CompositesWorld
Issue link: https://cw.epubxp.com/i/866813
SEPTEMBER 2017 82 CompositesWorld FEATURE: AUTOMATED PREFORMING, PART 2 this area, and this is what is placed onto the 2D or 2.5D preform. When you subsequently complete the 3D forming of the blank, the fibers will move and conform into this area." He cautions that this movement also depends upon the type of material placed to form the preform. For thermoplastic preforms, Dobiasch contends that robotic placement can achieve true 3D shapes, "but consolidation requires a second step and you must work in 2.5D to hit a 1-minute takt time. We have not seen 100% consoli- dation of thermoplastic tows during layup of true 3D shapes." FILL Gesellschaft (Gurten, Austria) is working to further develop its AFP system for 2.5D and 3D preforms, aiming to reduce forming steps required before molding. is system reportedly will be able to process a range of materials, including prepregs, thermoplastic tapes or dry fiber tapes. Continuous 3D preform processing line Another process that claims true 3D preforms with no further forming steps has been developed by COPRO Technology (Braun- schweig, Germany). A spin-off from the German Aerospace Center (DLR) facility in which it is located, COPRO emerged from research with Airbus and aerocomposites suppliers to automate preforms for aircraft door frames. Its patented continuous process FIG. 3 Continuous-process complex parts In COPRO Technology's (Braunschweig, Germany) contin- uous preforming process, opposing rollers on linear tracks change the width, taper and cross-section of bindered dry fabrics or prepregs into C-, T-, Z- and closed-profile preforms, complete with joggles, oriented ply build-ups and drop-offs and local reinforcement patches. Source | COPRO Technology GmbH optimized patch laminate and a set of machine data for SAMBA. You don't need to develop anything else. We've removed quite a few steps from the process to maximize efficiency." Another FPP distinguisher, already demonstrated by Cevotec in series production (see Learn More, p. 85), is the ability to effi- ciently produce curvilinear paths in the preform. "You cannot do this with tape laying," Groene insists. "We are producing 2D layups because this is production in automotive today," maintains Dr. Matthias Meyer at Broetje Automation (Rastede, Germany). "We can have a touch of 3D in our layers, but truly 3D layup is too cost-intensive for the auto industry." Compositence (Leonberg, Germany) also claims an ability to achieve preform geometry between 2D and 3D — i.e., 2.5D — a concept already widespread in CNC machining and computer graphics. "is is the maximum we can reach, depending on the geometry of the preform, because the diameter of the compaction roller and size of the placement head prevents reaching every angle for fiber placement," omas Dobiasch, head of sales, explains. However, Compositence' patented edge fixation for accelerated 2D placement provides a kind of "work-around" for achieving 3D layups. "It allows us to pull fibers into areas that we cannot reach due to the size of the AFP head," says Dobiasch. "Our software calculates the total fiber length needed to conform into For thermoplastic preforms, Dobiasch contends that robotic placement can achieve true 3D shapes.