Posted by: Mark Albert 20. February 2015

Cylindrical Grinding Technology in Motion

“The Cylindrical Grinding Universe” was the theme for United Grinding’s 2015 Motion Meeting in Switzerland. This theme was particularly appropriate because a key point was the expansion of ID grinding capability to provide universal coverage of the full range of workpiece sizes.

Every year, United Grinding hosts a gathering of its sales partners and trade press editors from around the world. The purpose of this annual ‘Motion Meeting” in Thun, Switzerland earlier this month, was to highlight the group's latest developments in grinding technology, especially in the area of cylindrical grinding, which includes the Studer, Schaudt and Mikrosa brands. United Grinding also used this occasion to deliver its prestigious Fritz Studer Award for innovative research in machine tool or grinding technology.

Topping the list of new products introduced at the event are the Studer S131 and S151 cylindrical grinding machines, which are built on the innovative S141 cylindrical grinding platform. The S141 platform is distinguished by ID and OD grinding capability enabled by a grinding spindle turret that accommodates as many as four grinding spindles. Both internal and external grinding operations can be completed in one setup to enhance accuracy and reduce non-cut times.

The S131 is smaller than the S141. It has a swing diameter over the table of 250 mm (9.8 inches) and a maximum grinding length of 175 mm (6.9 inches) for ID grinding and 125 mm (4.9 inches) for OD grinding. It accommodates workpieces as long as 300 mm (11.8 inches).

The S131 is a compact ID/OD grinder for smaller work pieces.

For reference, the S141 is available in models for machining workpieces with maximum lengths of 300, 700 or 1,300 mm (11.81, 27.56 or 51.18 inches) and IDs ranging to 250 mm (9.84 inches).

To complete the series, the S151 is larger than the S141. The new S151 features a swing diameter over the table of 550 mm (21.6 inches) and a maximum grinding of length of 400 mm (15.7 inches) for ID work and 150 mm (5.9 inches) for OD work. It accommodates workpieces with a maximum length of 700 mm (27.5 inches).

The S151 grinds workpieces as long as 700 mm (27.5 inches).

Studer’s line of ID/OD grinders now covers the range of shaft diameters and lengths with no gaps for both ID and OD capability for complete grinding in one clamping. In addition, all of the machines share the same ergonomics and clean, streamlined styling of the enclosure and pendant-mounted control unit.

Another recent product worthy of mention is the CrankGrind, a crankshaft grinding machine from Schaudt. Cosmetically, this grinder sports that “new look” that represents the unified corporate identity within the Cylindrical Grinding Group as well as the company-wide emphasis on functionality and ergonomics. More important is its capability. The CrankGrind is designed to do rough- and finish-grinding of both main and pin bearings on automotive crankshafts, all in one setup on one machine.

The Schaudt CrankGrind is designed to be a “superproductive” grinder for the complete grinding of automotive crankshafts.

The Motion Meeting also affirmed Studer’s leadership in energy efficiency, which is a concern among all machine tool builders and end users. Studer’s multi-prong approach may be a model for comprehensive energy management in industrial equipment. For detailed commentary, click here.

A further highlight of the meeting was the presentation of the 2014 Fritz Studer Award to Dr. Eduardo Weingärtner from the Swiss Federal Institute of Technology Zürich. Dr. Weingärtner’s work pioneered the application of the wire EDM process for on-machine dressing of metal bonded grinding wheels. This research was instrumental in the introduction of the Studer WireDress system detailed here.

Finally, as a bonus for visiting trade press editors, a tour of United Grinding's Mägerle brand was arranged in Fehraltdorf prior to the conclave in Thun. Mägerle, part of the company’s surface and profile grinding group, specializes in large, multi-axis grinding machines. These highly engineered systems are custom-built from flexible modules to combine unique applications with proven design concepts. Although Mägerle grinders represent some of the most demanding and advanced applications in grinding, the company continues to rely on a solid foundation of traditional skills such as hand scraping of ways for mechanical accuracy. In fact, the company's apprenticeship program aggressively courts young talent to replenish its highly skilled workforce, and is a model for sustaining the thoroughly Swiss tradition of precision and meticulous craftsmanship.

Although Magerle does not produce “standard” models of grinders, it does offer distinct product ranges, including the MFP line of multi-axis surface and profile grinders. The MFP 50 shown here is part of a grinding cell for a jet engine manufacturer. The new styling of the MFP grinders reflects the corporate redesign.

Posted by: Derek Korn 19. February 2015

Mind the Tool Center Height When Turning Small Diameters

Louis Trumpet with Vallorbs Jewel Company in Bird-In-Hand, Pennsylvania, wrote a piece that reminds us how small turned diameters can vary from their nominal dimension when a lathe’s tool center height is off. What follows is what he sent to me (which I’ve only mildly edited).

From Louis: Very small, precision turned parts may have several different diameters, making for complications here and there. For example, when turning these small parts, you may notice that when one diameter is on the nominal dimension while others may be off by several tenths. At first, you might think this is caused by different tool pressure at the different depth of cuts, but that’s unlikely. To be sure the problem isn’t mechanical, check for backlash, flex in the machine/toolholder and the fit of the material to the guide bushing (when using a Swiss-type lathe). If everything checks out, and you’re still experiencing a differential, the likely culprit is that your turning tool center height is off.  The following example shows how being off center can affect the diameters being turned.

First, let’s assume that if your tool was brought to XO, the tip would be dead on the centerline of the bar. Line “A” is how far your tool is off center. Line “B” is your programmed X-axis dimension. Line “C” is the actual distance to the cutting edge of the tool or half the actual turned diameter dimension on your work.

Imagine making line “B” longer and longer (turning progressively larger diameters), and you see that angle “A” flattens out, which in turn will make line “C” shorter relative to line “B.” In other words, the error becomes less the larger the diameter your turn is. So, when turning very small diameters, it is critical to be on center.

The Pythagorean Theorem tells us that a2 + b2 = c2. Using that information, let’s assume your tool is 0.003 inch off center and you are turning a 0.030-inch diameter (side a = 0.003 inch, side b = 0.015 inch). Side “c” is equal to 0.0153 inch because c = √(0.0032 + 0.0152), so your turned diameter will be 0.0306 inch or will be 0.0006 inch off of nominal size.

Now assume you are using the same tool to turn a 0.0125-inch diameter. Running the same math, we find that the turned diameter (rounded) will be 0.1251 inch or 0.0001 inch off of nominal size.

Since the 0.030-inch diameter was 0.0006 inch off of nominal size, we have a differential of 0.0005 inch between the two dimensions. It follows, then, that when you offset one dimension to nominal size, the other dimension will be 0.0005 inch off of nominal. All this makes it difficult to dial in the workpiece without editing the program (bad), or using two separate offsets (nearly as bad).

You can also add a macro variable to the programmed dimension, but when you think about it, all that does is provide a convenient way for the operator to edit the programmed dimension. It’s better to fix the root cause of the problem by getting the tool on center. You can use this information to calculate how far your tool is off center and correct it with an offset, assuming you have Y-axis capability. Some small-capacity Tsugami Swiss-types have a feature built into the control to calculate the tool height using this principle, but you can see it works best at very small diameters where angle “A” and the resulting error are greater.

Posted by: Peter Zelinski 18. February 2015

Interest in Additive Manufacturing Enters Phase Two

At CIMP-3D, visiting engineers from various companies look at a layer slice of an additive-manufactured part. Penn State research assistant Kenneth Meinert discusses additive build orientation and parameter settings as they relate to this part.

Timothy W. Simpson, Ph.D., professor of mechanical and industrial engineering at Pennsylvania State University, is co-director of the university’s additive-manufacturing-focused Center for Innovative Materials Processing through Direct Digital Deposition, or CIMP-3D. He has toured more than 1,200 visitors through this additive manufacturing demonstration facility, he says, and he believes he is now seeing attention to AM enter a second phase. The knowledge level of potential users has advanced.

The previous phase reached its high point 18 to 24 months earlier, he says. At that time, visitors to his facility asked basic questions. A common one was, “You can 3D print in metal?” Amazement at seeing functional metal parts produced additively was common. But now—strikingly—almost every visitor to the lab has moved well beyond that level of knowledge.

The new wave of interest that he is seeing takes the form of engineers working with the lab to produce one-offs or trial batches of additive manufactured parts. In almost every case, the engineer’s purpose is to take these sample parts to his or her company management as part of an argument for adopting additive production. As a result, Dr. Simpson expects to see a third phase in another 18 to 24 months, as some of the bosses of those engineers agree to start implementing additive processes for the production of initial parts.

Projecting these anticipated phases into the future, Dr. Simpson estimates that 3 to 5 years from today will be enough time for additive manufacturing for full-scale production of metal parts to move to a point of acceptance beyond the leading edge at which it’s practiced today. By that point in the future, he says, the production of end-use parts through additive manufacturing will be an established, day-to-day practice in facilities serving a variety of industries and end uses.

Read more about additive manufacturing at CIMP-3D.

Posted by: Matthew Jaster 17. February 2015

Large Machines and Large Capacity in Renovated Pfronten Facility

The exhibition floor at DMG MORI’s open house in Pfronten, Germany, featured 76 machines including four world premieres. 

DMG MORI hosted its 20th open house earlier this month in Pfronten, Germany. The event featured 76 machine tool exhibits, including four world premieres, and gave nearly 8,800 attendees (including global customers, journalists and guests) had the opportunity to tour the recently renovated and expanded facility to see its latest machine tool technologies. Here are some observations from the event:

  • Large-part machining: In more ways than one, DMG MORI is expanding its manufacturing portfolio. Case in point: The DMU 600 P is designed for machining extremely large and heavy components. It is well suited for automotive, rail, shipping and construction industry applications, with a travel of 6,000 mm in the X axis and 4,200 mm in the Y axis. An optional crossbeam has a path of 2,000 mm, and the ram stroke provides an additional 1,500 mm.
  • Increased production capacity: Pfronten’s new high-tech assembly hall was designed so that two DMU 600 P machines could be built in their entirety with room to spare. Upgrades and renovations in 2014 have doubled the facility’s previous capacity.In keeping with Germany’s Industry 4.0 plans for more intelligent production capabilities, the factory also boasts an integrated information system. Digital workstations installed throughout the factory enable employees to look at the exact configuration of customer orders, lock-in necessary materials and order supplies for each machine tool without leaving their workspace. The result is an increase in shopfloor efficiency.  
  • Updated equipment: One of the four machine tool world premieres was the second generation CTX beta 1250 TC. This turn-mill features the new CompactMaster spindle, and it machines workpieces ranging to 350 mm in length with tools ranging to 400 mm length. The second premier was the DMC 270 U, a five-axis machine featuring a gantry design and a new B-axis milling head. The company also highlighted the DMU 100 P duoblock and DMC 125 FD duoblock five-axis machines, now in their 4th generation respectively, which feature a new wheel-type modular tool magazine.
  • Celos: In the spring of 2015, DMG MORI will launch four new application tools for its Celos CNC operating system including Job Scheduler (production planning), Tool Handling (reducing tool setup times), Service Agent (predictive maintenance) and Messenger (machine status overview).  
  • A push for single-source machining: The other main topic of conversation in Germany involved streamlining the product lines. During the press conference, DMG MORI executives, including Dr. Ruediger Kapitza and Dr. Masahiko Mori, discussed plans to use the German and Japanese machine tool resources to the fullest extent. This means getting Celos on every machine. It also means discussing the possibility of a joint IT department. The goal is to centralize the company’s machine tool line to meet the increasing demands of its customers. Expect more information on this later in 2015.

Posted by: Emily Probst 16. February 2015

GE Aviation Inspection Technologies Challenge Announced

NineSigma, representing the General Electric Company, is accepting entries for its Inspection Technologies Challenge through February 24. This challenge is designed to find technologies, processes or approaches that can greatly increase the speed and accuracy of aviation parts inspection and greatly increase manufacturing efficiency.

Participants will compete for as many of three cash prizes of $15,000. Winning respondents who enter into a joint development agreement with GE will be awarded a $35,000 development grant to collaborate with GE to develop proposed solutions.

For this challenge, participants are asked to demonstrate their abilities by inspecting a Victorinox 4 inch paring knife instead of actual high-precision aircraft parts.

Visit this site for more information about the challenge and read the official rules. There is also a forum in which you can post questions about the challenge.

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