SEMINAR ONLASER

MICROMACHINING

Department of mechanical engineeringFaculty of Engineering and TechnologyM.J.P. Rohilkhand University, Bareilly

Nov,2015

Anil chaurasiya12ME08

BYSeminar Guide- Dr. T.U. SiddiquiCo-guide-Mr. Vineet Tripathi

IntroductionWorking principleClassificationApplicationAdvantage and disadvantageSafetyReferences

Contents:

Laser micromachining: cutting, drilling, welding, or other modification in order to achieve small features.

Micro machining implies that parts are made to the size of 1 to 999 µm. However Micro also means very small in the fields of machining, manufacture of small parts are not easy.

Introduction

Micro pattern machined on a steel plate inless than 0.5 secondsSource-https://engineering.purdue.edu/LAMPL/research_micro%20machining.html

Continued...Lasers have been in use in various industrial sectors such as the automotive and aerospace industries for many years performing cutting, welding and materials processing tasks.

Working Principle The laser beam is focused onto the work piece and can be moved relative to it.

The laser machining process is controlled by switching the laser on and off, changing the laser pulse energy and other laser parameters and by positioning either the work piece or the laser focus. A laser machine consists of the laser, mirrors for beam guidance, a focusing optic and a positioning system.

Setup of laser micromaching

Continued...

Components use in laser micromaching

Continued... Laser is emitted from the source is passed through the energy attenuator. After it is passed through the beam homogenizer to homogenize the beam.

The target illuminator and machine vision controls the beam to the focusing lens. The lens is moved by precision motion stages. The beam is then falls on the work piece and the machining takes place.

Types of Laser Micro Machining

1. Direct writing. 2. Mask Projection

Process Parameters Effect

Wavelength,Focal length of lens

Feature size

Beam shape Feature shape

Beam energy,Pulse width

Size of heat affected zone

Depth of focus Aspect ratio

Continued...

DIFFERENT TYPE OF LASER AND THEIR USES IN INDUSTRY

APPLICATION LASER TYPECutting

MetalsPlasticsCeramics

DrillingMetalsPlastics

MarkingMetalsPlasticsCeramics

Surface treatment (metals)Welding (metals)

PCO2; CWCO2; Nd:YAG; rubyCWCO2PCO2

PCO2; Nd:YAG; Nd:glass; rubyExcimer

PCO2; Nd:YAGExcimerExcimerCWCO2PCO2; CWCO2; Nd:YAG; Nd:glass; ruby

Note: P = pulsed, CW = continuous wave.

SCANNING ELECTRON MICROSCOPE IMAGES

SEM images of micro-trenches formed by laser micromachining at different focus offset plane.Source-www.intchopen.com

Fabrication of Micro Structures on Metals by Femtosecond Laser Micromachining(SEM)Source-www.mdpi.com

HEAT AFFECTED ZONE IN LONG-PLUSE LASER AND ULTRSHORT-PLUSE LASER

Source-www.cmxr.com

For drilling micro holes, laser beam drilling technique

is used.

Applications

High speed drilling of 20µm holes in 50µm thick foil

Cutting of 1mm tube

100µm wide v-grooves

Continued...

100 um holes drilled in 75mm high-density polyethylene with (a) a twist drill bit (b) a KrF laser.Source-://www.exitech.co.ukhttp

(a) (b)

Laser Micro machining technique finds application in the manufacture of micro channels and micro holes in integrated chips and microchips.

Micro holes on integrated chips Micro channels on integrated chips

Continued...

Surface micro machining is characterized by the fabrication of micro mechanical structures from thin deposited thin films.

Continued...

Used in machining threads in a single polyfibre and also used to give taper to the fiber.

Continued...

Easy capability of being automatedStraightforward process monitoringForceless and contactless machiningMinor heat-affected zoneMarginal modifications to the microstructureHigh flexibility regarding design of tiny structuresHigh machining speedHigh precisionConstant machining qualityNo additional tooling costs by wearNo solvent chemicals usedMaterial removal rate controllable down to the nanometer scale

Advantages

The equipment required for micro machining is very costly than other cutting processes.Need highly skilled persons to operate micro machining systems.Material limitations (including crystalline and reflective materials)Reflected laser light can present a safety hazard

Disadvantages

High intensity ultraviolet and infrared light hazardous to the eyes (cornea) and skinDuring normal operation of the equipment Interlocked protective housing is must.Required safety labels, inspections and record keeping.

Safety

Mechanical safety Large motion control systems may pose mechanical hazards to people Mechanical guards Machine must be checked regularly

Lethal high voltages in the laser headElectrical safety coversQualified service personnel only

Electrical safety

Toxic and corrosive fluorine and chlorine gasesCompressed gas cylinders need proper handling

Material safety

Micro machining technology not only provides a new manufacturing route for existing products, but also allows the creation of completely new products.

The surface micro machining technology predominates at the present state & this trend will continue in the future.

Nano is the buzz word of the moment. Thus the transition from Micro-Electro-Mechanical-Systems (MEMS) to Nano-Electro-Mechanical systems (NEMS) is taking place in present technology

Conclusion

Advancements in Laser Micro machining Techniques- By Nadeem Rizvi and Paul Apte.Laser Micromachining – By Udo Klotzbach, Andres Fabian Lasagni, Michael Panzner and Volker Franke.www.resonetics.comInternet(Wikipedia, Google etc)www.mdpi.comwww.extich.co.inwww.itechopen.comhttp://www.springer.com

References

Thanks for Listening!!