Van Wees has developed a tape placement robot for the production of thermoplastic tailored blanks. Using UD or Crossply tape (produced on a Van Wees UD and/or Crossply machines) the robot is capable of manufacturing multilayer tailored blanks with thermoplastic composite material.
The robot carefully picks up the tapes, by means of vacuum. It then accurately places the tapes to assemble them into a tailored blank. The tapes are fixed with heat welded spots. The temporary bonding allows handling of the blank for further processing, consolidation and in a next step, compression molding. The small spot welds leave the blank with some drape ability so that it can follow the shape of the mold, in case the blank is placed in a heated mold directly.
Being a relatively low-cost system, a number of robots can be used to provide blanks for a fast production line. In that case the majority of the material can be assembled from two layer oriented material with dedicated angles. These tapes are made on a Multi-axial UD Crossply machine and cut to the desired width. Each position in the production line will have two or three robots which will place the tapes in a sequence. The tapes are fed with a transport system with enough capacity to supply material to a number of robots.
On the other side of the spectrum, one single robot is very flexible in producing many different shapes and sizes of blanks and ideally suited for first prototypes. The robot is very user friendly and installation can be done in under an hour.
Constructing the blanks from tapes also ensures minimal loss of material during production. The tape placing arm is equipped with a motor that changes the position of the vacuum cups and enables the picking of different lengths of tape. The straightforward robot system provides a reliable, robust production method. The temporary bonding of the tapes provides levels of accuracy and reproducibility far beyond what is possible when laying and spot welding tapes by hand.
Although it is not the best example we could find, the crash member in the photo is being made from Crossply tapes as a tailored blank. The Crossply panel was made with the UD tapes at such an angle that, after cutting the panel by waterjet, the resulting angles were oriented in the desired manner. In this case mainly lengthwise and some plies in the plus/minus 45 degree direction. A perfect example would be an open frame (for example a window frame) in which a lot of material would be wasted by the cutting of the opening. The thickness of the laminate can be built with tailored UD tapes with orientation as on the photo, being 0 – 90 degree. The next step in using this robot system can be with thermoset prepreg tapes. This will require relatively dry prepregs but in principle it is possible. We have used prepreg UD tapes that are dry enough to be handled on our Multi-axial UD Crossply machine and such a prepreg would be a good candidate.