Laser Coding - What’s WATT?

Whether you’re looking to go green or just looking for an alternative to ink jet for your marking needs, laser coding could be the best of both worlds. We’ll examine:

• Understanding what’s watt (power, speed and distance)
• Why lasers are “green”
• Simple steps to success

UNDERSTANDING WHAT’S WATT
As more and more lasers make it into the market, one can’t help but hear all about which laser is faster and better and bigger: 10 Watt, 20 Watt, 30 Watt, 50 Watt and, oh yeah, 100 WATT.

To make it more confusing, you get a rundown on why the imaging technology is just as critical as the power, and you are asked to choose between dot matrix-style beam, galvos (galvanometer synchronized servos) or non-moving deflecting crystals. Choosing the right imaging technology & wattage could make or break your success. Each has unique characteristics affecting print quality, accuracy and speed. Let’s Keep It Simple.

The steered-beam sealed CO2 laser is the most common for marking on most food & beverage, consumer goods, cosmetic & personal care packaging, and pharmaceutical products, so that’s the one we’ll review.

POWER, the energy produced inside the tube which emits the light beam and produces the mark is measured in WATTS. Just like your light bulbs at home, the bigger wattage means the more power they use and the hotter they get. Make sure you use the right wattage for the right application otherwise you won’t have enough to leave a mark on your substrate or vice versa, you’ll have too much and you’re just wasting power. And also, that’s not very green, now is it?

Here are some simple guidelines to consider:

• Slow production lines under 200ppm marking simple date/batch code (i.e. paper, chipboard) by “burning” the outer layer …… use a 10 watt
• Medium-speed production lines running 200-500ppm marking one or two lines of print and/or “inscribing” into the product (i.e. PVC, PET, painted metal, glass)…. use a 30 watt
• Fast production lines 500-1200+ppm(i.e. canning/filling lines)… use a 50 watt. Sometimes you would require 100 watt depending on the environment (i.e. wet, cold/hot, etc.) and/or substrate (i.e. HDPE/LDPE).

SPEED, the measurement of your products/parts per minute, needs to be considered in conjunction with power. For example, think of this. Imagine passing your hand through a naked candle flame. If you pass it through slowly (ouch!), the heat increases and you get burned. If you pass it through quickly, you may not feel anything at all. The candle flame did not change, but has two different outcomes based on the speed at which you pass your hand. Now, consider the substrate of your product. Difficult to mark materials such as PVC, glass and hard plastics demand longer dwell times to code the substrate, which requires more energy. More energy equals higher wattage.

DISTANCE, the measurement of the laser coder’s marking head from your product, needs to be determined. Why? Laser Coders have a tube that produces a laser beam, mechanics to steer the beam, and a lens to focus the beam to a fixed point. And that distance is a critical component in laser coding. For example, remember playing with a magnifying glass as a kid? You would direct sunlight just right to burn a hole into a leaf. It was a special calculation of power and distance, really. Make sure you understand this because when you use a laser to code your product, it does not (DOES NOT) mean that you can now place your laser any distance from your product. Again, power and distance are critical.

I know what you’re thinking…this sounds like my ink jet system. In a way, it is. And it isn’t.

Incorrect distance from the product using an ink jet printer results in poor print quality (the ink will land somewhere). Incorrect distance using a laser coder may result in no mark at all. So keep those important factors in mind when considering “what’s watt”.

WHY LASERS ARE “GREEN”
Laser coders today are considered a green alternative to ink jet coding as no environmentally-dangerous consumables are required. Inks and solvents used in ink jet printers may be hazardous, toxic and/or flammable and may contain volatile organic compounds (VOCs). When using laser coders there are no consumables, so there’s no worries, right? Think again.

Laser marking generates fumes and particles. How much depends upon the substrate, the length of your message being marked, etc. Some of these fumes may be hazardous, so it’s important to address this from the time of installation and have them removed by using an extraction device. Also, when lasers are used without fume extraction systems, it can affect not only the environment, but also the performance of your laser coder. Here’s why. Airborne particles can accumulate on the laser’s optics resulting in increased power demand and decreased quality of the mark.

SIMPLE STEPS TO SUCCESS
Lastly, make sure that you’re working with a supplier who has your best interest in mind and can offer you the best-quality service. Everything needs maintenance and repair…everything! Make certain that you are being provided the best-fit product for your application. In some cases, it may be laser…in others it may be ink jet, but they should be able to offer you either. Work with a supplier who is not biased and can offer you options. You shouldn’t have to be shoe-horned into a solution that isn’t the right fit. Also, make sure that you request laser samples on your product so that you know what your code will look like on your substrate. This will also help determine which laser wattage is right for you, so that you can have the peace of mind in knowing that you’ve chosen the right product for your application. That’s what’s watt!

Diagraph, An ITW Company is a leading manufacturer and distributor of marking, coding, labeling and RFID systems and supplies. Products include small character continuous ink jet and laser coders; large character and high-resolution ink jet; waxjet; automated label printer/applicators; label applicators; thermal transfer overprinters; and thermal transfer label printers. Diagraph direct sales and service representatives are located across the country for prompt, expert, and personal service and connected with account management teams located at the corporate office in St. Louis, MO. For more information, a FREE no-obligation demonstration of Diagraph marking, coding, or labeling systems, please call 800-722-1125 or email info@diagraph.com.

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