[^]

May 6, 2009

Delcam to demonstrate high-speed machining at Haas Demo Days

Delcam will demonstrate the wide range of high-speed machining strategies in its PowerMILL CAM software at a series of Haas Demo Days in India. The events, which will also feature presentations on cutting tool developments from Sandvik as well as the chance to see the latest Haas machine tools, will be held in Delhi on 6th and 7th May and in Ahmedabad on 8th and 9th May.

PowerMILL includes advanced roughing strategies to take full advantage of the latest cutter designs. The most novel technique is Delcam’s patented Race Line Machining. With this option, the roughing passes are progressively smoothed out as the toolpaths move further from the main form. The resulting paths minimise any sudden changes in direction and so allow faster machining, with less wear on the cutter and lower stress on the machine tool.

PowerMILL also incorporates a trochoidal machining option. This avoids full-width cuts when machining narrow areas by generating toolpaths automatically that progressively shave material from the block in a circular motion. The option creates toolpaths that maintain efficient and safe machining in any areas where conventional strategies would put excessive load on the cutter.

A combination of strategies is available for finishing, with 3D offset toolpaths used on flatter areas and Z-level finishing used on steeper areas. The 3D offset toolpaths are calculated with the surface stepover varying so that a constant cusp height is applied over the part, reducing the amount of hand finishing needed.

A spiral path can be used as an alternative to the conventional Z-level approach. Instead of machining down the job level by level, this strategy uses a single, smooth toolpath that machines upwards in a spiral from the bottom of the surface. This keeps the cutter in constant contact with the job and so eliminates air moves. The smoother toolpaths also minimise any dwell marks as well as protecting the cutter and machine tool.

With both rough and finish machining, arcing moves are generated by PowerMILL when approaching and leaving the job. Plunging onto the surface of the part is avoided as this can damage the cutter.

Similarly, arcing moves are used to link the various cutting moves. The traditional approach of using right-angle moves is avoided as this requires the cutting speed to be reduced and can leave dwell marks.

An additional feature within PowerMILL to protect the cutter is the automatic fitting of arcs to toolpaths as the tool approaches any steep face. Without the arc, there will be a sudden increase in the load on the tool as it engages the steep surface. To prevent damage, the feed rate must be reduced so overall machining times will be increased. With the arcs added, a smoother toolpath results that can be run at higher speed with less wear.

For both roughing and finishing, efficient ordering of the toolpaths within PowerMILL ensures that air moves are kept to the minimum. In addition, the use of a reference stock model after every operation makes sure that subsequent toolpaths are only generated where material remains, again eliminating excessive air cutting.