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Sky’s the Limit for KraussMaffei’s FiberForm Technology

At NPE, the injection molding machine maker will display thermoplastic window plugs for cargo planes developed in partnership with the National Institute for Aviation Research.

Geoff Giordano

April 30, 2024

2 Min Read
thermoplastic window plugs
Image courtesy of KraussMaffei

A project to convert passenger jets to cargo planes during the Covid pandemic, using thermoplastic window plugs instead of metal, will be on display at KraussMaffei’s booth at NPE2024 in Orlando, FL, from May 6 to 10.

The two-year partnership between KraussMaffei and the National Institute for Aviation Research (NIAR) at Wichita State University used KraussMaffei’s FiberForm technology to  produce a 20% lighter alternative to the previous 590-gram metal plugs.

Organosheet overmolded with thermoplastic.

In the FiberForm process, a fully consolidated fiber-reinforced thermoplastic sheet, called organosheet, is inserted into the forming tool and overmolded with a thermoplastic.


Designed with the same oval geometry as the metal plugs, the thermoplastic replacements featured ribs added to increase stiffness that could withstand cabin pressure. In this case, the 16-ply organosheet was made of LM-PAEK reinforced with AS4 carbon fibers; the overmolded ribs were made of 30% chopped-fiber-filled PEEK. The final plugs were produced on a GXW 450-2000/1400 injection molding machine with a swivel platen.

Welding-compatible material.

Using this process, 40 window plugs can be produced in an hour, thanks to the shorter cycle time of fast injection molding vs. metal machining. And, the thermoplastics used in the FiberForm process allow for the welding of components, in addition to demonstrating high impact strength, resistance to high temperatures and chemicals, and flame retardance.

Related:Management Shakeup at KraussMaffei

Next, the NIAR team is working toward further weight reduction, making the thermoplastic plugs 40% lighter than the metal parts. And, NIAR is performing further tests to certify the plugs for series production — informed by KraussMaffei’s experience in high-production automotive applications.

Process transfer from automotive to aviation.

KraussMaffei “has not only set up a machine with multiple capabilities, but has also been actively helping us on-site with process development,” said Dr. Waruna Seneviratne, director NIAR Atlas. “Our students also gain a tremendous amount of hands-on experience and get to interact with the supply chain for several new capabilities we introduced in recent years. Our goal is to transfer the efficient processes such as FiberForm from automotive production to aviation.”  

The project is the subject of a technical paper, “Ultra-High-Rate Manufacturing of Thermoplastic Window Plug Using Hybrid Overmolding,” which won first place in the outstanding technical paper awards at the SAMPE 2024 advanced materials and process engineering conference and exhibition. 

Visit KraussMaffei in booth W600 at NPE2024 at the Orange County Convention Center in Orlando.

About the Author(s)

Geoff Giordano

Geoff Giordano is a tech journalist with more than 30 years’ experience in all facets of publishing. He has reported extensively on the gamut of plastics manufacturing technologies and issues, including 3D printing materials and methods; injection, blow, micro and rotomolding; additives, colorants and nanomodifiers; blown and cast films; packaging; thermoforming; tooling; ancillary equipment; and the circular economy. Contact him at [email protected].

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