UV Laser Marker Introduction
UV laser marking machines are the current players that have made a permanent place for themselves in the world of today. The marks on medicine packaging and on the tablets themselves are made by a laser. Furthermore, the complex safety features on ID and credit cards are made by laser and eyeglasses have almost invisible marks made by the same technology. The lasers in use for these applications are ultraviolet (UV) lasers that generate light with wavelengths in the range of 150 to 400 nm
But what is a UV laser and how is it in use for marking? We will discuss this and much more below. Our discourse will range from the technologies at play to its uses in the marking world and a few key UV lasers marking machine manufacturers gripping the industry today.
The World of UV Lasers
Laser technology has been in use for marking materials for quite some time and one can say the market is mature to an extent. This assessment is based upon the fact that many versatile solutions are available to cater to industrial needs.
For instance, handheld laser markers are available for marking extremely heavy or large objects. Similarly, solutions that can integrate with a conveyor setup exist to facilitate production lines. Within the laser segment exist several technologies and are in use according to the benefits they offer. These benefits can range from the type of materials they can mark to the precision and sensitivity they offer. UV lasers are a sub-category of this domain.
The wavelength of UV laser light is around one-third (355 nm) of that of standard wavelength lasers (1064 nm). Moreover, the name “UV laser marker” comes from its wavelength being in the ultraviolet portion of the light spectrum.
A: Ultraviolet range
B: Visible range
C: Infrared range
UV Laser in the Industry
The design of a UV laser allows it to be a practical solution for marking plastics and glass. Moreover, the UV laser machine can engrave a vast number of materials, from metals to paper. Following is a basic list of materials that these machines can engrave and mark.
UV laser common applications
- Marking some metals
- Engraving and marking of all plastics
- Glass marking
- Marking and engraving of some stones
- Paper marking
- Leather marking and graving
- Marking on fruits
- Marking on wood
- Ceramic marking
- Garment marking
Considering the list above, the end-users of this technology and this equipment span multiple businesses. For instance, they can be from food and beverages to industrial and medical products. Below are a few example images of products describing possible end uses. From package marking for traceability to identification marking on electronics, the UV laser engraver is a proficient tool for achieving the marking.
Over the last decade, infrared fiber lasers became the dominant solutions due to their cost, performance, and size advantages. However, recent application studies have shown that wavelength in the range of green and UV lasers are providing performance and flexibility advantages that provide benefits for system integrators and end-users alike. Furthermore, advances in compactness, weight, size, and performance parameters, as well as demonstrated reliability, ruggedness, and durability enabled UV lasers to resurface for laser marking applications.
How to select the best UV Laser Machine
When making the decision of selecting the most apt UV laser machine you need to consider a few basic characteristics of your selection process.
Type of Laser to Choose
We will start with the type of laser that can best suit your requirements.
One technology is that of solid-state, Q-switched Nd: YAG laser. In these lasers, a special crystal changes the infrared 1064 nm wavelength to the ultraviolet 353 nm wavelength. Consequently, these features allow for focusing the beam to spot sizes on the order of 10 µm. The high repetition rate and the small focused spot make these lasers well suited for machining on a micro-scale.
- Lasers below 1W are very popular today and can be commonly found. They sell separately and in combination with the so-called DIY engravers.
- The 1 W – 3 W lasers (1000 – 3000 mW) category is a less common find. These lasers can cut wood, plywood, PVC, acryl, cardboard, PLA, ABS. However, the thickness of the plywood does not exceed 2-3 mm.
- The 3 W – 6 W (3000 – 6000 mW) lasers have a strong fan following. These lasers are well suited for cutting plywood and wood 3.2 mm thick, and other materials of greater thickness.
Currently, manufacturers are exploring the 10 W (10000 mW) lasers range. Operating a laser has serious concerns as there are problems associated with heat dissipation.
The excimer laser is another type of laser for UV laser engraving and is a gas laser. The wavelength of this laser depends on the type of gas mixture. Instead of a round beam, the shape is rectangular and offers a comparatively consistent intensity distribution over the area. However, the intensity of the beam falls off sharply at the edges. None-the-less, process details can be as small as a few microns, while the distance between focusing optics and workpiece can be as large as 50 to 100 mm.
Excimer lasers are primarily in use by industries requiring extreme levels of precision. For instance, they are in use by micro-chip fabrication and manufacturing industries. Using a process known as photolithography, these devices help build millions of micro-level transistors on the surface of silicon substrates. Similarly, the medical world finds there use as well. Organic compounds are good at absorbing this laser type. Hence they can easily micro-machine organic compounds and this makes them suitable for highly sensitive surgeries such as eye surgeries.
Metal Vapor Laser:
The third type of UV laser is the metal vapor laser. The copper vapor laser is mainly used although vapors of several other metals can also be suitable. This kind of laser generates radiation at 511 nm and 578 nm wavelength. Moreover, frequency mixing and doubling are in use to generate ultraviolet radiation with 255 nm, 271 nm, and 289 nm wavelength.
Metal vapor laser engravers are more commonly known as copper vapor laser (CVL) engravers considering that the most common applications use copper vapors.
- CVL can machine metals, diamond, silica, glass, silicon, ceramics and many other materials that are difficult to machine by conventional techniques.
- They excel at high-aspect-ratio drilling and slotting.
- Moreover, the very high peak power density removes the material either by vaporization or ablation resulting in minimal dross, splatter, or recasts material thus giving clean and precise machined features that do not require finishing operations. Furthermore, the small amount of energy contained within the short pulses minimizes thermal effects.
Factors affecting your selection of UV Laser Machine
In addition to the type of laser machine, here are the other important factors that will help you in selecting the best UV laser machine:
- Type of material you want to mark: Selection of the laser machine majorly depends on the type of material that you want to mark. As explained above, there are separate UV laser machines that work best on certain surfaces.
- Budget: If you do not have a high budget, then you can choose a simple and basic UV laser machine that will get you through the basic tasks of marking on your products.
- Size of your company: Size of your company is also a major factor in selection of the UV laser machine. If you have a big company that needs many units to be marked in a lower amount of time then you may need a more sophisticated machine.
This next segment will further help you in selecting of the best UV laser machine for you business.
UV Laser Marking Machines: A Comparison of Market Leaders
Here are a few good UV laser machines that can help you improve your business in no time and you can select the best UV laser easily:
This UV laser machine is a versatile solution for a range of industries. This is the MECCO 3 watt SMARTmark® UV Laser Marking Machine. Medical device manufacturers use this UV or “cold marking” solutions to create smooth, hygienic marks to fulfill FDA requirements, including Unique Device Identification marks. Similarly, in the electronics and automotive industries, UV lasers allow companies to mark small, delicate components, including circuit boards and silicon wafers, with less waste.
This UV Laser Marking Machine uses a 355 nm UV laser wavelength and purports to deliver high absorption rates, minimizing heat stress that can lead to damaged products.
MECCO markets this machine to have the following features that differ it from competing products:
- Mark materials that are heat sensitive
- Real-time visible live pointer for previewing mark
- Small 19″ rack mount footprint makes it easy to integrate with other equipment and existing assembly lines
- No consumables and minimal maintenance help reduce operating costs
- Mount laser in any orientation
- Integrated safety shutter
This particular model is air-cooled and has a pulse-type UV fiber laser. Pulsed operation of lasers refers to any laser not classified as a continuous wave so that the optical power appears in pulses of some duration at some repetition rate. Such an application method allows the production of pulses having as large an energy as possible. Moreover, it uses a galvo-scanner for scanning in XY directions. Galvo scanners are motorized mirror mounts and systems used for laser-beam steering or scanning applications. This is a sophisticated method that allows for very precise control of the laser beam.
This is the HeatSign HS-UV03 UV laser marker. The latest UV laser source design helps achieve high accuracy marking. The source not only extends the machine service life but reduces power instability to less than 3%. Short pulse width and a high peak power allow the laser to achieve flow line standard. Many manufacturing processes involve fast-moving production lines. To avoid additional cycle time and in order to maintain product flow rates without interruption for marking, parts must instead be marked while they are in motion. This process of laser marking a component as it moves rapidly past a fixed laser is called flow line standard. This implies that the design of this machine is highly flexible when it comes down to applicability.
The model shown above has a marking area of 100mm by 100mm and a marking speed of 9000mm/s. This machine also relies on air for cooling, a critical aspect of laser equipment operation. One important characteristic is that this laser operates in the near TEM00 mode. A TEM00 beam has a spatial profile that is very nearly Gaussian (>95%) and that does not change as it propagates (i.e. from when it emerges from the laser right into the far-field). An unstable laser with a graded reflectivity mirror produces a beam that is only 70-80% fit to Gaussian in the near field. In simple words, the laser has very high accuracy when it carries out its marking tasks.
This is the Hunst Laser ET-UV3. It comes in three variants of UV laser power, 3 watts, 5 watts, and 10 watts. A major difference between this machine in comparison to the ones above is that this is a water-cooled machine. It has a marking speed of up to 8000mm per second a maximum marking depth of up to .5mm. Hunst markets this machine as having flight and rotary marking capacity. Moreover, the software the machine uses is compatible with common design software such as AutoCAD and Photoshop. This is a great feature allowing easy integration in the workflow of the designers designing the markings.
The prices of these machines can vary from 10,000 to 20,000 USD. The variance in prices is not only brand and quality dependent. Since these machines can be configured to meet end-user needs, customization can change the costs. Hence most manufacturers will reach out to customers by asking them to reach out for a quotation.
In the near future, laser technologies will be driving the market of marking and engraving. For sensitive materials and low-heat sustaining materials, or for processes requiring very high precision, UV lasers will be the dominant technology. Considering the versatility these devices can offer, UV laser engravers can become the go-to technology. Moreover, their uses have been discussed in much detail above to assist users to have a good understanding of the domain. It is critical to understand the strengths and weaknesses that each technology offers. Hence, the case for UV laser marking machines is similar. From a price standpoint, these machines may seem to have a hefty price tag, but their performance and maintenance-free operation cover the high price tag and a bit more.