History of Reishauer

Reishauer looks back on a 200-year long, eventful but successful history. It began in 1788 with hand tools and, in 1930, moved over into building machine tools. In 1945, the cornerstone of today’s success was laid with the launch of the first continuous generating gear grinding machine, incidentally one of Reishauer’s many inventions. Today, Reishauer remains the undisputed world leader in generating gear grinding machines. Since 1998, Reishauer produces its own tooling to exploit the full potential of their generating gear grinders.

History of Reishauer

Reishauer‘s history begins with Hans Jakob Däniker, a citizen of Zurich, toolsmith by trade, who in 1788 laid the foundation of today’s company, Reishauer AG.

Reishauer‘s history begins with Hans Jakob Däniker, a citizen of Zurich, toolsmith by trade, who in 1788 laid the foundation of today’s company, Reishauer AG.After completing his apprenticeship, he began his compulsory journeyman’s travels. Upon return from his travels, he completed his master tradesman’s workpiece. On March 31st, 1788, he was accepted as a member of the Zurich trade guild “Zum Goldenen Horn”, nowadays called trade guild “zur Schmiden”. Subsequently to his acceptance, he opened his own workshop in Zurich. In 1824, his son-in-law, Gottfried Reishauer, took over the workshop in which he began his own toolsmith apprenticeship some 12 years prior to taking over.

In January of 1870, the company was officially registered as a „Tool Factory”. The products manufactured were declared as „ the complete requirement of thread cutting tools“.

On July 10th, 1882, a public limited company was founded in Zurich and incorporated under the name of „Aktiengesellschaft für Fabrikation Reishauer’scher Werkzeuge“ (shareholding company for the manufacture of Reishauer tool) The product portfolio was enlarged by adding „Thread Gauges“ to  the existing range of „Thread Cutting Tools“.

Commercially available thread grinding machines no longer satisfied Reishauer’s own quality requirements. For this reason, in 1924, Reishauer started to design their own thread grinder. In 1928, the first in-house built machine, called RK, began to grind threads in Reishauer’s own factory.

This important step signalled the transformation into a machine builder. While the first machine tools were dedicated to grinding thread gauges, there were no machines for the efficient grinding of taps. Consequently, a tap grinding machine was designed and put into operation in 1931. The performance of this new machine was such that taps could now be ground from solid hardened blanks. The machines created commercial interest outside Reishauer’s own factory, and the company could enter into a profitable market segment of the industry. During the economic crisis after 1929, the market for taps and other tools dropped off drastically. However, Reishauer was able to compensate these losses with the sales of machine tools.

In 1945, the first ever continuous generating grinding machine, called ZA, was put into operation and introduced the „Reishauer Method“ as the process is still often referred to today. In fact, the underlying principle has remained the same to this very day.

An interesting aside worth mentioning is that the thread grinding machines were equipped with gears manufactured by Reishauer. Again, it was the dissatisfaction with the status quo of technology that drove Reishauer’s engineers to develop - or rather to invent - the continuous generating process as they were aiming for a more accurate, faster und cost-effective way of grinding gears. Following an intensive 15-year development time, the new machine was ready for operation in 1945. From this point on, Reishauer’s own gears would no longer be ground tooth gap by tooth gap but with a few passes of this new enveloping continuous generating method. This faster and more accurate method of gear manufacture, the continuous generating grinding, consolidated Reishauer’s reputation worldwide, and started a new chapter of its history, which, even today, keeps shaping the future of the hard-finishing of gears.

The visionary prediction of the ZA brochure of 1945 read as follows:

„In the future, gears will be ground which we cannot grind today due to high costs, even though it would be preferable to do so now“.

Although, the basics of the continuous generating process stayed the same for the AZA, the demands on operators were reduced and one person could now handle several machines simultaneously.

Apart from lowering costs, the added automation features led to a higher output and to a more constant quality. Wider grinding wheels reduced idle times and allowed the grinding of serval workpieces between two dressing cycles. The Reishauer method was no longer restricted to gears for machine tools, and therefore, opened up new market segments, and became economical for gears for printing machines, trucks, tractors and pumps.

The synchronisation of the threaded wheel and the gear part, which is necessary to generate the desired geometry, could be generated, for the first time, electronically rather than mechanically. This proved to be a giant step forward.

This electronic synchronisation further improved the geometrical accuracy of gears, firmed up the process stability, and met the high standards of the aerospace industry. Ironically, the precision ground gears that hitherto controlled the synchronisation within the machine tool became superfluous and were no longer needed.

The invention and the implementation of continuous shift grinding was a revolutionary step in the evolution of generating grinding. With this method, the threaded grinding wheel constantly shifts sidewise during the process such that grinding always takes place with fresh and free-cutting abrasive grains.

The grinding process became more independent of the operator’s skills, led to a more stable process, higher quality of the workpieces, higher material removal rates, more accurate profiles and a significant reduction in the risk of grinding burns.

The new overall machine design, jointly with parallel developments in grinding and dressing technologies, could reach, for the first time, the critical one-minute cycle time for the grinding of typical automotive change gears.

The RZ362A levelled the way for Reishauer’s entry into the automotive industry. In other words, continuous generating grinding entered the domains hitherto held by shaving and honing. The constant precision of ground gears, combined with low production costs, offered the automotive industry a new and interesting alternative for the hard-finishing of its gears.

With the RZ362, Reishauer also introduced Low Noise Shifting (LNS). The LNS method reduced undesirable gear noise, leading to higher perceived driving comfort. Ground gears could now be paired, and transmission manufacturers could concentrate on one production method only.

With its in-house diamond dressing tool production, Reishauer laid the foundation stone of its Circle of Competence, its performance portfolio. 

The gear grinding machine, both in qualitative and quantitative performance values, is at the core of the continuous generating grinding technology for the large volume production of high-accuracy gears. To ensure the high productivity at a constant quality output, and the low costs per piece, the making of its own diamond dressing tools further increased Reishauer’s overall competency.

The RZ400 embodied the highest productivity combined with flexibility; from low to high volume lot sizes. Originally designed for the automotive industry, the RZ400 found its secure and natural home base in job shops.

The RZ 400 combined several leaps in technology. First and foremost, this machine introduced Reishauer's new electronic gearbox with its disturbance suppression and its high rigidity drive kinematics. This increased stability and rigidity of the axes drives and set new quality and productivity standards. Additionally, this machine introduced a Windows user interface, thus allowing simple gear data input and modifications such as topological grinding, for example.

The machine featured safeguards regarding the drive axes, protecting both the user and the machine tool. A full range of dressing units, dressing tool options and dressing strategies were at the user’s disposal. It was the first machine with an NC-controlled coolant nozzle that continuously maintained its optimal position. Additionally, to increase productivity, the operating speed was increased to 63 m/s, and dressing and grinding could operate in a multi-start mode.

Reishauer managed a first successful entry into the automotive industry with the RZ362A machine. Nevertheless, the convincing breakthrough was left to the RZ150, which, with its twin-spindle technology, set new productivity standards.

The RZ 150 replaced alternative finishing methods such as shaving and honing not only because of its higher part accuracy but also through delivering lower costs by piece.  While one workpiece was being ground, the other workpiece was simultaneously meshed and oriented into the correct grinding position. This eliminated unproductive idle times. This machine was specifically designed for grinding automotive gear parts such as changing gears and gear shafts, balancer gears, transfer gears of automatic transmissions, planet gears, sun gears and timing gears.

The RZ1000 grinding machine combines universality, high precision and high material removal rates and offers all relevant functions of gear grinding.

Its grinding capacity of up to 1000 mm workpiece diameter and up to module 10 covers a large range of gear grinding applications. Today, this machine still has the strongest workspindle drive in the market which features highest control accuracy and which responds adaptively to a given grinding task. This adaptability is of great assistance if there is a high frequency of part changeovers. Profile grinding (tooth gap by tooth gap) and onboard gear measuring, highlight the broad field of application of this grinding machine.

With a focus on the Circle of Competence, the performance portfolio of Reishauer, starting an in-house grinding wheel manufacture was a logical consequence.

Hence, in 2008, in Pfaffnau, Central Switzerland, Reishauer built a fully automated grinding wheel factory, which set a new standard for the manufacture of grinding wheels. Going for full-on automation was not only to reduce costs but also to guarantee grinding wheels of unmatched homogenous structure. This level of homogeneity could only be achieved by eliminating the manual labour portion that, outside of Reishauer, is still common practice in the grinding wheel industry.

This family of machines is dedicated to the high volume production in the automotive industry. Additionally, the RZ260 can also handle gear parts of heavy vehicles such as trucks and tractors.

Furthermore, due to its inherent flexibility, the RZ260 can also be found in job shops for smaller lot sizes. The twin-spindle technology and the basic design concept were based on the RZ150, and further refined to achieve additional increases in productivity.

These machines set themselves apart by incorporating several technological leaps such as high speed grinding at 100 m/s, grinding of non-involute gears, polish grinding and twist control grinding.

In 2010, and again in line with the Circle of Competence, Reishauer began to develop its own workholding. In 2012, the first workholding devices successfully entered the market.

Since that time, Reishauer supplies hydraulic clamping arbours that feature excellent part changeover accuracy of less than three microns, long service life and very short clamping times.

Again, the inception of the Reishauer automation springs from the Circle of Competence philosophy. Hence, the Reishauer automation is an integral part of its performance portfolio.

Automation and machine tool are perfectly fine-tuned to each other as they come from the same source and share the same CNC-control philosophy and the same interfaces. Material flows can be efficiently synchronised and optimised according to production requirements. The Reishauer machine sets the pace, with the automation in perfect phase with the machine’s high cycle frequency, productivity and availability.