If you have not been in the market for a laser for a while, you will be surprised when you start your search. It’s not your father’s laser—it’s not even your older brother’s laser.
In the past five years, lasers have sprouted many new features and technologies. Some of these advances have come from laser makers’ R&D departments. Others have come from outside the industry. For example, cameras have come to play a multitude of roles in laser cutting. And nesting became a fine art thanks to augmented reality, drop and cut part capabilities, and edge detection of sheets and remnants.
While a few of these goodies have been around for a while and are standard equipment, some are either options or are limited to the top laser cutters in a manufacturer’s line.
It’s all about the beam
Five years ago, many people thought CO2 lasers were going the way of the buggy whip. To say that fiber lasers gained market share during that time would be an understatement. Yet most major laser suppliers continue to offer CO2 machines, mainly for thicker plate and for multi-axis work in three dimensions. For those who do only one type of work, it can make sense to stick with CO2. For others with sheet metal or mixed production, today’s fiber lasers are doing the job with new ways of making plate cuts very smooth.
With beam shaping, a laser cutter can control the beam to be thin and come to a point, or widen out and disperse the laser for a wider cut (useful on thicker material). Some work as a two-dimensional (a planar or “filled-in” circle) or one-dimensional (circle or loop) shape. It can also be more of a three-dimensional approach, with different and infinite “crests” at the point of the beam.
Another interesting capability is the ability to turn the laser beam on and off with great speed and accuracy. In doing so, a laser can take a new approach to cutting a grid with, say, 100 squares. A few years ago, that meant cutting 100 squares. Now, the laser head cuts faster by going in straight lines. Think of it this way, one trip east to cut the tops of the squares, with the laser turned off between the squares. Return west to get the bottom of the squares, and on down the line nine more times. Then, a trip south and north and suddenly you have 10 squares. Repeat nine more times and you have 100 squares way faster than if you cut 100 individual squares, and with less wear and tear.
Also pertinent to the beam is automatic focus. This feature increases productivity when, for example, moving between the piercing phase to the cutting phase. Today’s machines equipped with this feature can do the switch on the fly and automatically, saving time while the beam is running.
As we move from the beam into the cutting job, a reactive element is brought into play—we can’t always predict outcomes or even situations, and the laser must be able to function in the real, imperfect world based on a dynamic environment.
One important factor in cutting is piercing. When is something pierced? A while back, the answer was stated in time units. The laser cutter would be programmed with the knowledge that it takes “X amount of time” to pierce a particular metal and thickness. Now, something is pierced when the laser cutter says it’s pierced. Due to laser power increases, cutting process optimization, and changes in beam management, it’s much faster and more accurate to let the laser cutter itself determine when the pierce is done. Additionally, it can move instantaneously from piercing to cutting chores, making the whole process much more efficient. This becomes a significant savings with every pierce on a sheet or plate.
Once the cut is started, there are a number of ways that today’s lasers manage the cut. For instance, when cutting thicker plate with oxygen, a technology called kerf scanning or burn detection makes sure that the cut is clean, not leaving extra dross and slag. If the material is aluminum or stainless steel, plasma detection tells the machine when to stop and retrace the cut because of plasma buildup.
Finally, cut management includes power management and motion management. Cuts can go faster on the straightaways, and must slow down for the corners or for precise shapes or direction changes.
Update on nozzle-ology
The nozzle is the machine’s ultimate last step for the laser beam. Take a precision machine assembly, strap it on to either a rack-and-pinion drive or linear motors, make it fly around at up to 4 Gs (the same as what moon-bound Saturn V astronauts experienced), put it right next to a piece of metal that melts and can spatter, and you have the task of today’s laser cutter nozzle.
Most lasers have a way of measuring the height of the nozzle above the workpiece. It’s done by capacitance; how much of a charge does it take to go across the air gap between the nozzle and the workpiece. The smaller the gap, the less charge is necessary.
When it comes to some of the other nozzle management issues, things get old-school, but in a new way. Cleaning a nozzle is an example of this. Depending on the manufacturer, the nozzle is cleaned a) after a set number of pierces; b) before it is put away and a new nozzle is installed; c) when spatter is detected, or d) all of the above. The nozzle is brought to a brush and automatically cleaned.
If cleaning does not solve the problem, some machines offer automatic nozzle changing. Nozzles are kept in a small storage unit adjacent to the cutting area. The current nozzle is automatically removed, and a new one is taken from the storage unit and placed in the cutting head. The new nozzle is calibrated, the beam is centered, and the laser is back to work.
Cameras and nests
Cameras have made quite an impact on laser cutting. Remote vision was certainly the first and an ongoing application of cameras inside laser cutters. With a camera inside the enclosure, expo attendees could see demonstrations of the internal activities, fab shop managers could keep an eye on the cutting, and operators could literally monitor operations. Given today’s remote access environment, live feeds from these types of cameras can be utilized on the laser cutter’s control panel or even on a phone.
That’s only the beginning of the camerawork in laser cutting. Other uses of the camera pair the camera with software either for machine vision or augmented reality.
We mentioned beam centering in the last section of this article. In some laser machines, it’s done with machine vision, lining up the lens center with the center of the laser beam—very tricky to do manually but now done automatically and confirmed with machine vision.
The other way software can provide an assist is with something that approaches augmented reality. First off, using a camera, you can load either a sheet or a remnant piece of sheet metal. The camera and its software will “square it up” for you, without physically squaring it up. It can detect the edges, or in some cases, precut shapes, to orient the nest to the sheet. If so equipped, it will also show the nest as an augmented reality representation. If the sheet is at an angle, the nested parts are at the same angle.
Quick special items
Below please find three special items from among the most popular makers of laser cutting equipment.
Locus Beam Control: no smoke, but a mirror
Many companies now have some type of beam shaping technologies, but Amada (Isehara, Japan) R&D wondered if they could keep the beam with a fine point, put most of the energy at the point of the beam, and still make wide cuts. It seems counterintuitive but they managed to come up with Locus Beam Control (LBC). With LBC you can make the kerf very wide (perfect for removing parts cut from thick plate) and still keep the laser beam at its most accurate, delivering the most energy at a tiny target. The most important part: you achieve the wide cut by moving the beam, very quickly and accurately, and in any pattern that will give you a wide cut, efficiency, and accuracy. It’s done with a mirror; the mirror moves quickly and ever so slightly—so does the beam.
Modularity is available
No other top laser manufacturer says this in its marketing message: buy one laser source and it can serve up to six workstations (e.g. laser cutters, welders, etc.) either serially or simultaneously. Trumpf (Ditzingen, Germany) says exactly that. They designed their laser products to be modular and in fact share the laser source. It’s not free to share them across these platforms, you do have to prepare each device to do this, but it is much less costly to share the laser beam across laser devices, if that fits your plans.
Artificial intelligence comes to laser cutting
MC Machinery’s (Elk Grove Village, IL) GF-X Series uses Mitsubishi Electric’s Maisart artificial intelligence to enhance many aspects of the machine, including managing the cut. The AI software learns the tasks and has information about, literally, the sight and sound of the cutting process. It learns about cutting in many different circumstances, and compares its knowledge with current conditions. If things don’t look or sound right, it stops and tries again.
Our next installment in the laser technology overview articles will focus on automation. We’ll look at shuttle tables, racks, robots, sorting, and more. Please contact us at firstname.lastname@example.org if you would like to see a specific area covered.