Three-dimensional printing techniques

E.M. Sachs, J.S. Haggerty, M.J. Cima, and P.A. Williams, Three-dimensional printing techniques, US Patent 5 204 055, assigned to Massachusetts Institute of Technology (Cambridge, MA), April 20,1993. 

This process uses a moving laser beam, directed by a computer, to prepare the model. The model is made up of layers having thicknesses about 0.005-0.020 in. (0.012-0.50 mm) that are polymerized into a solid product. Advanced techniques also provides fast manufacturing of precision molds (152). An example is the MIT three-dimensional printing (3DP) in which a 3-D metal mold (die, etc.) is created layer by layer using powdered metal (300- or 400-series stainless steel, tool steel, bronze, nickel alloys, titanium, etc.). Each layer is inkjet-printed with a plastic binder. The print head generates and deposits micron-sized droplets of a proprietary water-based plastic that binds the powder together. 

Three-dimensional printing or additive manufacturing (AM) techniques generally focus on the production of stand-alone, individual objects often for niche markets such as prostheses for medical applications. Recently, Deleersnyder (2013) started to use this technique for textile coating and even the production of accessories for apparel (see Figure 2.1) and other textiles. 

Three-dimensional printing 3D printing or 3DP) is a rapid prototyping (RP) technique that was developed in 1992 at the Massachusetts Institute of Technology (MIT) [109]. In contrast to 3D plotting of hot polymer melts, 3DP uses CAD models that can be obtained with a personal computer [110]. 3DP is a layered fabrication process in which a layer of powder is spread onto the powder bed on which the model will be created. Then a print head ejects... 

Templating techniques rephcate a pattern or shape, allowing the inverse of the original pattern to be produced, for example, by either two- or three-dimensional printing, pressing or growing a structure against the voids of... 

This type of coil was prepared from copper cladded printed circuit board material by applying photolithographic techniques. The p.c. board material is available with difierent copper thicknesses and with either a stiff or a flexible carrier. The flexible material offers the opportunity to adapt the planar coil to a curved three dimensional test object. In our turbine blade application this is a major advantage. The thickness of the copper layer was chosen to be 17 pm The period of the coil was 100 pm The coils were patterned by wet etching, A major advantage of this approach is the parallel processing with narrow tolerances, resulting in many identical Eddy current probes. An example of such a probe is shown in fig. 10. 

Nanotransfer printing (nTP) is a more recent high resolution printing technique. It uses surface chemistries as interfacial glues and release layers (rather than inks ) to control the transfer of solid material layers from relief features on a stamp to a substrate [10-12, 44], This approach is purely additive (i.e. material is only deposited in locations where it is needed) and it can generate complex two or three-dimensional structures in single or multiple layers with nanometer resolu-... 

The manufacture of a three-dimensional circuit device from a molded plastic such as the demonstration part shown in Figure 1 differs from the traditional printed circuit board. Different imaging techniques are required due to the three-dimensional features of the devices. In addition, the metal comprising the traces on the surface of the substrate are now deposited rather than formed from the laminated copper foil. 

An inkjet printing of colloidal crystals was proposed by Frese et describing inkjet printing processes of monodispersed particles which are able to form two- or three-dimensional photonic crystals on the substrate surface by arranging in a closely packed lattice structure on the surface. The particle size was selected so that it will diffract light in the visible spectral region, i.e., particle size of 200-500 nanometers. In this work drop-on-demand inkjet printing techniques are utilized. 

Molecular imprinting technique was recently used to prepare highly selective tailor-made synthetic affinity media used mainly in chromatographic resolution of racemates or artiftcial antibodies [130-133]. A complex between the template molecule and the functional monomer is first formed in solution by covalent or non-covalent interactions (Figure 3.10). Subsequently, the three-dimensional architecture of these complexes is confined by polymerization with a high concentration of cross-linker. The template molecules are then extracted from the polymer leaving behind complementary sites (both in shape and functionahty) to the imprinted molecules. These sites can further rebind other print molecules. 

Offset lithography is used to decorate metal sheet for shallow drawn containers and lids since the resultant distortion is inherently small. When deeper one-piece containers, e.g. drawn and wall ironed aerosol cans, are printed most of the decoration is normally on the sidewall. One technique used is known as distortion printing. The original design is printed in the flat in a condensed or distorted fashion which is calculated geometrically so that when the three-dimensional can is formed... 

The new set of varied DF found in the previous section can be studied in the same way as the well-known eDF maps are represented since the first plots used in Quantum Chemistry [53a)]. Here an alternative point of view, similar as the one used by Mezey [9a)], will be chosen. Three-dimensional maps of isodensity surfaces can be generated with available computational techniques [84]. This corresponds to follow several steps, some of them so trivial that appear to be irrelevant in a study as the present. The representation process starts with the evaluation of DF grids, enveloping the molecular co-ordinates, which can origin wireframe structures related with the isodensity values. After that, they can be rendered and rotated in space as virtual objects, until some adequate point of view is found. Finally, the chosen object snapshot can be manipulated, represented on a screen and, if necessary, printed into a paper surface. The processing detail, the computational techniques and the required programs and data are briefly commented in Appendix E. All the necessary items are available to the interested reader and permit to generate surfaces of his own [93-96]. 

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