Vitap upgrades Blitz CNC drilling machine - cnc insert drill

 2024-07-09 08:03:53

“The Mazak had the power to cut faster; the bottleneck was the tool,” Ingersoll field rep Darrell Boatwright observed during a plant walk-through. He brought in a Gold-Duty cutter he had in the trunk and they tried it out on the spot. By the end of the day, parameters were optimized at 100SFM/0.014IPR/0250 DOC.

Granted, any CNC could theoretically calculate any number of toolpath set points offline. The problem is that calculations take time—enough time to make doing the work in advance impractical. In one experiment, the company used a conventional CNC in offline mode to calculate the tool path for an LED headlight lens mold. With no need for lookahead to scout ahead of the tool in real time, the system ran at 10 kilohertz (khz)—that is, it was tasked with processing 10,000 toolpath set points per second. The calculations took more than 12 hours.

Until mid-2014, DeZurik rough-turned their big valve body workpieces with conventional stick tools on a heavy-duty VTL. Then, the company installed a large, five-axis Mazak mill/turn machine, which opened the door to live turning.

The IL300 is designed for standard diamond turning as well as free-form and micro structure generation. ILSONIC models use ultrasonic assistance to diamond-turn steel and infrared materials.

With speeds maxing out at 3 or 4 khz (that is, 3,000 to 4,000 set points per second), most PC-based position-control systems are too slow. “The handshake that occurs when the CNC calculates and sends commands to the position controller is typically done online, but we do all of the work up-front,” he explains. “Essentially, we can feed more data from our offline CNC than (a PC-based system) could handle.”

Kern machines like this Micro are recommended for providing the productive, precise milling required to limit the need for diamond turning in the first place. This photo was taken at Kern's headquarters in Germany where, like Innolite, the company produces parts as well as machine tools.

The Nanogrip zero-point clamping system's modular design enables users to quickly and easily swap not only workpieces, but also various, multi-station configurations of cutting and measuring tools. Additionally, parts can be moved from Kern machines to Innolite machines without losing location references.

“Titanium just complicates ID work with conventional tooling because of its unhelpful chipping characteristics,” said Ingersoll’s Darrell Boatwright. “The aggressive chipbreakers on the new Gold-Duty tool make short work of long chips in OD turning, and soon for ID work as well.”

With the CNC freed from much of its calculation burden, the bottleneck shifts to the drive system itself. Individual axes move via a feedback loop in which the motor adjusts power output as-needed based on periodic position checks from the encoder. Most machine tools use a centralized, PC-based system (often the CNC itself) to control and coordinate the axis positions, which are determined by precisely timed commands for position, speed, acceleration and jerk calculated from CAM data by the CNC (or by DirectDrive3D). If the coordinated feedback loops do not cycle fast enough, the machine cannot take full advantage of a system like DirectDrive3D, Dr. Wenzel says.

The incoming castings had the usual, wide piece-to-piece dimensional variations and yet needed a lot of stock removed depending on those inconsistencies. “Definitely not the ideal candidates for a first stab at a new kind of process,” said Commerford.

The IL300 is designed for standard diamond turning as well as free-form and micro structure generation. ILSONIC models use ultrasonic assistance to diamond-turn steel and infrared materials.

Dr. Wenzel often refers to “diamond turning” because turning is the most common operation in diamond machining. However, Innolite systems like the IL600 are also capable of milling, ruling, fly-cutting and grinding. On this machine, the workholding spindle moves back and forth in Z and up and down in Y to present spinning parts to cutting tools and measurement equipment on the opposing X-axis slide. Periodic checks with both contact and non-contact probes keep the process on track, as do various temperature-control systems and hydrostatic, linear-motor driven axes leveraging high-resolution optical scales. With cutting edges so sharp—some turning insert edge radii measure only 20 nanometers—“everything must be perfect,” Dr. Wenzel says about the need for such features. “If you take a hair and cut it into 1,000 pieces, then take one of those pieces and cut it into four, that’s what we’re working with.”

The Innolite IL600 can be configured as needed with various tooling and gaging stations. Options include the Overdrive unit, milling spindles, and more. Machines can employ Nano-Grip zero-point clamping modules for easy changeover of tools and workpieces alike.

To ensure the drive system can react dynamically enough, Innolite entirely decouples position and current control from the CNC or any other PC-based “master” computer. Instead, the work is done by field programmable gate arrays (FPGAs) embedded in each axis drive. Dr. Wenzel describes an FPGA as “a computer chip that is very stupid—there’s no Windows running in the background; it can’t execute Outlook or Word. But it can do just one thing and do it really fast: position and current control.”

The same types of tooling also increased OD removal rates, enabling the whole fleet of screw machines to reach the shop managers’ goal of 30% higher capacity with no capital expenditures. “Even in miniature precision screw machine work, today’s higher-rake, chipbreaking inserts with advanced coatings can make a material difference,’ said Ingersoll’s Matt Hagenow, who worked on this project.

More specifically, even the most powerful computer can only handle so many set points—the points in space that approximate the curves and contours of a tool path—in so much time. Spacing the set points closer together enables smoother tool motion around smaller, more complex shapes, but a CNC must work harder to plot that motion, particularly if real-time lookahead is required to ensure fluid point-to-point transitions. Beyond a certain number of set points (typically a few thousand), a conventional machine tool CNC must slow down to allow time for processing.

The main concern was to remove 0.200-0.400 in. of stock fast without overloading the auxiliary spindle, especially laterally. In flange work, low lateral forces are essential to keeping the flanges perfectly flat, preventing leaks when the valves go into service.

Up in New England, a screw machine reconditioning shop boosted capacity by 30% on its fleet of Swiss Automatics using Gold-Duty CNMX 43.52 inserts. Their applications involve OD and ID work on wrought 8620 steel.

Innolite machines work differently. Rather than relying on the CNC to work while the machine runs, the company’s DirectDrive3D software calculates the entire tool path offline, before the cycle begins. Moving the work of the CNC offline eliminates the need for (and the delays associated with) in-process CNC look ahead. Meanwhile, a decentralized servo-system architecture ensures the machine can respond dynamically enough to execute high-resolution toolpath data without compromising efficiency. “We want to make diamond turning productive as well as precise,” Dr. Wenzel says. “The market demands it.”

The Gold-Duty tool easily handled the 33% higher machining rates with no pounding or scraping, the usual forerunners of an insert about to rupture. “We slowed the surface speed but fed faster and cut deeper,” explained Micor programmer Joey King.

It should come as no surprise that live turning speeds up a roughing operation on any machine with a C axis. The process gets two spindles working simultaneously, with tools having multiple cutting edges rather than just one.

LED Headlight insert molds like this one are driving demand for increased diamond machining productivity. All photos and video courtesy of Innolite.

Innolite equipment is available in North America as of late last year through Kern Precision, the Chicago-based U.S. arm of fellow German machine tool builder and long-term partner Kern Microtechnik. The two companies’ motivation here is the same as it is in their home market: to help manufacturers of parts with optical-quality surface finish adapt to the unfamiliar demands of new applications, particularly in the automotive industry.

The first step in meeting this demand is changing old habits. To that end, Innolite and Kern offer Nanogrip, a spring-loaded, zero-point clamping system that enables swapping entire pallets of fixtures and cutting/measuring tools in seconds with no need for realignment. Repeatability is less than half a micron. Well-established in more conventional machining operations, such a system represents new thinking for diamond turning operations where painstaking, manual setup of tools and parts in vacuum chucks is common practice. Dr. Wenzel says.

DirectDrive3D outputs the same information as any CNC: Coordinated motion profiles for each individual axis, all precisely timed to ensure the tool follows the intended path. However, these calculations are performed offline, before the cycle starts. With no need to look ahead, there is no need for the CNC to slow down.

LED Headlight insert molds like this one are driving demand for increased diamond machining productivity. All photos and video courtesy of Innolite.

Machined directly in steel, LED headlight mold inserts require layering ridges and other microstructures directly atop complex, contoured surfaces.

Switching to Ingersoll TCMT boring inserts with higher rakes, more aggressive chipbreakers and the proprietary TT8125 coating led directly to 30% higher machining rates. It also completely eliminated any ‘bird nests’ of chips and the labor involved to clear them. Chips flow out as uniform C’s, easily cleared with a shot of compressed air.

Micor, which built its reputation machining difficult metals, was only midway through a 150-piece rush job turning titanium, and was running late already. But, the tools they were using, with conventional two-sided negative rake inserts, broke whenever they tried to run any faster than 130 SFM/0.010 IPR/0.200 DOC. That operation, on a Mazak Quik Turn 450, was taking 45 minutes per piece, while the finishing machine nearby stood idle, waiting for feedstock.

You may think of rough turning as a bottleneck operation, maybe even a hazardous one, and rightly so. But, across the country several alert machine shops have found different ways around both problems, according to Ingersoll Cutting Tools. Users report material-removal rate improvements anywhere from 30% to 6-to-1 in OD and ID work, reliably longer tool life, and relief from ‘shrapnel’ flying from shattered tools.

The system also eases transfer of pallets from the three- and five-axis Kern milling machines recommended for “roughing,” which in this case can require machining surface profiles and shapes with peak-to-valley accuracy of less than ±10 microns. “Diamond turning is not very productive compared to conventional milling,” Dr. Wenzel says. “A Kern machine is going to be superb for providing the repeatability and accuracy required to limit the need for diamond turning in the first place.” However little diamond turning is required, Innolite’s DirectDrive3D offline CNC system ensures it proceeds as fast as possible.

Lenses, mirrors, optics and the mold inserts that enable making such parts at scale have long been machined with tools made of solid diamond. Despite a well-deserved reputation for precision, however, diamond machining can be painstakingly slow, says Dr. Christian Wenzel, CEO of diamond machine tool builder Innolite.

In a live-turning setup like this, the cutting forces are lighter than you might think, Winterlin explained. “As the tool rotates, its eleven inserts engage sequentially, dividing the cutting forces uniformly over them all. The stock comes off as a lot of small chips rather than the fewer thumb-size chips they were getting by turning with a stick tool.”

Machined directly in steel, LED headlight mold inserts require layering ridges and other microstructures directly atop complex, contoured surfaces.

FPGA chips operate at 100 khz—that is, the query for position feedback happens 100,000 times per second in every axis, versus a few thousand in the most powerful CNCs. With tool paths pre-plotted, axis motion values precalculated and the CNC’s capacity freed, enhanced diamond machining productivity is well within reach. “Say we’re cutting a heads-up display mirror for a car,” Dr. Wenzel says. “Conventional diamond turning would take about 11 hours. On our IL600 machine, we can cut that to about three and a half hours.”

Ingersoll’s Brian Winterlin made a counterintuitive recommendation: a Hi-QuadF high-feed style cutter and taking off the stock in a single pass. That’s definitely beyond the ‘comfort zone’ for conventional high-feed cutters, which are known for fast feeds and shallow cuts. But the tool — though primarily a high-feed insert — had worked in similar high-depth applications “This is really an all-purpose cutter,” Winterlin added.

With its advanced design, substrates, and coatings, the Ingersoll Gold-Duty line of rough turning inserts is a generation ahead of the field in large scale turning, according to Ed Woksa, Ingersoll national turning product manager. The inserts are physically much thicker and stronger than conventional turning inserts. Their unique seating scheme enables more efficient top-face geometries in two-sided inserts for the first time. ‘Rest pads’ on the insert faces mate with bumps in the seat pocket to lock them in place (see diagram). It’s the rest pads that bear the clamping forces, not the cutting edges on the reverse side. This is what enables 5-7 degree positive rakes and aggressive chipbreakers in a two-sided insert. Recessed clamping provides a flush surface for unimpeded chip evacuation.

The Hi-QuadF face mill features an extra-thick insert with the usual high-feed radius, extremely rigid seating, free cutting geometry and a 12-degree lead angle for lower lateral forces at entry and exit. It is so free-cutting that, in similar applications elsewhere, it has doubled throughput without the spindle-load needle even budging.

Micor standardized on those settings for the balance of the job, and delivered the job three days early as a result. “Despite the higher removal rates, the inserts lasted 33% longer,” King added. He estimated that, with an annual volume of 400-500 pieces, Micor would save $13,000 a year on that one titanium job. Consequently Micor is standardizing on Gold-Duty tooling for all rough turning and facing, for a projected $60,000 annual savings.

The burden on the CNC is due more to the intricacy of diamond turned microstructures like these than stringent requirements for surface finish and precision.

“The Mazak is a big ticket item with a high hourly burden, so it’s vital to get the most out of it,” said Chandler Commerford, manufacturing engineer. But, the Minnesota shop had no experience with the live turning process.

Micor Industries, Decatur, Ala., reduced rough-turning cycle time on titanium from 45 to 30 minutes with another Gold-Duty insert, shipping a rush order three days sooner. They’ve since standardized on that tool for all rough OD work, and are collaborating with Ingersoll to develop an ID-machining version — projecting the savings at around $500,000 per year.

DeZurik-APCO-Hilton, in Sartell, Minn., improved a host of valve-turning operations with the move to live turning at rates some people think could damage the spindle. On the first job, facing time on a large valve flange was reduced from 18 minutes to three, yet the spindle load reading rarely exceeded 50%. The C-axis spindle is equipped with an Ingersoll Hi-Quad F high-feed face mill that doubles as a full-depth face mill capable of depths of cut up to 0.200 in.

The IL300 is designed for standard diamond turning as well as free-form and micro structure generation. ILSONIC models use ultrasonic assistance to diamond-turn steel and infrared materials.

Stringent specifications for precision and surface finish are not enough to make the CNC a bottleneck to efficiency, Dr. Wenzel says. Geometry creates the problem. If a turning insert is to machine non-rotationally symmetrical, freeform curvature and complex 3D shapes into the face of a spinning part, it cannot stay in one plane, like a needle on a record player. Following along the hills and valleys of the spiraling tool path requires moving in and out in Z in perfect synchronization with the main spindle’s rotation. However this functionality is achieved, oscillating the tool is a demanding task for an already busy CNC.

When surface form accuracy is measured in microns and roughness is measured in nanometers, the CNC becomes a bottleneck, he explains. In any application, fluid, precise motion depends on lookahead functionality to scout ahead of the cutter and ensure ample reaction time to adverse conditions, all while the control is simultaneously engaged in other tasks. Diamond machining applications can require plotting motion in such detail that slowing down is the only way for the CNC to keep up.

Diamond turning is traditionally associated defense- and research-related work, such as missile or satellite guidance system optics. Such parts are expensive, application-critical and difficult to manufacture. However, a contract for an automobile rain sensor, or a mold for an LED headlight or a contact lens, requires prioritizing more than quality and precision, Dr. Wenzel says. New customers demand increased part volumes, faster deliveries and greater geometric variety.

The burden on the CNC is due more to the intricacy of diamond turned microstructures like these than stringent requirements for surface finish and precision.

The main obstacle in the New England rebuilder’s effort to raise capacity of its screw machine fleet was the boring sequence, which represented more than half the total machine time. The shop still used conventional, negative-rake boring tools, a carryover from the time when most of the work they took in involved free-machining mild steels. When more work came in that called for long-chipping 8620 steel, they simply accepted as an unavoidable detail the 100% operator attention for chip clearance.

LED Headlight insert molds like this one are driving demand for increased diamond machining productivity. All photos and video courtesy of Innolite.

Relieving the control of its calculation burden speeds production of complex, mirror-finish components machined with diamond tools.

In contrast, DirectDrive3D did the same work in less than 10 minutes. The difference between the two systems is how the calculations are performed, Dr. Wenzel explains. Running offline enables DirectDrive3D to use parallel processing, or the division of computing tasks among multiple cores (processing units). In contrast, CNC algorithms designed to work while the machine runs use a single core because the calculations are derivative—that is, adjustments made on the way to one toolpath set point can affect how the CNC might react when it responds to the next. “In the end we’re doing the same thing (as a CNC), but because we don’t need the online functionality, we can use different math and parallelize calculations,” Dr. Wenzel says.

Now, the DeZurik operation runs securely, cutting cycle time for a typical 36-in. flange from 18 minutes to three and leaving a perfectly flat mating surface. As the part rotates slowly on the machine table, the facemill works much like a woodworking router, rotating at 785 SFM and feeding outward from the center bore at 403 IPM. Synthetic oil is delivered through the spindle.

The burden on the CNC is due more to the intricacy of diamond turned microstructures like these than stringent requirements for surface finish and precision.

However, many auxiliary spindles are designed for light duty, unable to deploy the full capabilities of the high-performance face mills available today. “The trick in live turning is to find a cutter able to take deep cuts, yet hold down cutting forces,” said Ingersoll field engineer Brian Winterlin, who worked on the DeZurik live turning project.

With the original Hi-Quad F insert, edges lasted through two complete parts, or four flanges. Recently the company switched to a tougher insert grade with an improved coating treatment, IN4005. The change notched edge life up another 50% at the same removal rates. Edges now last through three complete parts.

Vitap upgrades Blitz CNC drilling machine - cnc insert drill

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