Mark Albert is editor-in-chief of Modern Machine Shop Magazine, a position he has held since July 2000. He was associate editor and then executive editor of the magazine in prior years. Mark has been writing about metalworking for more than 30 years. Currently, his favorite topics are lean manufacturing and global competitiveness. Mark’s editorial activities have taken him to numerous countries in Europe and Asia as well as across the United States many times. He is a graduate of the University of Cincinnati (Cincinnati, Ohio) and Indiana University (Bloomington, Indiana).
Chasing a precision sphere with a spindle probe as the sphere moves with the machine’s pallet throughout its five-axis machining range is the key to the new method.
One of the toughest challenges in five-axis machining of large parts is maintaining accuracy throughout the entire work zone. Ideally, a five-axis machine can produce results with the same accuracy when cutting in the far corners of the work zone or at its center. Grob Systems has developed a method of checking and compensating for possible distortions to a machine’s structure caused by the weight of a massive workpiece when machined in five axes.
Grob, a manufacturer of five-axis universal machines and production systems, says its new method improves accuracy of five-axis machines, especially those called upon to produce large, complex parts and components for critical applications. This is a summary of the company’s explanation of how this new system works:
The traditional approach to improving machine accuracy was to use laser interferometry to compensate the position accuracy of the individual axis, and the ball bar measurement to improve the perpendicularity between the axes. This is a simple technique and useful only for the three linear axes of the machine. When the spindle and table start moving around the work envelope, infinitely more deviations (both translational and rotary) come into play. That is the fundamental problem, and it becomes exponentially more complex when two additional rotational axes are introduced.
To improve the process for increasingly complex machines, Siemens pioneered the use of a six-dimensional pictorial compensation map. A 3D laser is used to simultaneously measure yaw and axis alignment, feeding data back to the machine’s control. The resulting picture is comprised of many, many points throughout the work zone. This created a much better measurement of geometry and positioning, allowing the CNC to compensate for distortion and improve volumetric accuracy anywhere in the work zone.
The limitation also of this approach is that the checks and compensation take place on the factory floor during final assembly, and it is available only for linear axes. In the real world, once you put a part on the pallet everything changes. Consider the capacity of some larger five-axis machines to accommodate loads up to 3,000 pounds. When a mass of that size is put into rotation on a five-axis machine, possibly suspended at 90 degrees, it creates a powerful force for distortion on any machine.
Simultaneous to the software developments at Siemens, Grob developed a function called Automatic Kinematics Adjustment. This process locates the true center of rotation, which is critical to accuracy in a five-axis work zone. It works like this: A spindle probe is paired with a precision sphere mounted on the pallet. A kinematic cycle touches probe to sphere, and then rotates to reposition the rotary axis. Repeat. Chasing the sphere around the five-axis envelope in this manner identifies the true center of rotation. The process takes about 10 minutes.
Grob has now integrated its kinematic process with the Siemens software to create what it calls the Volumetric Compensation System (VCS) for shop floor use. VCS applies the same basic software package used for Automatic Kinematic Adjustment, but takes it beyond the center of rotation. A probe stored in the tool magazine chases the sphere to map positional accuracy all around the work zone. By spinning and rotating the pallet, the probe identifies any rotational or translational deviation—from top to bottom of the Y stroke, maximum X to maximum Z and everything in between. The measured deviations are sent to the compensation software, which then perfects positioning accuracy. The process can applied to any critical component assigned to the Grob machine.
I find the concept of the Collaborative Commons both compelling and a bit disquieting. My recent column offered a few comments on this development as an alternative to the market-based economy that we take for granted. Author Jeremy Rifkin has written a book that explores this concept in great depth. It’s called The Zero Marginal Cost Society: The Internet of Things, the Collaborative Commons, and the Eclipse of Capitalism.
Mr. Rifkin’s office sent me a copy of his book, with a personal letter that included these paragraphs. Because they summarize the book so well (and match my impressions of the snatches I’ve been able to read so far), I quote them here:
“Mr. Rifkin believes that the Collaborative Commons is a critical part of a bigger story unfolding around the world that is going to fundamentally alter our global economy in the first half of the 21st century. He argues that a new economic system—the Collaborative Comments—is entering on to the world stage. It is the first new economic paradigm to take root since the advent of capitalism in the early nineteenth century. The meteoric rise of this new economic paradigm is coming at a time when capitalism is under great scrutiny, with lower growth, rising unemployment and greater inequality.
In his book, Mr. Rifkin describes a transformative new technology revolution—the Internet of Things—that enables billions of people to not only produce and share their music, videos, news, knowledge, and other virtual goods, but now also green electricity, 3D printed products, and other physical goods at near zero marginal cost, and for nearly free, on a vast global Collaborative Commons, bypassing the conventional marketplace. A younger generation is also beginning to share cars, dwellings, clothes, and countless other items and services at low or near zero marginal cost on the burgeoning Collaborative Commons, wreaking havoc on traditional industries and in the process, changing the very way we organize economic life.”
The Kaiser Tool Company is celebrating the 50th anniversary of its Thinbit grooving tools line in 2014. Though the company was founded in 1964 by William and Hazel Kaiser, Mr. Kaiser began developing the small grooving tools in the couple’s garage and attic in the 1950s. Such tools were not widely available at the time, and ordering custom grooving tools was expensive and time-consuming. The Thinbit line was created as a result, offering a selection of tools ranging from 0.010" to 0.050" in 0.001" increments.
Today, Kaiser Tool employs more than 40 people and produces nine different lines of cutting tools, including the Thinbit, Microbit and Littlebit lines. Its products are sold in the United States and 20 other countries worldwide. The company moved to its current industrial facility in Fort Wayne, Indiana, in 1994 and is still family-owned and operated. Lenore Perry, daughter of William and Hazel, has been company president since 1982.
Most important, Kaiser Tool Company continues to help manufacturing companies with successful solutions for demanding grooving applications. A good example is Mack Tool and Engineering, a contract shop in South Bend, Indiana, that is using Thinbit Groove ‘N Turn tools for tight-tolerance, application-critical operations such as cutting microgrooves on aluminum aerospace workpieces.
In the Mack Tool and Engineering example mentioned above, Joel Christensen uses Thinbit Groove ' N Turn inserts ranging in width from 0.0195 to0.065 inch with sharp and full-radius tips. He regularly achieves surface finishes of 16 to 32 Ra.
Last week, Methods Machine Tools Inc. hosted Metal Storm 2014, its annual open house and mini machine tool show at the company's headquarters in Sudbury, Massachusetts. Methods uses this popular customer event to showcase new machine concepts and designs from the numerous machine tool builders it represents in the United States. A line-up of informational seminars and tabletop exhibits rounded out this year's presentation. More than 1,500 attendees from 450 companies visited over its three-day run.
Highlights of the machine models and metalworking processes introduced or featured at the show are compiled in this slideshow.
For a video clip roaming the aisles of Methods’ showroom during the event, click here.
I’ve known Tony Staub for a long time. He is the president of Staub Inc, which was called Staub Machine Company when I first got to know Tony. Back then, Tony’s contract production shop in Hamburg, New York, had a reputation for adopting new machining processes and investing in up-to-date, automated machine tools. MMS has featured his shop in several articles over the years. Its machining operations are still remarkable.
So I was pleased to get an email report of Staub Inc.’s findings at the recent RAPID show in Detroit, Michigan. In fact, the report arrived a day after the show closed (talk about rapid)!
It quickly occurred to me that there were many lessons to be learned from this report. Here are four I jotted down:
This shop has aggressively moved into additive manufacturing and has launched this added business as a division called Staub Additive. The efforts to get this news out are energetic, too.
The company is using today’s media well and wisely. The email message is timely, readable and informative. It’s interesting to see this shop’s take on the technology innovations unveiled at the show.
The company clearly understands the importance of “building brand” and marketing its capabilities. Adding links to the message gets you to complementary content easily, too.
Linking to the company’s website shows how well Staub is using the Internet, too. One thing that comes across there is the focus on skilled people as a key asset in addition to technical capabilities.
In general, the manufacturing industry needs to “build its brand” in the national consciousness. Manufacturing companies that are savvy about their own brand building help this cause, too.