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Jun 29, 2023

Getting the Most out of Swiss Machines: Tips From Top Suppliers

From a new entrant into the equipment mix to an array of relatively recent but underutilized functions from top suppliers, Swiss machines are poised to take on more of the manufacturing load in 2022.

From a new entrant into the equipment mix to an array of relatively recent but underutilized functions from top suppliers, Swiss machines are poised to take on more of the manufacturing load in 2022.

In canvassing a handful of the industry’s top players, we uncovered a wealth of tips and tricks that can help shops unleash the true turning power of their Swiss equipment.

In running down unique Swiss machine functionality and peripherals, Ed Garber of Star CNC also offered a different take on measuring productivity.

“Around the world, we all have different views of what optimal production is,” said Garber, national sales manager for Star CNC, based in Roslyn Heights, N.Y. “In the U.S., we’re pretty much hung up on the cycle time: How many seconds is it? Elsewhere, they’re caught up in how many parts are in the bin at the end of the week.” In Japan, for instance, he recalled witnessing an operation with about 85 Star machines yet only three operators. “You saw the machines running a bit slower, but the goal was more throughput.”

That’s where High Frequency Turning (HFT) pays dividends.

“We’re not the first to come up with the basic concept, but so many people out there are missing the boat and misunderstanding what it’s really capable of doing,” Garber explained. “HFT is a chip-breaking routine. We’ve sold several hundred of these over the past couple of years,” with customers told to try it for 30 days. “I think we’ve taken it off only nine machines. The ones who didn’t like it thought it was going to reduce their cycle time. But with HFT, you don’t have your operator reaching in to the machine with a pair of pliers and pulling the bird’s nest out of there while the machine is shut down. It really is a game-changer.”

Another productivity-promoting tool is Star’s SMOOSS-i, or Star Monitoring & Operator Support System. Able to monitor up to 100 Star machines, the software package can be loaded onto a dedicated or shared server for under $5,000.

“You can retrieve all types of information, including alarms, downtimes and more,” Garber said. “It can reach out to you and send you texts, emails. It will also tell you the time an alarm occurred, what it was, and let you know when it went back into single cycle or automatic mode. It’s good to let you get a better understanding of what’s causing downtimes and look for the root cause and take care of it there.”

Another Star feature, Machining Load Detection, is emerging as a standard item. “It can monitor tools on a machine for load based on the servo load of the motors used for an operation, like turning or drilling,” Garber said. “You’ll be able to set upper and lower control limits to alarm you and let you know the tool’s dull or has broken. It’s not going to be as sensitive as some of the vibration-monitoring systems out there, just because it wasn’t developed to catch a 45 thousandths diameter drill breaking or anything like that. But if we’ve got larger tools and tougher materials, or are turning—especially metal—it will come in real handy.”

Meanwhile, Star’s CNC Motion Control system, a fixture in the company’s Swiss arsenal for roughly 17 years, is a sometimes overlooked option on Star’s B5 series controls, available with about eight machines, Garber said.

Initially appearing on a Siemens control, Motion Control was geared to gang slide capability. For instance, on a 10-axis machine, Garber explained, “if you were milling using the slide and then turning with the other slide, or vice-versa, you had the push-pull system in a CNC control. You input a line of information with an end-of-block signal. The machine sees the end of block and knows what to execute. It executes it then goes back to the control and asks for the next task.

“Even though there might be a 400-, 600- or 1,000-line lookahead, the processes are very, very fast. However, for instance, if you just finished turning and now you’re going to mill a flat—your next line of code is to start doing that—the machine is going to start to react: fire up the rotary spindle, move it into position, lock the main spindle and mill that feature. In a production situation, those are portions of seconds/milliseconds that are going to add up quickly. Motion Control optimizes the program to reduce the non-cutting time. You write your program, prove out your part, then tell the control to optimize. This compiles the program and stores the required moves in the servos and bases all movement on the position of the main spindle.”

In one example, he explained, if a spindle is at revolution 31,000 “and at revolution 31,001 you want it to be doing something different, the other axis—whether independent gang slides, turrets or turrets and gang slide—starts to go into motion to do what it has to do to be ready by that revolution 31,001. So you would see a cut being done on one turret or gang and the opposite one would be staging; you would see a turret indexing slowly. It doesn’t need to get there quickly because it knows when it has to be into the cut. It goes slowly to minimize unnecessary wear and tear and also to help reduce the transfer of vibration—anything that might come from a loaded turret jerking around—to get there just in time.”

A rising star on the Swiss market is the Nexturn SA32XII by Absolute Machining Tools of Lorain, Ohio.

With a dual independent gang slide and three-channel programming, it allows for three tools in the cut at once, said Jason Smith, Absolute’s national sales manager for production turning products. “There are a ton of applications where we can get both gang plates removing material and achieve reduced cycle times and more stable processes.”

An ideal situation for using the SA32XII would be with long turn profiles, Smith explained. In those applications, “it is common to exceed the recommended depth-of-cut rating on an insert. As a result, users must reduce feed rate. This causes a loss in chip breakage on cutting tools. By utilizing the pinch turn cycle with the dual opposed gang slide, users are successful in maintaining tools within the manufacturer’s recommendations, and therefore breaking a chip during the cut.” That chip control is critical for process stability, given the compact machining area of Swiss machines, he added.

Furthermore, the SA32XII reduces cycle times because “users are capable of ‘staging’ the next tool in the process, by preparing that tool on the opposite gang tool post,” Smith said. “There is nearly zero ‘chip-to-chip’ time when this is done.”

This machine also reduces the complexity of tooling schemes, Smith added. “Whereas your convention single fixed gang slide requires left hand tools and max land guide bushings, our double gang slide three-channel Swiss machine has an independent Z-axis on one of the gang tool posts. This significantly increases the tooling capacity on the main tool gang slide and provides larger redundant tool capacity. It is also useful for long unattended operations, allows more tools to remain resident within the machines and reduces setup times from one part to the next.”

Absolute plans to feature the Nexturn SA32XII at IMTS in September.

With an onboard automatic tool setting probe and high-damping composite casting (HDCC) base, Mazak’s Syncrex series launched in October provides another option for shops considering Swiss precision.

Mazak, based in Florence Ky., has brought on a wealth of Swiss machine knowledge to design its machines, which will not only help users perform more job changeovers but eliminate material waste, said Midwest General Manager Kevin Bates.

Syncrex machines will be available with an on-machine automatic tool probe, which will cut tool setup times in half, Bates asserted.

“This ties in to what Mazak customers are used to on their turning machines,” Bates explained. “We provide tool-setting probes standard on the majority of our turning machines, so our customers are familiar with and accustomed to that functionality. When we started looking at our Swiss turning line, we considered how we could reduce setup times in a Swiss-style machine.”

However, the Syncrex probe is distinctly different, he continued. “On a fixed-head machine, you have a lot more space—a lot more room to mount a probe—and a lot of those are on arms that come out of the head wall of the machine. On a Swiss machine you don’t have that type of clearance, and obviously you’re bringing your tools to the part not the probe to the tool. We’ve got a device that we can hold in the main spindle guide bushing or in the sub spindle collet, then touch off tools using that probe.”

In canvassing customers, Mazak found that those who avoided Swiss machines often did so because of changeover times. “It used to be that customers would set these machines up on a Monday, run one part all week, then change over,” Bates said. “We’ve got customers now using Swiss machines and changing them over daily or, in some cases, multiple times a day.”

In a Syncrex launch demo at Mazak’s Discover 2021 event in October, an applications engineer touching off all tools manually cut that time in half when using the automatic tool setting system on an eight-axis version with 29 tools. Syncrex machines will be available with up to nine axes and 35 tools with full B-axis contouring optional.

Changing demands for Swiss functionality helped drive Mazak’s Syncrex, Bates said.

“Swiss turning machine sales used to account for about 10 percent of the entire turning market; that number has jumped to about 20 percent, in large part because of technologies that are reducing changeover. Swiss machines have also grown in diameter; they used to be 1" (25.4 mm) and under for small-diameter parts and now they’re getting up into 38 mm and in some cases larger. We’re going to have a 20, a 25, a 32 and a 38 mm machine in our portfolio in 2022.”

Central to Syncrex accuracy will be the 3,200-pound vibration-damping HDCC machine base, which offers several benefits, including:

10 percent more rigid than cast iron

80 percent less vibration at the cutting point

30 percent longer tool life

Due to the design of the synchronized main spindle and guide bushing on the 20 and 25 mm models the material savings will also be substantial, Bates added, with the Syncrex reducing remnants that are typically 10 or 11 inches (25.4 or 28 cm) down to seven or eight (17.8 or 20.3 cm.)

As Swiss parts get more complicated, CAM is being used more—and machining strategies are changing, advised Swiss Product Specialist Christopher Leclerc of CNC Software, Tolland, Conn. And, machine capabilities are becoming more advanced in milling with the inception of “B” axis (five-axis) contouring.

“When utilizing full five-axis work, a CAM system is imperative,” Leclerc stressed. “The use of a CAM system also maintains uniformity when multiple CNC programmers are involved in the same workspace.”

While programmers can use Mastercam’s Dynamic Milling on Swiss machines, he added, it can lose effectiveness with smaller parts and rapid motion being contained to a small area. Where CAM is a benefit is in number of lines of code produced for complex five-axis milling.

“I have produced programs for five-axis geometries that contained hundreds of thousands of lines of code,” he said. “When surfacing is involved, the finishes on a part are directly related to how your CAM system integrates stepovers and machining patterns. When utilizing small, say .032" and below, ball endmills, stepover is critical to maintain surface finish and tool life.”

Medical implants and instruments can be done on one machine with five-axis machining, with multiple tools allowing for roughing, semi-finishing and finishing. “To be able to program off a solid model and get NC code accurately and quickly is a plus. Many large Swiss shops have many different Swiss machines from the same builder or different builders. Once a part is programmed in a CAM system, the code can be posted to different machines easily by loading a new machine and post processor.”

With more companies choosing to engrave part numbers or logos instead of roll stamping to improve visibility, programming is critical to producing that cleaner look.

“With roll stamping, if a chip gets caught in the process the feature will reflect that,” Leclerc noted. “With engraving, you can set up custom macros that can cut part numbers that are input into a variable. This reduces the number of roll stamps and setup time. Say you run a part that has 25 different configurations designated as -001 thru -025. You could write a program where #550= -015 or -008 etc., that is the part number, and change this when changing parts. This takes a few seconds rather than having to set up a new roll stamp. I have seen many shops that create their own product engrave the company logo.”

Other Mastercam timesavers Leclerc swears by are:

Threading tables, which let users select specific types and sizes and automatically populate that data in the program.

Functions that help trace and track part design changes. Levels, view sheets and more retain the original model and modified solid models.

Default settings for an individual or a group of programmers let them set up the CAM system based on their programming style.

At Marubeni Citizen-Cincom, CAM pairs with the company’s On Machine Program Check (OMPC) to confirm collision avoidance of tools, said President/COO Brian Such.

“Many users will prove out their first-time setup very slowly and make changes at the machine,” he explained. While allowing a safe setup, this “takes valuable machine time that the Swiss should be running.”

Avoiding tool collisions on a Swiss machine—which mounts many tools in a small space—must take into account several factors, Such explained, from setups on the sub spindle side depending on how far the part is extended from the sub spindle face to how many tools are used and the depth of each tool.

“Adjacent tools not in the current cut can interfere with other machine parts,” Such noted. “Many setup people do not look at this until the setup, then struggle to make changes to suit their needs.” He believes using CAM software can show these potential tool setting collisions and also inform the setup person of other tooling offsets used to run collision free.

“Some processes require longer cycle time and use many tools in many ways. The programmer knows the process, but the setup person is starting blind. For a complex job that the setup person never saw before, showing a CAM process before doing the setup can allow the setup person to totally see the process and know what to expect before the first run.”

Programmers, Such added, seem to err on the safe side. “When entering a tool into a cut, there is always an air cut before the actual process starts. With CAM, you can set the air cut distance for all tools as desired—say .03" (0.762 mm); many non-CAM users might use 0.1" (2.54 mm). That is a 0.07" (1.78 mm) savings of time, which is small but can add up.”

How does OMPC fit in? This feature, appearing on Citizen Cincom Swiss machines since the 1980s, has evolved into a must-have process, Such said.

“The operator enables OMPC, which enables the hand pulse wheel to be used to control the process at the operator’s preferred speed. This is not just start-stop; OMPC can be used forward and reverse, faster or slower, as the user desires. If an error is encountered, it can be corrected live in-process—just edit the program code then continue running.

“OMPC is not like any other builder’s feature; Citizen has only one feed control adjustment dial. A Citizen does not have a rapid override. On all other machine tools with two controls, one for feed and one for rapid, if you test run the process with no collisions at 25 percent rapid setting, you can then go to run at 100 percent and have crashes as the timing is all different. With the Citizen OMPC, as you adjust the one feed control, this 100 percent confirms and allows any speed to be tested and adjusted as desired—then at 100 percent feed, be 100 percent the same motion, eliminating any timing crashes.”

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