FOCUS ON ADDITIVE MANUFACTURING
The second AM technology fully melts the materials . This includes direct laser metal sintering , which uses a laser to melt layers of metal powder , and electron beam melting , which uses electron beams to melt the powders .
The third broad type of technology is stereolithography , which uses a process called photopolymerisation whereby an ultraviolet laser is fired into a vat of photopolymer resin to create torque-resistant ceramic parts able to endure extreme temperatures .
According to independent research and technology organisation TWI , there are number of distinct AM processes with their own standards . These include :
4 . Powder Bed Fusion . Powder bed fusion encompasses a variety of AM techniques including direct metal laser melting ( DMLM ); direct metal laser sintering ( DMLS ); electron beam melting ( EBM ); selective laser sintering
A 3D metal printer produces a steel part ; revolutionary additive technology for sintering metal parts .
1 . Binder Jetting . This technique uses a 3D printing style head moving on x , y and z axes to deposit alternating layers of powdered material and a liquid binder as an adhesive .
2 . Directed Energy Deposition . Direct energy deposition additive manufacturing can be used with a wide variety of materials including ceramics , metals and polymers . A laser , electric arc or an electron beam gun mounted on an arm moves horizontally melting wire , filament feedstock or powder to build up material as a bed moves vertically .
3 . Material Extrusion . This common AM process uses spooled polymers which are either extruded or drawn through a heated nozzle which is mounted on a movable arm . This process builds melted material , layer by layer , as the nozzle moves horizontally and the bed moves vertically . The layers adhere through temperature control or chemical bonding agents .
( SLS ) and selective heat sintering ( SHS ). Electron beams , lasers or thermal print heads are used to melt or partially melt fine layers of material after which excess powder is blasted away .
5 . Sheet Lamination . Sheet lamination can be split into two technologies : laminated object manufacturing ( LOM ) and ultrasonic additive manufacturing ( UAM ). Laminated object manufacturing is suited to creating items with visual or aesthetic appeal and uses alternate layers of paper and adhesive . UAM uses ultrasonic welding to join thin metal sheets . A low-energy , lowtemperature process , UAM can be used with various metals such as aluminium , stainless steel and titanium .
6 . Vat Polymerisation . This process uses a vat of liquid resin photopolymer to create an object , layer by layer . Mirrors are used to direct ultraviolet light which cures the successive layers of resin through photopolymerisation .
7 . Wire Arc Additive Manufacturing ( now known as Directed Energy Deposition-Arc ( DED-arc )). Wire arc additive manufacturing uses arc welding power sources and manipulators to build 3D shapes through arc deposition . This process commonly uses wire as a material source and follows a predetermined path to create the desired shape . This method of additive manufacture is usually performed using robotic welding equipment .
Trends , forecasts and challenges
The laser sintering method .
The outlook for AM is bright . New materials , sustainable processes and advanced software are priming the technology for a greater share
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