For the design of new manufacturing methods for mechanical metamaterials in compact motion systems, a new bonding technique has been developed. The manufacturing technique requires thermoformed PEEK films to be bonded together. Literature review has shown that laser welding, and specifically laser transmission welding, is a valuable method for this manufacturing technique, particularly for bonding materials that are tens of microns thick, such as thermoformed and PEEK films. This research demonstrates how to define a viable process and how to optimize laser parameters to achieve maximum joint strength and identifies factors that can diminish the quality of the bond, thereby affecting optimal speed.

Further investigation of the PEEK and absorptive coating spectral curves has revealed that absorption coating is effective in increasing the absorbance used in this research. Welding with an infrared laser around one µm wavelength can rapidly produce strong welds, where the tensile strength of the welds exceeds that of the material. A fluence of around 20 to 30 mJ/mm^2 results in optimal weld peel strengths.

The optimal parameters for 125 µm lap welding include a speed between 10 and 15 millimeters per second and a defocussing distance between 4 and 7 millimeters. The thickness of the welded films range from 25 to 125 microns. It has also been observed that thicknesses of 25 and 50 micrometers can produce welds with 125 thick thermoformed PEEK films, allowing for 2.5D film welding capabilities.

This research successfully establishes a proof of concept for the hot forming of PEEK sheets using resin-printed polymer molds.
Mechanical metamaterials, through their architected inner structures, offer unique properties that enable unparalleled functionalities. In the MECOMOS project, a novel manufacturing method is proposed to fabricate a multi-stable 3-DoF PEEK metamaterial that enables tip, tilt, and z-translation. The method involves forming PEEK layers to create the geometries of the unit cells, followed by joining these formed layers to produce a monolithic metamaterial.
In this research, a new forming method, hot forming, is developed and analyzed for shaping these layers. This method creates microscale features in PEEK sheets by implementing the process steps of hot embossing into matched die thermoforming.
Polymer molds with various geometries, including rounded cylinders, blocks and trapezoids, are successfully resin printed. Key variables influencing the mold output in resin printing include the cleaning procedure, post-curing, and layer thickness. The smallest printable features measure 400x400x100 µm, and the printing errors range from 40 to 150 µm and are predominantly independent of feature size.
The proof of concept for the hot forming process reveals its strong potential as a manufacturing method.The forming parameters are highly forgiving, with a broad range of process parameters still yielding high replication quality. The suitable forming temperature spans from 100 to 150°C, and pressing forces between 750 and 3000 N prove effective.

In this thesis report, the potential for high-throughput fabrication of micromechanical metamaterials is studied. Metamaterials are structures typically consisting of repetitive micrometre-sized features that introduce new and extraordinary ‘material’ properties. However, up to now these structures are predominantly fabricated with slow 3D-print fabrication techniques. In this work, a range of micromechanical metamaterial designs are closely studied for their design aspects, alongside an investigation towards the high-throughput opportunities of mechanical contact-based fabrication techniques like nano imprint lithography and microtransfer moulding. What is missing from current research, is the connection between the design attributes of micromechanical metamaterials and the capabilities of high-throughput micrometre-level fabrication techniques.

Here I showthat micromechanical metamaterials can be broken down into geometric elements and eventually elementary material transformations that can be directly linked to fabrication techniques with high-throughput potential. These material transformations can be used to form several fabrication process flows. During this breakdown, stencil printing emerged as a compelling fabrication technique for high-throughput fabrication of thin intricate 2½D features. At this moment little is known about the prospects for stencil printing with polymeric materials because stencil printing has its origins in printed circuit board (PCB) fabrication. By performing experiments on the most influential parameters of ordinary PCB stencil printing found in literature and applying these parameters to polymer stencil printing, an understanding of the operating mechanisms is obtained. It is exhibited that by tweaking parameters such as viscosity, wettability,
stencil design and substrate temperature, stencil printing with polymers like polydimethylsiloxane (PDMS) can be transformed from an ill-defined mess to a successful replication of the designed laser-cut stencil. The achieved stencil print shows good replication with a mean line width of 638 &m with a standard deviation of 20.8 &m against a 585 &m line width of the laser-cut stencil. The key to this rewarding transformation is the mixing of polytetrafluoroethylene (PTFE) into the PDMS matrix in a 50/50 wt% mixing ratio.