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Laser Maintenance – When Is It Time to Trade in the Old Laser for a New One?

July 2013

For some companies there is a tremendous value in purchasing a used laser. But there are also benefits for buying a new one, which might go beyond the obvious price difference.

For some companies the answer is obvious and for others the signs are present, but no one seems to notice its time to purchase a new laser.

New Features

When ordering new equipment you have the opportunity to add the latest and greatest features that manufactures have introduced to speed up part cycle times. Although your current laser might have some of these features, some don’t.

Consider some of the following features to raise productivity:

Auto focus allows a rapid focus change from piercing to cutting to dramatically reduce the pierce time in heavier plate. It will also remove the human error of manually changing focus between material types.

Focusing lenses come in many typical sizes ranging from 3.5 to 10 inches. Changing lenses or removing the entire cutting head to swap lenses takes time away from production. Manufacturers are developing parameters to reduce the list of lenses needed to process the wide spectrum of different materials that are cut. Reducing the time to change the lens decreases the cost of the lens inventory you need and increases the laser’s uptime.

A pierce sensing monitor (for piercing heavier plate) will oversee the time it takes for the laser beam to exit through the material and will immediately shift the laser into the cutting process. This saves valuable time, especially in lower quality plate. This feature could save cutting lenses too. If the operator sets the pierce time to short, then the sensor will override the timer and give the perfect pierce time. However, if the timer is set too long, the laser’s piercing sensor will override it and shorten the time.

You might think that if you’re careful you can just set the correct pierce time and not worry about it. However if the material is inconsistent or a lower grade, then piercing times have to be set long enough to accommodate the worse case pierce.

Beam diameter adjustments allow the operator to change the diameter of the laser beam depending on the material processed. This adjustment has two main features to consider: faster cutting and edge quality. However, remember that the laser’s power density is dependent on how focused the beam’s spot size is. When processing thicker plate, if the operator requests a larger beam diameter, the beam delivery optics will adjust normally using a deformable optic. As the larger beam diameter focuses through the cutting lens, it will create a larger spot size that will create a wider kerf. This wider kerf will allow extra molten material melted by the laser beam to exit out the bottom of the cut, giving a faster cutting speed and a better cut edge.

On thinner materials, a smaller beam spot size will allow faster cutting rates. As the smaller beam diameter focuses through the cutting lens, it will create a smaller spot size increasing the power density.

Higher wattage allows a laser to cut thicker materials or to cut thinner materials at higher feed rates. Depending on your current power level, this might give you a wider range of materials to process.

Fiber lasers, of course, are a complete change in technology and their benefits are still open for discussion.

Cutting lens optic sensor monitoring: This feature prevents accidental lens failure due to debris on the lens or a stressed lens. It’s currently offered on newer lasers. When a lens fails, it can cause a safety hazard for the laser operator. Most cutting lenses are coated with Zinc Selenide, which isn’t a hazardous material when the cutting lens remains intact. However if the lens fails and turns from the solid piece into powder from the failure, it can cause a health hazard for any personnel in the direct area of the failure.

Furthermore the powder will travel back into the laser beam bellows causing further damage to mirrors in the beam path and will require extensive cleanup and downtime. The sensors in the monitoring system are designed to shut down the laser and alert the operator to check the lens prior to failure.

Along with optic sensors, some laser manufactures will monitor the resonator optic temperature of the out-put coupler and rear mirror. These two items have a direct influence on the mode structure of the laser and ultimately the material being cut. By monitoring the optic temperature, an operator has the capability to troubleshoot cutting issues due to dirty resonator optics and can schedule service before it becomes a larger problem mandating unnecessary downtime.

Drive systems: These are getting faster than ever for lasers and offer greater production. Today’s lasers are fast, and offer reliable drives with low maintenance. Many have linear drives that offer significantly higher axis speeds than its predecessors without the wear and tear and tolerance problems. Today laser’s can reach rapid speeds of 15,000 IPM versus older machines at 2000 IPM. Part-cycle times dramatically reduce when a laser travels from one cut feature to the next at higher speeds.

Floor space – new lasers might have much smaller footprints. And floor space costs money. Each machine in the factory should have a cost associated to it by how much floor space it requires. Buildings cost money, and the more machines that can be squeezed into a plant, the more it will help spread fixed overhead costs.

Automation has come along way over the last few years to increase a laser’s usage. There was a time when just loading blank sheets on the cutting table from a storage unit was a major step from manual loading. These days automation not only loads and unloads, but parts can also be sorted. If a laser is run lights out all weekend, cut sheets will be stacked in a pile waiting for the operator on Monday. It might take a couple days for operators to pull the webbing apart and sort the parts. With part sorting, we can finally realize a true savings in labor.

Warranties – if you have a limited maintenance staff capable of correcting issues as they come up on the laser system, then consider the warranty a priority. All new equipment comes with either a one-year or two-year warranty.
While certified lasers can offer good value, certified warranties are never as good as the manufacturer’s new-laser warranty. Make a comparison of parts, labor and travel expenses that are covered on a used machine (if any) to that of the manufacture’s new warranty.

Taxes – as with all financial decisions we need to look at the current tax code for incentives. Often companies overlook tax incentives that can save them a considerable amount of money. Consult this option with an accountant.

Each laser manufacturer has its own features and enhancements, so it’s important to compare each machine that’s being considered. The right laser will increase your manufacturing competitiveness.

Remember the bottom line to a decision should always be, does this decision make financial sense?