This page is designed to provide useful information and important factors to consider when selecting a laser system.
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Buying Tips for Laser Systems
This page is designed to provide useful information and important factors to consider when selecting a laser system.
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What Are the Advantages of Metal Core Lasers Over Ceramic Core Lasers?
The main body of a laser, containing the critical laser gas mixture, is referred to as the core. The core can be made of metal, ceramic, or glass. The primary advantages of metal core lasers over ceramic core lasers are discussed below.
Ceramic core lasers were developed for commercial applications as water-cooled, ion gas lasers in the 1970s. All metal core laser technology has its genesis in military developments for demanding and mission critical applications. By the late 1980s, these military programs were complete. However, metal core laser development continued on to make the highly reliable and serviceable lasers available for commercial and industrial applications.
Metal core lasers are constructed from aluminum and go through a passivation (micro-coating) process during manufacturing, building a thin, dense layer of ceramic (AL2O3) on all internal components and eliminating the possibility of metal contact with the gas mixture. This very thin ceramic layer (just a few microns) does not impact thermal conductivity. Both ceramic core and metal core lasers are decontaminated and evacuated to high vacuum levels in the manufacturing process to remove any contaminates before gas fill. Therefore, ceramic and metal lasers both offer contamination free cores.
One of the key advantages of metal core lasers is ease of cooling. Only part of the electrical energy consumed by a laser is converted to laser power, while the rest of the electrical energy is converted to heat. A CO2 laser’s gas mixture is sensitive to high temperature, and removing excess heat is extremely critical. Metal is a much better choice (as opposed to ceramic) for required laser cooling because the metal core transfers heat quickly in order to keep the laser mixture at optimal operating temperature. Ceramic is a relatively poor conductor of heat, making it a less than an optimal choice, especially for air-cooled lasers.
Another distinct advantage of metal lasers is linear polarization. Laser beams with linear polarization can be combined into a single, cross-polarized beam to produce a broader range of power options and to deliver superior advantages in laser material processing. Additionally, in systems compatible with multiple lasers, metal lasers with different power and wavelengths can be combined, sharing the same optical path. Conversely, current ceramic lasers produce randomly polarized beams that cannot be combined.
Finally, metal lasers can be serviced easily, thereby extending their useful life indefinitely. Hundreds of thousands of metal core lasers have been manufactured by ULS and other companies in the last 20 years, with many laser sources over 10-years-old remaining in service. While ceramic lasers could provide a reasonably long operational life, they are not designed to be maintained easily due to the direct attachment of the laser resonator optics to the ceramic core, using glue as a bonding and sealing material. Metal core lasers, on the other hand, use metal or semiconductor grade elastomeric seals. Metal lasers also can operate for an extended time in the field before maintenance is needed and are designed for long term reliability and serviceability.
As summary, top global laser system manufacturers design, manufacture, and use metal core air-cooled CO2 lasers in their laser systems because these lasers offer the broadest range of power options and unlimited laser lifetime for a vast list of laser material processing applications. When making a decision regarding a laser system, consider the advantages offered by metal core lasers.
What’s the Difference Between DC Glass Lasers and RF Metal Lasers?
There are major differences between DC glass lasers and RF metal lasers that should be considered when selecting a laser system. These are described below.
DC Glass Lasers
The first CO2 lasers invented in the early 1960s were DC glass lasers. DC laser technology has not advanced since the 1960s primarily due to a shift in laser technology development to radio frequency and all metal laser design.
A DC glass laser consists of a long, fragile, blown-glass container filled with a laser gas mixture. Typically, the laser optics are attached directly to the glass in order to seal the laser mixture and form the laser resonator. A high voltage DC discharge is used to ionize the gas inside the glass container to produce a laser beam.
Due to poor heat transfer by the glass and low efficiency of the high voltage DC discharge, a DC laser needs special water cooling equipment to achieve continuous operation. The proper way to water cool a DC glass laser is with a water chiller. A chiller is essentially a combination of a refrigeration device and a pump that recirculates water around the glass laser to keep the laser at a constant temperature. Because DC glass lasers use very high DC voltage, they can also be extremely dangerous, even lethal, especially in combination with the cooling water, if water comes in contact with high voltage electronics.
Over time, the use of glass as a gas container and DC discharge between electrodes produces a contamination of the laser mixture by byproducts of the electrode’s erosion and depletion of the gas mixture. Contamination of the gas mixture and depletion of helium escaping through the glass walls and seals decrease the efficiency of the laser and severely reduce the lifetime of the laser.
DC glass lasers are characterized by very low speed of modulation. They cannot be modulated rapidly due to the limitation of continuously switching on and off high voltage DC power. This substantially limits the speed of laser processing and reduces throughput, especially in imaging applications that require high-quality laser pulsing.
Additionally, glass lasers can be damaged by routine handling or thermal shock from an interruption in water cooling. If no cooling flow is provided to the laser, the glass container will break, resulting in a non-functional laser that will need to be replaced. As a result, the service life of DC glass lasers remains very limited and is commonly measured in months of operation. DC glass lasers are not suitable for reprocessing and require replacement in order to restore a laser system to operational condition.
In summary, DC glass lasers are delicate devices. When integrated into a laser material processing system, they need additional cooling equipment to operate, can be dangerous to operators, provide lower quality output than other lasers, offer very limited laser processing speed, and have a short service life.
RF Metal Lasers
An RF metal laser has a hermetically-sealed metal chamber that contains the laser gas mixture. Precisely controlled radio frequency energy is used to create ionized gas plasma for the laser to produce a laser beam. The design of RF metal lasers is compact, durable, and contains integrated air cooling. RF metal lasers were originally developed for highly demanding military applications, and advancements in RF metal lasers continue today. One of the most recent advancements is a 500W air-cooled CO2 laser. Lasers of this power level typically require water cooling.
RF metal lasers are today’s lasers of choice for a vast variety of applications in numerous industries. These lasers are designed to operate without high voltage and water cooling. This makes RF metal lasers inherently safer to operate in almost any environment.
RF metal lasers are modern lasers offering a low cost of ownership. RF metal lasers are designed to be durable, provide the highest performance with high laser beam quality, offer indefinite service life, and help assure operator safety.
When considering a laser system, one should always ask laser system suppliers what type of lasers are used in the systems they offer.
Using Your Material Requirements to Select a Laser System Configuration
Laser material processing affords the use of many materials, including plastics, thin films, paper, wood, metals, adhesives, glass, foams, and fabrics to name a few. Although laser systems offer broad flexibility in processing materials, there are some questions to consider to make sure your system has the proper configuration to meet your material requirements:
Types of Materials
What types of materials will you be using? Think about the materials you use now or would like to use in the future. The effects produced by laser energy interacting with a material strongly depend upon the wavelength and power level of the laser and the absorption characteristics of a material.
Wavelengths for laser material processing are 10.6 and 9.3 micron produced by CO2 lasers and 1.06 micron produced by fiber lasers. A range of power levels is available for each laser type to optimize the laser energy-material interaction. However, the absorption characteristics of a material and the desired results greatly influence the selection of the laser type and power level. Therefore, knowing what materials you want to laser process will help you select the best wavelength(s) for your laser system – 10.6 (CO2), 9.3 (CO2), 1.06 (Fiber) or combination of wavelengths and power level.
Explore compatible materials in the ULS Materials Library. If you don’t see your material or have a question about a material, contact us.
Material Shape and Size
What are the dimensions of the materials? The laser system you select should have a laser processing area that will accommodate the dimensions of your materials, parts, or products. If using raw material, most materials will come in sheets or rolls. Material sheets and rolls in many cases can be cut to a size that fits within a laser system. If you are looking to laser process 3-dimensional objects that are spherical, cylindrical, square, or oddly-shaped, this is important to know in order to determine the Z-axis depth or additional components (rotary fixture, Pass-through with Class 4 Conversion Module, camera registration, etc.) your system will need to accommodate these objects.
Which laser processes do I plan to use on each material? Laser material processing uses laser energy to modify the shape or appearance of a material. This method of material modification provides a number of advantages, such as the ability to quickly change designs, produce products without the need for retooling, and improve the quality of finished products. For all laser processes that can be applied to a material, the energy of a laser beam interacts with the material to transform it in some way. Each transformation (or laser process such as laser cutting, laser ablation, laser surface modification, etc.) is optimized by precisely controlling the wavelength, power, duty cycle, and pulse spacing of the laser beam.
Understanding what you want to accomplish with your materials will not only determine the power level and wavelength you’ll need, it will also help determine the components you may need to achieve the best result with laser processing (i.e. type of lens), properly support the material (i.e., cutting table, pin table, rotary fixture), or minimize surface contamination of dust and debris or byproducts during laser processing (i.e. gas assist, air filtration).
It is difficult to know everything you want to do upfront and most often laser system users find new ways to use a laser system after they begin to use it regularly. When selecting a laser system, choose one that will give you the broadest system configuration flexibility to adapt to your material needs now and can grow with you in the future.
Why Top Speed is Not the Most Important Factor When Selecting a Laser System
The top speed motors can reach rarely influences the performance of a laser system. This is because of factors such as the material characteristics and the number of curves and corners in the design file that limit the laser processing speed. Therefore the motors seldom reach their rated speed. The amount of laser power available and the sophistication of the motion control system are much more important factors for optimum productivity.
- When cutting thicker materials like plastic, wood, and leather, the cutting speed is limited by the laser power. Increasing laser power does increase the laser cutting speed. However even with the maximum available laser power, the motors seldom reach 100% of their rated speed. ULS laser sources and Rapid Reconfiguration™ technology enable you to select the ideal laser power for each material you process.
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Learn More about Rapid Reconfiguration
- Even when cutting very thin materials like paper, operating the motors at 100% speed is not practical. Whenever the cut path changes direction (curves and corners), the motors need to slow down to avoid chatter and vibration. This is where a sophisticated motion system provides more benefit than a higher top speed. The ULS motion control system is an advanced path planner that evaluates every vector path and plans the optimum speed and acceleration for every segment of each path. The ULS path planner provides superior productivity in comparison to other laser systems.
Learn More about ULS Vector Performance Comparison Test
- High speed raster marking and engraving lead to blurred edges and unacceptable quality. ULS overcomes this problem with SuperSpeed™ technology, which utilizes two laser beams to double productivity without sacrificing quality.
Learn More about ULS SuperSpeed Technology
Learn More about ULS Raster Performance Comparison Test
What is the Difference Between Raster and Vector Motions?
When processing a design file there are two distinct ways the laser system handles different elements of the design. Raster motion (overlapping left-to-right/right-to-left movement of the optics carriage) is used for laser engraving, marking, and photo imaging.
Vector motion is used for laser cutting, scoring, and some marking. In these cases the laser system’s X-Y axis motion system simultaneously moves in two dimensions along the path to match the shape being processed.
The ULS laser system control software parses design files and interprets thin lines as vector objects. It then calculates 2D vector paths for the laser cutting, engraving, and marking machine.
Why Laser Wavelength Matters
ULS laser sources are available with output wavelengths of 9.3um (CO2), 10.6um (CO2), and 1.06um (Fiber laser). Many materials react differently to each of these wavelengths. By offering laser sources at different wavelengths, ULS significantly increases the flexibility and capability to laser process a wide and diverse array of materials. Each wavelength is suited to a different range of materials, processes and applications. When connected to a ULS laser system, ULS laser sources communicate with the Universal Control Panel (UCP) or the Laser System Manager (LSM) to let the software know what laser source is currently installed. This is important in that the software can then display the materials that can properly utilize the unique characteristics of each laser source wavelength in the Materials Database.