NOVELTY - Method of manufacturing at least a processing apparatus involves: generating electronic representations of several metal layers (72) that at least form the apparatus, in which metal layer(s) includes hole and/or slot, to allow fluid flow through it, when the layers are connected together; providing metal layers; forming metal layers into specific shapes based on the electronic representation; stacking and aligning the layers; connecting formed layers to form portion of the apparatus including fluid channel(s) to process fluid flowing through it.    USE - For manufacturing at least a portion of a processing apparatus including a furnace element designed to combust natural gas, and a reactor or micro-reactor designed to convert at least one by product of the combusted natural gas into a liquid alcohol (all claimed). Also useful for apparatus in automotive industry e.g. in fields of inertial measurement, micro-scale power generation, and pressure measurement; avionics industry in fields micro-thrusters, antennas, and displays; biological, biotechnology and chemical industry in fields of micro-fluidics, microbiology, DNA assays, chemical testing, chips, tissue engineering, analytical instrumentation, bio-filtration, bio-computing, and biomedical imaging; medical industry in fields of imaging, computed tomography, ear plugs, microwell arrays, orthopedic, cardiac and vascular devices, and stents; and energy industry including fuel cells, solar cells, automotive fuel production from natural gas, methane processing, and methanol production.    ADVANTAGE - The method provides an improved method for manufacturing processing apparatus for various chemical and biological agents including pharmaceuticals, required for scaling-up the manufacturing process; by generating electronic representations of metal layers of apparatus, in which metal layer(s) including hole or slot, to allow fluid flow, when connected, followed by forming metal layers into specific shapes based on electronic representation; and stacking, aligning and connecting the layers to form portion of the apparatus including fluid channel(s) to process fluid flowing through it. The metal layer(s) also function as a catalyst positioned in the stack of metal layers for a desired reaction. The method enables formation of processing apparatus having small but intricate and complex three-dimensional passageway system having high reaction surface area to strength ratio; enables materials passing through apparatus to be exposed to multiple catalysts; can be used to eliminate need for multiple reactor vessels in refinery; as increasing chemical production by apparatus requires adding additional processing apparatus to system, the processing apparatus eliminates the installing of large vessel reactors online; the chemical processing in apparatus is safer, cleaner, more accurate and efficient at various pressures and temperatures as compared to larger reactor vessels; has recovery of the catalyst (preferably precious metal catalyst), much simpler and less costly than melting entire reactor and separating elements, or using highly toxic methods of reduction, and thus is more environmentally friendly; enables multiple catalysts to be used and easily separated for separate recovery processes and changeover of catalyst beds can be done unit by unit while still under processing conditions instead of shutting down reactor to change tons of catalyst; utilizes alignment structures and construction structures to properly align the several metal layers to facilitate proper formation of the processing apparatus; utilizes metal coating for use in brazing metal layers together to form apparatus and enables portions and/or sections of apparatus to be easily connected and/or disconnected; can form apparatus in many desired simple and/or complex shapes; allows for easier scalability of the apparatus from laboratory settings to industrial settings; allows apparatus that can be designed to withstand large range of pressures and temperatures; and provides apparatus having modular design and standardized components, which can be used in forming a variety of different processing apparatus.    DETAILED DESCRIPTION - Method of manufacturing at least a portion of a processing apparatus involves: generating electronic representations of several metal layers (72) that at least partially form the apparatus, in which the metal layer(s) includes hole, and/or slot, designed to allow fluid flow through it, when metal layers are connected together; providing metal layers; forming metal layers into specific shapes based on electronic representation of the layers; stacking and aligning formed metal layers; connecting together formed metal layers to form the portion of the apparatus that includes at least one fluid channel designed to process fluid flowing through it. The metal layers have an average thickness of up to 1000 microns; and include alignment structure(s). The metal layer(s) also functions as a catalyst for fluid flowing through the fluid channel(s) in the apparatus. The metal layers are at least partially formed by at least one lithographic technique. The step of connecting metal layers involves involves brazing together metal layers, in which brazing metal (74, 80) has different composition from metal layers, and has melting temperature of greater than or equal to 10 degrees C less than metal layer; such that metal layers include coating of brazing metal on at least one side of metal layer(s). The step of generating electronic representations involves generating a computer image of at least a portion of the processing apparatus; and sectioning the image into sectional images that correspond to metal layers. The step of forming metal layers involves using at least one of the computer generated images of metal layers to at least partially control forming of metal layer. The method involves a step of forming at least one mask that is at least partially based from generated electronic representation(s), and at least partially forming the formed metal layer(s) using mask; and inserting catalyst(s) into the fluid channel(s), in which catalyst is not formed from metal layers. An INDEPENDENT CLAIM is included for a processing apparatus comprising: several metal layers, in which greater than or equal to 2 layers include hole and/or slot to allow fluid flow through it, when layers are connected together, which are connected together by laminate(s).    DESCRIPTION OF DRAWING(S) - The figure shows a cross-sectional view of the processing apparatus connected between two pipes.    Pipe (20, 22)    Flanges (44, 54)    Passageways (46, 56, 62, 64, 66, 68)    Metal layers (72)    Brazing metal. (74, 80)