What is laser beam machining?
As per the theory of laser-beam machining (LBM), the optical energy is produced with the help of a laser and is bombarded on the surface of workpiece.
The workpiece melts if the source of energy has good amount of density and is highly focused on the surface.
This process (which does not require a vacuum) is used to machine a variety of metallic and non metallic materials. Laser beam machining (LBM) removes material by melting, ablating, and vaporizing the workpiece at the point of impingement of a highly focused beam of coherent monochromatic light.
Which are the different types of lasers used in manufacturing process?
CO2 (pulsed or continuous wave).
What is the process capability of Laser beam machining?
The biggest advantage of this process is that it can be used for drilling, trepanning, and cutting metals, nonmetallic materials, ceramics, and composite materials.
As laser-beam machining produces clean surface it has become an attractive alternative to traditional machining methods.
Holes as small as 0.005 mm with depth-to-diameter ratios of 50:1 have been produced in various materials, although a more practical minimum is 0.025 mm.
Laser beams have the capability of cutting steel plates of size 32 mm.
What is a Laser beam torch?
In Laser beam torch (LBT) simultaneous focus of laser beam and gas stream is done on the workpiece to remove the material.
A continuous-wave (CW) laser or a pulsed laser with more than 100 pulses per second is focused on or slightly below the surface of the workpiece, and the absorbed energy causes localised melting.
An exothermic reaction is produced due to the oxygen gas which removes the molten material from the cut.
Sometimes the molten material is removed with the help of argon or nitrogen.
The type of gas used has only a modest effect on laser penetrating ability.
Typically, short laser pulses with high peak power are used for cutting and welding.
What are the different Laser beam machining applications?
This process has greater application in the electronics and mechanical industries.
Bleeder holes for fuel-pump covers and lubrication holes in transmission hubs are being drilled with lasers.
Laser-beam machining has achieved significant cost reduction as compared to electrical-discharge machining.
Laser beams are also used for the following applications:
° Heat treating of metals and ceramics to enhance their mechanical properties.
° Marking of parts, such as letters, numbers, codes, etc. Mostly marking is done (a) with ink, (b) with devices such as punches, pins, and scroll rolls, (c) stamping, and (d) by etching. Although the equipment is more expensive than that used in other methods, marking and engraving with lasers has become increasingly common due to its accuracy, reproducibility, flexibility, ease of automation, and online application in manufacturing.
What are the design guidelines for this process?
Sharp corner designs should not be used as they are difficult to manufacture.
Deep cuts will produce tapered walls.
Dull and unpolished surfaces are more preferred in laser beam machining.
Due to high local temperatures and heat-affected zone the machined materials should be investigated to check the effects on the properties of the material.
How is Single Crystalline diamond tool prepared from this process?
Ceramic moulds are machined with the help of single crystalline diamond (SCD) tools.
Laser machining helps in fabricating a number of complex tools.
The SCD chip is machined to cylindrical shape using IR YVO4 laser and bonded to cemented carbide shank.
End mill tool has 10 cutting edges with −40° rake angle and 0.5 mm edge radius.
Tungsten carbide dies are machined with the help of this tool.
The operating cost for Laser beam machining is Rs. 1500/- per hour in India.