CAM software for highly complex machining

Citation

(2001), "CAM software for highly complex machining", Aircraft Engineering and Aerospace Technology, Vol. 73 No. 2. https://doi.org/10.1108/aeat.2001.12773bab.021

CAM software for highly complex machining

CAM software for highly complex machining

Keywords Open Mind, CAM, Milling, Machining

CIM 2000 saw the launch of a software module developed by Open Mind for full five-axis CNC milling using its hyperMILL and hyperFORM computer-aided manufacturing (CAM) products (Plate 5). Considered suitable for mould and die, turbine blade and aerospace machining, the new modules are described as easy to use, providing rapid program generation, exhibiting high levels of process reliability and offering improved as-machined surface quality.

Plate 5 True five-axis programming within Open Mind's CAM systems uses a patented mathematical model for comprehensive collision checking, eliminating the need for simulation

Before embarking on the development, the company informs us that it identified shortcomings in existing software from other vendors, in particular the inability of most to support reliable automatic collision checking. This in turn led to problems in applying five-axis machining to deep cavity work where it has much to offer. As a result, a high proportion of such work within the manufacturing industry tended to use three interpolative and two positional axes to machine discrete features rather than the component in its entirety.

Open Mind collaborated with the Fraunhofer Institut in Germany to develop a more complete solution to five-axis program generation. It is based on a patented mathematical model which uses leading curves which define the inclination of the tool and therefore the machining axis position. By comparing the leading curve against the polyhedral surface model of the component, it is said to be possible to detect whether the tool and its holder will collide with the surface. The need for external simulation is therefore eliminated and programming time is minimised. Likewise, the program can reportedly utilise all of the machining axes to optimise cutting conditions so the run time of the machining program is reduced.

Ability to import all electronic data formats via standard interfaces is a key feature claimed of Open Mind's new hyperFORM V5 computer-aided manufacturing CAM system, developed specifically for the mould and toolmaking sector. Many data exchange formats are included such as IGES, STEP, DXF and VDA, and there is the option of a direct CATIA interface. Users with a multi-client customer base will, it is thought, have no problem in handling computer-aided design (CAD) models presented in a variety of formats.

With the introduction of this stand-alone product, which spans simple 2.5D pocket milling and drilling through to full simultaneous 5-axis work, Open Mind is now primarily focused on the mould, tool and die market. It is emerging as one of the leaders in the field, according to the US research organisation, CIMdata, in its 1999 industry report. The privately owned, German company was the fastest-growing CAM software vendor in Europe during 1998 and 1999. Last year, revenues grew by about 35 per cent over the previous year to in excess of US$15 million.

The rationale behind hyperFORM is that many toolmakers do not want to provide a design service, choosing instead to import component data in electronic form from their customers. Graphical exchange is normally required but invariably the models do not translate cleanly. Toolmakers which find themselves in this position are looking for a powerful, standalone CAM system married to basic CAD functions for performing limited operations on the imported model, such as surface functionality for closing gaps between surfaces, creation of boundaries and surface trimming. This minimises the need to shuttle between CAD and CAM when preparing the imported model for machining.

Milling strategies available within hyperFORM include Z-level roughing and finishing (waterlining), milling along leading curves, slope machining and fully automatic rest machining. High speed functions include 3D equidistant finishing, HSC loops for finishing applications and automatic pencil milling. Tool paths can be viewed using the hyperVIEW simulation package and post processors are available to suit the majority of CNC systems.

Open Mind's core product, hyperMiLL, was demonstrated at CIM 2000 in three new versions, all of which are embedded in their respective CAD systems. One was hyperMILL for CATIA V6.6, thought to be a de facto standard design system for the aerospace industry, incorporating enhanced functionality as yet to be announced. There will also be two improved CAM packages for Autodesk CAD products, one being hyperMILL V5.2 for the latest release of Autodesk Mechanical Desktop – V5.0 – again with the emphasis very much on mould and die making. It claims improved machining strategies, more flexible job listing, an integrated simulation module and HTML-based help.

The other version of hyperMILL was preview release. Based on new methodology, it is for integration into the new feature-based, solid modelling system, Autodesk Inventor. The package will introduce Open Mind's adaptive machining technology which automatically checks the features of the model and rearranges them into manufacturing features and then in turn into cutter paths for machining.

Full associativity is said to be provided between the model and the cutter paths to create a family of similar parts just by changing the model and saving it under another name. Revised cutter paths are calculated automatically according to the changed model.

Further details are available from Open Mind Ltd. Tel: +44 (0)1235 764529; Fax: +44 (0)1235 764659; E-mail: CliffordAshwin@openmind.de; Web site: www.openmind.de