Discover more about Mazak's S7 Variable Beam Parameter Product (V-BPP) and what beam shaping truly is.
By Al Bohlen, President at Mazak Optonics Corp.
Laser-cutting technology, like most modern technology, is constantly advancing. From CO2 lasers to fiber lasers, to advanced cutting heads with beam diameter control, and now generators that perform beam shaping. The next development in laser-cutting is here.
Laser-cutting technology evolution
When laser-cutting technology was first introduced for fabrication, in the 1980’s, CO2 was the only option. By the early 2000’s, laser manufacturers started to evolve the laser source and fiber laser technology began.
Fiber lasers gave fabricators increased cutting speed, especially in thin gauge material. Fiber lasers also helped the bottom line with a reduced cost for consumables and energy consumption.
The next laser-cutting advancement was high power lasers. Before 2015, the standard configurations for laser-cutting machines were 2kW and 4kW. By 2015, high power lasers hit center stage. High power lasers offered fabricators the ability to cut at high speeds with a reduced bottom line in a greater range of material thickness.
While the thin gauge material was covered, many job shops cut more than just that. Often, these fabricators cut a large range of materials up to thick plate. This expansive range of material meant that thick plate cutting needed to be accomplished on the same fiber laser as thin gauge.
By 2018, 6kW became the new standard for laser-cutting and the introduction to 8kW, 10kW, and 12kW started. The increased power not only gave fabricators an increased material cutting range, but it also offered improved edge quality through advanced cutting head technology. Right around the corner was high power lasers.
Initially, fiber laser cutting heads only used one lens with one focal length. Advanced cutting head technology changed that. Now many fiber lasers have sophisticated cutting heads with multi-lens, automated focus, and beam diameter control. This advanced cutting head functionality allows fabricators to process almost any material of almost any thickness on a single fiber laser.
While the combination of high-power fiber lasers and sophisticated cutting heads have an increased edge quality, it still is not the CO2 quality that many fabricators were striving for, until now. V-BPP, also known as beam shaping, now offers unrivaled edge quality with the fiber laser speed, low maintenance and reduce bottom line advantages.
What is V-BPP?
V-BPP stands for Variable Beam Parameter Product, often referred to as beam shaping. V-BPP offers beam shaping technology that comes directly from the generator rather than having to make beam diameter and shape changes in the laser cutting head. V-BPP is a way to command to the generator from the CNC a variety of shapes, sizes and power distributions that can be used for different cutting techniques and applications.
V-BPP can start with a very small diameter beam with the heat profile directly center to that beam. This shape is often referred to as fiber mode. But the beam can get wide and create a “donut-shape” mode. While V-BPP alters and changes the beam diameter, it is also altering the shape of the beam, where the power density is concentrated, and where the heat resides in the total spectrum of the beam profile.
Fiber cable delivery
From the inside the generator the proprietary beam types are created, but from there, that beam type is delivered through a fiber optic cable. With this next level V-BPP technology, a standard fiber cable cannot transfer these beams effectively.
Now Mazak has paired both, a new generator technology and a new multi-core fiber cable for the OPTIPLEX NEXUS FIBER S7. This new multi-core fiber cable has an inner core and an outer ring core.
By having a dual fiber core, it directs power to both the center core and the outer ring core allowing for a balance in power distribution. In doing so, the power can switch from the center core for rapid piercing through heavy plate, then switch and balance out that power to the outer ring core and reduce the power in the center ring core. This gives a wider kerf width but maintains the heat profile needed to get through heavy plate. By doing so, it gives an advantage in thick plate cutting in edge quality, straightness of cut and speed of cut.
Standard fiber versus V-BPP fiber
For applications of thin stainless steel, thin mild steel or thin aluminum, a smaller beam diameter with a higher power density in the center core is ideal, fiber mode. But for thick, heavy material it is necessary to have the beam substantially larger in diameter. An example, 1-inch mild steel cutting with oxygen.
A traditional fiber laser, the beam directed out of the laser is a fixed diameter, while the beam diameter can be increased through cutting head technology, it is not possible to change the heat profile of the beam. A standard fiber laser going from 0.250” to 0.500” to 0.750” it is still using the same type of parameter product out of the generator because that is all that is possible, just one fixed beam type.
With V-BPP users command to the generator not only a different size diameter of beam, but also where the heat resides in the total spectrum of the beam profile. For 0.250” mild steel utilizing V-BPP, all the heat is directed to the center core of the beam and the diameter is rather small. When climbing to a thicker material, the beam diameter is increasing along with a changing heat profile.
Comparing standard fiber to V-BPP, even with a standard fiber increasing its beam diameter, there will still be heavy striation and the speed is limited due to the diameter of the beam. With V-BPP, using a much larger diameter and the heat not in the center core but on the outer edges of the beam, gives a much smoother edge, a straighter edge and faster speed.
Don't be fooled
Since advanced cutting head technology started, there is slang regularly used which causes confusion. Much of this confusion is around beam diameter control, mode and beam shaping.
Beam diameter control is not changing the mode and is not beam shaping. Mode is both the thermal characteristics of the beam and the three-dimensional shape.
Mode is not focal length change. Focal length is just changing the convergent point of the beam. This is not beam shaping.
True mode changing is different, it is changing the shape of the beam and the heat profile in the beam.
With standard fiber lasers, whatever comes out of the generator, it is. It is not changing beams in the generator. It is not different shapes.
One question that may be asked with the introduction of V-BPP is, are advanced cutting heads technology of the past? The answer is a hard no. There are even more advantages to beam shaping technology when combined with an advanced cutting head.
Overall, V-BPP is much different than a standard fiber laser. V-BPP provides a variety of beam shapes, sizes and power distributions that can be used for different cutting techniques and applications.