Laser Drilling Technology

Laser drilling is accurate and repeatable. It offers an attractive and essential technique for drilling holes in materials that will be developed in the future.

In fact, laser drilling applications are now emerging in the aerospace and automotive industries, where large volumes of holes are produced o a daily quality production rate.

In particular, the auto industry has been looking into laser applications for some time. At present, one application in the automotive industry is using laser to drill lubrication holes in car transmissions.

The main advantage of lasers for the automotive and aerospace industries is the ability to allow design latitude for drilling, cutting and welding. The flexibility offered by lasers for drilling holes in difficult locations, and for accommodating design changing, provides increased cost effectiveness for producing applications.

For example, one U.S. auto maker currently uses a laser to drill three lubrication holes in an internal gears used in transmissions. Previously the company used carbide bits to drill the holes, but the bits wore out or broke after six or seven holes.

A laser removes material by melting and vaporizing it. The energy density for normal hole drilling is over five million watts per sq. in, and the resulting heat is capable of vaporizing diamond, tungsten carbide, or any high temperature metallic or ceramic material.

A laser can produce holes as small as 0.0002 in dia, while holes larger than 0.050 in are trepanned or cut out. In general, industrial lasers are limited to a maximum of 1 in in-hole depth that can be drilled efficiently.

The major elements of a laser system are a laser cavity, power supply, optics, beam delivery system, support structure, laser enclosure, system control, and exhaust system.

The primary types of laser used in material processing are the Neodymium-dopes Yttrium Aluminium Garnet (YAG) laser and the CO2 gas laser. Other lasers used in material processing to a lesser extent, are excimes gas, argon gas, neodymiumglass, and alexandrite.

The YAG laser is especially suited for drilling and cutting metals. Most metals reflect much of the incident light energy emitted by lasers, but the YAG couples its energy better than most lasers.

For typical drilling operations, certain YAG system can penetrate up to 25 mm thicknesses of material. Hole sizes ranges from 0.1 mm up to a maximum of about 1 mm without beam, manipulation. With beam or part manipulation, almost any size or shape hole can be cut.

CO2 lasers are suited for cutting organic materials and synthetics such as plastics, rubbers, cloth, and paper. They also perform well for cutting, welded, and heat-treating iron and its alloys.

YAG and CO2 lasers can operate either in pulses or in continuous mode, with the pulsed mode usually being most effective. The number of pulses required to drill a specific hole depends on the hole diameter, material thickness, and material properties.