The creativity of the designers knows no bounds with new drive element and gear geometries. Faced with constantly increasing demands from a wide variety of industrial sectors, today solutions are being sought that often cause major problems in production. In addition to the challenges of mass production, the trend towards special products, small and special series, prototypes and test setups is omnipresent. But can these specific components still be manufactured economically and efficiently? Without compromising the required precision and repeatability in the manufacturing process? Previously, the production of small series had to be carried out at very high cost, which ultimately caused unit costs to explode. So far!

Haas Schleifmaschinen: Bevel gear produced on a Multigrind® CA.

For bevel gears, there is now a completely new solution on the market that will make both designers and production departments sit up and take notice. Precision grinding of small batches on the Haas Multigrind® significantly increases surface quality and component accuracy, while at the same time reducing manufacturing costs many times over.

Circular arc or cycloid - The Multigrind® realizes all conceivable gearings in quality 2 and 1.

On the Haas Multigrind® grinding machine, almost all variants of special bevel gears can be ground extremely economically, both circular arc and cycloid geometries. And not only that: the ground bevel gears set new standards with regard to precision and reproducible quality. Wolfram Hermle, Chief Developer at Haas Schleifmaschinen, describes this in an example: "In every industry, be it automotive, aviation, robotics, wind power, etc., there are standard requirements for series products and a growing number of specific special applications. A modern high-performance transmission or differential in a production car can always be produced in series on a conventional milling machine. But not a special gearbox for a racing car. The demands on material and precision are so extraordinary that it makes sense to choose a much more suitable production route. Or let's think of a satellite, whose awning has to be unfolded reliably after reaching the final position. The conditions in space make a second, third or fourth chance difficult. Also in the prototype development of the robot industry, no designer wishes that expensive blanks be milled and ground until the desired result is almost perfect."

Haas Schleifmaschinen: Multigrind® CA.

Bevel gear - milling or grinding?

Grinding of course! For special productions in small series the use of expensive milling tools is not worthwhile. And in order to produce a perfect surface, you would have to regrind anyway. The Haas Multigrind® grinds even highly complex workpieces directly from the solid, faster, more precisely and also considerably more economically. And this article describes in detail how this succeeds.

Bevel gear all-rounder + problem solver = Multigrind®

In terms of flexibility, precision and productivity, the Haas Multigrind® grinding machine series is the perfect choice for small series production of highly demanding bevel gears. With at least 5 axes and an enormous drive power in spindle and rotary axes, this production unit offers a maximum of power and dynamics. The machine's thermostable, vibration-damped cast mineral bed provides the required stability.

Multigrind®: Gear cutting and (or) cylindrical grinding in a closed loop

Complex workpieces such as special toothing on bevel gears can be completely machined in a single clamping, which significantly increases precision and saves a lot of unnecessary set-up time. Should, in exceptional cases, further clamping be necessary, this is done with repeat accuracy and without loss of precision. In automated machining, the patented tool changer guides the required grinding wheels of various sizes and designs into the spindle up to 58KW drive power. The grinding wheels with a size of up to 300 mm are dressed again and again during the entire grinding process, i.e. brought back to their correct geometric shape. The desired quality 2 and 1 for all gearings can only be achieved by exact form dressing in a closed loop.

How new customer requirements push the boundaries of what is feasible

Wolfram Hermle knows what relevance this new standard will have in bevel gear production in the various industries. "With our customer-centric approach, Haas Schleifmaschinen is part of the solution for many design engineers and workpiece manufacturers. We are often asked when the limits of what is feasible should once again shift in favour of more precision, economy and complex special shapes. The fact that a Multigrind® grinding machine, i.e. a universal grinding machine, masters these special tasks best seems to be a contradiction for many people who are not familiar with our technology. Our customers and users know that the high degree of flexibility of our grinding technology is also based on the intelligent control by the Multigrind® Horizon software.

Haas Schleifmaschinen: Wolfram Hermle.

The perfect interaction of software and hardware makes the difference

Thanks to the cooperation with Ph.D. Claude Gosselin of Involute Simulation Software Inc. and the software solution HyGEARS, the projected bevel gear is calculated according to exact path specifications. The interaction of Multigrind® Horizon and HyGEARS enables a very fast and exact 1:1-simulation, which is visualized three-dimensionally. In this way, the real image of the bevel gear to be produced is obtained and minimal programming errors can be resolved in advance. The automatic collision monitoring before the start of production provides additional safety. The path-optimized calculation of traverse movements saves a lot of time later in production.

The Multigrind® Horizon software together with the HyGears module allows you to configure, control and operate control instructions as well as machine data such as measured values, sensor data, control variables and parameters from the tablet. The complex mathematical design data can be described by a few parameters. The result: a user-friendly user interface with an intuitive operating concept. There is no need to spend a lot of time setting up the system individually with "fingertip sensitivity". Orders are allocated automatically, either via the RFID codes of the raw parts and comparison with the ERP system or from the online shop. Haas has implemented the integration of production and measuring technology in the closed loop both with its own software and in the Multigrind® grinding machine. This means that the Multigrind® Horizon software is optimally designed for the production environment of Industry 4.0, a consistent step towards digitization in bevel gear production.