Want Machining Productivity? Look Closely at Components
Machining center productivity is at the heart of economic growth. Without a doubt, connectivity across the shop floor (MTConnect), to and from mobile devices (Industry 4.0), and the Industrial Internet of Things (IIoT) is affecting how manufacturing gets done and requires increasing digital savvy from those doing it. As smart as machines are getting, at the end of the day the goal remains meeting delivery dates (machine and process throughput) and customer satisfaction (final part accuracies and finishes) that separate the quick from the dead.
Machine tool builders continue to unveil and integrate a number of interesting motion-control components in both the hardware and software realms that take critical machine tool properties such as spindle speeds, axis travel and tool life and make them faster, more accurate and more effective.
Makino (makino.com) recently announced new advances in its Inertia Active Control (IAC) to continue cutting non-productive time on its equipment. Originally introduced in 2012, the foundation of IAC is in Makino’s direct-drive rotary table design. Sensors take inertia feedback from the B-axis motor and continually provide data to the control system. Acceleration and deceleration rates for rotary tables are typically set at maximum inertia and weight for accuracy reasons. Makino machining centers can use IAC to adjust rotary table acceleration and deceleration to optimize speeds for specific pallet loads.
Now IAC technology is able to improve acceleration and deceleration rates along the Z-axis—the most frequently moved axis during cutting, the company says. IAC has also been added to the rotation of the ring-type tool magazine. Each time tools are loaded into the magazine, IAC sensors quickly evaluate total ring weight and adjust motor acceleration to match the total load for reducing the time the tool magazine seeks tools. These may be percentage-point productivity increases, but they add up to advantages.
Speed of Sound
DMG MORI (us.dmgmori.com) is touting ultrasonic generators and actuators on its aptly named ULTRASONIC second-generation line of machining centers as efficiency improves. Tool holders with adapted actuators are changed into the milling spindle simply and automatically. Each of these holders contains piezoelectric elements, (materials that can produce electricity when pressurized and also produce and detect sound) that are activated by a program-controlled inductive system with a high frequency of between 20 and 50 kHz. The ultrasonic tool holders superimpose actual tool rotation with an additional tool movement in the longitudinal direction so that a defined amplitude of up to more than 10 μ is generated on the cutting edge of the tool. During drilling, milling or grinding, this ultrasonic superimposition of vibrations has a direct, positive impact on process forces, metal-removal performance, and tool life.
The payoff, the company says, is a higher metal-removal rate, along with more accurate edge machining and up to 40 percent reduced process forces. Deflections are minimized while workpiece accuracy and process reliability are increased. In addition, this oscillating contact interruption works to better lubricate and cool the cutting edge as well as optimize particle removal from the active zone. Interestingly, the ultrasonics also make chips break shorter, reducing tool wear and enabling longer tool service life as well as excellent surface qualities of up to Ra < 0.1 μ for hard-brittle high-performance materials such as glass, ceramics, corundum and other difficult-to-machine materials such as nickel-based alloys or carbon-fiber composites.
Subsequently, DMG Mori produced the ULTRASONIC 20 linear 2nd Generation machine, combining high-speed cutting and highly efficient grinding of conventional and advanced materials on one machine.
Integrating Inspection for Faster Setups
Inspection probes from Renishaw Inc. (renishaw.com) and the new SMOOTH CNC from Mazak Corp. (mazakusa.com) work together in what Mazak calls “SMOOTH Set & Inspect.” The process streamlines the use of inspection technology for part setup, inspection, or tool setting on Mazak machine tools with the new control.
Intuitive and easy to use, according to Mazak, the user interface, inspection programs and data collection can be customized to fit specific shop applications. Creating inspection cycles is simply a matter of following straightforward click-through navigation guides. To perform the SMOOTH Set & Inspect process, the user positions the probe over the feature to be measured, then selects the type of feature from the software. The operator then enters the appropriate feature parameters and runs the program from the SMOOTH control. The user has instant access to inspection results, and instant opportunity to implement and recheck the necessary corrections to machining programs.
Position Vs Speed
Productivity gain is always positive, but often involves a tradeoff—faster throughput or increased accuracy. Naturally this depends on customer requirements, but motion-control providers can usually suggest a process-improvement solution. Aerotech (aerotech.com) has many mechanical system controllers into its product portfolio. “Over the last few years, we’ve introduced the ability to position and control delta robots, hexapods, piezo, and galvo (galvanometers—motors with mounted optical mirrors for positioning lasers) axes. Add this to controlling brush, brushless, stepper and third-party drives means one controller can govern all the axes of a machine,” says Joseph Profeta, director of the Aerotech control systems group.
This results not only in improved machine throughput and/or accuracy, depending on customer requirements, but easier-to-use machines that decrease design and commissioning time. “Engineers use only one tool, meaning less training and quicker expertise. And we’ve developed advanced control algorithms to provide better tracking than conventional control structures,” he adds. Whether defined as improved accuracy or higher throughput, better productivity is the result.
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