## 4 Outlook  
The labour intense manual process of realisation of the 1:1 bobbin laced demonstrator encourages further investigations of possible ways for its automation. One possible solution is the reconstruction of fibre layout using Tailored Fibre Placement (TFP). TFP is an embroidery technique in which rovings are stitched to a membrane in a continuous process in a 2D environment (Figure 23). Fibre path placement can recreate complex curve patterns from a digital file. Consequently, in this workflow desired structural performance of a composite element can be translated to specific fibre paths. TFP was developed for fabrication of complex preforms from carbon fibre rovings for applications in aircraft and automotive industry. However, the potential of adapting the technology to fabrication of building elements from natural fibres is currently being researched [8; 16; 23].  
In the considered scenario, TFP would be used for fabrication of preforms from non-twisted TEX1000 flax rovings, attached to a glass fibre membrane with a cotton thread. In such preforms only the flax fibres would play a load-bearing function in a later laminated bio-composite element.  
An initial TFP chair was produced from preforms with a single layer of TEX1000 flax fibre rovings to determine the production workflow. The unrolled pattern is adjusted to work with the continuous fibre path requirement and uploaded to the machine as CAD files (Figure 24). The final chair weighs 0.95 kg in total, including 256 g of dry flax TFP preforms (Figure 25).  
The geometry of the bobbin laced chair was successfully reconstructed with a high level of precision and the TFP prototype demonstrated the capacity to support a 55 kg user. Additionally, the initial experiments exposed several limitations of TFP process in comparison to bobbin lacing, which must be taken into consideration in future work (Figure 26).  
Figure 23: TFP machine layout. (**A**) Embroidery Needle (**B**) Flax Fibre (**C**) Glass fibre membrane.  
* Maximum preform size: The maximum size of a single preform produced is limited by the size of the machine working area. In case of the Tajima TFP machine, which was used in the experiment, it required discretization of the chair design into preforms of max. 70 x 70 cm. The individual pieces were later stitched together and hung on the frame.
* Fibre interactions: TFP specimens lack the unique fibre-fibre interactions in bobbin lace. Manually laced pieces allow fibre movement at each node, giving the global pattern freedom to deform when it is stretched. In the hanging process, this means the nodes can slip and hinge to \"find\" a suitable form. However, in TFP, fibres are layered on top of each other and fixed with cotton threads, constraining the angle between conjoining fibres. This change in the mechanism of fibre interaction adversely affects forming by constraining movement at the lace nodes. Fibres are prevented from self-adjusting, resulting in a less natural global form. A more deformable, knitted membrane material could be used to compensate for this effect, which might allow the geometry to find its natural equilibrium shape when hung. This can be verified in the future through physical testing.  
Figure 24: CAD drawings of unrolled geometries for TFP production. One for each leg in the chair.  
Figure 25: Second prototype fabricated with automated Tailored Fibre Placement (TFP) machine.  
In future work, prototypes with comparable fibre weight as the hand-laced chair will be tested, to allow a better understanding on the structural effects of fibre-fibre interaction and propose strategies for reinforcement.