A GOOD CONTOUR CALCULATOR SHOULDN'T TAKE UP ROOM IN YOUR POCKET

Intelligent kinematic transformation is the technical term, but all it really means is that today?s CNC should be able to maintain the proper orientation of the cutting path, even in pockets or on contoured surfaces. This applies whether you?re milling a workpiece in a rotated plane or turning the front face or peripheral surface of a turned part.
So, if you?ve become attached to your pocket calculator or sophisticated and expensive CAD/CAM post-processor programs, you can still keep them, but they might soon become like that appliance repairman from the old commercials.

Here?s why: The advanced integrated processor geometry of today?s CNC allows you to assign specific position patterns such as lines, circles or grids for milling and drilling cycles, with just a few inputs on the keyboard. The kinematic transformations in the CNC enable these position patterns to be called up without any calculation or other programming steps, even on inclined workpiece surfaces of milled parts or the end faces and peripheral surfaces of turned parts.

Cycle geometries for standard operations such as turning shoulders, thread undercuts and trapezoidal grooves can be assigned in a similar way. Since you can use these turning cycles in all workpiece quadrants, even the machining of inside contours becomes simpler and more predictable ? and all these cycles can be applied to a counterspindle, as well, without any restrictions.

Hold on, though, it gets better. These cycles are not limited, by any means, to creating standard geometries. You can produce any type of contour or pocket with islands, even with rotating tools on turning machines. What applies to the milling contours can be done with rotating turn tools, as well, using a recently developed contour stock removal cycle. This type of cycle facilitates not only the typical longitudinal and facecutting operations, but also contour machining with recess or plunge-turning tools.

Even complex contours can be generated on the more sophisticated CNC, because of this processor geometry, and partially defined contour elements are calculated automatically. In addition, DFX files can be processed by installing a simplified CAD reader onto your PC to convert your DFX files into the proper geometric language for the CNC.

Lastly, a tougher one: Swiveling a plane can be done by entering the desired coordinate rotation, whereupon the CNC automatically orients the machining to the proper position. This function can also apply to a counterspindle, whether it?s being used to support the workpiece or machine the backside. A good numerical control today can handle spindle synchronization, gripping, pulling and even parting the workpiece ? all automatically. This straightforward counterspindle cycle enables the operations to be accomplished without any additional CNC language commands and even sloping surfaces can be programmed very easily. The machining plane can be rotated to the correct orientation, without the need for either that trusty pocket calculator or CAD/CAM system prep.

In the end, if your machine has a more sophisticated CNC, machining the most complex inside contours with relief cuts will become much easier. The geometric tracking function even handles the identification of residual material automatically.

Special Note: I?ll be attending IMTS, so stop by the Siemens booth and say hi. Bring your CNC questions, too!

– – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – –

Randy Pearson is the sales support manager for U.S. dealers and OEMs of Siemens Industry, Inc., 390 Kent Avenue, Elk Grove Village, IL 60007, www.siemenscnc.com. A veteran of the machine tool industry, his interest is the training aspect on CNC machine tools, through classes conducted at votech schools, shops and Siemens training facilities. For questions or comments on this column, contact Randy at 847-952-4250 or randy.pearson@siemens.com.