The Challenges to Innovate Manufacturing Industry Social demand for

March 15, 2022 - US cutting tool manufacturer Tool Alliance celebrates 50 years of highly successful business in March 2022. During this time, the company has grown steadily and in the process has built an enviable reputation for the quality and durability of its solid carbide and indexable carbide cutting tools. Tool Alliance makes extensive use of CNC grinding machines from various manufacturers, but has chosen to standardize the machines’ control systems on NUM’s Flexium CNC platform and NUMROTO software, primarily for reasons of performance and production efficiency. Tool Alliance is one of the largest licensees of NUMROTO in the United States. Founded in 1972 and still privately held, Tool Alliance operates a number of company-owned factories – its principal manufacturing facilities are located in Huntington Beach, California, and in Fort Myers, Florida. The company’s cutting tool products and services include such renowned brand names as Ultra-Tool, RoundTool Laboratories, Tungsten ToolWorks, Routco and Mil-Tec. All five brands are sold worldwide, and are supported by shared research, design, engineering, manufacturing, marketing and sales facilities. The owner and president of Tool Alliance, Dave Povich, is no stranger to the cutting tool industry. A past-President of the United States Cutting Tool Institute (USCTI), he has worked for the company since 1987. According to Povich, “NUM is our CNC technology partner, which creates a win-win situation for both companies. We benefit from having a direct technical input to NUMROTO software development, while NUM gains valuable feedback on the design and production of the very latest cutting tools.” Tool Alliance’s innovative Ultra-Tool Series 365 high performance end mills are a case in point. Designed specifically for the machining of exotic materials, these solid carbide tools feature a patented variable-helix geometry combined with a proprietary edge preparation/PVD coating combination that allows for world-class dynamic milling of tool paths, including most slotting cut applications. The tools are produced on high performance 5-axis CNC grinding machines using NUMROTO, employing monitored tool run-out, real-time deviation compensation and the latest diamond abrasive technology utilizing advanced wheel truing equipment. Mark Wortsman, Tool Alliance’s technical director, said that collaborating with NUM has multiple advantages. “The NUMROTO team is very supportive and always amenable to suggestions, which makes life a lot easier for us, as well as our customers. For example, we recently suggested adding categories for collets, and some new features for wheel probing and automatic 3D collision checking; these have all been implemented in the latest version of NUMROTO software.” “We consider the 3D-simulation capabilities of NUMROTO to be the most accurate in the tool grinding world; they help us to optimize tool programming by preventing any grinding errors that might otherwise be caused by imperfect wheel measurement or incorrect machine alignment.” Wortsman also points out that NUM’s software helps simplify shop floor management. “Over the years we have built an extensive library of tools that we have produced with NUMROTO. The NUMROTO team has done a superb job of incorporating the library in a centralized industry-standard SQL database which can be accessed by any of our machines or programming stations. The database can store tens of thousands of tool programs which can be accessed by several hundred users–at the same time if needed.” “It is much easier to backup a single centralized database file instead of having to backup files from the computers on each machine–we perform automated backups several times a day, just to ensure productivity continuity in the event of a machine breakdown. Software updates are also handled very efficiently. As soon as a key NUMROTO update is available, we can bring all our machines, regardless of make or model, up to the same software revision level.” Many of Tool Alliance’s CNC grinding machines are equipped with automatic loading systems to facilitate overnight production–in fact, some run for two days in a row without interruption and without the need for any manual compensation. To keep the tool dimensions within tolerance, the company relies on the NUMROTO software’s ‘measurement in process’ feature, which automatically measures tools after grinding and applies appropriate compensation. A number of projects undertaken by Tool Alliance have warranted installing early generation CNC machines and then retrofitting them with NUM’s latest motors, drives and CNC systems. According to Steven Schilling, General Manager of NUM Corporation, “Again, we were able to help. Our CNC team in Chicago provided local support, and we were able to improve the performance of the machines’ spindles and axes. It has been, and continues to be, a pleasure to be a partner to the success of Tool Alliance.” NUM will be exhibiting at the GrindingHub trade fair in Stuttgart, Germany, from May 17-20, 2022. ENDS   Ultra-Tool, RoundTool Laboratories, Tungsten ToolWorks, Routco and Mil-Tec are registered trademarks of Tool Alliance.

Meanwhile, Industry 4.0 features appearing in all sectors of manufacturing are making their way to grinders, with sensors monitoring processes and component wear and predicting when machine parts must be repaired or replaced.

Aluminum-oxide wheels are the more conventional and relatively less-expensive option, generally used for steel and flexible in their ability to be dressed with various profiles and shapes.

While thicker synthetic or general cutting oils are available, the ideal oil is thin and low viscosity with high flash points, he advised. “A lot of the grinding wheels have been developed around oil-based coolant.” And, grinding oil makers like Oelheld and Blaser SwissLube are “constantly working on the chemical makeup of their coolants.”

US cutting tool manufacturer Tool Alliance celebrates 50 years of highly successful business in March 2022.

About the author: Geoff Giordano has been a contributing editor for SME since 2016 and a manufacturing and tech journalist since 2005. Contact him at geoff@driveninbound.com.

And, more sophisticated hinged or stationery probes can measure complex part features—length, shoulders, tapers, outer diameter (OD) and even internal bores—while compensating for temperature and wheel wear, all without unclamping the workpiece.

“We see more customers requiring some sort of automation system,” Ueltschi said. “In cylindrical grinding, with its short cycle times, you don’t typically talk about lights-out processing.” However, United Grinding’s flexLoad Automation Cell allows an operator to stock enough parts for the grinder to run 30 minutes to an hour untended.

Calculating feeds and speeds, spark-out times and other process parameters to ensure desired accuracies and surface finishes requires grinding software to be more technology driven, advised United Grinding’s Ueltschi. A lack of skilled operators demands that software allow cylindrical grinders to calculate how to grind and how fast.

“Oil now has a very high flash rate for fires,” he explained. “It’s much safer to use oil as your main part coolant, especially for peel grinding, which requires good lubricity.”

Improved grinder design is helping reduce thermal displacement issues. Toyoda has changed its casting design to control heat fluctuations in the manufacturing atmosphere by isolating the casting from the coolant with a steel plate with an air gap, explained Farrant.

“Grinding technology is a little bit different than the rest of the machining world,” Titus explained, noting that there are features and practices that smaller customers or those who don’t use grinding as a primary process might not be using and benefiting from.

Meanwhile, recognizing that some cutting tools initially require a round of cylindrical grinding, ANCA Inc. (Wixom, MI), has refined its machines to allow them to spin the headstock at up to 3000 rpm or house a 10″ (254-mm) diameter wheel. ANCA machines also feature in-process gaging.

For instance acoustic emissions sensors have been in Okuma and other machine makers’ machines for 25-plus years. They listen for when the grinding wheel touches the workpiece to slow the wheel to grinding speed, as well as for when the dresser contacts the wheel during dressing. But Titus still encounters customers who have not heard of them.

One process gaining traction is peel grinding, which removes a large amount of steel or carbide in a single pass using high feed rates and spindle speed in a manner reminiscent of a lathe.

For instance, the Studer machines from United Grinding North America (Miamisburg, OH) provide a new level of flexibility, said Hans Ueltschi, vice president of cylindrical sales. A contemporary part might be partly coated with carbide or another material via High Velocity Oxygen Fuel (HVOF), requiring a diamond wheel for that section. The alloy or steel substrate requires a different wheel. With a multiple-wheel setup, the grinder can process the entire part, avoiding multiple setups and runout issues.

ANCA’s portfolio includes the MX7 Linear and larger TX7 Linear, which can be used to grind a range of parts, including pinion gears for power steering shafts, journal bearings, helical gears and carbide blanks for cutting tools like end mills and drills. The MX7 features up to six wheel pack stations for configuring multiple operations; the TX7 cell features two to 21 wheel packs.

Chevalier Machinery Inc. (Santa Fe Springs, CA) offers two proprietary grinding software solutions. The company’s conversational graphic program offers a “Q & A” setup style that asks the operator what the job requires, then creates the program. “Anyone without experience in engineering, programming or CNC operating can use it,” said Johnson Lan, vice president of sales. Chevalier also offers the iMachine Communication System, which uses its MT-LINKi to monitor performance data, prevent downtime and forecast production issues. “Remote monitoring of the factory will not only increase productivity but also produce systematically controlled outcomes,” Lan noted.

“You have a library of wheels you can call upon,” Riddiford said. “You can tell the machine to get wheel pack number 15 and do this particular operation, and that wheel change time is about 12 seconds.” Mounting and truing the wheels prior to operation can take about 15 minutes.

In the past, end users would chrome-plate parts, grinding off some chrome to maintain durability in a final assembly. HVOF involves spraying a chromium carbide mixture on a part—mild steel, for example—that allows more even and consistent coating and greater wear resistance, he explained.

Such monitoring is standard on Toyoda grinders in the form of the Toyopuc AAA module, which allows factorywide connectivity. The recently introduced Toyopuc-Touch control “helps facilitate the conversational aspects of the control with the operator,” Farrant said. From a maintenance perspective, the control allows faults to be easily traced in the ladder for quick diagnosis, for example down to a faulty wire, and the grinder’s manuals are available at the touch of a button on the control.

He also noted that the Studer line features more accurate linear scales graduated in nanometers instead of microns.

Titus noted that a potential hindrance to optimal use of cylindrical grinding is often the practice of using decades-old process specifications limiting adoption of current grinding speeds. Today’s superabrasive wheels can be fed at Q-prime rates in excess of 5 mm3/min, he explained, whereas aerospace specs crafted in the 1980s might be based on 2.5 Q-prime.

In addition to libraries of wheels and wheel profiles, United Grinding software offers a quick-set option that uses the machine’s probe system to measure parts without touching off each wheel to the workpiece and recalibrates the machine immediately. Setup time can be reduced up to 10% with one wheel and 90% with four wheels. And, the software can set feed and speed rates and grinding methods, resulting in a good part quickly without an operator taking half a day to dial-in the proper setup. A user could generate a part in 10 minutes instead of about 30 minutes, Ueltschi noted.

Coolants are also application driven, he continued; carbide might require something different than stainless steel. Whereas a job shop might seek a coolant with average features for a range of grinding jobs, a production run dedicated to carbide alone would allow use of a higher-end coolant.

Ultimately, “we want to be able to hit cycle start and let that machine run as long as possible without any intervention.”

Among recent additions in the cylindrical grinding repertoire is the replacement of chrome plating with HVOF spray coatings, said Rob Titus, grinder product specialist for Okuma America Corp. (Charlotte, NC). The aerospace industry in particular is utilizing the process to great effect.

Historically, said ANCA’s Riddiford, water-based coolants have been favored for OD grinding, but oil is coming to the fore for some users, being better for the wheels, surface finish and the machine overall.

“The position of the coolant is critical in all grinding operations, especially OD,” he said. “The nozzles that project coolant onto the wheel need to be in the right place” to allow cooling at the point of contact between the wheel and part. Proper coolant flow is required to remove the resultant particles, or swarf.

“The makeup of those wheels in terms of their compounds and other chemical agents vary based on application,” Riddiford said. “You might use a larger grit wheel for a roughing application, then a finer grit wheel for finishing.”

On tool and cutter grinders, the option for a cylindrical grinding first step “is a nice feature to have,” said ANCA President Russell Riddiford. It minimizes the number of setups or “hand-holding” of the tool from one machine to another.

Oil is “absolutely” better for the grinding process, said Okuma’s Titus. “If you talk to a grinding wheel manufacturer about a superabrasive grinding wheel, he’s going to say, ‘I would love for this to be run in oil because it will perform much better and last a lot longer.’” That said, about 90% of the company’s customers prefer water as a coolant in light of the environmental impact of oil disposal. Also, the requisite fire-suppression equipment in the machines is an added cost.

With multiple-wheel machines that allow a single setup for a complex process to probes that measure parts on the machine to maintain critical tolerances, cylindrical grinders have grown more flexible and easier to operate.

While cylindrical grinding has been used for some time, its capabilities may not be fully appreciated. New grinding wheel technology, controls, materials and dressing processes, coolant and pump options—as well as smarter software—make today’s machines worth getting acquainted with.

However, with the WireDress electrical discharge method, wire-generated sparks remove bonding between the diamond particles of a metal-bonded wheel to expose the diamond or CBN grit and hone the wheel’s grinding ability. “It clears the bond without pressure or deflection,” all with simple CNC programming.

And at Toyoda, monitoring factories as a whole as well as machines individually has been a focus for the past year or so, Farrant said. Many grinding-related issues can be identified before they occur by monitoring vibration, noise and temperatures of castings, coolant and lubricants.

Grinding wheel suppliers like 3M and Saint-Gobain “will give you good information about a starting point in terms of speeds and feeds,” he said, guiding users on where their wheels work the best. “But then you put that grinding wheel on two different machines and it is likely to perform differently on both. It can depend on whether one machine is more rigid than another, for example.”

In the automotive industry, grinders are adjusting to tighter tolerance features and lighter-weight components, said Shane Farrant, national product manager for grinders at Toyoda Machinery USA (Arlington Heights, IL). Toyoda specializes in camshaft and crankshaft production.

To facilitate wheel R&D, two of ANCA’s larger machines are in the US labs of key grinding wheel manufacturers, who develop and test their products with them.

“On a conventional wheel, we mainly use a single-point dresser,” Ueltschi explained. “If it is a plated wheel, you cannot dress it—you cannot influence the shape or the geometry. If it is a vitrified-bond wheel, you can use a rotary disk-type dresser and dress the shape, but you are limited in what type of profiles you have—typically a straight shape or basic profile. If it’s a resin bond diamond wheel, you are reduced to truing the wheel with a silicon carbide grinding wheel.”

Another critical function software provides is wheel balancing, said ANCA’s Riddiford; his company offers a software suite that includes in-machine balancing to prevent vibration and harmonics. With its machines grinding parts anywhere from 20 thousandths up to 6″ in diameter, “we are constantly working on improving the software in terms of getting machines to grind quicker,” particularly by speeding setup.

Optimizing wheel life and output depends on a variety of factors, he noted: part run; listening to the wheel; examining parts coming off the machine; monitoring CNC controller data that tracks a wheel’s amperage draw, which increases as the wheel dulls; and using software that adjusts rpm to keep the wheel working within a given parameter range.

There are numerous techniques for renewing the cutting action of or truing the wheel on a cylindrical grinder—including single-point, roll, crush—in-process while the wheel is in contact with a part, and postprocess, said ANCA’s Riddiford. Grinding wheel makers are developing units that minimize the number of dressings required and work longer and harder.

Different materials produce different swarf, he added. For instance, OD grinding stainless steels produces stringy swarf, whereas a heat-treated blank will produce particles like fine sand.

It’s particularly useful for generating a very fine-pitch thread form on the wheel to produce a thread on a carbide workpiece, he added.

The quest to accelerate grinding machine setup and part production and expand usefulness has led to notable modernizations.

According to Titus, Okuma’s grinders have joined its turning and milling machines in incorporating a Windows-based open architecture OSP-P300G control that is “very suitable for Industry 4.0.” With that comes a conversational CNC programming package, “reducing the need for a dedicated programmer for the machine. The operator goes through a series of menus and fills in the blanks, and that will develop a CNC program based on those inputs,” he said.

Meanwhile, oil-based coolants are finding favor over water among some users. Improved chillers and heaters are maintaining stable processing temperatures vital for meeting the tighter specs required of aerospace, automotive and other components made with super-hard carbide, ceramic or coated materials. Programmable variable frequency pumps provide the exact amount of coolant when it’s needed most.

The feed rate for peel grinding “is quite aggressive,” he continued. The machine calculates optimal spindle rpm when the operator inputs the job’s surface footage on the controller.

It all adds up to a contemporary lineup of cylindrical grinders that deftly handles parts as large as shafts and gears or small as ballscrews, threads and cutting tools.

Chevalier also offers two spindle sensors, one for automatic balancing and another for the spindle loading meter to determine the wheel dressing cycle. “Customers can leverage it as an indicator to maintain the machine,” Lan said.

To evacuate coolant, Toyoda added a channel beneath the wheelhead to eliminate pooling around the wheelhead. “Being thermally stable helps reduce the number of offsets needed when operators return from a break or during the machine warm-up period,” Farrant said.

To keep grinding wheels working with optimum effect, United Grinding is unveiling the 2.0 version of its WireDress technology for metal-bonded diamond or cubic boron nitride (CBN) units.

“Various industries are introducing new materials for us to work with, which is good to see and challenges us and the customers with application solutions. In many cases we look to our grinding wheel manufacturers for recommendations for handling materials outside of our typical mild and hardened steels and cast iron.”

He noted that peel grinding with cylindrical machines is gaining traction for its ability to remove several millimeters of material in a single pass. “We’re doing a lot of development with grinding wheel suppliers,” Riddiford noted. “There’s a lot of focus being put on peel grinding and the grinding wheel’s ability to hold the edge for long periods of time to allow this mass removal of material.”

WireDress is an EDM method for removing bonding material from superabrasive wheels, explained Ueltschi, allowing sharper wheels with easier-to-produce profiles. The smaller, less-intrusive version being introduced fits right on Studer machines. The technology allows better control over grinding wheel shapes, profiles and accuracies as opposed to traditional methods.

Studer machines are also being asked to grind more bearings, especially for the aerospace industry. With one setup, the machine can grind the OD of the ring and interior of the race with the same clamping in the shoe system. Traditionally, Ueltschi said, bearing grinders would perform different functions on up to three or four machines.