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...article ] The electron beam is generated in an "electron gun" consisting of a hot filament, which acts as a source of electrons. The filament is held at a negative potential, and the electrons are accelerated through a large potential to the anode. The electron beam converges to a focus as it passes through the anode, then diverges between two focusing coils that focus it...

...article ] A high energy laser beam is focused onto the surface to be welded, by means of mirrors and lenses. The laser beam is coherent (waves in phase), monochromatic (single wavelength) and highly collimated (parallel beam). Output can be continuous or pulsed. Solid-state lasers pulse by turning the flashlamps on and off or by "Q-switching" (Nd-YAG), where an optical...

...article ] Comparison of TIG and plasma arcs Plasma has a narrower weld, less HAZ, deeper penetration and lower current demand. Operator has greater flexibility, as stand-off distance with plasma has little effect on bead width. [Images to demonstrate 'Plasma arc welding' - see article ] Manufacture: Plasma arc welding is similar to TIG welding. An arc struck between a...

...article ] Methods of pre-placing the brazing alloy for furnace or induction brazing [Images to demonstrate 'Brazing' - see article ] Surfaces to be joined are degreased, abrasive grit blasted and pickled. Components are assembled or jigged, very often with a ring of braze metal charge placed in position. Components are heated by torch, in a conveyor furnace or by...

...article ] Manufacture: Surface preparation – degreasing using organic solvents and/or alkaline solutions. Abrasive cleaning and pickling to remove oxide films. Assembly/jigging (see Brazing L01) – where possible joints should be self-locating. Heating – mass soldering uses the molten solder as a heat source to melt the pre-coated flux. Direct coating uses a separate...

...article)] [Diagrams to demonstrate Superplastic forming (see article)] ​Female drape forming: Blank coated with releasing agent, clamped over tray containing male mould and heated to correct temperature. Air pressure applied forcing metal into close contact with the mould. [Diagrams to demonstrate Superplastic forming (see article)] [Diagrams to demonstrate Superplastic...

...article ] Surfaces to be bonded are cleaned if necessary. In some cases, light oil films can be left on. Two-part adhesives are accurately mixed and blended together. Most adhesives are placed at the joint position using a dispenser. In some cases jigging is necessary, with the application of a clamping force. Most adhesives require heating in an oven for a certain curing...

...article) ] (b) inflating [Diagram to demonstrate Blow moulding (see article) ] (c) inflated and cooling [Diagram to demonstrate Blow moulding (see article) ] (d) [Diagram to demonstrate Blow moulding (see article) ] Manufacture: Parisons for blow moulding are produced by extrusion or injection moulding. In conventional extrusion blow moulding (EBM), the parison is simply...