Holographic Lithography for Manufacturing LargeScale Biomimetic ...
Holographic Lithography for Manufacturing LargeScale Biomimetic Structures Executive Summary Ultralightweighting, improved safety, reduced cost, and reduced environmental impact will all be achieved through a combination of biomimetic structural design and manufacturing by holographic interference lithography. This manufacturing process has the potential to produce three dimensional variable density nanocrystalline structures in any form, which in the present proposal means a funicular monocoque vehicle frame with a substructure similar to bone. This will replace stateoftheart composites while being stronger, lighter, less expensive and more energy absorbent in impact. It will be simpler to recycle (no separation of bonded materials) and produce zero waste during manufacturing. Weight Reduction Methodology Maximum structural efficiency will be achieved by structural optimizations on three scales: 1. Micro scale: lattice structures will be the underlying micro or nanostructure. 2. Meso scale: packing density of the underlying lattice will vary as needed. For example, cross sections of the frame will resemble bone with a hard, dense surface and a more porous core. Structural efficiency of sandwich panels and foam core cylinders is well documented as a method of hugely increasing the ratio of moment of inertia to weight. Combined with the unique properties of micro lattice structures, the proposed solution will surpass all stateoftheart composite structures. 3. Macro scale: a funicular structure minimizes bending stresses, which allows less material to be used in this case. A vehicle is essentially a 4point supported bridge structure with strategically placed loads. Optimally, the loads should be supported by the overhead structure instead of an underbelly chassis in pure bending stress. A structural skin or true monocoque will therefore be employed, which will also eliminate fasteners, welds, and other imperfect joining methods.
Innovation Computer generated holographic interference patterns produced in a large vat of photoreactive material have the potential to rapidly produce 3D objects in any form. This manufacturing process will be radically more cost effective than stateoftheart alternatives and it enables the production of previously unattainable structural
geometries that can be radically lighter and stronger. The strength, weight, and crash worthiness potential of nano crystalline structures has been recently been documented. “The question now is: how do you scale this?” 1 The answer is largescale holographic interference lithography. The slow process of beam laser interference photopolymerization must be replaced with true holographic image polymerization. Bill of Materials Photoreactive monomer Aluminum Required Manufacturing Processes Photoreactive materials and coherent lasers are the backbone of the manufacturing technology. Research has already demonstrated micro and nano crystalline structures created by interference lithography .2 In order to advance the current research in interference lithography to a capable state will require scaling the technology of computer generated holography. Passenger Safety Energy is dissipated by the flexure and crushing of microlattice structures that compose the frame and body of the vehicle. Energy absorbance of these structural geometries has been shown to far exceed stateofthe art materials. Innovative/Safety Component Safety is most enabled by the variable geometry microstructure lattice frame, which will exhibit radically improved energy absorbance and is made possible by the manufacturing process proposed herein. Composing the frame of a single material that exhibits variable density and geometry of its microcrystalline lattice structure produces a material that is both exceptionally hard and flexible. Combining these qualities has always been the motivation behind composite materials (from steel reinforced concrete to carbon fiber reinforced polymers), but evidence suggests that stateoftheart composites would be far surpassed in energy absorbance capacity and strength to weight ratio by variable geometry microstructure materials. Significant lightweighting is therefore achieved while radically improving occupant safety.
Potential Challenges Scaling the interference lithography process from the micrometer scale to the meter scale is the largest hurdle. We propose shift from current research approaches of beam laser interference photopolymerization to one of true holographic image polymerization. This manufacturing process depends on research in computer generated holography, which is a rapidly advancing field but one that may realistically take 10 or more years to achieve the scale and image quality required for this proposal. 1. http://www.technologyreview.com/featuredstory/534976/nanoarchitecture/
2. http://onlinelibrary.wiley.com/doi/10.1002/adfm.200700140/abstract
Innovation Computer generated holographic interference patterns produced in a large vat of photoreactive material have the potential to rapidly produce 3D objects in any form. This manufacturing process will be radically more cost effective than stateoftheart alternatives and it enables the production of previously unattainable structural
geometries that can be radically lighter and stronger. The strength, weight, and crash worthiness potential of nano crystalline structures has been recently been documented. “The question now is: how do you scale this?” 1 The answer is largescale holographic interference lithography. The slow process of beam laser interference photopolymerization must be replaced with true holographic image polymerization. Bill of Materials Photoreactive monomer Aluminum Required Manufacturing Processes Photoreactive materials and coherent lasers are the backbone of the manufacturing technology. Research has already demonstrated micro and nano crystalline structures created by interference lithography .2 In order to advance the current research in interference lithography to a capable state will require scaling the technology of computer generated holography. Passenger Safety Energy is dissipated by the flexure and crushing of microlattice structures that compose the frame and body of the vehicle. Energy absorbance of these structural geometries has been shown to far exceed stateofthe art materials. Innovative/Safety Component Safety is most enabled by the variable geometry microstructure lattice frame, which will exhibit radically improved energy absorbance and is made possible by the manufacturing process proposed herein. Composing the frame of a single material that exhibits variable density and geometry of its microcrystalline lattice structure produces a material that is both exceptionally hard and flexible. Combining these qualities has always been the motivation behind composite materials (from steel reinforced concrete to carbon fiber reinforced polymers), but evidence suggests that stateoftheart composites would be far surpassed in energy absorbance capacity and strength to weight ratio by variable geometry microstructure materials. Significant lightweighting is therefore achieved while radically improving occupant safety.
Potential Challenges Scaling the interference lithography process from the micrometer scale to the meter scale is the largest hurdle. We propose shift from current research approaches of beam laser interference photopolymerization to one of true holographic image polymerization. This manufacturing process depends on research in computer generated holography, which is a rapidly advancing field but one that may realistically take 10 or more years to achieve the scale and image quality required for this proposal. 1. http://www.technologyreview.com/featuredstory/534976/nanoarchitecture/
2. http://onlinelibrary.wiley.com/doi/10.1002/adfm.200700140/abstract
