Released on 10/1/21

Realized advantages :

  • Complete machining without complex reclamping processes
  • Fast set-up thanks to automatic tool change
  • High cutting volume thanks to stable machine connection
  • Suitable for long-term use
  • Notes on service intervals using operating hours recording

 

Exchange front tools automatically

Angle heads have been state of the art in the machining of complex components for many years. Angle heads are used in particular for the internal machining of housing components in aircraft engines or stationary gas turbines, because the main spindle often cannot plunge or swivel into the interior of the housing. As a result, numerous different tools are usually required for production. Until now, changing these tools was a rather uneconomical process. In an innovative project, DMG Mori therefore joined forces with Benz Werkzeugsysteme to develop an angular head for automatic insertion and replacement of the front tools.

Demanding workpieces made of difficult-to-machine materials such as titanium or nickel alloys require the use of many different tools as well as sister tools due to high wear. Until now, the tool change in the angle head was done either manually with the machine stopped - with a correspondingly high influence on personnel costs and cycle times - or by automatically changing complete angle heads, which are carried along with each sister tool or stored on special pallets. This results in high investments and a limitation of the overall system. To counter these cost-intensive solutions, the machine tool manufacturer DMG Mori, Bleifeld (www.dmgmori.com), together with the company Benz Werkzeugsysteme, developed an angle head for its series machines with which the front tools can be automatically exchanged.

Green button process without manual intervention as a goal

Low throughput times and production that is as unmanned as possible are common criteria for high competitiveness in machining. This is especially true in the highly competitive aerospace sector. "The machining of components in the industry is increasingly taking place in a 'green button' process, where manual intervention is no longer necessary," explains Michael Kirbach, Head of the DMG Mori Aerospace Excellence Center in Pfronten. From numerous customer projects, the challenge of efficiently integrating an angle head into this manufacturing process is therefore also known. Our goal was a solution in which only the front tools are automatically exchanged in and out of the angle head. The need for such a solution was also confirmed by DMG Mori customers in a survey. The trigger for the implementation was ultimately a new project at a leading engine manufacturer.

Technological competence through development partnership

In Benz, DMG Mori has found a competent technology partner for the development of an angle head that meets today's requirements. The company from Haslach in the Kinzigtal is one of the world's leading manufacturers and suppliers of components and systems for tool and machine technology. The southern German specialist for tool systems was already involved in the project during the concept phase in order to test the feasibility of an angle head with the corresponding functionality. Andreas Motus, Technical Sales at Benz, remembers the enquiry: "We already had the design for such an angle head in the drawer and had already implemented it, but due to the lack of available machine platforms, we did not develop it further for series machines from DMG Mori at the time." This has changed with the patented wheel magazine of the machine tool manufacturer.

This magazine technology offers the possibility of guiding both appropriately large and heavy angle heads as well as the front tools in a holder in the tool wheel that is matched to the respective angle head. At DMG Mori, the machine basis for manufacturing with angle heads is usually a machining centre of the "duoBlock" or portal series. Mostly, milling-turning technology is used due to rotationally symmetrical housing components," adds Kirbach. Thus, the concrete project with the new angle head includes two "DMC125 FD duoBlock" and one "DMU 210 FD".

During the intensive cooperation, Benz gradually adapted the existing design to the series machines. First of all, the changeover weight and the tilting moment had to be adjusted," explains Motus. "We also integrated the additional clamping elements into the angle head to minimise interference contours on the machine spindle." The angle head must ensure reliable clamping of the front tools. This requires a hydraulic transfer from the spindle and was implemented by Benz with special hydraulic couplings. In addition, the company has found a way to transmit signals inductively instead of via separate plugs.

Interaction of tool changer, angle head + software

According to Motus, a major challenge during development were the requirements for repeatability during tool changes: "The tolerances in the production of the angle head are consequently very low." The interaction between the tool changer, the angle head and the software was also crucial, Kirbach adds: "The software regulates the sequence of the change process as well as the management of the angle head and the front tools including their holders, which remain in the tool wheel after the change. "In particular, the compatibility with series machines is an advantage: "Users can order the solution in the machine together with a proven angle head concept as an option and do not have to design an elaborate special solution that limits the complete system."

Already high customer interest in the innovative concept

After completion of the project, DMG Mori and Benz are more than satisfied. The result is a solution that allows the machining centre to change the angle head and front tools in and out independently of each other and organise them in the tool magazine. This enables users to manufacture the complex components unmanned with just one angle head. The first customers have already seen the concept and signalled great interest in the option. Above all, the justifiable amortisation period is convincing, says Kirbach.

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