Tool to tool, tooth to tooth

New machine tools with coupled shafts are suitable for the production of gears, whereas previously this was only possible with special machines. HORN stands for high-quality tools, but is also a partner in the development of new production strategies. After all, when designing a tool, the machining parameters and settings of the machine tool must also be determined. Meanwhile, the tooling specialist continues to invest in innovation.

In the past, gearing was done with obsolete tools on special machines, which caused time-consuming changeovers and long lead times. With circular milling 613, HORN introduced a solution for complete machining in one fixture with better accuracy and finish and shorter machining times. This circular milling plate has a tool life of 1,000 workpieces, a cutting speed (vc) of 310 m/min and a feed, programmed at 600 mm/min. The tool with an opposing milling direction mills all eight teeth to the full depth of 2.1 mm in one pass.

Cutting Tools

The performance of the existing pitch tools from HORN met the wishes and requirements of the users, but due to the large series, an optimization of the machining time was urgently required. The conventional pitch method with many individual strokes took too much time. For a tool with eleven teeth, it took about 3 minutes. HORN developed a new solution in which the rotational movement of the drive shaft is converted into a linear movement of the head. The tool life of the axial pitch tool Supermini N105 was increased from 30 to 100 notched teeth and the process time decreased from 3 minutes to only 1.

Five-axis milling of large modules

The mills in HORN's standard program produce various gear geometries whether they are teeth for gears, shaft/hub joints, worm shafts, bevel gears, pinions or custom profiles. Pre-milling is done with DGM, DSDS and DAH37 type milling cutters or with tool M279, while VHM milling cutters machine the edges of the teeth and DGFF milling cutters are used for deburring and chamfering.   

Standard milling cutters made of particularly hard steels are used for final machining. Thus, complex cuts can be produced on universal five-axis turning and milling centers, saving a great deal of time and costs.  

Skiving for large acceleration modules

The method of producing larger modules reduces machining time, especially for internal gear teeth. Gear skiving of larger modules requires large and stable milling and turning centers that allow precise synchronization between the rotation of the workpiece and the movement of the cutting tool. The experience with small carbide tools can now be applied by HORN to larger modules. The solution is based on insert type S117 and is characterized by precise clamping and positioning as well as highly effective chip removal from the machining zone. All cutting edges are directly cooled by internal cooling on the inserts. HORN tools are specially designed and manufactured for each application. The feasibility of each application is verified by HORN engineers prior to implementation and the tool design and process recommendations are discussed with the user. HORN's product range consists of a broad tool program for the production of various gear geometries from module 0.5 to module 30.  

Milling tools for bevel gear teeth

With the new tools, HORN - in cooperation with machine builder INDEX - enables the complex machining of bevel gears on universal turning/milling centers. Everything can now be performed in a single fixture, resulting in high precision and efficiency as well as short machining times. The parts can also be efficiently produced in small quantities, which is interesting for medium-sized and smaller companies, which until now had to purchase gears externally or have them manufactured. HORN developed the two-section plates type S276 and S279 for this purpose. By equipping the milling body with different heads, among other things, various numbers of teeth can be realized. The development of the complete system (cycle, tool and fixture) requires a lot of know-how, both from the machine manufacturer, and from the tool manufacturer. HORN offers the milling body with the HSK-T40 and HSK-T63 takeups. The profiles of the cutting plates are module-dependent and precision ground.

Defined deburring of gears

Deburring gears with brushes and pressure discs is relatively simple, but increasing requirements for precision and quality of gears often no longer allow undefined chamfers on the edges. For the production of defined chamfers, HORN developed a technology including the corresponding production process. With this, for example, a gear of module 1 and 25 teeth can be provided with a defined bevel of 45° in less than five seconds. The prerequisite for the production process is a turning/milling center with coupled axes. The process is particularly suitable for machining large series of gears. The cutters are special tools and must be matched to each toothing. Depending on the application, HORN technicians select the appropriate cutting geometry for the module, head circle diameter and desired chamfer. HORN supplies the process data for machining with the tool.