Germany, is made up of three member companies: Kuhne Maschinenbau GmbH, which manufacture extruders as well as flat film and sheet lines; K-Tool, a maker of various components, such as a screws and barrels, used in extrusion; and Kuhne Anlagenbau GmbH, which engineers and builds its trademarked Triple Bubble lines for biaxially-oriented films, Cool Bubble water-quenched lines for deep-draw thermoforming and medical films, and Smart Bubble conventional air-cooled lines for high-barrier films used in food packaging and industrial applications.
"The die is a critical component, and over the years, we've been adding more and more layers to our dies," Adolfo Edgar, vice president of blown film systems for the United States and Canada, said during an interview at the company's booth at NPE2018 in Orlando.
The expandable feature of the Mo-Con die gives customers the option of purchasing a die with nine layers, for example, that later can be expanded to 11 or more layers, the company said.
The highest number of layers produced so far is 13 on Kuhne's Triple Bubble line, which was sold to a European customer. In the U.S., the company said it recently installed a nine-layer Cool Bubble water-quenched blown film line to a customer who plans to later expand to 11 layers.
Rather than using a flat pancake-style module like other stackable dies, the Mo-Con is engineered with spirals that form a cone at the center. The design allows the die body to be more compact, the company said, and positions the melt flow in a shallow angle to merge with the other layers.
"It's not a new concept, stacking modules, but one thing we do differently is … the traditional stackable die was called a pancake die because everything was completely flat — even these spirals were not in a cone like we make them," Edgar said.
"You can imagine, if you flatten these spirals out, what you end up with is a bigger diameter plate or module, but in order to avoid that, we put all of the spirals in a cone, so the diameter of the disc will be reduced."
In addition, the melt is fed into the center of each module instead of between two plates. The company said this enables a more straightforward assembly of the melt adaptor to the die as well as a reduced risk of leaking where the melt adaptor meets the module.
"It's more of a processing benefit because the smaller the die body — the more compact the die body — it's easier to control the temperature," Edgar said. "If you want to make temperature changes, if you have less steel, then you can imagine it's easier to make that change. That's the benefit."