A Shop's One-Setup Secret--It's In The Swivel

This young shop relies on its ability to complete difficult grinding jobs in a minimum of setups so that it can offer its customers an economical and efficient grinding solution. Grinders that can swivel the wheelhead under fully programmable control are the enabling technology.

Article From: 12/1/1996 Modern Machine Shop, ,

In the three and a half years it has been in existence, ABBA Systems of Brantford, Ontario, has built a growing business by offering high precision grinding services. The shop goes after the difficult, tight tolerance grinding work that other shops would rather not have to do themselves. And in today's world of tighter tolerances and finer surface finish specs, more and more of that kind of grinding work is out there.

Originally, the shop was founded by four ambitious Canadians as a mold regrinding and repair shop, but the high level of grinding required for this operation quickly attracted other kinds of work. Before long, it was clear that high precision grinding in general was a niche that offered a much greater potential for growth. The shop went out soliciting the toughest grinding jobs it could find. As Henry Vaandering, one of the founders and currently the shop's VP for manufacturing explained, "Once we turned that corner, our business really took off."

Grinding Is Great

The shop's strategy is simple. It has the equipment and the know-how to overcome the problems that often make grinding a troublesome last step in the machining process. Central to this strategy is a bank of cylindrical grinders with programmable B-axis capability. Sophisticated measuring devices are another key component of the equipment side of the formula. On the people side, the company emphasizes preparation and training of its workforce and a team approach to planning each grinding job. But most important, the shop has an unusual perspective on--and respect for--the grinding process.

To them, grinding is a can-do process. Grinding is great. No other process can reach the same levels of dimensional accuracy and fine surface finish. Early on, Mr. Vaandering and his co-founders correctly saw that the problem wasn't with grinding, it was with the limitations in grinding machines. Mr. Vaandering and Len Brak, one of the other four partners, had experience with grinders and understood the obstacles that made the grinding process difficult and inflexible. They knew they had to look for something different in the class of grinders their new company would be built around.

Swiveling wheelhead CNC machines proved to be the answer. So the first new grinding machine their start-up company acquired was a Kel-Varia CNC cylindrical grinding machine from Kellenberger Inc. (now part of Hardinge, Inc.). This Swiss-built grinder has a swiveling wheelhead that can be automatically positioned under CNC command. This fully programmable B axis allows the shop to do ID, OD, face and angle grinding operations in a single setup. The shop has structured itself to exploit this inherent flexibility in its basic approach to high precision, high quality grinding.

ABBA Systems now has three of these B-axis grinders from Kellenberger. They represent the core of its high precision grinding capability.

What Is A "B Axis"?

On a cylindrical grinder so equipped, the B axis is wheelhead swivel. A swiveling wheelhead allows the grinding wheel to be repositioned to approach the workpiece from various angles. Otherwise, the wheelhead feeds into the workpiece on the Z axis and travels across the workpiece in the X axis as all cylindrical grinders do.

On the Kellenberger machines, the B axis is embodied in a block-shaped, turret-like wheelhead with OD grinding wheels at opposite sides on the front. On the rear of the wheelhead is mounted the ID unit. The swivel of the wheelhead on these machines is fully programmable in increments of 0.00001 degree. The wheelhead can swivel up to 195 degrees.

The B axis is able to reposition the grinding wheels to grind all surfaces of a hypothetical workpiece in a single setup. Note that angling the wheelhead allows tapered workpieces to be ground with a straight wheel. Likewise, side grinding of the shoulders could also be performed without indexing the wheelhead if the characteristic cross hatch pattern on the workpiece surface is desirable.

Although flexibility for single-setup grinding is the chief advantage of the B axis, it also contributes substantially to grinding quality. According to Mr. Vaandering, the most important benefit in this regard is the virtually perfect concentricity that can be maintained between OD and ID grinding operations. This is valuable to ABBA Systems because many of the workpieces they process, particularly in aerospace, call for a ground finish on almost every surface. ID grinding accounts for 40 percent of the grinding this shop carries out.

Grinding radii is another area where the B axis pays dividends. For example, it is not uncommon for designers to specify corners with different size radii. One option is to dress each of the two OD grinding wheels with a different radius on the edge, and then index to the appropriate wheel to generate the specified radius. Or, the smallest specified radii can be dressed on one of the wheels for plunge-grinding the radii of that size. The same wheel can then be used to generate larger radii by profile grinding them with continuous path CNC commands.

However, the presence of the B axis is not the only feature of the Kellenberger grinders that ABBA Systems considers essential to its approach to high precision grinding. Hydrostatic ways on both the X and Z axes of these machines make them very rigid and resistant to vibrations. Increased accuracy of feed and travel (programmed moves have a resolution of ten millionths of an inch) speeds cycle times by reducing spark-out.

Another feature that Mr. Vaandering points to as a valuable time-saver for his shop is automatic compensation for wheel dressing. Spindle speeds are automatically adjusted after each dressing cycle to maintain a consistent surface speed. "We need this reliable consistency for predictable surface finish," he says. "Sometimes it's only a matter of the cosmetic appearance of the workpiece, but more often it's to protect the surface from any damage. Aerospace parts are especially sensitive to less-then-optimum grinding conditions."

People Make Quality

This is not to say that having exceptional grinders is the only thing that enables ABBA Systems to do exceptional grinding. "Top notch grinders have to be a given," Mr. Vaandering explains. "Any shop can invest in this level of grinding capability. What we concentrate on is the strength our people bring to the grinding process."

Thorough job planning and preparation are paramount. To this end, the shop has developed a program they call Advanced Quality Planning. Before a job is accepted, it is reviewed by a team consisting of the sales person involved, the programmer, the shopfloor "cell leader," and one or both of the vice presidents (Henry Vaandering and Len Brak).

This team decides together what they judge to be the most efficient and effective way to grind the part. Obviously, one of the first things they consider is how to grind the part in a single setup by taking full advantage of the grinding machine's flexibility. "About 80 percent of our jobs utilize the B axis because it represents our best opportunity to eliminate part refixturing or additional setups," Mr. Vaandering points out.

Right after it determines how to grind a workpiece, the team looks at how to measure the workpiece. The rule here is, "If we can't measure it confidently, we can't grind it confidently." Indeed, next to high precision grinders, ABBA Systems has invested most heavily in high precision inspection and measurement equipment. It's not unusual at this point in planning for the team to consult with the customer to clarify any potential misunderstandings about inspection procedures. In a growing number of cases, ABBA Systems is involved early enough in the customer's engineering process to have input on design issues based on what can or cannot be done with precision grinding in mind. This has proven to be the best way to take into account how the workpiece is to be checked and inspected.

This Advanced Quality Planning process covers fixturing and tooling, inspection procedures, record keeping routines, and all details of the grinding process. The idea is to spell out everything so that the operator doesn't have to waste time or delay a job because he doesn't have all the information needed.

Simulation

One important software tool that the shop has been developing is a method for simulating the entire grinding process on a CAD system. Working with a contract software developer, ABBA Systems has put together a complete library of 3D CAD files representing every dimension of the grinding machines, their components and accessories.

Using this software, a grinding job can be set up in virtual space to check for adequate clearances and accessibility. Planners can be sure that a fixture will not interfere with wheelhead swivel or that a grinding wheel will not gouge an adjacent workpiece surface or feature.

Intellectual Capital

This Advanced Quality Planning process, however, assumes that the machine operators will exercise their own initiative and finesse in performing their duties. They are not expected to simply follow instructions as outlined in the job plan. When a new job is released to the shop floor, the operator and the cell leader review it together to be sure that everything is understood and that all tools and materials are ready to go. Operators are encouraged to look for improvements or efficiencies that they might discover. This feedback is carefully recorded in the job file.

Operators are responsible for conducting their own inspection routines and for keeping measurement records. Near every grinder is an inspection station with a granite surface plate and complement of height gages, dial indicators and other metrology instruments. An optical gaging station is also available in an enclosed area adjacent to the shop.

A word about the company's shopfloor management structure. It doesn't really have one. There are no supervisors and no time clocks. The more experienced operators have been designated as Cell Leaders, who act as mentors and problem solvers. Cell leaders make sure schedules are followed and that priority jobs are attended to. They also conduct training and conduct performance reviews, which are informally structured and emphasize skill development.

"One of our principles is to make sure everyone knows what is expected on a job and what the criteria for success are," says Mr. Vaandering. "The most frustrating thing in a work environment is not knowing exactly what is expected of in terms of performance. We owe it to our employees to make sure they are equipped and prepared to do outstanding work. If we do that, we can trust our people to come through."

What Leads Up To Superior Grinding...

. . . is superior pre-machining. Just as an atmosphere of mutual trust is essential on the shop floor, a similar atmosphere is deemed essential between ABBA Systems and the shops that it works with for pre-machining, or rough machining as it is sometimes called. Rough machining is a term that causes Mr. Vaandering some discomfort in the context of high precision grinding because there can't be anything rough or unpredictable about the turning or milling operations that precede grinding.

That is precisely why the shop has established "alliances" with a couple of local shops that it routinely turns to for turning and milling. By working together regularly and by being willing to attend to each other's special needs, ABBA Systems and these "partners" have come to know what to expect from each other.

For example, turning operations have to yield highly consistent results to ensure that even stock conditions can be counted on when the workpieces reach the grinders. Sharing workholding fixtures or agreeing on common workholding strategies is one way the shops work together. If they can solve a clamping challenge, such as a thin walled workpiece with a tendency to distort in a chuck, in a compatible way, both shops gain. Likewise, they may jointly purchase special fixture components and exchange them between shops as needed.

The shop that provides milling has copied many of ABBA Systems' methods for quality, which are based on ISO-9000 principles and procedures. This has boosted the milling shop's quality performance across the board, with all of its customers benefiting.

Vision Of The Future

One thing that ABBA Systems has that many shops fail to appreciate is a picture of what they want the future of the company to look like. John Douglas, the partner who takes the lead in developing new business and interacting with customers, sees the shop continuing to grow in a controlled fashion to preserve the tight-knit teamwork that it values so highly. It has 39 employees right now.

"We intend to expand into the medical market because we see a growing need there for high precision grinding of difficult materials. We expect to draw more customers from the United States--a third of our current base is in the U.S.A.--but it's a strong, growing economy. We're going to do more work with superabrasives. Our machines have the rigidity and power to handle the higher grinding forces superabrasives entail. And superabrasives take out many of the variables that go along with conventional grinding wheels. Superabrasives would also push us toward a more balanced blend of production jobs and small batches."

What Mr. Douglas and his partners do not see in the future is a departure from their commitment to high precision grinding as a core competency. "It's what we do best." Nor do they see a departure from their values and guiding business principles. As Mr. Douglas says as a reminder, "It's part of our company name."

What's In A Name?

ABBA Systems may seem a puzzling name for a grinding shop, but it has an interesting and appropriate meaning behind it.

"Abba" is an ancient Aramaic word that means "father," although the modern English word that comes closest to capturing the meaning and flavor of the original is "papa." Bible scholars point out that when Jesus taught his disciples how to pray to God in heaven, he chose this word. "Abba" is the first word of the Lord's Prayer in the language Jesus spoke. He wanted his disciples to address God as Papa, to think of God in terms that were intimate and trusting, the way a child would naturally respond to a loving parent. Using "abba" in prayer marked a radical change in the relationship that was implied between the human and the divine.

When the founders of ABBA Systems were thinking of names for their new company, they wanted something that would not identify them with one technology or process but would instead characterize their outlook and approach to business. A key aspect of this approach was the relationship that the founders wanted to develop between the company and its customers, the company and the local community, and between managers and employees. Trust, mutual respect and a commitment to quality, honesty and ethics were to be guiding values in these relationships. Because the word "abba" was associated with dramatic changes in a relationship and had many of the same connotations they hoped to convey, one of the founders suggested it. They added Systems to the name because it implied the coordinated and unified activity between machines and between people but did not specify any particular type of equipment or class of skills. As John Douglas puts it simply, "You might say that ABBA Systems means working together for the benefit of all involved."

These are lofty ideals, and the company works hard to live up to them. Evidence that they do can be seen in the loyalty of its workforce, its growing customer base, its spreading reputation, and its support for local charities and community programs, most noticeably the United Way, for which it received special commendations recently.

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