When EMO was last held in Hannover, Germany, four years ago, the show was in a word, depressing. The mighty German machine tool industry, as well as the rest of Europe, was mired in the worst slump in a generation. And the news from this normally technologically elite exhibition had more to do with corporate realignments and cost reduction than with anything else, as so many European companies were moving into a survival mode reminiscent of the American machine tool industry of the mid 1980s.

This time around, however, the story was very different. While the general European economy is still in recession, conditions are far better for the machine tool builders. For one thing, the builders as a group are on stronger financial footing, having cut much of the fat out of their organizations and having established more viable business alignments—we'd call them mergers and acquisitions—where individual companies were in serious trouble going it alone. And equally important, European manufacturing in general is stepping up its investment again, cognizant of the need to cut costs through the development of more efficient production processes.

This situation, thankfully, has many European machine tool builders returning to more aggressive product development strategies of their own. While, like usual, many builders are pursuing a range of approaches to solving the manufacturing puzzle, there were some strong themes that played consistently throughout the halls of EMO. Most apparent were the notions of achieving greater speed and flexibility. By speed, we mean machines that move faster both in and out of the cut. And by flexibility, we mean machines that set up faster or otherwise move more deftly from one workpiece to the next. Here are some of the ways those ideas were on display at EMO.

Simply Fast

Ex-Cell-O's second-generation linear-motor machining centers have been optimized for cellular, dry, high-speed machining.

Perhaps the most striking presence at EMO is how commonplace high speed machining has become. Most of the leading European machining center builders had high speed models on display, and not just machines with fast spindles, but with significant other machine features that support accurate contouring at high feed rates as well.

High speed spindle makers are looking both to push the speed-and-power combination higher and to make their designs more dependable. Urged on largely by the aerospace industry, some builders are actively pursuing the technological goal of building a 100/100 (100,000 rpm/100 kW) spindle. But more are focused on addressing some lingering practical concerns in the 20,000 to 40,000 rpm range, which is growing common. Once such concern is service life. Currently a good life for a high speed spindle is 3,000 to 6,000 hours. That translates to just about two years.

High speed spindle failure is generally not catastrophic, says Siegfried Weiss, president of the German high speed spindle builder Weiss GmbH (Dyna Drive, Inc., Mentor, Ohio). "We've found that spindles are subjected to numerous little wrecks that over time that add up to a failure." According to Bill Popoli, president of the U.S. arm of Swiss spindle maker Ibag (Milford, Connecticut), there is a need for shops to understand that high speed spindles are not as "tough" as spindles found on standard machine tools. Still, it is a goal for Ibag and other spindle builders to get average service life up to five years.

As for control capabilities, it seems like the whole industry has upgraded to high speed CNCs capable of executing extraordinarily accurate cutter paths at very high feed rates—an enabling technology that has machining centers cutting everything from hardened tool steels (as hard as 62 Rc) to cast iron and aluminum auto and aerospace parts. For die/mold machining, the newest capability now in the spotlight is curve interpolation, which a number of machine tool builders were touting—mainly those with Siemens and GE Fanuc controls. This feature allows complex curves such as non-uniform rational B-splines (NURBS) to be imported directly into the CNC rather than having to approximate those curves with point-to-point moves as is done in conventional contouring. The CNC interpolator then references the true curve math to contour more accurately, smoothly and, by most accounts, much faster too.

However, not everyone believes that curve interpolation is yet the total answer for high performance contouring. German control builder Heidenhain, Schaumburg, Illinois, for instance, thinks that curve interpolation makes sense only where data points in a conventional part program are clustered too close together to maintain a desirable feed rate. The far larger issue, they contend, is to apply look-ahead capabilities for the sake of real time "jerk control"—that is, to soften abrupt moments of axis acceleration and deceleration in order to create a smoother execution of conventional point-to-point contouring cuts. And that is a feature the builder was emphasizing, though they have introduced a curve interpolator as well.

German NURBS interpolation proponent Siemens Energy & Automation (Elk Grove Village, Illinois) also believes "jerk limitation" is critical, and claims to apply three types of look-ahead to keep the cutter path as smooth and vibration-free as possible. But this builder is now looking at dynamic management of feed rates and spindle speeds in order to maintain a more constant chip volume as the cutter encounters different conditions—for instance, as the tool moves into and then out of a corner. Siemens also is developing methods for maintaining more constant cutting conditions in five-axis applications.

One long-standing question CNCs typically can't answer is how to bridge the gap between the theoretical environment of NC programming and the very real world of a machine tool. Unpredictable factors such as variations in material volume and hardness, cutting tool wear, unknown workholding locations and other factors all force the programmer into a conservative anticipation of worst case cutting scenarios, and machining rates are set accordingly. However, an Israeli company, OMAT Control Technologies (Jerusalem), thinks they have an answer with their OptiMil adaptive control system. The heart of the product is an expert system with a database of optimal cutter load profiles for various types of cutting tools in a wide variety of materials. In operation, the system monitors the actual machine tool spindle load, compares that data to optimum values, and dynamically adjusts the machine tool's feed rate override accordingly in real time. The developer states that the system is capable both of maintaining the highest desirable feed rates and reducing air cutting, as well as detecting broken tools.

OMAT's adaptive control system allows optimum feed rates to be constantly maintained. Data input is based on spindle load.

Many machine tool builders are also beginning to rethink some of the fundamental electromechanical design principles of their machines. The vast majority of high speed machines now have their axes rolling on ball or roller bearing linear guides rather than the box ways that ruled machine tool technology for so many years. And increasingly, incredibly quick linear motors are replacing ballscrews on the highest performance production machining centers and modules. Up until now, linear motors have had trouble moving beyond novelty status in the eyes of many observers; but at this show they looked much more like a staple of the next generation of high production milling technology.

Some aspects of high speed machine design are perhaps less glamorous, but just as important. For instance, German builder Ex-Cell-O (Sterling Heights, Michigan) has given a great deal of thought simply on how to deal with chips. On the new XHC 240 horizontal machining center—a second generation linear motor machine—all flat surfaces inside the enclosure have been removed so that chips fall freely to the centered conveyor below. One of the machine axes was also moved from the vertical to the horizontal plane primarily for the same reason. These and other factors facilitate the HMC's dry machining capability which, interestingly, probably could have been possible with the first generation model were it not necessary for coolant simply to clean away the chips.

Much More Flexible

Flexibility can mean of lot of different things to different people, but in the machine tool world it mostly has to do with versatility and the ability to quickly change over from one job to the next. Those concepts were in ample evidence at EMO in sometimes subtle ways, and sometimes dramatic.

EMAG's inverted turning spindle design can accommodate turning, drilling, and grinding operations on a single platform.

Perhaps most prominent is how so much functionality is now being packed into individual machines. European manufacturers are demanding machines that not only reduce individual cycle times but that take significant amounts of the total processing time out of a workpiece. It's an approach that rethinks the overall process capability rather than just individually boosting the speed of sequential operations. Builders are answering these demands with machines that resemble less a single purpose machine tool and more a stand-alone, multi-process cell. Along with the additional processing capability within the confines of a single platform, flexibility to modify processes to respond to product changes are also part of the equation. Moreover, the traditional methods of building machines to order is too slow for the rapidly changing manufacturing scene in Europe, and the rest of the world for that matter.

At EMO we saw several examples of machine tool builders' responses to these demands. Many machine tools are using common platforms to support a variety of process-specific metalcutting modules. These modules effectively bolt on to a base and allow the builder to pre-build a machine to a certain level before focusing it more tightly on a specific application. Two benefits of this approach for the market are that the delivery of equipment is significantly shorter and the use of common components reflects favorably in the price of the machine.

A good example of this idea was shown by EMAG (Farmington Hills, Michigan). The base concept is an inverted vertical turning center, which they first built in 1992. The inverted vertical turning center uses a configuration similar to a vertical machining center with the chuck located where the cutting tool would be. In this configuration, the chuck is used to pick up a workpiece and move into the cutting zone. Originally this design was intended for turning only, but it has evolved to include other processes. In addition to turning, EMAG's VSC 400 can mill and grind in one setup. A blank workpiece enters the cutting zone and a complete part exits the machine. A common frame for these various configurations allows EMAG to pre-build much of the machine before its processing attachments are added. This reduces cost and leadtime.

Vero International's CAD/CAM system includes extensive knowledge of the total mold design-through-manufacturing process.

More processes capability also could be found in other kinds of turning machines. For example, Index (Shelton, Connecticut) introduced a new six-spindle CNC automatic. Actually, it's better described as a 12-spindle because there are six counter spindles facing each of the six main spindles. It's called the MS 32 (bar capacity is 32 mm) and is available in three "building block versions" starting with a more traditional single drum, six-spindle configuration, and progressing to the counter-spindle model. Technically, this machine moves beyond the traditional electro-hydraulic slide actuation to fully electric feed drives for cross slides and end slides. Each spindle can be individually programmed to rotate at an optimum speed. Each counter spindle uses a Z-axis quill to pick work from the main spindle for back turning operations that would normally require additional processing outside the screw machine. A complete set of cross slide and end slide tooling, under CNC control, is available on the counter spindle.

Putting It All Together

Another aspect of both speed and flexibility is the ability to quickly discern what to do in a machining process, and then to quickly and flawlessly execute that plan. Here, CAD, CAM, and process planning software comes to the fore, and we saw some interesting applications in the numerous halls of EMO, sometimes in places we didn't necessarily expect them to be.

Hexapods were in full bloom at EMO, with a range of builders exhibiting conceptual designs. However, this one from Geodetic Technology (Glen Allen, Virginia) is ready for production, says the builder.

For one thing, very intelligent programming software could be found on a number of controls. It takes a great deal of sophistication to make a complicated task seem simple, and that's what a number of developers have achieved. Several builders displayed new combination manual/CNC lathe and milling controls designed to ease the manual machinist's transition to CNC. These controls are amazingly easy to program, and often offer a host of clever features to address very practical concerns. On a Siemens lathe model, for example, once a two-axis path is programmed, an electronic handwheel can be put into a manual feed mode. That is, by turning the wheel, the operator can manually advance the feed by "touch," while the control keeps the tool tracking along its two-axis path, and at a constant surface speed.

Some applications are going further back into the planning process. CAD/CAM developer Vero International (East Hartford, Connecticut) showcased an intelligent design-through-manufacturing system for mold makers. The solid modeling system automates many of the design and NC programming tasks of building molds. For instance, rather than having to construct standard mold components from dumb geometry, they are pulled from a library of objects. Once a designer indicates the size and location of a component—say an ejector—the system automatically adds an appropriately sized hole in the cavity block and adds the ejector pin to the assembly drawing. Moreover, the fact that the CAD and CAM functionality are tightly integrated provides a platform on which design intent can more smoothly and quickly be converted to a proven machining process. CAD/CAM technology has finally arrived at the point where standard design features can be recognized automatically in CAM and associated with a pre-planned manufacturing process. While such capabilities are still in the early stages of development, these object-oriented systems will deliver very high levels of total process efficiency and consistency in the not-too-distant future.

Indeed, there was smart technology to be seen all over EMO. European machine tools still may not be cheap. But as these technology developers are learning to cope with economic pressures of their own, they are increasingly focused on providing total low cost solutions to their customers.

Good Ideas:

Anyone who has spent any time around surface grinders has experienced the reciprocating table shuffle. That is, the dance one does to get out of harm's way when the X-axis stroke of the machine has you in its sights. But English builder Jones and Shipman (Meriden, CT) unveiled a different idea at EMO. Called the Dominator, this new machine reciprocates the grinder wheelhead instead of the table. The worktable is fixed in the X axis. It moves in a rise and fall motion in the Y axis, feeding the work toward the wheelhead like the knee on a milling machine.

That significantly reduces the footprint necessary for the machine and opens up other interesting process possibilities for surface grinding applications. For example, by reciprocating the spindle motor and wheel, the moving mass is constant so grindin speeds are not determined by workpiece weight. Also, component wear should be reduced. Moreover, this design can easily be fit with a pallet shuttle mechanism. It's even conceivable that this fully automated surface grinder design could be fit into a flexible cell configuration.

Good Ideas:

An innovative turret design from German lathe builder Spinner combines the best of both gang tool and turret tool configurations. The design uses a stacked turret arrangement with Y-axis motion to present a total of 28 tools to a main or subspindle. Of the 24 tools, 18 can be powered. The arrangement of the turrets on this 80 mm turning diameter machine allows a programmer to bring three gang tools to work with a simple Y-axis move. For simultaneous cutting on the secondary spindle, a total of six gang tools can be used without a single turret index.

The design and orientation of this multiple turret setup uses a programmable B axis that permits the cutting tool to attack the workpiece in one degree increments for angular cutting. The company claims that five-axis milling can be performed on this combination turning and milling center. The Spinner line is being marketed in the United States through Monarch Machine Tool Company [now Genesis Worldwide] (Cortland, New York).

Good Ideas:

While most shops use live tool stations for their intended purpose—rotating a milling or drilling tool—Eppinger (Denkendorf, Germany) has developed some accessories that use the drive power available in the turret for other tasks. One example is a four-in-one tool carrier. It has two OD and two ID tool stations, all of which mount in one tool pocket on the turning center turret. If a shop's turning center has an eight station turret, with all stations powered, the programmer can pick from 32 tools instead of eight. Each of the four-in-one tools is actuated by a rotation command to the live tool station using a CW and CCW M-code. The index mechanism runs off the output gear in the live tool station. The station uses a VDI shank.

Another CNC turning accessory application is for a "bolt-on" high pressure coolant unit. It uses a VDI shank attached to a compact high pressure pump that mounts in one of the live turret pockets. The unit is powered by the live tool driver in the pocket to generate pressure up to 700 psi. It is regulated by the rotational speed of the live tool station. Eppinger's accessories are available in the United States through Exsys (Granada Hills, California).