Development of a Shape Replicating Draping Unit for Continuous Layup of Unidirectional Non-Crimp Fabrics on Complex Surface Geometries

Abstract

The manufacturing of large-scale structural components is still dominated by manual labor in many sectors of the modern composite industry. Efforts are being made to establish an automated layup technology for complex structural elements. Processing dry non-crimp fiber fabrics (NCF) offers great cost opportunities and high deposition rates, compared to prepreg-based technologies like automated fiber placement (AFP). Here, the fabric architecture is considered during the draping of the plane textile on curved surfaces. In this paper, the development of a draping unit for balancing fabric tension and consolidating continuously across the layup width is presented. We introduce a geometrical process model to achieve a fabric-friendly draping of the used unidirectional NCF. The shape of the resulting draping front depends on the surface geometry, the shearing of the previously laid-up textile, and the positioning of the material feed. To consolidate the fabric at the altering draping front in an automated layup process, the shape of the continuous consolidation element can be controlled by the elongation of serial soft actuators, manipulated by parallel robot kinematics. The shape replication ability of the draping unit is promising for the implementation of a continuous, fabric-friendly draping process for complex surface geometries.

Advances in composite forming through 25 years of ESAFORM

“…Understanding of the draping mechanics of NCFs has led to industrial developments: a draping unit, for balancing fabric tension and consolidating continuously across the layup width, accounting for shearing of the previously laid fabric [108], automated draping methods for layup of NCFs for wind turbine blades [109], flexible clamping methods [110], design of the stitching based on the draping requirements [111], identification of the forming limits for NCFs [112].…”

“…Robotic layup consists in the replacement of the human intervention in the operations of fibre reinforcement placement and orientation [326]. In this case, the manufacturing system consists of anthropomorphic robotic arms equipped with multifunction end effectors capable to pick, place, compact and handle dry or pre-impregnated textiles, achieving complex shape and minimizing the presence of defects, such as wrinkles or misorientation [108]. In all of the aforementioned cases, the composite material is deposited or shaped with the support of a mold.…”

Analysis of the performance of a new concept for automatic draping of wide reinforcement fabrics with pre-shear: A virtual prototyping study

“…Wind turbine blades are long structures (currently 100+ m for a typical modern offshore blade) and made from thick non-crimp fabric (NCF), but the shear angles involved in the draping of the fabric are typically low. Different concepts have been developed to accommodate these conditions, and typically take the form of a gantry with a layup head continuously draping the fabric from a feed roll, see, for instance, Weigel & Müller [7] , Franke et al [8] , Denkena et al [9] , and Kaufmann et al [10] . These systems rely on brushes, rollers or other draping elements that force the fabric to conform to the mold as the layup head advances.…”

“…To control the movement of the layup head, some form of path planning algorithm must be devised. One approach is to employ a kinematic draping algorithm for calculating a feasible target configuration on the mold, including the necessary shear deformation [5] , [9] . To this end, a framework was developed by the authors of the present study in which a kinematic draping model in combination with optimization is used to specify the individual courses in a laminate based on a structural layup plan [17] .…”

Spray binder for automated preforming: Spray process and preform properties

“…[3,19,20,34] When spraying melted binder powder [35,36] or hotmelts, the binder loses heat and the ability to bond the textile layers together rapidly. [37,38] Consequently, the binder often has to be reheated after its application by infrared radiators, lasers, hot gas or intrinsic fiber heating. [15,20] Spray binders with properties similar to pressure-sensitive adhesives do not have this downside.…”