Machinery

Glass vs. metal CO2 laser tubes

25 February 2020

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Why are Epilog Laser machines built with air-cooled metal laser tubes?

There are several points to consider when looking to purchase a CO2 laser machine. One of the primary attributes that differentiates systems on the market is the type of laser tube the machine uses as its laser source. The two main options are water-cooled glass tubes and air-cooled metal tubes. Epilog Laser machines come equipped with metal tubes. Epilog’s tubes are also built with quality ceramic components. An examination of both glass and metal laser tubes reveals why Epilog Laser believes metal tubes are the better option.

Glass laser tubes

Water-cooled glass tubes are often an enticing option, primarily because of their lower cost. Glass tubes themselves cost less, plus their laser is produced by exciting gas with direct current (DC), which is a relatively inexpensive process. Glass tubes also produce quality beams that work well for laser cutting. However, glass laser tubes come with several drawbacks.

Figure 1: A glass laser tube. Source: Epilog LaserFigure 1: A glass laser tube. Source: Epilog LaserNearly all glass tubes need to be water-cooled. Glass is a poor thermal conductor, which means circulating water is needed to assist in the removal of heat. Without a water-cooling system, a glass laser tube would overheat and become inoperable. Such a cooling system will increase cost and the machine’s footprint, and introduce more points of failure that must be maintained.

The need for a water-cooling system also presents some significant safety concerns. The DC power supplies that excite the CO2 gas in a glass laser tube need to operate at very high voltages. When combining such levels of voltage with a water-cooling system, the results can be lethal should something go wrong.

The DC-excitation process inherently limits the rate at which the laser tube can pulse. When a laser engraves it does not fire in one continuous burst. Rather, it “pulses” as it moves across the material, firing many times per second. DC-excited laser tubes pulse less frequently, which significantly reduces engraving speeds and lowers engraving quality.

There are also concerns regarding the lifetime of DC-excited glass tubes. Glass is naturally more fragile than metal, and the risk of damage during shipment and installation is greater. The largest failure concern with glass tubes is that the DC-excitation process bombards a tube’s optics and electrodes with ions, which increases the chance of deterioration over time. Most glass tubes are only backed by six-month warranties, and when a glass laser tube fails outside that time period, a brand-new laser tube usually needs to be purchased, increasing costs and waste.

Metal laser tubes

The only drawback of metal laser tubes is their higher cost. That cost, though, ensures peace of mind with regard to performance, durability, safety and size.

Epilog’s metal and ceramic CO2 laser tubes are air-cooled, and their gas is excited by radio frequency alternating current (RF). Properly regulating temperature only requires fans, which are built directly into Epilog’s machines. This not only reduces the spatial footprint, it also removes the need for (and cost of) additional equipment, and it limits the number of items that need maintenance. Plus, it avoids the safety concerns presented by water cooling around high voltages.

Figure 2: Epilog’s metal laser tubes. Source: Epilog LaserFigure 2: Epilog’s metal laser tubes. Source: Epilog LaserThe RF-excitement process allows for more rapid laser pulsing, which delivers higher engraving speeds and finer detail in the resulting engravings. Metal tubes are also more durable and last much longer than the glass alternatives.

Epilog Laser chooses to build their machines with air-cooled metal and ceramic CO2 laser tubes to ensure that customers receive the best-performing systems possible. All of their tubes are backed by two-year warranties, ensuring minimal hassle in the rare event something does go wrong. And in those rare instances, Epilog’s metal laser tubes can often be serviced rather than replaced.

Glass laser tubes achieve quality laser cutting at a low price point. With metal laser tubes, customers get both laser cutting and laser engraving of the highest quality, along with the confidence that the laser will last much longer, will engrave faster and will be much safer.

Every situation, and budget, is unique, and it is important to research which laser machine, and which laser tube, is the best option for customers and their businesses. Epilog believes investing in an air-cooled metal laser tube will set customers up for long-term success.



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