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3D Illustration by Coherent Images
Within Arms ReachWritten by David Geer FARO Technologies, a global 3D measurement company with headquarters in Lake Mary, Fla., brings 25 years of experience in developing precision articulators to the quality assurance table. And now Bluetooth technology is making it easier for FARO customersto take measurements in industrial environments. According to Orlando Perez, senior technical product manager, FARO has produced and delivered portable coordinate measuring machines(CMMs) since 1981. Product lines include the FaroArm Quantum, the FaroArm Platinum, the FaroArm Fusion and the FARO Laser ScanArm. FARO customers use the articulated FaroArm and its probe attachments to collect coordinates used to render and compare objects in three-dimensional modeling software. Practical applications for the device include first-article inspection, quality control and digital modeling for reverse engineering. Beyond product manufacturing uses, the FaroArm has been employed for reverse engineering, rapid prototyping and 3D modeling. The company recently added Bluetooth technology to its line, helping the FaroArm go where it could not go before. Historically, CMMs have been stationary. At the Kiel Foundry Company in Kiel, Wis., that meant moving each 54-ton block to an articulator by crane. Today, customers like Kiel are taking advantage of the mobility of Bluetooth enabled FaroArms to reduce measuring time and lower costs. Measuring in the Extreme
The FaroArm measures and inspects three-dimensional objects through contact with a spherical probe installed below the “wrist” of the articulated appendage.The sphere has a known diameter and location in space. The Arm determines the position of the probe based on calculations using the dynamic angles and static lengths of the Arm’s several articulated segments.“Wherever you touch the sphere to the surface of an object in space, the FaroArm records the three-dimensional coordinates of the precise location,” Perez says. The Arm then streams that data as linear strings of text to a laptop. The probe also has a built-in sensor that reports its temperature to the laptop to compensate for contraction and expansion of components in thermally changing environments.A software driver converts the data into the required format for processing bythe FARO CAM2 CAD-based manufacturing software, which compares the measurements to a baseline CAD model. The FaroArm measures in increments that seem impossibly small; the line has has devices that are accurate to within 13 microns, or .013 mm (0.0005 in.). Flexing a Wireless Muscle
The FaroArm has always been fairly portable, but until recently power cables and USB connectors kept the device tethered. After manually setting up the equipment and securing the connections, operators maneuvered the Arm around large partsfor inspection – within range of the cables. With Bluetooth technology, data cables are eliminated, which provides safety benefits and extends the Arm’s range. Also, by replacing power cables with anon-board battery, FARO gave the Arm portability in extreme environments. Consider, for example, “clean” rooms. High-tech fabricators must maintain environments free of airborne contaminants. A single offending submicron particle could damage circuitry on a microchip, turning it into a useless piece of silicon. Bluetooth enabled FaroArms leave wires and computers behind, transmitting data through walls, with no line of sight required. The absence of wires, laptops and elaborate setup routines minimizes the FaroArm’s impact on clean rooms through vibrations, electrostatic discharge and other particle-producing risk factors. There’s also the practicality of going wireless in extreme environments. FARO’s machining customers often use CNC tables to plasma-cut materials over a watertable. “You cannot run cables through a pool of water,” says Perez. But with the FaroArm machinists can safely take measurements near the cutting table, importing the appropriate measurements into a CAD software program, whichthen generates files readable by the CNC table. Choosing the Right Technology
Why did FARO choose Bluetooth technology? Because it is a robust, low-powerwireless specification and a perfect fit on bandwidth, according to Perez. He notes that the National Semiconductor LMX9838 Bluetooth module FARO selected uses 65 milliamps. This saves battery life, contributing to the Arm’s six-hour run time. Bluetooth technology also presented sufficient bandwidth for FARO’s serial text transmissions, with an effective rate of 365 Kbps. Wi-Fi offered much more bandwidth than FARO needed, according to Perez, while ZigBee offered too little. “Bluetooth was right there in the middle; it was perfect for us,” says Perez. FARO customers initially were concerned about security issues, such as wireless hackers and disruption by electrical noise. Bluetooth technology’s security protocols, including link-level and service-level security, preclude outside access to sensitive data and operating system software, keeping the Arm safe from outsideinterference. “The Bluetooth communications protocol uses security that cannot be broken,” says Perez. The technology also has the ability to switch frequencies to reduce electrical noise. “That was important to FARO,” he adds. Finally, Bluetooth technology offers FARO customers intuitive, one-time setup. An operator pairs the FaroArm with the laptop’s Bluetooth wireless host to establish a link between the two devices. FARO uses its own management software to create a link between the Bluetooth wireless module and the FaroArm hardware driver. After a one-time setup, an operator simply launches the FARO CAM2 metrology software or any third-party application that works with the FaroArm, and the Bluetooth wireless link is set automatically. Measuring the Past and Future
FARO product sales increased by 25.7 percent – from US$152.4 million in 2006 to US$191.6 million in 2007. This growth has continued after the introduction of Bluetooth wireless capabilities, according to FARO. Many FARO customers had been asking for wireless enabled FaroArms, according to Dan Alred, product marketing. In response to customer demand, FARO has enabled all existing FaroArms with Bluetooth technology as of September 2008. “We stand behind Bluetooth as the right technology for the FaroArm. That is how we market it,” Perez says. FARO is also looking at using Bluetooth technology to enable diagnostics.“Bluetooth can allow us to transmit diagnostic data in real time while the equipmentis in use,” says Perez. While an operator is measuring a part, an analyst can come alongside and take wireless readings to diagnose the system without downtime. David Geer has covered robotics and wireless technologies for the IEEE Computer Society’s Computer magazine, SERVO Magazine and Nuts and Volts.
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