Trumpf Adds RFID to Its Laser Cutting Machines

By Claire Swedberg

To make it easier to know if a machine's lens is being properly used and maintained, the company is embedding an RFID tag in its lenses, as well as installing a reader in its cutting heads.

When manufacturing companies use laser machines to cut through pieces of sheet metal, the maintenance of such devices falls in the hands of the machine operators. Cutting through metal requires a very precise laser beam that passes through a lens to ensure it is directed properly. If the lens is dirty, worn or damaged, things can go wrong during the metal-cutting process.

Trumpf, which has provided laser cutting machines for sheet metal since 1979, is incorporating RFID technology into its products to help end users track how long and how often a particular lens has been used, as well as when it was cleaned, in order to ensure that the lens receives the maintenance it requires and is not being utilized past its lifespan, which could result in bad cuts. An RFID tag embedded in a lens not only stores data about the processes conducted on that lens and its use, but also makes it possible to determine if a lens is being installed incorrectly, since its RFID chip would not respond to the reader built into the machine if the lens' orientation was wrong. What's more, if someone were to attempt to install the wrong lens (there are multiple types with differing focal lengths), the system could identify this mistake as well.

A 6-millimeter-wide passive HF RFID tag is embedded into the outer edge of a lens that is only 7 millimeters thick.

The RFID technology has been available in Trumpf's TruLaser 3000 series of laser cutting machines since mid-summer, according to Jürgen-Michael Weick, the company's head of optical components development. "Products manufactured with the company's technology can be found in almost every sector of industry around the world," he states, including computer and automotive manufacturers and custom manufacturing shops. In February 2014, it will also be available in the TruLaser 5000 series. With the technology, he says, customers can not only track the lens' usage, but also determine which processes may be wearing the lens down faster than others, and thereby better plan lens cleaning and replacement schedules. "It's intended to make things as user-friendly for the customer as possible," Weick says.

Traditionally, when operators use laser cutting machines, they must visually inspect each lens on a regular basis, in order to determine whether it has become dirty and will thus be less effective for cutting metal. In many cases, however, the thin dirt layer that can compromise lens performance cannot be seen via the naked eye. Therefore, Trumpf has recommended that users clean the lens regularly (such as once a week) whether or not they can view dirt on the lens. In some cases, Weick adds, customers have told him they clean the lens daily, just to ensure there is no dirt present at any time. This process takes about 10 minutes and disrupts the machine's use, he says, thereby delaying production.

In 2007, Trumpf developed a sensory system known as LensLine to detect when dirt may be collecting on a lens, based on measurements of contamination levels. The machine's software receives the sensor data and displays an alert based on a traffic light display on the machine's screen, indicating if a lens should be cleaned soon (yellow light) or must be cleaned before a user operates the machine further (red light).

Customers indicated, however, that they could still use additional data from the system, such as how much the lens had been used and when it was last cleaned. This information not only helps plant managers better determine how the machine is operating, as well as how often they should expect to conduct cleanings, but also helps them track a lens' history within a cutting head that might be moved to another machine. Trumpf began developing a solution that would provide this data using an RFID chip in the lens, along with a reader in the cutting head in which the lens is installed. The firm found that RFID could also be used to help users ensure they never install the wrong lens, or install the correct lens in the wrong orientation.

An RFID reader built into the cutting head of the company's TruLaser 3000 series is used to track the lens' operation and maintenance.

Each lens comes with a 13.54 MHz passive high-frequency (HF) RFID tag embedded in a hole in its side. The tag is being provided and installed by the lens manufacturer for Trumpf, Weick says. He declines to name the tag's manufacturer (which is based in Asia), but says it was the smallest tag the company could find—measuring 6 millimeters (0.2 inch) in diameter—to be fitted sideways into a lens that is 7 millimeters (0.3 inch) thick.

Trumpf then developed an RFID reader (manufactured by a third-party provider from Germany) that could be built into the cutting head. The device would read the chip only if it came within a few millimeters of the tag.

Each chip is encoded with a unique ID number, as well as the time and date of the lens' manufacture—information that could be used in the event of a lens recall. The interrogator reads that data when the lens is installed in the cutting head. The machine also tracks how long the lens is being used, as well as the lens' condition, and periodically writes that data to the chip. When a user needs to know a particular lens' history, he or she can access the software on the machine and press a prompt requesting that data, which will then be read from the chip, translated and displayed on the screen. If the lens' condition has reached a critical level, the user would see an alert indicating that status, based on the machine's sensor data. "The lifetime of a lens is, in general, not predictable because it is individual," Weick explains. "Its end of use depends on the amount of deposited material that cannot be removed by cleaning."

Each time a user cleans the lens, he or she would press a prompt on the machine's display. That action would then trigger the cleaning event data to be written to the lens' RFID chip as well.

If a lens is installed properly in a cutting head, its tag comes within close contact of the reader, which captures the chip's ID number and displays the lens' status on the machine's screen. If the lens is mounted incorrectly (backwards, for instance), this means the tag is not within range of the reader, prompting the software to display an alert that either the wrong lens has been installed or the lens has been installed incorrectly.

Trumpf's Jürgen-Michael Weick

If a user installs a lens without an RFID tag built into it, he or she must indicate that fact in the software while completing the installation.

The technology makes it easier for companies to track lens usage, and that information can then be compared against the condition of a particular lens. Without the data collected by the RFID system, Weick says, "When I ask people 'How long have you used the lens?,' they often can't answer that question." With the RFID technology, he notes, the question can be answered simply by pressing a prompt on the machine's display.

According to Weick, deployments of the tagged lenses are still in their earliest stages. But to date, he says, "Customers are very satisfied with the system."