Although Fiber Lasers are being introduced to many applications at this time, most engraving lasers are of two varieties, CO2 & Q-Switched Nd:YAG.
If you are engraving in wood, plastic, paper,or glass (most organic materials) the usual choice is a CO2 laser. A CO2 generates a beam at 10.6 micrometers wavelength. This wavelength reacts better with these materials.
If you are engraving in dark anodized aluminum, either a CO2 or a Nd:YAG works well.
For metals, the common choice is a Q-switched Nd:YAG. These metals include aluminum, tool steel, stainless steel, soft steel, etc. A Nd:YAG laser produce a beam at 1064 nanometers. This is approximately 1/10 of the wavelength of a CO2 laser. Partly because of this wavelength reacts better with these materials, partly because at 1/10 the wavelength you can focus the laser to a smaller spot size and partly because of the Q-switching, Nd:YAG lasers are used for engraving metals. (Q-Switching is a method of quickly turning the beam on and off. By doing this, a laser beam with high peak power is created.) It is the wavelength, the spot size and the high peak power that allow the Nd:YAG laser beam to dig into metals.
Lasers are used for cutting many non-metal materials like acrylic, glass, wood, leather and rubber. They are also used for metals both ferrous and non-ferrous.
When cutting materials, there are a number of things to consider as follows:
- (1) The material one is cutting.
- (2) The thickness of the material.
- (3) The speed at which one wants to cut.
Materials are sometimes cut using a Nd:YAG laser but the CO2 is the much more usual laser used...
|Material||Thickness||100 Watt||200 Watt||500 Watt||Assist Gas||Focal Length|
|304 Stainless Steel||.010||N/A||220||440||Oxygen||2.50|
|Low Carbon Steel||.031||N/A||90||180||Oxygen||2.50|
|Glass-Reinforced Polyester Delrin||.225||75||150||300||Nitrogen||2.50|
|The listed cutting speeds are starting values which might need to be modified up or down, depending on the actual material and the desired edge quality. Please note that the assist gas is optional on all materials except steel.|
|Material||Thickness||1500 Watt||2200 Watt||3500 Watt|
(2 point kerf)
|Plastics||Up to 1" thick||To 350||To 400||To 450|
|NOTE: Reduce speed by approximately 20% When using high pressure nitrogen assist.|
The typical laser used for welding is the pulsed Nd:YAG laser. These pulses are longer than the Q-switched pulse of a Nd:YAG engraving laser. Typical pulse widths are 0.5 to 29 milliseconds. Energy per pulse can range from 10 joules or less to 70 joules or more. Some Nd:YAG welders can have pulse shaping networks.
General: When selecting a laser. It is important to get a laser that has enough power and is otherwise suitable for your application. Feel free to contact Laser Resale Inc. for a free consultation.