Machining Madness: Advances in HSM

Rising labor costs, the demand for less finishing time, quicker turnaround time, and improved surface finished have all been driving the tremendous advances that have been made in the machining industry these past 10 years. In particular, advances in HSM are eliminating costly benchwork, spindle speeds have nearly doubled, and a new machine/controller duo promises a constant velocity. Some leading machining manufacturers and suppliers discuss these hot trends below.

Industry Changes

According to Okuma America Corporation (Charlotte, NC) COO and President Larry Schwartz, the changes that have occurred in the last decade go beyond 10 years—to 15 or more. “Quite frankly, we saw a lot of manufacturers moving offshore looking for lower cost dies and molds for the industry back then,” he recalls. “For some time, the qualified finished die or mold with the technology that had been available was very labor intensive, and the level of expertise that existed in the United States also was dwindling at the same time. Though there was a fair enough amount of developing technology during that period of time mostly around the EDM, wire EDM technology and ECM (electrical chemical machining); these also were very costly. The issue was that almost all of the dies or molds needed a great deal of handwork to achieve the finishes, shapes and smoothness of contours that were required to get the product out of those dies or molds to the level of quality that they were looking for.

“During all of those 10+ years, CNC manufacturers probably lost a considerable amount of that business—with exceptions, of course,” Schwartz continues. “I believe that the technology that we have been introducing as an industry as a whole has been seeking ways to minimize the handwork required to make a finished die or mold. To do that there was some sophistication that was desired in the machine tool design and I’ll use the terms of thermo stability or thermo-friendly that would be required to maintain the finishes that would be needed to eliminate hand polishing. The goal has really been to have zero handwork. The question is to what level can one go into metal removal—using today’s technology—to eliminate that. I personally believe that if we have reached it in some areas, but maybe in time we will reach it in all areas. The combination of control technology, servo controls and the whole balance of mechanical devices—along with some developments in spindle designs and characteristics—has created the opportunity to eliminate a lot of handwork and will continue to improve.”

Rich Ormrod, National Distributor Manager of GBI Cincinnati (OH), also believes the market is shrinking because of offshore competition. “Companies are struggling and consolidating because of the increased threats from Asian and Indian markets,” he notes. “Because of this, the industry has started to view itself as technology-driven. With high tech industries like medical and aerospace and the intellectual properties that accompany this, highly technical processes are staying in this country, so we are seeing a swing on the positive side that a lot of the bleeding has stopped; and the companies that have survived the downturn are looking for ways to become more lean and efficient—and are looking at newer technologies and higher tech product lines.”

At Haas Automation, Inc. (Oxnard, CA) Marketing Product Manager Scott Rathburn adds to Schwartz’s and Ormrod’s thoughts on offshore challenges. “Customers are demanding higher quality, faster turnaround times and lower prices,” Rathburn states. “To reduce costs, an increasing amount of work has been—and continues to be—shifted to countries with lower labor costs, such as China and India. In order to remain competitive, U.S. moldmakers have had to become more efficient and add more value to their processes, such as rapid turnaround, custom design work and personalized service. Increasing material costs are another issue, but one that is faced by companies worldwide—including the low-wage countries.

”From a machining standpoint, moldmakers continue to strive to reduce the amount of benchwork required after the parts are machined,” Rathburn continues. “This means their machine tool must be able to produce finer surface finishes and better quality parts right off the machine. Advances in CAD/CAM software, tooling and 5-axis machining over the past 10 years have made it much easier for moldmakers to produce parts that are much more complex in a shorter time with fewer setups—if not a single setup. The goal is to get a finished part off the machine as quickly as possible.”

In agreement is Steve Ortner, President of Absolute Machine Tools (Lorain, OH), who notes, “The challenges are the same and are not going to change for the American mold builder. Mold shops are constantly striving to get their labor costs down and let the machines do the work. Skilled moldmakers and bench guys who can hand fit molds are scarce. That's why high speed machining is essential. HSM machines are eliminating costly benchwork. Ten years ago, mold shops were just starting to talk about high speed machining. Today, you have to be doing it in some fashion or you won't be competitive. On the machine side, there have been tremendous advancements in controls and spindles as well as cutting tools. In 1998, we weren't really talking about shrink-fit and now everyone is using it.”

Ortner compares the evolution of HSM to advances made with CNCs. “A few progressive people bought CNC machines when they were introduced,” he explains. “Over the years, the technology became widespread. Now, how could you have any type of machine shop without CNC? It's almost the same thing with the high speed machining. Ten years ago, a few people were experimenting with HSM. Today, everyone is doing it. I don't know of anyone in the mold business without a high performance machine tool of some kind. However, not everyone is using HSM to the extent they could. You see that happening in shops with conventional CNCs too. But HSM is a little different because it's not just having the machine; you have to have the right programming and the tooling to go with it. Over the past 10 years, there have been advancements on all three fronts. On the machines, the spindle and controls are faster and more powerful. Tooling is better. And CAM systems are more robust. Ten years ago, no one was cutting to size or negative stock. There are still a lot of people who aren't doing either, but it is coming.”

Advances in HSM and hard milling are at the top of KERN Precision, Inc.’s (Webster, MA) list. According to President Gary Zurek, these two technologies developed very quickly with the introduction of faster machines with higher spindle RPMs. “Accelerations of 1G and RPMs of up to 50K became widely available,” Zurek comments. “In the early stages, the cutting tool industry struggled to develop the necessary coatings for all of this aggressive machining. Today, cutting tool manufactures have made some fantastic advances in coatings that have helped part manufacturers to substantially reduce cycle times while increasing tool life.”

Five-axis machining also has grown, notes Zurek. “One of the key components of this grow was the development of advance programming tools,” he says. “Many major software companies placed a lot of emphasis in developing the necessary machining strategies required to utilize all five axes in a productive and efficient manner. Tools such as true 5-axis machine simulation were incorporated into their software—allowing a good view of what the machine will do before actually cutting on the machine.

“There also were some great achievements made in the standardization of workholding devices,” Zurek adds. “These would include standardized pallets and other work holders. Initially developed for the EDM market, these devices found their way onto milling machines helping to reduce setup times and costs. Moving a part from one machine to another began quite simple.”

Gisbert Ledvon, Business Development Manager at GF AgieCharmilles (Lincolnshire, IL), Business Development Manager adds his thoughts on the emergence of both high speed and 5-axis machining. “With increased pressure from foreign competition, successful moldmakers have been forced to constantly improve their processes. Most low-tolerance work migrated overseas, so it has often become important to focus on smaller, more complex molds with intricate features and high accuracy requirements,” he says. “Additionally, most shops have faced a constant demand for shorter turnaround times from their customers. Several milling technologies emerged to help meet these needs. The development of high speed machining centers provided significant benefit to moldmakers. The introduction of 5-axis machines further increased the value that milling centers offer to the industry. Machines employing these technologies have become very popular with moldmakers and continue to offer significant competitive advantages.”

Product Line Changes

At Haas Automation, the company’s machines have gotten “bigger, better, faster and less expensive—offering higher value to the end user,” Rathburn notes. “The increasing sizes of molds over the years have required larger machine tools to machine them without refixturing. Haas offers CNC machines with travels to accommodate even the largest of today's molds. Today's Haas CNC machines also provide much higher performance, with faster spindle speeds, higher rapids, more tools and a wide selection of high-productivity options, such as high-pressure through-spindle coolant, high-speed machining with look-ahead, our Intuitive Programming System and low-cost probing systems. Haas also continues to simplify the operation of our machine tools, making it easier to train new operators and programmers—an issue faced by manufacturing worldwide.”

Similar changes have taken place at Absolute Machine Tools. “Our machine designs have evolved over the years to take advantage of advancements in high speed spindle and control technologies,” Ortner notes. “We have expanded our product line, adding ram-type C-frame VMCs and small double-columns that are designed specifically for HSM operations. Spindles have improved to keep up with these machine designs and new tooling on the market. In 1998, spindles delivered 10,000 to 12,000 RPM. Today's high speed spindles offer shops double those spindle speeds. In addition, cutting feedrates have doubled and in some cases tripled. We're now using HSK tooling—we didn’t in 1998. And, control speeds have quadrupled. In 1998, the high look ahead was something like 180 blocks. Now, we're up to 600 or 1,000 blocks and servo systems are much better.”

Speed is utmost on GBI Cincinnati’s mind, according to Ormrod. The company, along with MTI Technologies (Essex, ON) has developed a series of machine tools with a new controller that results in true, constant velocity. “This yields, fast, constant feedrates,” Ormrod elaborates. “The average speed of the cutter moving across the part is more accurate and uniform, which prolongs tool life and reduces finishing time. We are completely changing the way machining is done in the U.S.”

According to Okuma America’s Schwartz, the company has focused on thermo stability and has won numerous awards for designing a very stable, rigid, strong platform. “We have some very special thermo control capabilities where we are making machine position changes automatically based on thermo compensation, and along with that came some additional Super NURBS which dealt with processing speeds,” he states.

“One of the things that I think most people run into when they are doing exotic, elaborate molds or dies is that the amount of data crunching that goes on is unbelievable,” Schwartz continues. “In many cases, the programs are so extensive and so long that many controls have a problem retaining all of that data in their platforms. Therefore, the information is streamed from a major mainframe design computer that is feeding data to the machine tool as it is being consumed. Delays in information and flow can potentially cause issues with getting the transitions and geometry shapes in the speeds that one would like because one just can’t transfer information that fast. I would say that with our new control, its processing speeds have been improved, and with our Super NURBS capability, allow us to move at very rapid rates with very fine, very exotic geometries. Along with thermal stability we have created what we’d say is probably a finished product out of the machine tool with very little, if any, manual polishing or deburring.”

For GF AgieCharmilles, Mikron’s introduction of the high speed milling center has proven to be the most significant development for the company is the past decade. “All of our achievements in milling since that point have been contributions to the evolution of that innovative technology,” Ledvon elaborates. “Also, the development of a one-piece polymer granite base enables high speed milling to manifest its true potential. By offering high rigidity and thermo-stability, it allows for the achievement of incredible levels of accuracy and precision.”

Ledvon also acknowledges software development’s role in maximizing the effectiveness of high speed milling. “The creation of much more user-friendly CNCs and operator interfaces has boosted productivity and efficiency,” he notes. “Innovations in this area have also made it much easier to automate machining processes—reducing the cost of labor per part to compete with foreign manufacturers.”

The company’s smart machining modules also have impacted the word of high speed milling. Gisbert explains, “The system uses a built-in radial acceleration sensor to generate graphical representation of vibration during the machining process. If vibration grows to a pre-defined unacceptable level, the software can automatically cease cutting and notify an operator. An operator support system presents users with an interface for easily prioritizing speed, accuracy and surface finish requirements; and an intelligent thermal control integrates complex algorithms to determine thermal effects on spindle performance and then automatically compensates for them to maintain high levels of accuracy. In total, SMMs dramatically increase the performance of high speed milling machines.

“The introduction of 5-axis milling also has reshaped moldmakers’ milling operations,” Ledvon continues. “By integrating B- and C-axes into the milling process, many complicated parts can now be completed in a single setup. This has provided moldmakers a cost-efficient method to produce highly complex components.”

KERN Precision has made inroads in the world of micromachining—especially in Europe. “Initially micro machining was done on small parts only requiring only small machines, i.e. bench type machines,” Zurek emphasizes. “In 1997, we introduced high speed precision cutting on a 3,000 kg C-type machine frame—addressing the topic ‘precision’ to HSM. New materials like polymer concrete were used as material for the machine base in order to minimize possible vibrations that were generated by high feed rates.

“Furthermore, the first integrated automatic workpiece changer was introduced,” Zurek continues. “Automatic tool measuring by laser and automatic workpiece measuring by touch probe in the machine were integrated thus allowing fully automatic 5-axis machining unmanned. We also developed an absolutely new dimension in machining technology in 2005 by using hydrostatic guideways and hydrostatic drives into our one of our machining centers. This technology avoids any metal-to-metal contact in the guideways and the drives of the machine. Consequently, there is no friction, no heat generation and no wearing parts. Amazingly, surface finishes of Ra 0.05 and better can be achieved in hardened steel. Further, the hydrostatic drives allow a positioning accuracy of 0.3 microns which is 300 nano meters or 0.0000118". Such accuracy is not just limited to high tech companies that require ultimate accuracies but also to shops that require ‘tight’ tolerances and do not have temperature-controlled environment.”

Future Challenges

In a market that clearly is rising to meet the current demands of the industry, what does the future hold for machining manufacturers and suppliers? Schwartz of Okuma America believes the outlook is bright. “As we advance machine control processing speeds, increase solid modeling ability, create a die from its CAD/CAM environment, and download it directly to the machine tool with little or no operator intervention, we will streamline the whole process from the initial product out of a mold to the calculations dealing with what the true mold geometry is based on: shrinkage, materials used, and how do you drive the program using all the SuperNurbs that we have available,” he states. “To really yield from beginning to end a very seamless process of a finished product off of the machine tool, I believe that we will eventually achieve 100 percent of our goals.

“I believe it is well within the next 10 years that computer technology, the servo controls and the onboard computer processing machines speeds of the machine tool will work together to create a truly finished product,” Schwartz continues. “We are investigating the use of higher end chips that go even beyond the finite analysis engineering that would help us achieve our goals in both the collision avoidance technology and in processing speeds to get even finer geometry, faster moves and create a real seamless process from beginning to end. Our ultimate goal is to move at speeds beyond our comprehension right now. So I think we are on the level and stream of continuing our progression of advanced processing speeds to the next level.”

Ortner of Absolute Machine Tools aggress that technology innovation drives this market. “For the next 10 years, you can expect that the trend line will continue toward better tooling, better spindle technology, and advancements in machine tools with the rigidity, reliability, and strength needed to tackle complex contours and ultra-fine surface finishes,” he states. “I believe that moldmakers will diversify their operations into areas like aerospace. They'll apply the techniques they learned machining tool steel and transfer them to aircraft aluminum and carbon fiber machining. Some high end mold shops are already on this cutting edge and branching out. As these shops transfer HSM technology and techniques to new markets, they'll demand innovation in machine tools, tooling, and programming. So you can expect incremental advances that will let moldmakers continue to push the limits of HSM and stay competitive in a challenging global market.

At Haas Automation, Rathburn notes that continued advancements in machine tools, software and tooling will be evolutionary rather than revolutionary. “Companies will strive for incremental improvement in their processes and products; and automation will play a larger role as a means to remove labor content and increase throughput,” Rathburn says. “To remain successful and compete in the world market, moldmakers also will need to provide more value-added services to distinguish themselves from their competition.

”As the standards of living improve in countries such as China and India, their wages will increase—thus reducing the advantage of outsourcing to those countries,” Rathburn continues. “Those countries will remain competitive, however, because they are investing heavily in modern equipment and automation, much as U.S. manufacturers must do to compete.”

Again, Zurek of KERN Precision notes the importance of micro-milling and extreme high tolerance part manufacturing emerging in the U.S. “Like HSM and hard milling, micro machining and high tolerance machining is beginning to develop and mature,” he comments. “It’s the next wave of technology to hit the U.S. and is fast becoming a hot topic. Designers and engineers are realizing certain technologies are available and are now developing products to push the micro and tolerance limits. There is a hot growing trend toward miniaturization in product design. This is a result of our ‘green’ thinking and concerns for our environments. Resources and materials are continuing to drive manufacturing costs up. As a result, micro manufacturing is growing rapidly and is being realized in all manufacturing sectors. Although there are many technologies on the market for micro machining, like photo etching, laser, etc., many parts can only be made by injection molding or direct machining.”
GF AgieCharmilles’ Gisbert concludes, ““Moldmakers will become more like project managers—coordinating the workflow from EDM to milling to grinding. This is in contrast to the traditional system, where a mold could be built from start to finish. In short, U.S. shops will have to build molds faster and in a production setup to continue to compete in the next 10 years. Keeping abreast of the latest technologies will play a vital role in meeting this demand.”