CAD/CAM software company WorkNC (
www.worknc.com) recently partnered with Hermle, Ingersoll and Gressel to provide a one-stop machining solution for producing a prototype motor-sport wheel carrier.
Using WorkNC’s 2-D, 3-D and five-axis tool-paths, the wheel carrier was machined from an aluminium alloy (AlMgCuPb) using adaptive trochoidal roughing and ‘global re-roughing’ strategies before finishing largely with 3+2-axis machining.
The component was produced on a Hermle C32U machining centre, with the stock held in place by a Gressel work-holding system.
The Ingersoll cutting tools used for this application included a FormMaster Pro for the pre-roughing and machining of the back of the carrier, a ChipSurfer for re-roughing operations, an OctoPlus for facing, a ChipSurfer Ball for contour finishing, and a variety of tools for drilling, tapping and boring.
WorkNC sales engineer Gerhard Hermann says that the partnership shows co-ordinated teamwork in the manufacturing chain between machine tools, cutting tools, work-holding and CAM software. “We have worked together on many occasions in the past few years.
This wheel carrier for a racing car is a perfect example of how a proven, single-source solution ensures that manufacturers can optimise their machining process.”
In producing the wheel carrier, WorkNC automatically considered the tool-holder during its calculations, thereby obtaining the optimal machining of all areas. “This was achieved principally through the use of a dynamically updated stock model,” says Mr Hermann. “Due to the availability of the exact information relating to the current state of machining, only areas with remaining stock were milled.
"WorkNC automatically separated those three-axis tool-paths into several inclined 3+2-axis paths. The angles can either be set by the user or defined in a very simple way using the Auto 3+2 module, reducing programming to just a few mouse clicks.
“Furthermore, WorkNC’s five-axis simultaneous milling generates continuous tool-paths, creating an excellent surface finish with short tools — and programming is considerably more simple as only a few tool-paths need to be defined.
“Each WorkNC tool-path can also be automatically converted into a collision-free five-axis path, meaning that there is no need for the time-consuming definition of guide curves or surfaces.”
Tool-making in India
Meanwhile, Pune-based SP Tools, which produces injection moulds and precision tool-room parts for many leading companies, relies on WorkNC CAD/CAM software to program parts quickly and accurately.
Moreover, the company has such confidence in this software that it is happy to leave machines cutting unattended out of normal working hours, further increasing productivity.
The company recently bought five vertical machining centres with Mitsubishi controllers.
Manufactured in India by Bharat Fritz Werner, these machines have work envelopes ranging from 650 x 450 x 450mm to 1,700 x 900 x 800mm, allowing SP Tools to machine large and intricate moulds as well as small electrodes. WorkNC also provided the post-processors for all the machines.
When producing injection moulds, SP Tools needs to rapidly remove large volumes of material before undertaking semi-finishing and finishing operations.
WorkNC’s Global Roughing strategies achieve this by using highly accurate stock and rest models so that the software knows exactly where excess material is located, thereby minimising redundant air cutting and retract moves and ensuring that shock loading of the tool is avoided.
To maximise metal removal rates, WorkNC automatically generates tool-paths that can machine smoothly with large depths of cut and step-overs up to 95% of the tool diameter.
The techniques used include trochoidal machining (where the cutter describes a spiral path when it encounters a full-width cut condition), helicoidal lead-in moves (which again avoid cutting with the whole tool), and both spiral and smooth radial movements at corners (these stop the tool rubbing in corners and avoid sudden direction changes, keeping tool loads constant).
Furthermore, WorkNC’s Flat Surface machining further speeds up metal removal. With this strategy, the software can automatically identify flat areas in the mould directly from the imported CAD model.
It can then apply the fastest cutting trajectory, using large tools to machine the area in the shortest possible time; this strategy not only results in quicker machining, but also produces a superior surface finish. Furthermore, SP Tools uses WorkNC on the shopfloor, such is the ease-of-use of the software.