HORN USA is proud to present the new 32T system for grooving and parting off on Swiss-type lathes and smaller fixed-head lathes. With a precision-sintered grooving insert and central clamping screw, the tool system offers high changeover accuracy for the cutting insert and direct entry into the insert seat of the tool carrier. Additionally, there is no need for clamping elements, which may have a detrimental effect on chip flow. The screw head of the clamping bolt does not introduce interfering contours and therefore permits both grooving on a collar and parting off directly at the spindle. The grooving insert can be used as a neutral insert, and as both a left-hand and a right-hand insert. The 32T system completes HORN USA's portfolio of triple-edge cutting inserts by offering a solution for smaller-scale applications. By adding the new system to its range, the tool manufacturer is responding to customer requests for a triple-edge cutting insert system for Swiss-type lathes and other smaller turning machines, in particular in applications where space is at a premium. The precision-sintered 32T insert is secured to the holder with a central screw, removing the need for additional exterior clamping components that negatively affect chip flow. Available in 2 and 2.5 mm (.079 and .098") widths with maximum depth of groove up to 4 mm (.157"). For grooving operations, the inserts are available with both straight and full-radius cutting edges. HORN USA offers the indexable insert with a 15-degree chamfer for parting off. A cylindrically ground chip-breaker geometry makes for reliable chip removal. The tool carrier is designed as a square shank measuring 10 x 10 mm or 12 x 12 mm. Both versions feature an internal coolant supply and are available in both left-hand and right-hand designs.
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At IMTS 2018, HORN USA presented two new developments in the area of whirling processes. The JET Whirling System is the first whirling tool to feature an internal coolant supply. This whirling system offers optimized cooling directly at the cutting edge and was developed by HORN USA in conjunction with W&F Werkzeugtechnik. Another innovation is the High-Speed Whirling Technology, which delivers high levels of productivity. In this process, the speeds have been specially adapted so that preturning and thread whirling can be carried out in parallel using a single work operation. Through the JET Whirling process, HORN USA is demonstrating its expertise in the area of thread whirling. As part of a collaboration with W&F Werkzeugtechnik in Großbettlingen, experts from both companies have jointly developed a whirling system with an internal coolant supply. By cooling the cutting edges directly, this system enables long tool life to be achieved. What’s more, when used in conjunction with the stable whirling unit, the system achieves better surface quality on the workpiece. Thanks to the patented W&F interface with its coordinated contact system for the tapered and planar surfaces, the whirling head boasts a high changeover accuracy and is easy to change with just three screws. The internal coolant supply reduces the risk of chip build-up between the cutting inserts. It takes less than a minute to change the whirling head on the whirling unit interface. This interface offers a radial and axial run-out of 0.003 mm. The maximum speed is 8,000 rpm. The whirling heads are available with type S302 triple-edged indexable inserts or with type 271 double-edged inserts. The cutting edges are available with diameters of 6 mm, 9 mm and 12 mm. The interfaces for adapting the whirling unit are available for all standard Swiss-type lathes. High-Speed Whirling HORN USA is proud to present another new technique in the form of high-speed (HS) whirling. This technology is being exhibited in collaboration with machine manufacturer Index-Traub. High-Speed whirling boosts productivity significantly by performing the turning and whirling operations in parallel. With this technique, the speed is high enough for a turning process to be carried out prior to whirling. The turning tool, which is located upstream of the whirling tool, reduces the volume of material that would otherwise have to be removed by the whirling tool. This enables longer tool life to be achieved and improves surface quality. The whirling heads are very similar to conventional ones. The only difference lies in the geometry of the cutting inserts. Single-start and multi-start threads can be produced using just one cutter unit. Highly Productive Technique
Thread whirling is generally used in the production of bone screws. In this application, the whirling head rotates at high speed as it travels over the slowly rotating workpiece. The whirling head is set for the required lead angle of the screw. The workpiece is fed axially and as this happens the whirling tool cuts the thread. Due to the high level of screw quality required, special attention must be paid to precision and surface quality when it comes to whirling tools. In addition, special materials are used for bone screws to ensure that the body is able to tolerate them when they are implanted. These include stainless steels, titanium, or cobalt-chromium alloys, although the disadvantage of these materials is that they are difficult to machine. Therefore, expertise and experience are required if these materials are to be machined productively. For instance, the carbide substrates, coatings, and cutting edge geometries all have to be tailored to the application concerned. HORN USA offers further whirling technologies in addition to its JET Whirling and High Speed Whirling solutions. Of these, the most universal technology is the standard whirling method. The whirling head can be connected to any whirling unit. For faster whirling head and insert changes outside of the machine, HORN USA has developed a modular whirling system. Thanks to the precision interface, there is no need to readjust the whirling head once it has been removed from the machine. In addition, the spacer rings make it possible to adapt the whirling tool to different interfaces. With HORN USA Turbo-Whirling, high productivity is a sure thing. The cutting division between the roughing and finishing inserts reduces the load on the whirling tool’s profile cutting inserts. As a result, the system offers faster process times and lower tool costs. A manufacturer of spinal implants and surgical instruments achieves immediate results in a switch from rotary broaching to hex broaching from Horn USA. Small changes can make a big difference. Shopfloor personnel who have been in the business for a long time usually know this. A new CNC machine or a complete overhaul of procedures isn’t necessarily the only way to make a substantial impact on the shop’s output. And it’s a good thing. Sometimes a simple change in tooling can be just the ticket to the next level of success. When a shop is a relative newcomer, resources might not yet be available to invest in additional machine tools, and processes are often still being established. But even when a shop is young, it’s still often the beneficiary of well-trained and even well-established operators and engineers, along with knowledgeable suppliers. And these individuals are the right people to look toward for instituting changes that will make a difference. A Medical Upstart Amendia (Marietta, Ga.) opened its doors in 2008 with a mission to design and build spinal implants and instrumentation in the spinal device market. The company designs and manufactures its own cervical and lumbar implant devices and markets them to its distributors and direct sales force, who service spine surgeons at hospitals or surgery centers. The company currently has about 65 employees, all but two of them work the first shift. Those two employees work the second shift, and the third shift is totally lights-out. Unattended operations are continuous throughout the night, 6 days per week. The well-maintained shop floor has a lineup of Mazak Integrex and Multiplex machines that are used to manufacture implants such as interbody devices made from PEEK. In the Swiss area of the shop floor, four Nexturn SA-20e Swiss machines, two SA-20b machines and one SA-32e crank out hundreds of lumbar and cervical screws per day, along with other components needed for the implant system. “Several things are going on to make up the entire system that is used in surgery,” Application Engineer Steve Selvia says. “You have a screw, a tulip, a saddle and a set screw. Cycle times and quantities vary, but we run these around the clock in the Swiss Department.” Horn USA supplies much of the tooling in this area. Challenges All of the parts produced in the Swiss department are from implantable-grade titanium, which is strong and light, but also tends to be very unforgiving and tough to machine. And, of course, some parts present more challenges than others. According to Mr. Selvia, the most challenging parts are the pedicle screws. “They’re a double-lead thread,” he says. “We have to whirl that thread, which requires a double-lead insert and is kind of tricky to make just right to produce the thread you need.” But the more remarkable part of the process, which Amendia recently adjusted, is broaching the hex form. Originally, the parts were being produced with a full-form broach made from cobalt steel, which generated about 300 to 400 parts per tool. The process was not every predictable. The tool life was fair, but the unpredictable way the tools would break down was not very favorable. Mr. Selvia felt sure a better method was available. About 3 months ago, Horn USA Application/Sales Engineer Michael Morgan was in the shop discussing tooling options in some other processes. Mr. Selvia happened to notice the N105 carbide broaching tool in the Horn catalog. “It was exactly what I thought we needed to make the hex,” he says. This tool is not a full form, but rather a 60-degree form that pecks at the workpiece and creates the form one side at a time. The gradual forming process enables it to be more controllable, and the material is, therefore, more forgiving on the tool. “I’m now getting about 10 times the tool life from a tool that costs half as much as what we used before,” Mr. Selvia says. Broaching a Hex Mr. Selvia says the new broaching tool works better for Amedia because the entire tool form is not forcing itself into the titanium at one time. Instead, only a piece of the tool goes in and scrapes a small amount of material away with each pass. “Imagine a shaper tool,” he says. “As it creates a hex hole, it’s only touching two of the six sides at a time. It removes material at about a thousandth at a time down to the right size, and then indexes 60 degrees. It pecks away at the material without too much pressure on six sides of the tool.” Because only two sides of the hex are machined at a time, the process is considerably slower. But Amendia performs the broaching operation on the subspindle while the other machining takes place on the main spindle. Running simultaneously, the broaching is completed first anyway. “This process doesn’t cost us any time,” Mr. Selvia says. “And it saves us money and increases our throughput.” The improved performance and longer tool life have enabled Amendia to run unattended through the night with more confidence, which has further increased the production capabilities. “With the previous process, the tool would break unpredictably,” Mr. Selvia says. “That’s no longer the case.” The icing on the cake is that the quality of the finished parts seems to be better, as well. The improved surface finish can be partly attributed to more efficient and effective chip removal. With the full-form, six-sided tool, a large chip would be pushed down to the bottom of the hole and then often would need to be dug out with a drill. The broaching process, by pecking away only a thousandth at a time with each pass, creates very small, fine chips that clear away without complication. Also, according to Mr. Morgan, the Horn broaching tools are sharper than a wobble broach or rotary broach, and by shaving the material away rather than pushing it, a smoother, shinier finish can be achieved. Other Advantages The broaching system has led to other improvements in the process for Amendia, as well. Because only one corner of the hex shape is being cut at a time, the process has more adjustability. If the machine is misaligned, for instance, or if the hex is undersized, additional taper can be added or an additional pass can be added to the program. With rotary broaching, the operator has only one shot at getting it right. If the form is not right, the part is scrap. Amendia has also realized significant savings in setup time. The broaching tools can utilize the same toolholder as any Horn USA boring bars or face grooving tools or any others from the 105 Series. The operator simply replaces one insert for another one, without any need for Customer Satisfaction
Although it’s a completely different approach with a different tool, the process has fit in well at Amendia. “Everything about it has been an advantage over the old method—cost, speed and finish,” Mr. Selvia says. “We’re very pleased with it.” With plenty of experience, he feels that learning how to best use the tool was pretty straightforward. He wrote a macro program to peck the hex out to the right size based on the variables that applied to each screw design. “Just drill the hole to the right size and use the tool in a common sense way,” he says. “Anyone with some experience with CNC Swiss wouldn’t have a problem with it. It didn’t take us long at all to get it incorporated into our system.” Amendia is regularly broaching on three of its Nexturn machines for anything with a hex in it. Currently that includes pedicle screws, cervical screws and set screws. The company also uses the Horn broaching tools for Torx work on a variety of cervical screws. The hex and Torx tools bring the same advantages, but simply use a different form. With Torx, material removal is done one lobe at a time, as opposed to the hex doing one corner at a time. A common method for the Torx form is milling using a very small-diameter mill. While effective, this method can be time consuming because the small diameter end mill requires close attention all the way around the periphery of the form. Overall, the company’s relationship with Horn has developed nicely, and Mr. Selvia is considering moving to Horn tooling for some other jobs as well. “We’re happy with the way Horn USA operates,” he says. “Michael (Morgan) is knowledgeable and very available when we need him. Their network is very responsive and easy to work with. They don’t hesitate to adjust their stock if we need them to.” And who can argue with a tool life increase of 10 times? Besides the obvious savings in tooling costs, it also carries over to better production rates, reducing the frequency of machines being stopped for tool breakage. With fewer broken tools that go unnoticed, scrap has been reduced, as well. And the door has been opened for successful lights-out machining. So the results speak for themselves—a simple change in tooling has had a big impact on production savings. |
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