Celebrating Works of Friction
By James Sawyer
On the surface it seems like a case of putting the cart before the horse: "Good [grinding] hardware used to be more important than software," says Eric Schwarzenbach, president of Rollomatic Inc. (Mundelein, IL), "because the control systems were not ready for elaborate software functions. All this has changed, and the current control systems run on Windows or other open software platforms. Nowadays, software is the key to a good grinding machine."
There are a number of reasons why this is so, and it starts with the "horse."
"A modern five-axis CNC grinder is a very versatile tool," explains Grant Anderson, CEO of ANCA Inc. (Victoria, Australia). "The ability to utilize it to its full potential is fully dependent on the capability that the software provides it. Flexibility is the key to providing a competitive edge not only in being able to manufacture and regrind a wide range of tools but also the ability to design new sophisticated tools with unique geometric designs."
These complex tool shapes help increase the importance of software, particularly in the manufacture of cutting tools.
"Cutting tools are typically formed by complex curved surfaces, which accurately intersect in specific ways to define various important geometric features of the tool," explains Anderson. "The mathematics required to manufacture such tools using a grinding wheel at the end of a five-axis kinematic chain is considerably complex and further complicated by surface finish, wheel wear, and other conditions which affect accuracy, repeatability, and aesthetics. The software must be able to produce the tool and utilize the best processes possible to achieve it. Incorporating this process know-how into the software is key."
Grinding and ERP
ANCA has identified another trend that is becoming more important.
"Increasingly, we are seeing more requests to integrate our machines into factory ERP systems," Anderson says. "This tool order received from our customer’s customer can be taken straight out of the ERP system, and used to automatically generate a correct tool grinding file and then to produce the finished tool. This is really pushing towards a just-in-time production system to quickly turn around individual customer orders, rather than delivering parts out of stock.
"This implies smaller batch runs—as small as one or two pieces. This means that simplicity and speed of setup from one tool to the next becomes a very important consideration in our designs. Our customers are looking for a single-setup solution that can grind a variety of tool types and/or sizes, switching from one tool type to another, perhaps based on separate customer orders, automatically."
In addition Anderson sees other key drivers affecting grinding today:
Automation to improve productivity;
Tighter tolerances, tighter accuracy and repeatability requirements;
Grinding of alternate materials, such as those found in aerospace and medical applications.
ANCA’s focus for IMTS 2012 will be on each of these areas with the launch of new automation, software and new machines.
The Impact of Helix End Mills
Rollomatic’s Schwarzenbach feels what has had the greatest impact on grinding has been the variable helix end mill. But, he notes, "Most of the innovation in this respect has been software." As does Anderson, he feels the reason for this is the materials that are being worked.
"The trend in the cutting tool industry is towards the ‘more difficult’ material to be machined. That requires new geometries and new coatings on cutting tools."
The cost of machining is also an area, Schwarzenbach says, where manufacturers are trying to bring things under control in order to compete with overseas competition and with off-shoring.
"Incorporating this process know-how
into the software is key."
For IMTS 2012 Rollomatic’s main focus is a wheel changer offered for five- and six-axis tool and cutter grinders, as well as a new laser cutting machine for ultra-fine cutting and ablation of PCD, PCBN and CVD cutting tools. "We will also launch a new in-process wheel and tool measuring system in our five- and six-axis machines," Schwarzenbach says.
What Jeff Hilliard’s customers are looking for are "longer machine capacities to produce larger parts for the power generation/energy, gas and oil drilling and aerospace industries. We also have found that customers are trying to do more with their grinding machines today," says the grinding sales manager for Hardinge Inc. (Elmira, NY). "They’re looking for capabilities such as out-of-round grinding and the ability to hold tighter tolerances than technology may have offered in the past."
"Grinding will continue to evolve
into a mainstream production
process with automation and process
optimization being the focus."
CNC Control Technology
His colleague, Andy McNamara, Hardinge’s director of sales and marketing, holds that "CNC control technology has fostered most of all of these innovations to date. As CNC controls become more capable, faster, and open to other technologies, this helps drive new innovations for all types of machine tools."
As for the impact of software, the company views it as being quite beneficial for those who do not have a lot of experience with grinding.
"For a company with limited knowledge in grinding, today’s grinding software allows operators to take on more challenging applications without excessive programming knowledge," states Hilliard.
The Hardinge Grinding Group will be focused on demonstrating new technology at IMTS. New features will include Kellenberger’s direct-drive C-axis workheads and direct-drive, hydrostatic B-axis wheelheads. "We’re also excited to have the opportunity to introduce the all new Jones & Shipman Ultragrind 2000 with a 2-m grinding capacity," says Hilliard.
Grinding is on an upward trajectory in the estimation of Larry Marchand, VP of the Profile Division of United Grinding Technologies Inc. (Miamisburg, OH). "Grinding has been on a growth path after several years of decline," he contends, "thanks to the growth in usage of very-difficult-to-machine materials in customer products and better economics of the grinding process. Grinding will continue to evolve into a mainstream production process with automation and process optimization being the focus."
Evolution Through Innovation
This evolution of grinding is driven, he feels, by innovation, particularly in terms of CBN, diamond and ceramic wheel technology "that drives the operational requirements of the machine system." The adaptation of automation to grinding systems has helped boost productivity and quality, he says.
Hans Ueltschi, VP of UGT’s Cylindrical Grinding Division, also believes that automation has been a boon. He also cites quality, value, and single-setup operations as areas where innovation has taken place. Flexibility, though, is the most important area of innovation that cylindrical grinding has experienced.
"Hand deburring work is not only
costly and imprecise, it can present
a real physical hardship for the
technician performing the work."
"Flexibility requirements seem to really drive things more than anything," Ueltschi says. "Machines which are flexible in processing options, quick to change over and that can multitask are in demand."
As for the evolution of grinding from its position today, "I would estimate that grinding machines will continue to evolve with respect to accuracy, rigidity to machine a wider range of harder materials, and more use of linear technology, he says. He also believes that there will be more use of "smart" controls and that "more value will need to be brought to the customer’s table. I also see automation playing a bigger role."
At IMTS, UGT’s Cylindrical Group will be showing the new Studer S41 CNC universal cylindrical grinder. The Profile Group will display the Magerle MFP50 that offers high levels of flexibility and production in one machine. The Blohm MT 608, a heavy-duty continuous dress grinder suited for difficult-to-machine materials, also will be shown.
The Abrasive Arena
Ryan St. Gelais, manager of Technical Business Development at Saint-Gobain Abrasives (Worcester MA), contends that industry application challenges associated with more exotic materials have accelerated their development of new abrasives solutions.
"We’re definitely seeing a steady trend toward the use of materials that are difficult to process via traditional machining methods," St. Gelais states. "That trend is leading manufacturers to seek out alternative processing options, which in turn has led our Norton brand to develop new abrasive products that couple premium bond technology with the latest superabrasive and ceramic grain technologies.
"In industries such as aerospace where difficult-to-machine materials such as high-temperature alloys are common, cycle times can be slow and tool wear is high. Anticipating the need to address these issues, we have introduced new products to meet the demands of these applications. One of the new products we are highlighting at IMTS is our Norton Quantum X Creepfeed grinding wheels. The wheels are manufactured utilizing three proprietary technologies."
"More value will need to be brought
to the customer’s table."
The wheels, he goes on to explain, can substantially increase stock removal rates while maintaining the traditional grinding advantages of accuracy and precision. "In one aerospace turbine blade example, Quantum saved almost 30% on the cost per part and reduced cycle time by over 40%," he says.
Honing Homes in on Two Trends
In the honing field, a good deal of innovation is being generated by the need to reduce automotive emissions and a trend to mixed-part production. "Engine manufacturers are studying or already using plasma-spray coatings on cylinder bores as one of their emission-reduction technologies," according to Dennis Westhoff, business development manager, Sunnen Products (St. Louis). "These coatings can be highly customized in their metallurgy, so there’s an infinite range of material possibilities. We are working with OEMs and manufacturers of the coatings to develop new abrasive formulations, bonds and configurations, as well as new feed algorithms, honing oils and coolants, to meet a changing array of requirements in this area. We are also designing automated honing systems for mixed-part production, with lot sizes down to one."
A recent development that is gaining wide acceptance is controlled-force honing. "We actually control the pressure on the abrasive feed system," says Westhoff. "Controlled-force honing ensures the optimum cutting load on the abrasive throughout a cycle. It works in conjunction with our rate feeding system, which adjusts tool size in increments as fine as 0.1 µm.
Depending on the application, controlled-force honing is said to cut cycle times by as much as 50%, lengthen abrasive life for lower consumable cost, and allow finer control of surface finish parameters than was previously possible.
"We will introduce upgrades to several lines of machines at IMTS," Westhoff, "that will open a new range of possibilities in what we can do with the tool and abrasive during the honing cycle. In addition, we’ll introduce a large-part vertical honing machine for job shops and service facilities as well as new developments in tube honing, honing oils and tools."
Automation and Abrasives
Brush Research Manufacturing Co. (Los Angeles) will present its new Nampower line of abrasive disk brushing tools at IMTS. These feature a blend of ceramic and silicon carbide abrasive combined with a unique flow-through toolholder. The company will also feature its new Diamond Flex-Hone tool that will finish and deburr hard materials like carbide and ceramic.
From the perspective of Michael L. Miller, Brush’s VP of global sales, a major trend that is driving innovation in the field of deburring "is the quest to move more work from the deburring bench onto the machine tool that produces the part."
"Hand deburring work is not only costly and imprecise," Miller says, "it can present a real physical hardship for the technician performing the work. It is now possible to remove burrs from cross-drilled holes, clean and deburr threads, deburr face-milled and fly-cut surfaces, remove tool marks and generally improve the surface finish on any area of very complex parts. In addition to new brush types, probably the greatest impact is the introduction of new abrasive materials including diamond and ceramic, which are being routinely used to provide the benefit of automated deburring to a much wider range of base materials." ME
This article was first published in the August 2012 edition of Manufacturing Engineering magazine. Click here for PDF.