Precision tools for micro and longitudinal turning operations

Manufacturing, for example, screws for hearing aids, balance weights for automatic wristwatches or micro-turned parts for medical applications requires know-how, precise machines and special tools. After all, due to the generally very small cutting depths down to 0.01 mm, very high demands are placed on the tools. These include shiny surfaces and high dimensional accuracy of the parts thanks to the low cutting pressure. Horn developed suitable solutions, such as the μ-Finish system for micromachining and tools for sliding head lathes. 

Outer diameters of 0.1 mm, recesses of 0.5 mm and feedbacks of 5 µm - welcome to the world of micromachining, which places very high demands on tools. Since the cutting depths in such applications are sometimes very small, the cutting edges must be very sharp to keep the cutting pressure as low as possible. Sharp cutting edges, however, increase the risk of micro chipping. Even a small chipping of a few µm at the cutting edge has a negative effect on the machined surface. Furthermore, the surface quality of the rake surface plays a decisive role. To avoid raised edges, the rake surface must exhibit good sliding properties. Therefore, it is finely ground or polished.

The clamping of the chisel plates is also a priority in tool design. When machining small-diameter turned parts, the center height of the tool must be accurately measured. Indeed, even the smallest deviation has a negative effect on the quality of the workpiece. At best, the operator should be able to turn the insert without having to adjust the center height. With the μ-Finish system, HORN offers a changeover accuracy of +/- 0.0025 mm when turning the double-sided insert. This is made possible by the precise grinding of the circumference of the cutting element, combined with the solid integration of the plate. In addition, the contact surfaces of the square holder are also ground, which enhances the holistic precision of the horn system.

Grinding a sharp and flawless cutting edge requires a great deal of knowledge. Grinding wheels with the finest grains, special new grinding techniques and a microscope with 400x magnification are crucial to ensure that the tool actually achieves the required level of performance. Each element within the μ-Finish system is therefore subjected to thorough inspection. The high surface quality of the spit and flank surfaces, the center height and especially the sharpness of the cutting edge are important criteria in this regard. Visually recognizable irregularities on the cutting edge are immediately out of tolerance with the μ-Finish system.

However, Horn not only develops and supplies solutions for such micromachining operations, but is also a total supplier for all common longitudinal turning operations. The extensive range of inserts can easily be adapted to the requirements of different operations when turning on sliding heads. There is close cooperation with the companies Graf Werkzeugsysteme, Boehlerit and W&F Werkzeugtechnik to also provide solutions for interfaces between the insert and the machine and with regard to ISO tools.

Companies all over the world use Horn tools. The family business from Tübingen has therefore become a technologically leading manufacturer of precision tools for demanding machining operations. In addition to 25,000 standard tools, this manufacturer of carbide tools has since supplied its customers with more than 150,000 special solutions. Its core competencies rest on four pillars: an R&D department, coating technology, carbide production and manufacturing technologies. Horn's know-how is not only related to cutting tools. Among other things, the tool manufacturer also supports its customers and partners with knowledge on the correct application and development of new tool systems and production processes for longitudinal turning operations. This includes, for example, competencies regarding driven units, tool holders for rear-end machining, and complete tooling solutions.    

PAUL HORN - Booth Number 150