Lasers inManufacturingPresent: Erfan Zaker EsfahaniEmail: firstname.lastname@example.orgNumber: 09131299216Lecturer: Dr. saebnooriUniversity: najaf abadNumber of student: 890914688Course: Surface Engineering
Introduction Laser Welding Laser Cleaning Surface treatments Laser Cladding Direct Laser Fabrication Selective Laser Sintering Laser Forming - an emerging process
Laser Welding Established in the early 80’s Now used on many production lines Low volume applications andsubcontract limited to niche areas suchas mould tool repair, jewellery anddentistry
WeldingKey features of deep penetration laser welding include: High energy density – Keyhole welding Less distortion High processing speeds High throughput Rapid start / stop Unlike arc processes Welds at atmospheric pressures Unlike EB welding No filler required But good fit up is essential Narrow welds Less distortion Very accurate welding possible Good fit up & fixturing needed Good weld bead profiles No beam wander in magnetic fields Unlike EB Little or no contamination Depending on gas shroud
WeldingA 10 kW fibre laser used inshipbuildingA hybrid laser welding system
Spot and MicroWelding Repairing mould tools Medical devices400 m spot welds on aorthodontic bracketSensors Read / Write headsOrthodontic Bracket
Other Laser Welding applicationsPlastics and Polymer WeldingPossible to use laser to weld transparent plastic toopaque plastic (n.b. “transparent and “opaque”refer to laser wavelengths)Clear weld®Uses absorbing dye in joint interface to weld twonominally transparent polymersCan even be used for clothing!
Laser Welding DevelopmentsHybrid WeldingUses combination of arc and laser processesMore tolerant to poor fit upFiller metals can positively modify weld metalOver performance better than expected for thiscombination“Remote Welding”Use high beam quality “slab” and fibre laserscoupled to a scanning head to weld at multiple x-y-z positions
CleaningEmerging process, particularly driven by art andmonument restoration (I.e. National Museums andGalleries on Merseyside (NMGM) conservation centre.Engineering applications are being identified – drycleaning of metal components prior to welding andPCB’s and component leads prior to soldering.
CleaningAdvantages of laser cleaning Laser Cleaning does not damage No abrasive effect (No abrasive) No mechanical contact No heat effect Laser cleaning does not pollute No solvents No polluted effluents Fumes extracted easilyThe operator protection is reduced to a simple eye protection
Engineering applications of laser cleaningare being developed. Applications include mould tool cleaningStripping of paint from aircraftCleaning
Surface treatments Three main processes –hardening, melting and alloying.Aim to improve surface propertiessuch as wear and corrosionresistance, one can: Temper Laser Hardening Laser fusing / cladding(depositing a hardwearingcorrosion resistant surface) Alloying surfaces Nitrate Treat many different materialsLaser hardeningLaser Alloying
Surface treatmentsSpecial hardening process for titanium Surface is laser heated. Nitrogen is blown over the surface formingtitanium nitride under on the surface. The surface hardness is increased many timescompared with the parent material.
Laser CladdingDeposition of wear and corrosion resistantmaterials.Reduced heat input gives lower distortion.
Direct Laser FabricationDLF combines 4 common technologies CAD CAM Powder Metallurgy Laser Technology A high powered laser creates a melt pool Powder is deposited into the melt pool Moving the laser beam in a prescribed pattern a component istraced out layer by layer
Direct Laser FabricationGeneral set-up of Direct Metal Deposition
Selective Laser Sintering Parts built up layer by layer A CO2 laser beam selectively melts powder into a designatedshape The component sinks into the bed, a layer of powder isdeposition above the component The process repeats until the component is finished
Laser Forming - an emergingprocess Bending metal with light Laser beam induces thermal stresses The plate expands, cools andcontracts The flat plate deforms into a newshapeIndustrial sectors Aerospace Automotive Marine
Structuring and texturing Periodic Structures (with period <1um) machined into metalsand ceramics, and also produced by material modification inpolymers
Direct writing in FusedSilicaPulse duration 100fs,Wavelength 400nm,Pulse energy 0.8μJScan speed 200 μm/s10 μm pitch, 0.5NA
CW Fibre laser generationof NanoparticlesHigh intensity laser beams vapourise materialsthat then condense as sub-micron powders.CW fibre laser combine high intensity with highintensity
pS fibre lasers Fianium laser system: Pulse Length 20ps. Wavelength 1064 nm. Rep Rate 200kHz or 500kHz Maximum Pulse Energy 6 J Laser Power 2.1W Experimental Spot Size 26 JDTI Funded project “Ultrafast” completed at LLEC – scored 56/60 in final assessment