Producing threads in hardened steel is costly. This applies to blind hole machining in particular because reversing the tap during this process can cause torque peaks when the root of the chip is sheared off, resulting in fractures.
Walter is solving this problem with two new taps – offering its customers a full product range for producing threads in hardened steels with an additional thread milling cutter: The TC388 Supreme (50–58 HRC) or TC389 Supreme (55–65 HRC) and the TC685 Supreme (> 44 HRC). The TC388 and TC389 Supreme solid carbide taps boast special cutting geometries. These fully shear off the root of the chip when reversing; torque peaks are minimised. This prevents fractures, prolongs the tool life and increases process reliability. Lubrication with oil, which was often necessary until now, is no longer required. Instead, emulsion can be used, which optimises handling and saves additional machining time. Both taps are characterised by a short machining time.
The TC685 Supreme orbital drill thread milling cutter enables maximum process reliability and the highest possible tool life quantity. The core hole and thread (chamfer if required) are produced in a single operation, thereby saving tool spaces. The milling geometry on the face produces stabilising forces in the axial direction. This improves the stability when milling and reduces the deflection. Advantages for the user: Fewer radius corrections and reduced wear, with a high tool life quantity and minimal costs per thread. The 15° helix angle and internal coolant from M6 guarantee reliable chip evacuation. This allows even tougher steels and deep threads to be machined reliably. Common applications for all the tools mentioned include mould and die making, for example.
The optimum machine tool combined with the optimum tool results in a perfect combination. And that makes cost-effective processes and impressive machining results possible. Article contributed by MAPAL.
Figure 1: Dietmar Maichel (left), project manager 3D milling at MAPAL, and Steffen Nüssle, sales director export and head of applications engineering at Zimmermann, in front of the FZH horizontal machining center (HMC).
The optimum machine tool combined with the optimum tool results in a perfect combination. And that makes cost-effective processes and impressive machining results possible. One good example of this is the cooperation between machine manufacturer F. Zimmermann GmbH and MAPAL.
F. Zimmermann developed its first horizontal machining centre (HMC) especially for the machining of structural parts for the aerospace industry. The aluminium structural parts, such as wing parts and frame ribs, are generally milled from solid material—with up to 95 percent material removal.
Fault-free machining with respect to dimensional accuracy and surface finish is crucial here. And the component structure that becomes more and more delicate with increasing material removal represents an additional challenge.
In order to make the milling process as efficient as possible even in these areas, Zimmermann has developed the FZH machining centre that offers maximum rigidity and features a robust, water-cooled travelling column. Whereas conventional machine concepts suffer from lever-related deviations with increasing slide, the guide carriage distance of the FZH increases with increasing plunging depth into the material.
In order to achieve maximum efficiency, Zimmermann employs its own patented M3ABC three-axis milling head in the machining centre, especially in the pocket corners of a workpiece. This milling head has to perform only very small swivel movements, allowing the feed rate to be kept constant and hence, the machining time to be significantly shortened.
At an open house in June 2017, Zimmermann demonstrated its machining centre with tools from competitors. These tools failed to meet the expectations, however, and were unable to exploit the performance of the machine.
“Why not test the performance of the MAPAL tools?” thought the project managers at Zimmermann, as MAPAL was presenting its milling cutters for high-volume machining at the event. A short time later, representatives of the two companies carried out extensive milling trials with different tools together.
Figure 2: MAPAL tools used at Zimmermann (from left to right): SPM-Rough ISO shoulder milling cutter with indexable inserts as roughing solution for diametre ranges above 25mm; SPM-Rough solid carbide milling cutter with wave profile as roughing solution for diametre ranges up to 25mm; OptiMill-SPM solid carbide milling cutter for multi-stepped semi-finishing of thin-walled structures; and SPM-Finish solid carbide milling cutter for finishing of deep pockets and delicate structures in a single pass.
The Milling Cutters
“Our goal was to choose the optimum tools from our portfolio for the machining operations on the Zimmermann machine,” explains Dietmar Maichel, project manager 3D milling at MAPAL. The tool manufacturer’s portfolio contains different milling cutters for the different tasks during the high-volume machining of aluminium structural parts. The tools are perfectly designed for use on such high-performance machines as the Zimmermann machine.
In particular, the SPM milling cutters, which are available in a solid carbide design and with PCD and ISO inserts, are being used today—a total of four tools, to be exact—at Zimmermann for the different demands of the roughing and finishing operations.
“The perfect combination of the machine, the three-axis milling head and the tools from MAPAL give the user a real performance boost,” says Steffen Nüssle, sales director export and head of applications engineering at Zimmermann, immediately after the first tests. “With the SPM-Rough ISO shoulder milling cutter, we achieved the best results that we have ever achieved with a tool with indexable inserts.”
The ISO tools with polished indexable inserts are the latest addition to the MAPAL SPM product range. The SPM-Rough with wave profile also surpassed the expectations for material removal with excellent smooth running.
“The complete machining of a 190x190x40 mm pocket is now effectively possible in less than a minute,” explains Nüssle.
The experts at F. Zimmermann are convinced by the MAPAL tools. “The use of the SPM milling cutters has given us a quantum leap forward in the aluminium machining. And it shows us what the perfect combination of tool and machine means in terms of performance,” says Nüssle. The tools are the first choice when it comes to machine acceptance tests or demonstrations for customers from the aerospace industry at Zimmermann.
The Zimmermann machines are suitable not only for the machining of metals. “Many of our customers manufacture parts of composite materials,” says Nüssle.
Zimmermann, therefore, also wants to mill trial parts of these materials using MAPAL tools.
“We are optimistic that with the MAPAL milling cutters for composite machining, we will also find a new secret weapon to exploit the performance of our machines even better,” says Nüssle. The corresponding plans are already in hand.
Walter AG is releasing the new TC620 Supreme thread milling cutter in diameters up to M20.
High cutting pressure and tool deflection are the greatest challenges when it comes to thread milling. This results in restricted cutting parameters, necessary cutting passes and short tool lives or even tool breakage. With the TC620 Supreme universal thread milling cutter, Walter is now transferring the functional principle of its T2711 indexable insert thread milling cutter to smaller diameters too. Tool wear is drastically reduced thanks to minimal cutting forces and the resulting high feeds per tooth. The multi-row concept not only reduces the machining time and wear, but also improves process reliability and handling – even when used with more demanding materials such as stainless steels or Inconel 718.
Reliable chip evacuation, thanks to internal coolant, and simple handling of the TC620 Supreme guarantee maximum process reliability. Radius corrections are seldom necessary, and when they are required, it is often only once competitor tools have already reached the end of their tool life. Walter is launching the TC620 Supreme for thread depths of 2 and 2.5 × DN in the dimension range from M4 to M20 as well as UNC 8 to UNC ¾ – and is therefore seamlessly linking to the Walter T2711 indexable insert thread milling cutter.
Seco Tools has expanded its popular family of T4-12 helical milling cutters to include five new cutters for economical and versatile roughing and semi-finishing operations. The addition of three metric and two imperial sizes makes Seco’s range of long-reach, replaceable-end tangential helical cutters the industry’s most complete, spanning diameters from 40 mm to 100 mm.
Designed specifically with aerospace manufacturers in mind, the new long reach cutters with HSK-100A back ends optimize side-milling operations. With replaceable ends, the cutters allow for custom solutions if needed and the capability to replace the first row of pocket seats without replacing the entire system.
The cutters excel in applications with sticky materials such as stainless steels and high temperature alloys. The high-positive, free-cutting insert geometries and grades boost tool life, while the tangentially mounted multi-edged inserts enable efficient chip flow and provide stability.
Tungaloy has successfully designed the insert of its TungForce Rec line of end mills with a “V” bottom that fits into a mating “V” bottom pocket on the tool. This design removes much of the centrifugal forces from the screw, putting the forces into the rigid pocket and allowing much higher revolutions per minute. It also allows for a larger screw of manageable size which increases the stability of the insert. As compared to solid carbide end mills, these features equate to higher metal removal rates.
It is available with a modular head that can use a carbide shank, thereby matching the reach capabilities of solid carbide at a fraction of the price.
OSG’s ceramic end mill series is for high-speed machining at high temperatures in difficult-to-machine materials such as Inconel 718. Two types of ceramic end mills are included in the series—the CM-RMS peripheral cutting edge type and CM-CRE end cutting edge type.
The CM-RMS has a negative cutter form to increase rigidity, and is available in four or six cutting edge specifications to accommodate individual application needs. The CM-CRE is suitable for flat surface milling and also in 3D applications, such as the machining of blades. It is also regrindable and can be reused by cutting away the used portion.
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