HORN Mastering Processes: Swiss Turning and Micromachining

 

Mastering Processes: Solutions for Micromachining and Swiss-type Turning

Outer diameters of 0.1 mm (0.004″), recesses of 0.5 mm (0.020″) and feed rates of 5 µm (0.0002″) – welcome to the world of micromachining! Screws for hearing aids, balance weights for automatic wristwatches or micro-turned parts for medical assemblies: Manufacturing such parts requires know-how, precise machines and special tools. With cutting depths of down to 0.01 mm (0.0004″), users place very high demands on the tools used. They include shiny surfaces and high dimensional accuracy of the components through the use of low cutting force. HORN has developed suitable solutions with the μ-Finish system for micromachining as well as with other tool systems and manufacturing processes for Swiss-type lathes.

The demands on the tools for micromachining with Swiss-type lathes are high. Due to the sometimes very small cutting depths, the tool edges must be very sharp in order to keep the cutting force as low as possible. However, the ground cutting edges are susceptible to microchipping. Even limited chipping in the range of a few µm at the cutting edge has a negative effect on the surface of the machined workpiece. Furthermore, the surface quality of the rake face plays an important role. To counteract built-up edges, the rake face must have good sliding properties. For this reason, it is finely ground or polished.

Changeover Accuracy of 2.5 µm

Clamping of the inserts is another important point in tool design. When machining turned parts of small diameter, the centre height of the tool must be precisely measured. Even slight deviations in centre height have a negative effect on the quality of the workpiece when machining the smallest diameters. In the best case, the machine operator should be able to turn the insert without having to readjust the centre height. With the μ-Finish system, HORN offers a changeover accuracy of +/- 0.0025 mm (0.0001″) when indexing a double-edged insert. This is made possible by the precise peripheral grinding of the insert in conjunction with the stable insert seat. In addition, the contact surfaces of the square shank toolholder are also ground, which has an effect on the holistic precision of the HORN system.

The grinding of a sharp, flawless tool cutting edge requires a lot of know-how. Grinding wheels with the finest grits, special new grinding techniques and a microscope with 400x magnification are necessary to ensure that the tool performs as required. In the process, every batch of the μ-Finish system produced is subject to 100 per cent inspection. Important quality assurance criteria are the tightly toleranced high surface quality of the rake and flank surfaces, the centre height and, in particular, the sharpness of the cutting edge. There must be no visually recognisable irregularities on the cutting edge with the µ-Finish system.

HORN presents itself as a holistic supplier of tools for all Swiss-type machining operations. The extensive insert portfolio can be easily adapted to the requirements of different processes in sliding-headstock turning. Close partnerships have been established with the companies Graf Werkzeugsysteme, Boehlerit and W&F Werkzeugtechnik to provide solutions for the interfaces between the cutting insert and the machine, including for ISO tools.

Broad Knowledge

Horn’s know-how does not only apply to cutting tools. The tool manufacturer also supports its customers and partners with knowledge of the correct application data and the development of new tool systems and manufacturing processes for sliding-headstock operations. This includes, for example, competence in driven tools, tool holders for backworking and entire tool solutions.

HORN Mastering Processes: High Feed Milling

 

 

Tool Systems manufactured by Paul Horn GmbH offer users the ability to design machining processes for high productivity and cost efficiency. Especially in tool and mould making, high feed milling can be used economically and productively. High performance milling is not only defined by high infeeds, but in high feed milling also by small infeeds coupled with high traverse speed of the cutter.

 Machining applications have changed and challenges have become more complex and demanding. Shorter product life cycles and reduced development times dictate that several different components must be produced on one machine in shorter cycle times. For the tool manufacturer, this requires designing tool systems for the different applications. It means, for example, that a tool may not only be used for corner milling, but should also have the optional ability to plunge cut. Another aspect is modern machine dynamics. The acceleration and deceleration of the axes as well as their synchronisation have been significantly optimised. For relatively new technologies such as trochoidal and high feed milling, tool systems must be able to withstand the high dynamic loads.

Low Infeed – High Metal Removal Rate

A few years ago, Horn introduced a system for high feed milling – DAH cutters for face milling. Due to the load being in the axial direction, the tool and spindle mainly experience compressive force and the shear forces are relatively low. Due to their low tendency to vibrate, the tools are able to withstand the high loads typically generated by a feed per tooth of fz  = 1 mm at cutting depths ap up to 1.2 mm. The large radius on the main cutting edge of the three-edged inserts creates a soft cut, ensuring an even distribution of the cutting forces and long tool life. On the inside, a small cutting edge radius ensures trouble-free and fast plunging. A primary and secondary clearance angle leads to a stable wedge angle and very good cutting edge stability. Due to significantly higher feed rates compared with conventional milling, metal removal rate in high feed milling is significantly increased, despite the lower infeed depths.

 

 

HORN: New Coating RC2 / RC4

New Horn coating RC2 / RC4

With the new RC2 and RC4 coatings, Paul Horn GmbH is exhibiting new developments in the field of high-performance tool coatings. The high toughness and hardness allow the machining of steels at high cutting speeds and lead to a significant increase in tool life. The high temperature resistance enables productive use in dry machining as well as with minimum quantity lubrication. Numerous tool systems are available from stock with the new HiPIMS coating. In-house coating enables fast delivery times even for special tools.

Horn is constantly investing in new and modern technologies. In 2015, the company CemeCon delivered the world’s first of three HiPIMS systems to Horn. The High Power Impulse Magnetron Sputtering technology brings specific advantages and new possibilities in the coating of precision tools. It enables the build-up of dense, compact coatings that are very hard and tough. The coatings have a homogeneous structure and uniform coating thickness even if the tool geometry is complex. Research and development of new and existing coatings and technologies is a central component of success. Horn employs a team of engineers who work exclusively on this subject. Since in-house coating started, research and development projects have been carried out in cooperation with equipment manufacturers.

HORN: Gear Cutting to the Power of Three

Gear Broaching,  Gear Milling and Gear Skiving – otherwise known as the technology cycles: gearBROACHING, gearMILL and gearSKIVING. Paul Horn GmbH and DMG MORI have launched a campaign covering these three core areas in gear cutting to demonstrate the high performance of the solutions that have been jointly developed through a combination of machine, cycle and tool. A major advantage is that many existing machines can be adapted to the individual processes.

The exclusive DMG MORI technology cycles assist shop floor programming for increasing productivity and safety as well as for expanding machine capability. The advantages are clear: up to 60 percent faster programming, error minimization through conversational programming, new technologies (gear cutting) and the technology know-how stored in the application software.

As far as the tool is concerned, Horn’s standard or customer-specific special tools may be used, depending on the process and application. When skiving internal and external gears, sizes up to module 8 are possible in gear quality up to ≥ 7. Gear milling with standard tools up to module 3 achieves a gear quality of ≥ 5. Gear quality of ≥ 9 can be achieved when gear broaching internal and external gears up to module 4.

To provide practical proof of these results, there will be numerous events and trade fairs in 2022 that will focus on the joint gear cutting processes developed as part of DMQP (DMG MORI Qualified Products). The first event will be the DMG MORI Open House in Pfronten from 9th to 21st May.

For more Info: www.PHorn.de/dmqp

HORN: Milling Systems

Horn Milling Systems

Presenting a demo of Milling Solutions from Horn.   The demo showcases a variety of different HORN milling cutters – the tangential milling system 409, high feed milling system DAHM, milling system DS and milling system DG.