CO2 YAG Laser Replacement
Technological advantage over CO2 and YAG lasers
Blue lasers are technologically superior to other available solutions. Their introduction to the market has revolutionized the economy in many priority areas such as medicine, the military, and science. As a result, there is a growing demand for the use of exceptional physical and optical parameters of blue lasers, such as an emitted wavelength of about 450nm, high power density, and a high rate of absorption of blue light by a large proportion of materials. These features are the high potential of using blue laser based on diode technology - high speed of work and achieving the desired effect on various types of materials, low failure rate, as well as ease of adapting the product to individual order and mode of operation.
The previous attempts to develop a high-power diode laser for various reasons ended in failure. Currently available products on the market - which can be safely mounted and used in CNC equipment - reach a power of several watts, the maximum value is about 5-6W. Some laser head manufacturers, recognizing the great potential of this technology, offer combined 12-15W laser modules consisting of two 6W laser heads. These are prototype solutions, however, with a number of imperfections and disadvantages. The most important are: the lack of a dedicated optical system, which makes the laser dot high, the power density drops and with it the laser performance, the inability to install this type of laser heads in a processing device (e.g. milling machine, 3D printer) due to physical limitations (the need to install additional control heads, power supply system, heat dissipation, etc.), a very high risk of laser jamming and obtaining two dots next to each other instead of one connected.
Therefore, in industrial use, lasers constructed in CO2 and YAG technology (using infrared light) with powers of 30-500W are most often used. Despite numerous limitations of the above-mentioned products, i.e. worse electrical parameters, efficiency, a design that makes it impossible to mount to many processing devices, low absorption coefficient, or expensive maintenance, these are the devices most often used by the recipients of this technology mainly due to the high power achieved.
It should be emphasized that the physical and optical parameters of blue laser light will allow us to perform many works on materials, for which so far high power lasers were used. The efficiency and speed factor of the device on which the head will be mounted will also be improved. In addition, the use of blue diodes will result in greater electricity savings. These types of laser heads achieve an efficiency of about 35%, compared to YAG lasers with an efficiency of about 15-20% and only 8% CO2. In addition, laser diodes differ from competitive lasers in their lifespan, which is several times longer - 10,000 - 20,000 h compared to a CO2 laser.
The small size of the heads, the passive heat dissipation system, and the safe design will also open up new opportunities for laser applications, including the possibility of developing miniaturized portable markers for materials used, for example, in sawmills, welding shops, in the manufacture of stainless steel pipes and components.
Recognizing the enormous potential of absorbing the wavelength of blue diodes and trying to respond to current market demand, Opt Lasers uses blue diodes in lasers for engraving and cutting various types of materials such as textiles, rubber, plastics, wood, stainless steel, etc. The use of laser diodes for engraving and cutting processes is becoming increasingly popular. High power 6-30W laser heads are an attractive alternative in many market segments using large and often uncomfortable YAG and CO2 lasers.
The high power diode laser will be able to effectively compete with CO2 and YAG laser devices. The 450 nm wavelength diode laser has the ability to dissipate from a few to almost 20 times more energy to the illuminated material than CO2 and YAG lasers, thanks to a reduced spot size and a much higher absorption coefficient, which will achieve the same effect with a much lower head power. Taking into account the purpose of the laser, indicating its innovative features, it is necessary to refer to the parameters and functionality of the two above-mentioned lasers, i.e. the CO2 gas laser and the pumped YAG, which perform similar basic functions. The following innovative features of diode laser heads for cutting and engraving on CNC machines should be indicated:
High optical power density
Diode engraving heads based on blue laser diodes are characterized by the highest power density due to the smallest size of the laser spot (spot) of about 0.1mmx0.003mm - 0.15mmx0.003mm and a "top hat" type power distribution. The laser power density obtained by a 30W multimode head will be significantly higher than in competitive devices available on the market. For a 30W CO2 laser it is 430kW/cm2 (an order of magnitude lower), for a 30W YAG laser, it is 450kW/cm2.
The high absorption coefficient of blue laser light
Laser heads use light-emitting diodes with a wavelength of 440nm - 450nm, which have a very high absorption coefficient for most materials. A higher coefficient means that more energy will be absorbed by the illuminated surface. For example, the absorption coefficient for copper and gold is 450nm (blue laser) - 65%, YAG laser - 5%, CO2 laser - 5%, for stainless steel laser 450nm - 45%, YAG laser -35% CO2<3%, for titanium 85%, 70% and 6%, aluminum 12%, 8% and 3% respectively. High power laser heads will not only match the power level to the competition but will also transfer several times more energy to the processed material.
High frequency of the laser diode current modulation.
Opt Lasers heads will provide a high modulation frequency of 1 - 100 kHz. This parameter is 5kHz for CO2 laser and 25kHz for YAG laser. Such a slow control of the CO2 laser does not allow for quick engraving of complex details, despite a large power reserve.
The compactness of the laser heads.
New products in the form of multimode heads, thanks to the materials and technology used, will be characterized by small sizes <= 70x70x220 mm^3 and weight of about <2000 g. As a result, they will be the most compact engraving solutions of 20-30W power available on the market. For comparison, the dimensions in the case of a 30W CO2 laser are around: 60x60x600 mm^3, and the weight of 2500 g in the CO2 laser also requires an additional high-voltage power supply (200x200x150 mm^3) and a water cooling unit, while the dimensions of a YAG laser of 30W are about 290x220x100 mm^3 and the weight of about 3500 g. It should be noted that in the case of CO2 and YAG lasers, these are the dimensions of the laser source only, not including the beam guidance system. Lasers based on laser diodes can be integrated with portable or manual devices. The design of laser heads is more compact, lightweight, easy to assemble, universally usable on most CNC machines and 3D printers, and even in industrial robots where the use of CO2 laser is almost impossible and YAG laser is very difficult. What's more, without a lot of effort to adapt the device to work with the laser, it is possible to connect engraving heads to CNC machines and 3D printers, which originally did not have laser functions. In comparison, a CO2 laser requires a larger protected housing, water cooling, a larger high-voltage power supply, and a complex system of mirrors supplying the beam and lenses. The optical system that supplies the laser beam requires maintenance and proper alignment.
Safety of the laser heads.
For the construction of laser heads, aluminum components milled on a CNC machine are used. The aluminum body ensures proper heat transfer to other metal parts, which cools the laser head. Thanks to the simplicity of construction and coping of laser heads, they are characterized by a high degree of IP protection of the laser controller - IP62, which makes it possible to protect the controller against mechanical damage, dust, dust, and water drops. Commonly available heads provide almost no controller protection at all or only to a limited extent (IP 00 to IP 30) so that these controllers are exposed to damage during installation or operation. To ensure an even higher level of safety, the control electronics have a thermal protection system that protects the laser diode from overheating. Also, the driver is built into the head, close to the laser diode, which minimizes the risk of induction currents and damage to the laser diode that occurs in the industrial environment in which the laser heads are used. This also prevents the connection between the diode and the controller from breaking, which is a very common cause of damage to laser diodes. As a result, these features positively influence the total cost of operation of a CNC machine using a diode engraving head.
Marking and supplying the laser light underwater.
Moreover, among additional features, it should be noted that Opt Lasers diode heads can be used for underwater marking, while other available lasers on the market do not have such possibilities. The wavelength of the blue laser diodes is in the range 440-460nm. This is the wavelength for which water is transparent while CO2 and YAG lasers are not able to work underwater because the light from this type of laser is absorbed by water. The engraving equipment based on blue laser diodes, due to its small size and the absence of the need to install complex systems, has a very attractive and competitive price compared to competitive products available on the market for this type of application.