Automated Removal of Prepreg Backing Paper - A Sticky Problem

Automated solutions for manufacturing composite products based on prepreg often imply Automatic Fiber Placement or Automatic Tape Laying. These systems are generally associated with huge investments. For certain manufacturing applications it is interesting to investigate alternatives to find simpler and less costly automation. One example of an automated system could be the use of a standard industrial robot to pick single prepreg plies from an automated cutting machine and stack them to form a plane laminate. This paper is based on a case illustrating a product from the aircraft manufacturing industry. The case will demonstrate a pick and place concept on a general level and illustrate challenges that must be solved. The challenge selected to be the main focus for this paper is an automated process for backing paper removal. A literature review of different gripping technologies reveals several interesting technologies, and the most promising are tested for backing paper removal. The tests show that an automated removal process can be designed by using standard vacuum grippers in combination with mechanical clamping grippers. In order to lift the backing paper with a vacuum gripper an initial separation between the backing paper and prepreg is needed. This separation is most easily mechanically induced by bending the material. The proposed solution for automatic backing paper removal can be integrated in a manufacturing cell for manufacturing of the studied product. INTRODUCTION In the strive to reduce fuel consumption by saving weight in aerospace and automotive applications, composite materials present an appealing alternative. Polymer fiber composite materials offer a combination of low weight and high stiffness and strength. An increased use of composite materials contributes to an enhanced need for rational manufacturing methods suitable for manufacturing components in a cost-efficient way. Several automated manufacturing systems for composite products have been developed, but in some manufacturing systems much of the work is still performed manually. Further development of automated manufacturing systems is interesting in order to lower production cost. Automation can also increase the quality by making the manufacturing process more repetitive compared to manual operations. In this article, automation using a pick and place concept is analyzed in the context of a case from the aircraft manufacturing industry. For this automation concept, the task of automated backing paper removal is identified as one of the key areas where a solution that suits the case application needs to be developed. A general literature review of gripping technologies for flexible materials is performed to identify gripping technologies. An evaluation of the suitability for each gripping technology results in the selection of one technology. Tests show that the selected gripping technology does not work in the intended application unless an additional Automated Removal of Prepreg Backing Paper A Sticky Problem 2013-01-2289 Published 09/17/2013