Using an efficient solid-state, diode laser source, the 7210 and 7310 fiber laser coders from Videojet Technologies Inc. (Wood Dale, IL, U.S.; www.videojet.com) can achieve coding speeds up to 350 and 700 characters per second in continuous production environments. Compared with traditional CO2 or YAG lasers, says Paul Schildhouse, laser product manager, the fiber laser converts electrical power to light energy more efficiently and generates less heat, using only one-tenth of the electrical power compared with a YAG laser of the same output power. The low heat generation not only reduces stress on critical light-generating components, but also eliminates the need for water-cooling systems that require periodic maintenance. This gives the laser source a life span of 50,000 to 100,000 hours—about four to eight times longer than YAG laser sources, according to Schildhouse.

The Videojet 7210 and 7310 fiber laser coders, available in 10 and 20 W of output power, respectively, allow manufacturers to easily add real-time product identification such as brand names and logos during the manufacturing process. They can be used to create unique serial numbers on portable MP3 music players, for instance, to aid warranty tracking. Compared with nameplates or serial number plates fabricated and stocked separately, the laser marking systems offer more flexibility. “For example, marketing and selling devices internationally may require various agency approval symbols to be incorporated onto the product, depending on the region where sold,” Schildhouse explains. “Consumer electronics also have short life cycles, so changes in product features or specifications (e.g., memory capacity) that are part of the product identification can easily be changed by programming without scrapping inventory or incurring delays waiting for new parts to arrive.”

Not all materials, however, are suitable for marking with solid-state lasers, which emit light in the infrared spectrum at wavelengths in the 1 µm range. Fiber lasers are typically used to mark bare metals, anodized metals, and painted and plated metals like aluminum, stainless steel, and nickel. “Certain plastics compounds interact with 1-µm wavelength laser light to perform a color change, including some forms of polyethylene like HDPE,” Schildhouse says. “In other plastics and rubber compounds, master batch additives can be employed to achieve a similar result with very little added cost or change in performance.”

At 3 × 4 × 18 in., the laser marking head is positioned near the parts or product to be marked and connects through a flexible, 6-ft umbilical cable to the controller. “The small marking head and flexible cable allow for easy integration even in tight spaces around a production line,” says Schildhouse. Their enclosures are IP54-rated, making them reliable even in harsh manufacturing environments. The laser marking systems also include the inputs and outputs needed to integrate into a product line or machine. “Inputs are provided for a rotary encoder to track production line speed, detectors to sense the presence of a product to mark, and safety interlocks to the machine guarding,” says Schildhouse. “Outputs are provided to signal marking conditions, alarms, and errors. Operator control can be provided with a handheld pendant, a permanently mounted color touch screen, or networked to a remote PC or PLC.”

The standard interface of the Videojet 7210 and 7310 fiber laser coders is high-speed Ethernet using TCP/IP protocols. Whether users choose the handheld pendant controllers, local touch screen, or remote PC or PLC, all of the programming, diagnostic, and operational controls are available. “This gives designers great flexibility in configuring the installation to suit their specific needs. For example, a single laser marking station could be set up with a handheld controller, eliminating the need for a PC on the manufacturing floor,” Schildhouse tells APPLIANCE. “Or, several marking stations could be networked to a single touch screen interface to minimize floor space and the number of operator control points along the production line.”

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