laser based manufacturing
DESCRIPTION
manufacturingTRANSCRIPT
Laser Based Manufacturing
What is Laser
LASER is the acronym for Light Amplified Stimulated Emission of Radiation
Laser is a device which generates or amplifies light
Stimulated emission of electromagnetic radiation
Coherent, monochromatic, directional and high power laser beam is used
Elements of Laser
Lasing Medium (Gas, liquid, solid) Pumping process Optical feedback element
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Types of Laser
Gas Laser
Solid State Laser
Excimer Laser
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Gas Laser
Electric current is discharged through a gas to produce a coherent light
Operate on the principle of converting electric energy into laser light output
Gas acts as pumping medium to attain the necessary population inversion
Common gas laser are CO2 Gas Laser, He-Ne Gas Laser
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He-Ne Gas Laser
Source: Google Images
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Solid State Laser
Constructed by doping a rare earth element into a variety of host materials
Pumped optically by arc lamps or flash lamps Respond well to Q-switching Ruby or Nd:YAG is the most common host
material
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Ruby Laser
Source: HowStuffWorks
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Excimer Laser
Uses a combination of an inert gas and reactive gas
Excimer is form of Ultraviolet Chemical Laser
Excimer is short for ‘excited dimer’
Source: Google Images
Laser Beam Machining (LBM)
Used light energy from a laser to remove material by vaporization and ablation
Energy is concentrated optically Laser emits either continuous or pulsed light
beam
LBM schematic.
Schematic diagram of Laser Beam Machine
Physical processes occurring during LBM
Material Removal Mechanism In LBM
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Parameter Affecting LBM
• Working Material
• Assist Gases
• Focusing Lenses
• Laser Beam
• Environment
Laser Beam
Machining
Laser Beam Machining – Capabilities
In laser machining there is no physical tool. Thus no machining force or wear of the tool takes place.
Large aspect ratio in laser drilling can be achieved along with acceptable accuracy or dimension, form or location
Micro-holes can be drilled in difficult – to – machine materials
Though laser processing is a thermal processing but heat affected zone specially in pulse laser processing is not very significant due to shorter pulse duration.
Laser Beam Machining – Limitations
High initial capital cost High maintenance cost Not very efficient process Presence of Heat Affected Zone – specially in
gas assist CO2 laser cutting Thermal process – not suitable for heat
sensitive materials like aluminum glass fiber laminate
Laser Metal Deposition(LMD)
Laser Metal Deposition(LMD) Laser beam creates molten pool on part Metal powder is fed into pool by precision
powder feed system Powder is melted and incorporated into the
pool to create a weld bead
Laser Metal Deposition(LMD)
Valve Ball & Seat Weld Development
Valve Ball & Seat Hardness Profile
Laser Metal Deposition–Capabilities
Metallurgical bond (not mechanical – thermal spray) Wide variety of available powders Very low dilution is possible Relatively high deposition rates Process is highly repeatable Low impact on base material compared to similar
processes (HAZ) Superior metallurgy compared to similar processes Virtually unlimited build height Very flexible tool path compared to wire applications
Laser Metal Deposition–Limitations
High capital equipment costs Powder cost is typically higher than wire Capture ratio of additive material < 100% (based on
process parameters) Cannot control the process manually – CNC is required Experienced, specialized staff required (e.g. laser
safety engineer, skilled operators) Less OEM competition than with traditional
techniques Limited domestic application and equipment support
Selective Laser Sintering (SLS) Parts built up layer by layer A CO2 laser beam selectively melts powder into a
designated shape The component sinks into the bed, a layer of powder
is deposition above the component The process repeats until the component is finished
Selective Laser Sintering Machine
Example of SLS Part (Drill)
Selective Laser Sintering–Capabilities
Robust System and High End Products. Conceptual Models. Functional Prototypes. Pattern Masters for casting. Rapid Tooling. Wide Range of Building Materials. High Throughput Capability. intelligent powder tracking Largest available part size
Selective Laser Sintering–Limitations
Large Amount of Up-Front Capital. Designed for Large Manufacturing Industries. High Maintenance Cost High power requirements for Sinterstation
Process. Requires lots of open space.