Sleek Style in Composite Materials, Thanks to Multi-Axis Machining

July 21, 2010
Vero expertise optimizes gantry milling program for Artega GT 'supercar'.

Front view illustration of the Artega GT.

A completed body panel, machined using the VISI Machining 5-Axis program.

DECS GmbH designs and manufactures interior and exterior trim components in composite materials for customers like Audi, BMW, Lamborghini, Mercedes, and Porsche. Since 1994, DECS has been adopting and exploiting new process and production technologies and process optimization, and a combination of these factors helped it with its latest automotive design achievement, the Artega GT.

The Artega GT is a mid-engine, rear-wheel drive, high-performance sports car designed by Henrik Fisker, the designer who’s responsible for the celebrated Aston Martin Vantage and BMW Z8 — both celebrated for their sleek, curvaceous styles. The two-seat Artega GT has an aluminum space frame and carbon-fiber reinforced body. A Volkswagen-sourced 3.6L V6 engine provides the power that allows it to reach 60 mph in less than 5 seconds.

The DECS GmbH contribution to the project involved the manufacture process for the front hood, tailgate, and roof panels.

"Artega originally contacted us because we have been involved in a number of projects with other prestige automotive clients and possess the skill and knowledge required for the development of composite components,” recalls Ulrich Krämer, managing director of DECS GmbH. “For the initial pilot project, we first created five parts using a prototype tool. This must have left a good impression with Artega, as we were then invited to participate in the second phase in which we produced a pre-series set of tooling for the front bonnet and tailgate for testing. After successful pre-series testing, we now manufacture the complete suite of production parts for the front bonnet (hood), tailgate and roof."

One example of technology innovation is the expertise DECS GmbH have developed in the production of polyurethane-based composite components using a honeycomb core. This is especially relevant in the development of automotive interiors as the potential weight reduction is extremely attractive to car manufacturers. Natural fiber-reinforced polyurethanes are being used more and more in the automotive industry and it is now possible to produce parts with wall thicknesses of 1.5 to 2.0 mm — depending on the unit weight of the natural fiber mat used. These end products weigh about 45% less than products created using conventional injection molding materials.

One example of process optimization is the use of Huber & Grimme gantry milling machines, which are equipped with efficient two-shaft spindles and tandem worktables for multi-axis part trimming. Once the body panels are removed from the tool, they are placed onto jigs and fixtures for part trimming and additional CAM operations. All 5-axis operations are programmed using VISI Machining from Vero Software and posted using a Siemens 840D controller. Due to the complex nature of multi-axis machining, NC programs also are simulated prior to running on the shopfloor. The simulations are checked against the physical machine limits to ensure process-safe toolpaths.

3D tooling constructed using VISI from native CAD data.

Multi-axis toolpath trimming, simulated using VISI.

The relevant jigs and fixtures are also designed using VISI and produced at DECS. "VISI is the ideal tool for the construction of the trimming jigs", explains Ulrich Krämer. "One major advantage is the ability to constantly switch between solid and surface technologies. This is vitally important to us and allows us to follow a flexible design path. VISI provides interfaces to all the significant data formats such as CATIA, UG, Pro E, STEP, IGES and SAT and this allows us to handle our clients native CAD data with confidence."

VISI has been in use at DECS GmbH since 2005 when the software was provided as a solution for simultaneous 5-axis milling to solve a problem that involved the complicated trimming of plastic parts with undercut positions that could not be could be processed with water-jets.

Ulrich Krämer concludes, "We looked extensively at the CADCAM market and we decided on VISI, not only because the solution impressed us the most, but also because of the price-to-quality ratio of the system. The VISI system caters to all our needs, and has in fact exceeded our expectations. We stepped in at version 12 and from there to the current version has been a gigantic leap forward. VISI is continually under development, and we are often asked what we would like in the software. We know that the software will be around in the future which means security in planning."

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