You don’t have to probe too deeply into good machining results to find how they are being achieved with tried-and-true as well as innovative new toolholding technology. Chatter and pullout are but two of the enemies of high-speed and heavy-duty machining of the latest difficult-to-machine alloys. Anything less than the most secure toolholding makes lights-out machining a crap shoot.
It’s why variations of toolholding technologies from shrink-fit to mechanical to hydraulic continue to vie for important investments for machine tools that can command seven figure price tags. And on the shop floor, who is going to explain away devastating crashes or machining results that fail to meet stringent quality standards. In the following case studies, you might just find a win-win or two from manufacturers in their toolholding choices.
A Minnesota CNC shop is using a Heimatec speed increaser to up rpms and feed rates, reducing cycle time on an aluminum engraving application. Kurt Industrial Products Division, Minneapolis, specializes in providing precision CNC machined parts, using state-of-the-art technologies and up to five-axis machining. A flexible shop, Kurt produces parts ranging from micron-sized semiconductor components to 2,000 lb (907 kg) workpieces for the defense sector.
On a recent project, for which 5,000 pieces of 6060 aluminum were to be engraved on a Hwacheon horizontal turning center, Shawn Eisenshank, engineering manager for Kurt, had concerns over the cycle times. He turned to his local tooling distributor, Abrasive Specialists Inc. (ASI) and its tooling partner, Platinum Tooling Technologies Inc., Prospect Heights, Illinois, for suggestions. Leigh Kinnan of ASI worked with the local Platinum Tooling representative, Cody Papenfus, to test run a Heimatec speed increaser.
The goal was to increase rpms on the machine and decrease part cycle time and to document the potential savings. After performing the calculations in consultation with Preben Hansen, president of Platinum Tooling, the exclusive importer for Heimatec products in North America, they determined a significant savings could be realized.
Detailing the application, ASI demonstrated that a 1:3 speeder increased the spindle rpms enough so that, when coupled with the nearly 3X increase in the feed rate on the machine, it produced a significant improvement in the machining cycle. Calculating the reduction in machining cost per part and factoring the cost of the speed increaser, they determined that using the Heimatec product onboard the Hwacheon turning center would result in a 9X cost saving for the customer in the first year’s production run on the engraved aluminum component.
As Shawn Eisenshank noted, “This is one of those classic scenarios where the theoretical was proven out in practice, as we’ve seen exactly the results ASI and Platinum Tooling proposed in their test calculations.”
Cody Papenfus of Hexis, Plymouth, Minn., the area rep for Platinum Tooling added, “We say we put our expertise to work at the spindle of the machine and, in this case, that’s exactly what happened. The speed increaser performed as expected, the customer got the promised results, and it was a win-win, for all. We serve our customers for the long haul and successes like this one are the big reason.”
When Harold Hunt first started the Madison, Ind.-based company SuperATV in his garage, it was to fill a small need for off-road enthusiasts like himself. It turns out that need was much bigger than Hunt could have ever imagined.
As the demand for the exclusive 2″ (50.8 mm) Sportsman small lift design grew, so did SuperATV’s product line. The company’s passion to fuel riders, and their rides, drives SuperATV to constantly innovate and improve every part of every machine available, according to the company. Today, it offers aftermarket ATV and UTV parts and accessories—from axles to long travel kits—that are designed to amp up machine performance.
With a much larger manufacturing and warehouse space, a 600-acre test facility and a team of in-house designers, engineers and fabricators, every idea, prototype and production-ready part is built and tested.
SuperATV requires equipment that can keep up with the speed of its production—and new ideas.
To ensure manufacturing equipment is running efficiently and producing parts and accessories, SuperATV looked to make upgrades. One of those decisions was to invest in a MEGA Double Power milling chuck from BIG Kaiser Precision Tooling Inc., Hoffman Estates, Illinois, to replace its existing end mill toolholders for faster, heavier duty machining.
“With over 20 years in the tool and die industry, I have learned that running mill chucks will sometimes help with chatter, taking the harmonics away from the spindle and absorbing it into the chuck,” said John Westrick, machining supervisor at SuperATV. Milling chucks like the MEGA Double Power from BIG Kaiser are a solution for high-speed machining and aggressive milling because they provide more gripping force than other options. Plus, their size can help dampen vibrations that lead to chatter.
“The end mill toolholders we were using couldn’t utilize the full spindle range of tooling due to some balancing issues. While our previous max was 8,000 rpm, we can now use the full 12,000 rpm if needed,” said Westrick.
The MEGA Double Power chucks are precision ground and balanced with a high-rigidity design for heavier duty machining, according to BIG Kaiser. In fact, every component of the toolholder is designed for higher speed applications. The ability to handle fast tool changes had a positive impact on cycle times and productivity in SuperATV’s warehouse, according to Westrick.
Many top manufacturers invest in superior tooling because they understand the value and return that will come with that investment. Like those companies, SuperATV is already seeing the benefits of upgrading.
In fact, Westrick will tell you how SuperATV has “achieved about a 19 percent decrease in roughing cycle time since changing to the MEGA Double Power chuck.”
Precision Tool Technologies Inc., Brainerd, Minn., is a manufacturer and distributor of premium products for wholesale optical laboratories and retail optical industries. Its first success came in precision machining of polishing tools and mold inserts for the optical industry, where accuracy of ± 0.0001″ (0.003 mm) and surface finishes of 4 Ra are required. For successful operations, this level of excellence must be repeatable on a daily (and nightly) basis. During the course of perfecting its techniques, Precision Tool became the “go-to” company for solving difficult machining problems for many industries and Haimer USA LLC, Villa Park, Illinois, became a key partner.
Haimer entered the picture when Precision Tool began running lights outs (what the company calls a “virtual shift”) due to an increasing demand for its services. This posed a challenge since its equipment consistently runs at speeds up to 40,000 rpm. “We didn’t want to take the chance of buying equipment for seven figures and then start blowing out spindles,” said Jim Goerges, president of Precision Tool.
Goerges and his team set about building a better process that would enhance the company’s digital platform, increase productivity and improve product quality. According to Georges, there were two vital elements required to move Precision Tool ahead of the pack. One was to acquire the Haimer HSK tooling and shrink-fit systems. Shrink fit provides repeatability and helps reduce tool stick-out. The other element was to invest in balancing.
“Many of our customers had the same problems (accuracy, blown spindles and poor surface finishes). Because of the Haimer balancing machine, we now have the means to provide them with a solution,” Goerges stated.
One of Precision Tool’s customers had a part problem that had its in-house engineers stumped. The part was a conical funnel with holes used to fill chemicals or test equipment for genetic decoding. This complex aluminum part has internal finishes with conical shapes, 40-50-60X stick-out length and must have a 4-6 Ra finish after coating (which doubles the surface roughness). This combination of requirements made it impossible for other shops to do the job.
The engineering staff at Precision Tool’s customer admitted they couldn’t make the part. As a result, the company was having a hard time making delivery times, so they decided to give Precision Tool a shot.
The Haimer balancer has made all the difference. Precision Tool manufactured the part and sent it back to its customer. “Nobody could make the part to the finished specs that they wanted,” said Goerges. “We did it and a big part of that was how exact we were able to get in terms of balancing special machine tooling to achieve the surface finish on the internal features. In fact, we would not have been able to perfect the harmonics without the Haimer balancer.”
Another example of what Precision Tool and Haimer managed to achieve was in the manufacture of an aspirator attachment for a seeding machine. When the part spins in the machine, it gets up to 12,000 rpm. If it is out of balance, it shakes the entire seeding machine—making all the components vibrate and causing premature retirement of the machine due to excess wear.
Precision Tool made the part to spec. While its attachment carried a premium price compared to others, the customer saw the value that the part would bring to the overall quality of its seeding machine.
Precision Tool’s next investment will be a Haimer automatic presetter. “It will give us a better, faster, more accurate way of bringing a complete tooling solution to the machine,” Goerges said. “Adding presetting to shrink fit and balance will allow us to create a total throughput solution for all of our operations.”
In traditional high-volume thread production, productivity can be limited by machine tool spindle rotational speeds and feeds. Synchronous spindles often do not achieve the programmed rotational speeds above a certain spindle feed. Especially when using small cutting tool diameters, the programmed cutting speed may not be achieved without decreasing tool life and increasing cycle times.
Additional machining challenges include high energy consumption. Typically more than half of the energy consumed by a machining center is required for the cooling system, and high speed rigid tapping operations can contribute to energy consumption.
These challenges have been answered today with innovative toolholding solutions. For example, new toolholder technology incorporating transmission gearing is capable of keeping up with the programmed spindle speeds, featuring an integrated transmission of 1:4.412 to optimize thread production on CNC machines with synchronous spindles, according to Emuge Corp., West Boylston, Mass.
In one example of manufacturing gear boxes, in order to compensate for projecting edges and taps of different lengths, three tapping attachments were being used. A Speedsynchro toolholder from Emuge was substituted for the three tapping attachments, making use of a short tool extension to maintain rotational speed. Also, to save costs, shorter, less expensive DIN taps can now be used.
The Emuge Softsynchro minimum length compensation capability has improved the quality of the threads by compensating for any synchronization errors on the machine and ensuring an even load on the cutting edges of the taps. At the same time, Speedsynchro guarantees a consistent depth of thread as well as reduced cycle times and a decrease in required maintenance.
Combining the integrated transmission with minimum-length compensation offers a way to efficiently work with high cutting speeds and a relatively low synchronous machine tool speed, compensating for synchronization errors during the threading process. The results are significant time and cost savings, particularly in high-production tapping operations, according to Emuge. This technology makes it possible to run machine spindles in a non-critical energy saving RPM range during thread production.
Emuge reports up to 40 percent time savings can be achieved due to shortening thread production cycles. This results from the combined fast acceleration and cutting speeds facilitated by the integrated transmission. The time savings increases the number of tapped holes achieved in a given operation and is especially effective in high production tapping. Tool life and thread surface quality are both optimized.
According to Emuge, in addition to selecting the right toolholder to produce optimal threading results, it is critical to select the right tap or thread mill for the high production application-at-hand.
Pay close attention and examine your application’s needs. Take the time to get advice from cutting tools experts. It will be time well spent towards success.
Editor’s Note: This Emuge case study is based on information that was published previously in Manufacturing Engineering.