If you have ever attempted to mark these types of materials with a CO2, fiber or diode pumped laser, you may have noticed poor marking quality. These lasers have very long wavelengths and may not react well with more sensitive materials.
So, to get more precise markings, you need to switch to a shorter wavelength laser. However, since these machines are generally less powerful, you will end up with slower marking speeds.
What is the best way to laser mark soft products for part identification or traceability? Is there a way to get the best of both worlds?
In this blog, we'll find out which industrial laser markers can be your ideal choice when you need readable, high-quality marks without damaging your parts. Also, learn which marking techniques work best on a wide range of soft materials, including silicone, thin plastics or metals, and even glass or ceramics.
If you are working with soft materials, a green laser with a wavelength of 532 nm may be your best option. However, we do not recommend running out and buying right away. In addition to materials, there are many considerations in choosing the best laser marking technology, such as application and marking type.
A simple definition of laser wavelength, measured in nanometers (nm), is the amount of energy or light produced by the laser. Different types of lasers emit different wavelengths. The shorter the wavelength, the more concentrated the energy. The higher the energy, the more light the material absorbs.
Laser marking of soft materials is generally recommended with shorter wavelength lasers, including green and UV lasers. They offer higher absorption rates than infrared lasers such as fiber and CO2 lasers, and are less likely to burn surrounding materials because they generate less heat. This is why such lasers are also called "cold lasers".
For example, laser markers in the infrared category, such as CO2, fiber optic or diode-pumped technology, are capable of creating high-quality permanent marks on a variety of materials, from metals to plastics. However, these same machines can alter and even burn some heat-sensitive materials. This is because the laser energy is not fully absorbed, allowing too much light to pass through without interacting with the material (or, as we say, the mark).
You'll be left with illegible logos, unreadable barcodes, or damaged parts—none of which are effective for part identification or traceability, let alone overall equipment effectiveness (OEE).
Why is this happening?
Lasers essentially concentrate light, and each material absorbs light energy differently. When the laser comes into contact with a material, it is changing the surface of that material—sometimes even a compound. How it varies depends on the type of laser application.
For example, carbon migration occurs during the heating of a metal or metal alloy, causing the metal to chemically bond with trace amounts of carbon molecules on or near the surface of the part, resulting in dark (and sometimes black) permanent marks. Laser etching or engraving is an application that requires deep laser marking for durable barcodes, serial numbers or logos on a variety of part materials.
An experienced laser marking equipment supplier will ask you comprehensive questions about your process and requirements to determine which laser marking system you need.
While we're on the topic of marking speed, we'll examine the differences between two lasers you might consider using in your soft marking applications.
If you are considering an alternative to infrared laser marking systems, you may have done research on UV laser marking machines and green marking lasers. These techniques are similar in that they are all used to mark soft products. However, there are some important differences to consider when making your final decision.
Ultraviolet lasers are often used to make complex, precise markings at the microscopic level. Their focused wavelengths allow high beam intensities and extremely small spot sizes.
Both green and ultraviolet lasers emit less energy than infrared lasers. However, in my experience, when your IR laser fails to mark effectively, the next logical step is to use a green laser.
Less power is required to obtain clean, readable markings on soft products. This is a given. So, we need to compromise somewhere.
Take the example of a typical fiber laser, which operates at 1064 nm. Green lasers operate at half that wavelength, 532 nm. Most UV lasers emit even less power, about one-third the power of 355 nm or fiber lasers.
Therefore, green lasers provide more power than UV lasers, but are still fine enough to mark a wide variety of soft products. You can get high quality marks without significantly slowing down the markup speed. Think of it as that kind of Goldilocks-like quality that's not too chunky or slow, but just right.
Why is laser power important?
We've talked a lot about laser wavelengths so far, but another key factor that determines the marking speed of a machine is the power output.
Laser wavelength is a measure of light energy, while watts (W) are a measure of laser power output. For example, a typical industrial fiber laser marker will operate in the output power range of 10W to 100W. They provide high speed and deep, permanent marking.
Most green marking lasers on the market today only provide about 4W to 6W of power output. Generally, this means relatively slow speeds and shallower markings.
How can I get the speed and quality I need? Don't give up on green lasers just yet, because as they say, necessity is the mother of invention.
What can a green laser machine mark?
Do you have a material that cannot be marked because it is too thin or fragile for a "traditional" laser marker?
Green lasers not only provide finer marking, but are also versatile. Create readable traceability, branding and identification marks on materials ranging from soft plastics and thin metals to glass and ceramics.
Green lasers are becoming more common among medical device manufacturers. In recent years, the medical industry has had to take extra precautions when labeling surgical equipment, trays, tubing, and other common products. That's because new FDA standards require unique identifiers (UDIs) and "hygienic markings" to ensure patient safety and speed of recalls.
A better green way
To mark soft materials without damage or readability issues, manufacturers need to use shorter wavelength lasers. These types of lasers generate less heat, which is why they are also called "cold lasers".
Two popular cold lasers used for marking and engraving are green lasers and ultraviolet lasers. Both options are capable of creating high-quality marks on delicate products, but the green laser offers more output power. Higher output power (in watts) translates into faster marking speeds.
However, most green lasers on the market only offer 4-6W of output power. Relatively slow if you are currently using a CO2, fiber or diode pumped laser marker.
Thank goodness there is a better option.
Take a look at the green laser marking machine that can achieve a maximum power output of 20W, which is more than 3 times that of other green laser marking technologies. If you're interested in seeing if a green laser is right for your material or application, take advantage of our sample marking. It's a free service delivered by experts in our labs that allows you to be sure you're getting the right score every time.