CompositesWorld
Issue link: https://cw.epubxp.com/i/830100
NEWS CompositesWorld.com 23 Pultruding Curved Profiles FIG. 2 Developmental licensing Licensee KraussMaffei's (Munich, Germany) iPul machine, with direct resin injection system and incor- porated Radius-Pultrusion technology, is capable of pultruding either curved or straight profiles. Source | KraussMaffei FIG. 3 Enabling elegant arcs A close-up of a curved channel (arc profile) made by the Radius-Pultrusion process. Source | Thomas Technik FIG. 4 Curved profiles demonstrate strength Radius-Pultrusion curved profiles sustain 100 kg load in strength demonstration. Source | Thomas Technik leaf springs were installed on production cars. Curved pultrusion technologies conceived by other machinery manufacturers were similarly unable to attain commercial success. Nearly four decades later, however, omas Technik & Innovation (TTI), part of omas Holding (Bremervörde, Lower Saxony, Germany), is reporting considerable success with its version of curved pultrusion technology, developed in part with financial support from the European Union and Lower Saxony. Notably, TTI's principal business focus is healthy sleep: Since 1957, it has invested in research, development and production of beds for homes, hospitals, rehabilitation and care facilities, and mobile applications in trucks and recreational vehicles. Two decades ago, that led to composites production — using carbon and glass fiber, and more recently natural fiber- reinforced polymer composites — initially to improve the comfort of its bedding systems. One of its core composite competencies, as a result, is pultrusion. Rethinking the stationary die Trademarked Radius-Pultrusion, the company's curve-capable technology operates like conven- tional linear pultrusion, but with some impor- tant differences, as explained by Klaus Jansen, CEO of TTI. Conventional pultrusion uses a reciprocating pulling system to draw dry fibers through a resin chamber, then through a heated forming/ curing tool (die), and then into an automated cutoff saw. e key here is that the part profile is cured as it is pulled through a stationary die. A constant cross-section, linear profile is continu- ously produced by this system. "In the Radius-Pultrusion process," Jansen explains, "the heated die tool is no longer stationary but works as the upstream, and only moving, stage of its pulling system. e heated die tool is a reciprocating puller, and a stationary gripper on the downstream end of the line opens and closes as programmed, but does not travel. e die tool grips incoming raw material at the upstream end of the line, then moves downstream, curing the profile as it proceeds toward the gripper unit. As the die moves down- stream, the gripper remains open and the cured profile is pushed through it, toward the auto- mated cutoff saw. When the die reaches the