Lasers Are Us

How do I choose a laser?

Introduction – I love lasers. They are great. Watching a beam of light silently slice up some material with no apparent effort still captivates me. Lasers are like no other tools used in the history of human civilisation, their precision, their controllability and their raw power is just awe inspiring. Lasers are used in CD players, in internet broadband transmissions, in surgery and in ship building. They are such versatile tools. Unfortunately there is not one laser that can do everything! Some lasers are great for cutting metal, but can melt and burn plastic. And others that mark plastic well, cannot mark metals at all. So the first step in choosing a laser is deciding what’s its main use will be.

Step 1 – The right wavelength

We name lasers either by the wavelength of the light it produces, or more commonly by the substance that actually produces the laser light. The “substance” can be either solid, liquid or gas, and this also can be used to describe the laser. Here are some examples

A Carbon Dioxide Laser – A Gas Laser operating at a wavelength of 10.6 microns
A Nd:YAG laser – a solid state laser operating at a wavelength of 1064 nanometres
A Dye Laser – a liquid laser using Rhodamine 6G operating at a wavelength of 580 nanometres

Now follows a list of common laser applications with their associated laser

Metal Cutting – Very High Power CO2 laser
Metal marking – YAG laser
Paper cutting – CO2 laser
Leather engraving – CO2 laser
ABS Marking – YAG laser
Cardboard cutting – CO2 laser
Melamine marking – Ultra violet UV laser
Acrylic cutting – CO2 laser
Acrylic engraving – CO2 laser
Nylon mesh cutting – CO2 laser
Rubber drilling – CO2 laser

You can see from the list that the CO2 is the most versatile laser, followed by the YAG laser.

Step 2 – Choosing the Power

Next step is to determine the power of the laser required. The higher the power, the higher the cost so it’s important to buy what you need rather than pay for excess capacity that isn’t really needed. The power of the laser is expressed in Watts (W) for example a low power CO2 laser might be 10W or 25W. A medium power CO2 might be upto 500W and a high power CO2 is kilowatts of power. Typical YAG powers are 50watts for a marking system and more than 100watts for cutting thin metal or for deep engravings.

But, don’t be fooled by comparing laser power watts with household light bulb watts. A filament lamp of 40watts would barely light a room enough to read, but even a 12watt CO2 laser can cut through 5mm of acrylic plastic sheet. That’s because its laser light, not normal light. Laser light can be thought of as concentrated light or concentrated energy.

Greater power allows thicker materials to be cut, or allows engravings to be performed faster. It doesn’t normally mean that it can cut new materials that a lower power laser can’t. In other words, Table 1 applies whether it’s a low power or a high power laser.

Step 3 – Choosing the bed size

The bed size or marking area is the next decision point. Think about the size of mark or engraving you need, and the cut area required. Think also about the size of the material to be processed and if one item will be processed at a time. All these questions are about physical size. Typical examples are,

YAG Marking lasers usually have marking areas of 100mm x 100mm. So markings have to be within this size.

CO2 flat bed lasers typically have cutting and engraving areas of 600mm x 500mm, for example our ILS-III system.

Some, of these systems will allow parts to be placed in the laser that are larger than the process area, but its not necessarily the case.

Step 4 – Choosing the right supplier

Despite the amazing versatility of the laser, they are still quite rare as machine tools go. This means that there are only normally a handful of suppliers in any given country. Most of the suppliers are distributors of laser equipment. Manufacturers are scattered around the world with some notable manufacturers in USA, UK, Germany, Taiwan and China.

There are two main kinds of distributors, those that have a history of laser engineering, and those that have a history of sign making or engraving and have added the laser to their product catalogues.

Suppliers that are expert in laser technology can understand how to use the laser for maximum benefit. They understand what can be done and what can be done well with the laser, and importantly what marking or cutting jobs cannot be performed well on the laser.

Summary

Be clear about the main use of the laser so that the right laser type is selected
Be clear about how fast or how many products need to be lasered per day so that the power and cost of the laser can be established
Choose the bed size or process area
Choose a supplier that is right for you

Questions?

Got more questions? Don’t hesitate, contact Lasers Are Us