The Effectiveness and Working of the

Laser Drilling Machines

Laser an acronym for (Light Amplification by the Stimulated Emission of Radiation)

is a technology that makes use of the coherent beam of light in stimulating molecular

or electronic transmissions to the lower energy levels resulting in the emission of the

photons. This is the core principle behind the working of the laser drilling machines.

The Laser Drilling

Laser drilling is an automated process that can be used to make drills of alloys and

composites that cannot be drilled by the use of the conventional methods. Laser

drilling provides the only solution for the toughest and the hardest drilling challenges.

The use of laser drilling machine enables nearly all the solid materials ranging from

metals to diamonds can be drilled by the use of a suitable laser. Time minute holes

that are impossible to create with the use of mechanical processes cab be facilitated by

the use of a laser. The drilling is done contact-free with the use of the extreme small

optical systems that make drilling be possible at locations where the use of other

methods could fail.

The laser beam melts and evaporates the material. This leads to an increase in the

material volume in the drill hole leading to the creation of high vapor pressure. The

high vapor pressure drives the melt out of the drill hole. In laser drilling, all the laser

light is reflected from the rear mirror with 30-50% of the light passing through the

front mirror. The laser light continues through the shutter assembly to the angled

mirror and down through the focusing length up to the work piece. The laser beam in

the laser hole drilling process is coherent with a high energy content. When focused

on a surface, the laser light creates the heat that is used for the hole drilling.

Types of Laser Drilling Processes

1. The Single-pulse drilling and percussion drilling

This method is used in the penetration of the drill holes which have a small material

thickness, creating a few micrometers of depth. Percussion drilling makes use of the

desired drilling depth with the thicker materials by the means of a couple of laser

pulses with a low pulse energy and short pulse duration. This results in the creation of

holes that are deeper, more precise and with the smaller diameter as compared to the

single pulse drilling.

2. Trepanning

Trepanning is a combination of the drilling and cutting process that is used in

obtaining larger diameter. The starting hole is created by the use of percussion drilling

with the use of several laser pulses. The laser beam the travels over the material in

increasing large circular tracks over a certain work piece enlarging the initial hole

with the melted material displacing downward from the drill hole.

3. Helical Drilling

Helical drilling is used in the creation of large and deep drill holes of high quality.

Using this process, no initial hole is created bit the drilling is done with the use of

many large pulses in a circular track into the work piece. Here, the material is

displaced upwards and the focus is controlled so that it always remains at the bottom

of the hole. When the material has been penetrated, the laser is used to widen the

bottom of the drilling and to smoothen the edges.

The benefits of using laser drilling include;

The processing of high alloy metals without difficulty

Low cost tools that do not wear

Facilitation of the angled drilling of holes even at the most difficult access areas.

There is an economic setup time

It is a non-contact process as there is no tooling wear or breakage with minimal

material distortion

Produces high accuracy and consistent results

There is the ability to produce small diameter holes with high aspect ratio

Ease of programming and the adaptability to automation

Increases the production rates with flexible and faster setup times and less tooling

The use of laser drilling machines enhances versatility as the same tool can be used

for laser drilling and laser cutting. There is flexibility in the changeovers for the

different prototypes used with small batch processing. The machine has the capacity

for a higher degree of beam manipulation including the ability to drill shallow angles

and shaped holes. The laser machine has the capacity to drill multiple features

simultaneously with the ability to process a wide range of materials.

The Effectiveness and Working of the Laser Drilling Machines