Laser engraving equipment comes in all sizes and all price ranges so when is it time to consider a bigger laser and what should you know about going big before you whip out your checkbook? |
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If you do a lot of promotional products, a large-format system would serve you well for the same reason. Using a positioning jig, you can engrave 50 or 100 lighters, key fobs or flashlights at a time while the employee who would normally be changing them out every minute or so can be doing something more constructive while the jobs engrave. I know of a company in Ohio that purchased a large-format laser that changed the way they do business forever. The company makes stainless steel buildings like the ones you see along railroad tracks at crossings. These buildings house all the switchgear and electronics to operate the crossing gates and lights, and send information to the people who watch the progression of trains. For years the company cut the metal pieces by hand, then drilled and tapped the holes before assembling them. Each building had to be completely assembled on the plant floor because holes didn’t always line up and adjustments often had to be made. Brackets to hold the electronics on the inside often took days to drill out and mount inside the structure. In all, it took five days for at least two employees to construct one building. Hoping to reduce the time to two and a half days, they bought a 4000 watt large-format laser and programmed all the parts into the computer. As it turned out, they no longer had to assemble and disassemble each building because all the pieces were exactly alike. Holes and brackets lined up perfectly and parts were even interchangeable. The bottom line was they could now build an entire building, including the complex switchgear, in about four hours—that’s two buildings a day and most of the time, it only required one worker to do it. They not only eliminated their backlog, they began renting out their laser and the rent they received actually paid for the laser! |
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Of course, most of us don’t build steel buildings, but the point is, if your demand is high enough, having a large-format laser can pay for itself in time, labor and quality. From time to time, I use a laser that accommodates a 4' x 8' sheet of material. I think it can actually handle even larger pieces but the material I use is the size of a sheet of plywood. I don’t own the laser, but I can rent time on it for about $75 an hour and use it to cut metal panels. If you have an occasional job where a large-format laser is needed, there may be one in your area that is available for rent. This certainly isn’t as convenient as owning your own but, for occasional use, it works out well. When considering large-format lasers, one of the first things to consider is the class of the laser. Lasers fall into one of four basic classes which are dictated by the Center for Devices and Radiological Health (CDRH), Food and Drug Administration (FDA). Most of the lasers we use are totally enclosed in metal cabinets which make them class 1 lasers. These are the safest type and other than observing common sense rules like not defeating the safety switches, there aren’t many regulations for their use. If your laser is rated as a class 2 laser, it is probably because of the red indicator/spotting beam built into it. Because these red lasers are intended to help position your substrate and show where the laser is going to strike, they can be operated with the laser’s lid open. Although these red lasers are very low power and not dangerous unless abused, that makes the laser a class 2. |
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Today’s class rating for lasers can be a bit confusing. Initially, it was pretty simple. Class 1 was an enclosed laser and class 4 was an open laser where the laser beam can reflect off the substrate and then bounce off walls or people. These lasers require dedicated sealed rooms with no windows and a variety of safety devices, including safety glasses, to protect the user. These class 4 lasers were and can be extremely dangerous, especially to the eyes and especially if it is a YAG or fiber laser. Over time, however, improvements to confining the laser beam have called for alterations to the class system. Now, some lasers rated as class 4 have protective cones or protective “curtains” that prevent the beam from escaping. Because that curtain can be removed, however, they are still rated as class 4. There is another class of laser that looks like it is an open laser but isn’t. These are rated as class 2 lasers although they look the same as a class 4. Companies like Kern and Trotec Laser, Inc. offer these types of lasers and although the laser is not housed in a metal cabinet, a shield or protective curtain around the laser beam keeps it contained. I would still probably recommend the use of safety glasses, especially if it is a YAG or fiber laser, but they aren’t required. The big deal with wearing safety glasses is that if the laser beam escapes the protective barrier, it will cause instant and permanent blindness if it strikes someone’s eyes. By the way, safety glasses for CO2 lasers and YAG or fiber lasers are very different both in the type of glass used and the price. CO2 glasses usually are provided with a new laser and cost $20. Glasses suitable for a YAG or fiber laser cost about $600. Like conventional lasers, the laser tubes used in these machines fall into two categories: glass and metal. Glass laser tubes, also known as “DC” or direct current laser tubes, are often made in China and are much less expensive than “RF” or radio frequency laser tubes which are made of either metal or ceramic. Glass tubes do have several limitations, one of which is they don’t do very well with raster engraving (text and photos). However, depending on the wattage and type, the glass lasers are fine for vector cutting things like wood and acrylic (I’m not aware of any that can cut metal). RF tubes, both CO2 and fiber frequencies, can be made much more powerful and last considerably longer before service is required.
RF lasers up to 120 watts can be air cooled. That’s an advantage because there are a number of “issues” which can arise with water chillers. Most DC lasers and all RF lasers over 120 watts are cooled by circulating water around the tube typically using an external device called a chiller. Some lasers use oxygen and/or nitrogen to assist the laser’s cutting ability when cutting metal. GCC America, Inc. offers several large-format cutting lasers with glass tubes, including the LaserPro T500 which has a 51" x 35" bed (up to 200 watts) and the LaserPro X500III which has a 51" x 36" bed (up to 150 watts). GCC has also just introduced a new laser called the S400 which has a “smaller” 40" x 24" work area but is large enough we can consider it large format. The advantage of this laser is its lower price ($49,000 for 100 watts), compared to its next larger cousin, the T500 ($68,000 for 100 watts). The S400 is also one of GCC’s dual source hybrid systems that combines a CO2 laser for engraving/cutting wood and acrylic, and a fiber laser for marking metal. Mackenzie Quiros with Jorlink USA, Inc. (Greensboro, NC), a GCC distributor, has installed and serviced a number of large-format lasers and attests to the stability of GCC’s glass-tube lasers. Along with having to add a way to cool very large lasers and use exotic gases to make them more powerful, you might also need to add a larger power source. Really large, high power lasers can require three-phase electrical power ranging from 220 volts to 440 volts. Even the smaller ones require 220-240 volts. They can also require very large fume extraction systems. Some use updraft exhaust, others use downdraft exhaust and some offer both depending on the material you are cutting. Either way, these exhaust systems must be large. Even some of the smaller large-format lasers can require 800 cfm and two exhaust ports. No matter how you exhaust or filter your large-format laser, it should be built into your plan from the beginning, not an afterthought.
Because few in our industry have the need or budget for a huge multi-thousand-watt 120" laser, let’s focus on the in-between sizes for the remainder of this article.
Another restriction on the speed of these lasers is basic physics. If you want to engrave something at 600 ppi (standard for many substrates), that means the laser must fire 600 times per inch of travel. The faster the laser runs, the faster the laser has to fire. Although these lasers fire in Nano-seconds, it still takes time and as a laser reaches speeds of 120-165 ips, physics begin to play more and more of a role. Ideally, a laser would turn on and off instantly, but the reality is, as a laser turns on, there is a slope of power that builds up to a peak. Then, there is a slope of power as the laser cools and there has to be some instance of time between each time a laser fires. At some point, these slopes will overlap and that shouldn’t be allowed to happen. As a result, there is a limit on how fast a laser can move and still engrave a quality image. Gravograph’s contribution to the large-format world is the LS1000XP. This unit has a 24" x 48" bed and a maximum speed of 157 ips. Like the Epilog and other brands, this laser is a fully enclosed class 2 laser with a RF tube. RF lasers can not only cut, they can engrave raster files with quality. Be it a 20 watt or 120 watt laser, the quality should be the same with a RF metal or ceramic tube.
Many of the large-format lasers, such as the ILS 12.75 from Universal Laser Systems, feature a pass-thru table option that makes the laser even more versatile. This option is typically in the form of access doors, e.g. doors on the top and/or sides of the system that open and allow you to engrave even larger and odd-shaped items that otherwise would not fit in the engraving machine. In addition to smaller large-format systems, Trotec offers the SP series of really large class 2 lasers. The SP series includes lasers with beds ranging from 49" x 28" to 66" x 98" with up to 400 watts of CO2 power. The SP2000 and SP3000 models allow the user to break the engraving table in half (figuratively speaking) so the laser will engrave or cut on one half of the table while the user is loading the other side. Then while the laser is engraving that sheet of material, the user can remove and reload the first section. Is a Large-Format Laser Right for You? Should you buy a large-format laser? If you already own a small- to medium-sized laser(s), should you consider upgrading to a large-format system? If you are shopping for your first laser, is it worth it to start off with a big laser? Of course, the answers to these questions are all based on one basic caveat: Thoroughly assess your needs. There are certainly many advantages, including the fact that you can venture into a whole different area of work—things like large signage and even things like furniture, flooring, doors and memorial monuments—that can lead to some very lucrative revenue streams. You can also boost your production enormously for certain types of work. As mentioned, imagine being able to set up a job for 100 key chains for that promotional products customer and just letting the laser do the rest of the work!
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