Maschinenfabrik Berthold Hermle AGMaschinenfabrik Berthold Hermle AG

From one to another!
User reports

Getting the ratio right

12.11.2020

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from left to right Christian Simon, area sales manager at Hermle (Schweiz) AG, Midhat Dedovic, foreman at Humbel Zahnräder AG,

Humbel Zahnräder AG has developed into an engineering services provider that not only manufactures gearwheels and gears, but also supports its customers in questions of design and layout. The Swiss company maintains its market position successfully through flexibility and reliability. This, in turn, is comprehensively underpinned by Hermle: For the last five years, Humbel's reliance on the 5-axis concept and automation solution from Gosheim has enabled it to expand its capacities significantly and secure new orders.

"It all began in 1928 with a broken gearwheel that my great-grandfather was asked to replace by a farmer friend," relates Urs Humbel, CEO of Humbel Zahnräder AG. Willing to help, the mechanical engineer Wilhelm Humbel modified his lathe so that he could make gearwheels on it as well. He founded the Zahnradfabrik W. Humbel and steadily expanded the business. In 1964 he relocated to Kradolf in the canton of Thurgau, and these premises remain the company headquarters to this day. Since then, the Swiss family-owned company has transformed from a straightforward contract manufacturer to a component and system supplier with its own engineering department.

Urs Humbel sees the decision to set up a subsidiary in the Czech Republic as being something of a milestone. "Novogear Technologies that we set up in 1993 was our first subsidiary company, and it was the first factory that we opened outside Switzerland." At first, only the soft machining was done there. With its relocation to new premises in Frýdek-Místek, Humbel expanded the Czech operation by way of its own hardening facility and modern assembly facilities. A second subsidiary in eastern Europe followed in 2001 with the foundation of HPT Humbel Produktionstechnik SRL in Romania. "One can regard the Romanian factory as something like our extended workbench. This is where we usually manufacture large series, including simpler components. Sales operations are conducted entirely from our Swiss headquarters and NOVOGEAR in the Czech Republic," explains Humbel.

With the C 62 U, Humbel can now also machine the cast housings of railway gearboxes.

Reliable transmission

The Swiss specialist's gearwheels can be found wherever forces must be transmitted with precision: In motor sports and electric vehicles, in rail vehicles and machines used in the plastics and tooling industries. "Motor sport represents an important part of our portfolio – and it's a challenging one, too," explains Humbel. Development times are extremely short, and the components have to function reliably while under maximum stress. The rate of development has also accelerated in the field of e-mobility – and that has been reflected in this business area's strong growth at Humbel. The CEO does not see a problem for the family-owned company here, as short-term project business is one of Humbel's main disciplines. "We meet the high expectations through agility and flexibility." Being able to outsource orders to Romania or the Czech Republic is a further point in the Swiss company's favour. The complexity and the size of the order generally determine what is to be done where. "Our eastern European locations represent our response to competition from Asia. We can offer competitive prices together with significantly better quality," explains Urs Humbel.

Irrespective of the application, Humbel Zahnräder AG has strongly promoted the engineering aspect. "We provide development, design and construction through to production and assembly, supplying our customers with everything from one source", explains Humbel. The company can respond flexibly and fast thanks to its broad scope of competence and its own production capacities. Naturally enough, Humbel not only deploys its engineering competence to the benefit of others, but also for optimizing tools and machines for cutting gear teeth. The engineering experts are also in the front line when it comes to automation. "Whenever machine manufacturers cannot come up with the solution we require, we do our own automation," adds Humbel.

The PW 3000 pallet changer with 8 storage locations is an essential part of Humbel's plan to use the C 62 U in four-shift, unattended operation. 

New strategy for more capacity

That this is not always necessary can be seen in the Kradolf plant, where three 5-axis milling centres from Maschinenfabrik Berthold Hermle AG are installed. These machines allow for high productivity through automated pallet changer technology. The first machine, a C 22 U, moved in five years ago. Urs Humbel recalls: "That was after we changed our manufacturing strategy – and moved away from the vertical and horizontal machines." The aim was to achieve more efficient workflows. "The great advantage of the Hermle concept compared with the 3-axis and 4-axis systems is definitely the simultaneous multi-side machining," explains Midhat Dedovic, foreman at Humbel and responsible for process optimization. "We were able to dispense with reclamping the parts several times. That makes for short running times and higher throughput." The overall package of operation, availability and service made the difference. A year later, another C 22 U with pallet changer followed. "We also manufacture complex components with varying drive components for rail technology customers on both machines and without an operator," adds Dedovic.

At 180 kg, the weight of the cast housings is relatively low compared with the maximum carrying capacity of the pallet changer, namely 3 tonnes.

Ready-programmed in Gosheim

The plant was delivered at the end of March 2020, and production started two weeks later. "Right from the start, we were under time pressure. Hermle provided excellent support to enable us to work on the first housings as fast as possible," relates Midhat Dedovic. For instance, Humbel tested and refined programs and processes tailored to the gear housings in advance on a C 62 U in the Gosheim technology centre. The moment the machine was available in Kradolf, the foreman and his team were able to concentrate on the workflows with the pallet changer, aiming for setting up shifts without manpower. The workers can prepare the pallets for subsequent operations in the easily accessible setup station in parallel with the running operation. As soon as the respective job is to be executed, the handling unit positions the corresponding pallet on the C 62 U's swivelling rotary table – fully automatically.  "It helped us enormously that we were already familiar with the job management and operation of the changer via the Hermle Automation Control System, aka HACS, from the other Hermle plant. The concept is identical for the C 62 U, despite the difference in size," explains Dedovic.

He can also rely on the quality and repetition accuracy of the system: "On average, the parts are worked on for 4 to 5 hours on the large machine. In view of our positive experiences with the smaller Hermle machines, we know that the results are always accurate, even in non-stop operation." Currently, the plant is 100% operational. As the foreman explains: "Our task now is to increase the amount of unattended running time so that we can run 3 or 4 shifts in the near future.

From a single source

Different sizes, one concept: All Hermle machines are operated via the Hermle Automation Control System (HACS) intelligent order management system.

For Humbel, reliability is a central aspect. "Speed and agility are our daily bread," says the CEO. In some cases an order has to be finished in five weeks, including turning, milling, heat treatment and subsequent hardening. "We can only guarantee that with corresponding machinery," explains Humbel. That also requires a rapid and competent response on the part of the service technicians when anything goes wrong. "In our experience, Hermle is one of the few machine suppliers who really deliver what they promise," he says in approval. Midhat Dedovic adds: "I didn't expect anything else, although my expectations were high – after all, the same goes for our own standards, too. Working with Hermle we simply see eye to eye."

This is a decisive factor when it comes to building up a long-term strategic partnership. Urs Humbel uses two examples to show where this cooperation may lead to: The company has entered the spiral bevel gear technology field and is currently verifying alternative manufacturing techniques for creep feed grinding. This is very time consuming. "Even when the grinding machine is fully utilized and automated, the 5-axis technique can still have benefits in terms of cost, especially for small series." Skiving is another project. The CEO drops this hint: "Generative grinding places extreme demands on both the kinematics and the drive of a machine as well as on the user's know-how. We regard this as a promising technology, and there is a fair chance that the next Hermle machine will be a mill-turn machining centre."

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