Grinding Toward Industry 4.0

Machines are designed for ease of use and versatility to fill the gap from the shortage of experienced operators

There is a grinding process to produce the required degree of precision to form and dimension for virtually every workpiece. Medical devices, cutting tools, and automotive parts are among those that directly benefit from the latest machine technology and automation. Leading grinding machine builders are incorporating these advances in spindle technology, controls and software, and robotics into their equipment to meet production requirements, tighter tolerances, and finishing specifications. Facing a shortage of experienced grinding machine operators and technicians, machine builders are making their machines as easy to use as possible and building digital connectivity support to aid manufacturers in setup, operation, and trouble shooting.

Advances by Anca Inc., Wixom, Mich, include spindle heat control, automation for loading, grinding, and measuring of blanks linked together with a robot, along with gear-grinding technology for producing skivving cutters and regrinding hobs. According to President Pat Boland, the newly introduced Anca Integrated Manufacturing System (AIMS) optimizes cutting-tool production through factorywide Industry 4.0 integration and connectivity. "AIMS includes all the key support elements including the hardware and full software suite to support the information side of the cell," he said.

"With AIMS automation, customers can achieve continuous unattended production that dramatically reduces non-productive machine time and smart automation that connects sequential tool production processes across the whole factory," Boland said. "AIMS is designed to be modular, configurable, and expandable and can be deployed in stages, allowing for easy, gradual, and smooth transition from traditional manufacturing to automated and integrated manufacturing," he explained.

Anca's new cutting tool grinders include the MX7 ULTRA, which is designed to manufacture large volumes of end mills and other cutting tools, according to the company. The system incorporates new software, hardware, and design features, Boland explained, to make "significant advances in surface finish, accuracy, and controller run-out to deliver batch consistency from the first ground tool to the thousandth."

The MX7 ULTRA features the patent-pending Motor Temperature Control (MTC) compensation for thermal expansion on the grinding spindle. It also boasts a nanometer control system, new servo control algorithms for smooth motion, and system and mechanical upgrades to enhance stiffness and rigidity, as well as in-process measuring, balancing, and run-out compensation for consistent accuracy.

For manufacturers that want to tap into the rapidly developing e-mobility automotive market for skivving cutters, shaper cutters, and regrinding hobs, Anca's GCX Linear gear tool grinder offers a complete solution with temperature control on the external wheel dresser as well as the grinding spindle. GCX features include all axes with LinX linear motors, MTC on grinding spindle and dresser spindle, integrated gear tool measurements, and direct compensation.

Boland cited an example of GCX Linear's capability grinding a double- or triple-A skivving cutter in half the time normally required using conventional grinders. "Controlling spindle temperature with MTC for the length of time required to grind the cutter is essential to reduce variation in tools produced. Laser measurement of wheel wear profiles the tool for compensation. At the micron level you don't want vibration caused by wheel imbalance," Boland explained.

Royal Master Grinders Inc., Oakland, N.J., is a family owned company that has been making centerless grinders for more than 70 years. The company specializes in centerless grinding conventional automotive and aerospace parts, as well as medical applications. "We have been challenged with many unique parts over the years, including bone and cranial drills, cannula, dilators, balloon catheters, catheter shafts as well as specialty guidewires," said John Memmelaar Jr., vice president. "We have also experimented with many products that never saw a human body. During r&d, they were ground and tested on Royal Master machines, resulting in medical innovations that helped companies develop new products and processes."

Royal Master offers a wide range of models based off its TG-12x4 and TG12X8 platforms. Different accuracy packages are available, including basic to mid-level servo cycle to high-level system that can grind to submicron tolerances. The common thread, according to Memmelaar, is that each machine—from basic systems to the most complex—will grind round and straight under 1 micron prior to shipment. "I was taught a long time ago that if you are running a product 24/7, every quarter of a second makes a difference," he noted. "Our challenge is to squeeze every bit of production out of our equipment."

With the medical industry looking for more automated solutions, Royal Master offers fully lights-out systems for grinding catheters, guidewires, orthopedic needles, and other micro-machined components. "However, we haven't forgotten start-up companies," Memmelaar added, noting the manufacturer helps such companies develop design-prototypes and make samples and small production quantities in Royal Master's r&d lab.

"One of our really cool new machines for medical products is used for grinding biopsy needles in a fully autonomous manner," Memmelaar enthused. The device uses a robot to move the part in the correct orientation to the grinding wheel, he explained, to grind the flats, trocar shapes, and other required shapes needed on the needle.

For low-volume automation, Royal Master opts for a less complicated approach to robotics, using Universal Robots’ collaborative units that anyone on the shop floor can set up for production runs as small as 1,000 or 2,000 pieces. For higher volume applications, Royal Master uses a Fanuc robot with a pallet designed for an elevator system.

"Using a vertical stacking system, the operator never has to break the light curtain or the safety circuit to move pallets in or out," Memmelaar said. "It's very efficient. The operator just needs to exchange pallets," he declared, noting that gaging and compensation of wheel diameter are done automatically.

To meet the challenge of finding experienced grinding operators, Royal Master tailored its interactive operator interface to be user friendly. "We’ve made the grinder's HMI easy to navigate and set up, and have included tutorials with suggestions and shortcuts to help operators save their data, learn the machine, and get answers to any questions they might have."

In addition, the company populated its machines with detailed "grinding recipes" for specific parts. "We have a lot of customers who want us to mimic their setup sheets right in the operator interface so that operators can call up that setup sheet with the part number and with all of parameters."

Ferndale, Mich.-based Unison Corp.'s origins date to the late 1950s when the company invented its DedTru fixture, which was affixed to the table of a surface grinder to transform it into a cylindrical grinder for round grinding.

Applications for the machine have flourished over the years. Indeed, according to President Dave Swider, there are about 10,000 DedTru and TruFlute grinders worldwide today, serving the medical, dental, aerospace, automotive, off-highway, plastics, and petrochemical industries. Unison's TruFlute line includes tool cutters and burr grinders, peel grinders, and punch grinders, which can hold tight tolerances required for medical device manufacturing.

"A DedTru fixture holds a minimum of 50 millionths in concentricity, something that was revolutionary in its time," said Swider. "In 1977, about the time when the first personal computers were created, Unison installed a programmable computer on a manual grinder that is said to be a first in the industry.

"From there we developed three-, four-, five- and eight-axis grinders as well as offer three-axis pick-n-place autoloader/unloaders on our machines," Swider continued. "We have a dual-ended spindle on some models, which provides a 9th axis," he added, elaborating that "if you have a spindle with a grinding wheel pack of up to four wheels on one end, you can rotate that spindle 180° and use a second grinding wheel pack of up to four wheels on the other side."

Unison's medical manufacturing customers use TruFlute grinders to make drills, reamers, end mills, and a variety of specialized tools such as trocars for the medical market. Three new models were showcased at IMTS in September.

The smallest one is the Model 2150 DedTru CNC three-axis centerless grinding system that is ideal for prepping blanks for use in manufacturing cutting tools, according to the supplier. The Model 2150 features Unison's proprietary software and control that allows operators to customize centerless grinding, such as through feed, in-feed, and secondary operations, including plunge grinding tapers and grinding cylindrical parts with a range of diameters from 0.005" to 5" (0.127-127 mm).

The Model 2150 has the capability to dress grinding wheels in cycle with automatic size compensation for wheel wear. Whether dressing a simple flat wheel or an intricate profile, dressing can be automatically executed during grind cycles controlled by a machine operator.

"It's a totally enclosed system," Swider said. The Model 2150 is a three-axis machine featuring Yaskawa AC servo motors and drive amplifiers as well as glass scales, while control feedback facilitates automatic compensation for wear. "In the past, an operator who knew grinding would tweak the machine by moving the handles. The operators today use Unison's CNC control to automatically move the machine into position to grind."

For finishing tools and flute pointing, Unison offers the Model 3000 dual spindle five-axis CNC profile tool and cutter grinder. Designed for rapid tool blank preparation, the machine "can rough and finish grind in one pass" with its 9,000-10,000 rpm direct-drive spindles, according to Swider. Unison's new EZ Software allows the Model 3000's operator to quickly customize and/or modify tool geometry with a user-friendly interface, he explained, by merely filling in blanks and then verifying the part program by using the machine's real-time 3D Parts Predictor.

A computer control monitors critical machine functions and alerts the operator to problems encountered during grinding, tracking, and logging errors. The Model 3000 can be networked and/or monitored via the Internet, and can be equipped with a remote control feature to enable direct interaction with Unison technicians.

The grinder features Yaskawa AC drive amplifiers and servomotors, as well as an automatic pic-’n-place parts loader/unloader for continuous parts grinding. The Model 3000 is equipped with a Schaublin W25 pneumatic workholding system and precise probe assembly, which the company claims guarantees part repeatability.

Unison's Model 9300 six-axis CNC tool and cutter grinding system is designed for manufacturing high-precision drills, end mills, and reamers quickly and precisely with its 21.5 hp (16 kW) direct-drive dual-ended grinding spindle. The Model 9300 also features Unison's new EZ software with "fill-in-the-blank" capability, as well as a complete software package and library of tool programs.

Norton | Saint-Gobain Abrasives offers a broad range of custom abrasives to meet challenges in precision engineering markets, including new, harder-to-grind materials, tighter finishing specifications, and more automated and controlled manufacturing processes.

Unveiled at IMTS, Norton | Saint-Gobain's Quantum Prime grinding wheels feature proprietary nano-crystalline ceramic grain that offers significant productivity gains across a wide range of applications, according to the supplier. The new system delivers "exceptionally high grinding efficiency and part quality," company officials said, as well as significantly longer wheel life than traditional ceramic grains.

The new high-performance Norton IDeal-Prime Internal Diameter grinding wheels for precision applications also feature the Quantum Prime grain. The combination of the micro-fracture properties of the new ceramic grain from Saint-Gobain and the retention capability of the advanced bond, ensure long IDeal-Prime wheel life, excellent grinding efficiency, and consistent part quality with superior surface finishes which results in cost savings of 30 percent or more, the company asserted.

Paradigm Plus’ "Next Generation" diamond wheels have a new premium grain technology that complements a brittle metal bond, delivering higher grinding performance on carbide round tools and periphery grinding on carbide and cermet inserts. This technology, together with an advanced new lightweight core, produces lower specific cutting energy with a 25 to 50 percent higher material removal rate (MRR), the company said, and results in significantly improved wheel life when compared with current Paradigm wheels. For round tools and inserts, new G-Force Plus Next Generation wheels use premium grain technology with an improved hybrid bond, providing significant improvement in MRR and wheel life when compared with current G-Force wheels.

The new Norton Abrasive Process Solutions (APS) Program provides custom grinding expertise by helping customers determine the optimal grinding or finishing solutions for a specific use. Applications range from simple to complex, off-hand or automated, and for metal fabrication, production grinding and virtually any abrasives operation. The APS Program draws upon the knowledge of the Norton team along with access to 30 different machines and a state-of-the-art APS Robotic Automation Cell, which is at the core of the new APS Program located at the Higgins Grinding Technology Center in Northborough, Mass. The APS team provides abrasive process development, optimization, automation, and in-house testing. APS services encompass the testing and optimization of new abrasives, improving quality and/or throughput, and exploring entirely new and customized processes.

Next Generation NORaX N889 Micro-Structured Engineered Abrasive Belts feature a precise, flexible design for producing consistent, fine part finishes for a range of industry applications such as medical, aerospace, automotive, marine, metal fabrication, and general metalworking. The new belts provide up to 30 percent better performance compared with other belts in their class, according to the company.

The TQ and TQX shaped ceramic abrasive grains, which Norton said offer the longest-shaped ceramic grains in the industry, are optimized to achieve the highest MRR and coolest cut.

For automotive and bearing manufacturers in need of high-performance grinding solutions for the external grinding of cam and crankshafts and internal grinding applications, Saint-Gobain Abrasives offers Norton Vitron7 cBN grinding wheels with a high-precision vitrified bond.

For gear manufacturers, the Xtrimium range of gear grinding solutions are designed for high-performance gear grinding in extreme, tight tolerance environments. The portfolio of gear grinding products is specifically designed by category to provide higher profile accuracy, supreme form holding, and burn-free grinding in worm, profile, and bevel applications. Highlighting the range is an innovative dual-worm wheel design that enables two operations in one grinding wheel, substantially saving time and cost.

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