Tungaloy introduces new product lines - types cnc turning tool insert

 2024-07-07 16:31:34

The P-style blades have many options with indexable blades that are designed to fit in existing tool blocks. Solid-carbide options allow for direct replacement of these blades for groove and cutoff applications.

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.

Chip control ensures that chips will not cause problems during the machining process. The goal is to produce short helical, spiral, comma, or tear chips (shaped like 6s and 9s). These types of chips are more likely to provide stability in the grooving and parting-off process.

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

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.”

Through-coolant holders eliminate the need to adjust coolant lines and always direct the coolant to the tool’s cutting edge. External coolant lines can be bumped out of alignment while operators are changing tools or loading parts, which can cause process variation or premature tool failure.

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.

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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.

Coolant from above can greatly improve chip control, which is a key to longer tool life. It can also reduce built-up edges (BUE).

It is important to consider the economics of parting off. Since parting off is often the final operation in manufacturing a component, reliability is crucial.

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

Materials are changing, and they are generally not getting easier to machine. Challenging materials such as heat-resistant superalloys, stainless steels, and lead-free alloys such as brass pose new challenges that demand modern machining strategies.

The pre-plumbed systems simply bolt on to accommodate many coolant delivery options that offer quick changeover without the need to hook up coolant lines. Many of the modular systems also allow for center height adjustability that can be especially helpful when cutting difficult materials. A large number of combinations are possible with a relatively small number of components, which enables standard tool systems to be used throughout an entire production process regardless of the machine interface.

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

So what about cam machines that are 20 or 30 years old or older? Truth is, many companies still run older cam-style machines, and these machines aren’t being ignored. There are new options for them too.

Coolant supplied below the cutting edge will reduce the cutting zone temperature while minimizing flank wear. This also aids in chip removal. Reducing the temperature makes it possible to use tougher varieties of inserts while maintaining tool life and cutting parameters or, in some cases, increasing tool life and improving process reliability. This process also delivers the best results when engagement times are long and temperature is a limiting factor.

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 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.

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.

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 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.

Coolant can be supplied by an external or internal means. When external coolant is supplied via nozzles spraying on the toolholders, only a small amount of the coolant actually gets to the cutting edge so it has less of an effect on the cutting application than coolant delivered using a through-coolant toolholder delivery system. This is especially true when machining deep grooves and working with materials that are easily work-hardened, such as superalloys and stainless steels.

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.”

Cooling and lubricating coolants can reduce the temperature of the material being cut and improve chip removal.

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

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.

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.

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.

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.

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

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.

We can’t talk about coolant delivery without talking about coolant pressure. With the right coolant pressure it is possible to influence chip formation in grooving and parting off. Coolant pressure as low as 5 bar (72 PSI) can start to reduce crater wear. As the pressure increases to 20 bar (290 PSI), it can reduce BUE. Coolant pressure of 40 bar (580 PSI) can influence chip control and direction. High pressure application of 80 bar (1,160 PSI) or more can aide in chipbreaking.

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.

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.

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.

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Consider two key points to avoid problems. One is chip forming and the other is chip control. Good chip forming ensures that the material is plastically deformed by the tooling so the chips are narrower than the width of the cutting insert to avoid damage to the groove flanks. An example is a 5-mm-wide groove insert that creates a chip that is 4.85 mm wide.

The negative chip angle that works so well in free-machining brass does not work nearly the same in the lead-free version. Machining trials have shown that lead-free brass is best machined with geometries more suited for steel. For the best process capability it is important to apply the correct geometries and grades for the material you are machining. Not all brass is the same.

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.

New modular tools make it possible to produce assemblies that are tailored for specific applications while being made up of completely standard components. This can reduce the need for special tools. These systems provide a stable structure, while their modular design gives you flexibility and a large variety of tool configuration options.

Cooling lubricants and cutting fluids can dramatically affect the reliability of grooving and parting-off processes. When applied correctly, cooling lubricants can reduce the temperature of the material being machined and improve chip removal. Keep in mind that no matter how much coolant is poured on an application, or how effective the coolant is, it will have little to no effect if it is not applied to the cutting edge.

Grooving and parting-off applications present unique challenges. Unlike a longitudinal turning application that allows chips to move in three directions without restrictions, during grooving and parting-off processes you are machining between flanks, which confine chip movement to just two directions.

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.

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.

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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.

Coolant applied through the toolholder is precisely directed to the cutting edge, where it will have the most impact on the cutting process.

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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 narrowest indexable inserts should be used in the parting-off process as this can factor into significant material cost savings. These savings multiply exponentially when you are machining alloys that have a substantially higher material cost, such as high-temp superalloys.

Turning application technology has come a long way from the time when you simply clamped a piece of tool steel in place for a turning application. Today the flexibility, simplicity, increased stability or rigidity, and improved accuracy are making modular grooving systems popular.

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.

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

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.

Editor’s Note: This article was developed from information presented during the Horn Technology Days 2017 event held at Paul Horn GmbH in Tübingen, Germany, May 10-12.

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

Let’s use a lead-free brass alloy as an example of a challenging material. Brass is known for its good machinability properties. A leaded, free-machining brass is particularly popular in the production of turned parts. Tools used to machine free-machining brass have a negative chipping angle that produces small, short chips. With new laws that regulate the use of hazardous materials such as lead, new grades of lead-free brass have emerged that require a change in machining processes.

When internal coolant is supplied directly through the toolholder, it is directed precisely to the cutting edge, enabling a much more reliable process. Internal coolant, or through-coolant, holders are available in many variations. Some direct the coolant to immediately above the insert, some to immediately below.

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.

Tungaloy introduces new product lines - types cnc turning tool insert

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