Leveraging modern CNC capabilities: Drilling Performance

You’ve just received the latest release of your favorite CAM software and loaded it on a new PC. As a result, your shiny, new machine tool with a state-of-the-art controller awaits its next challenge. Yet you’ve still got the same nagging problems once everything is up and running. The G code isn’t quite right and still requires manual tweaking. The files are overly large and hard for the operator to interpret. And the machine doesn’t “sing” the way it should.

That’s caused by an outdated NC post-processor, an often-overlooked piece of the chain between the CAM system and the machine’s CNC. Everyone must have an NC post-processor but no one wants to think much about it—if it just works and stays completely in the background, so much the better.

But CNCs have various new features that an updated post-processor can leverage. The right post can also adapt to take full advantage of the machine’s characteristics, based on toolpath data. This column explores how to get the most out of a post-processor.

The capability to define an arbitrary orientation for machining operations and treat them as if you were doing normal 3-axis machining is a powerful feature of today’s controllers. Commonly called “working plane,” or “tilted working plane” in Fanuc vernacular, and “frames” according to Siemens, this capability allows the use of canned drilling cycles and cutter compensation for contouring in “3+2 machining” or “5-axis positioning.”

Courtesy of IMS Software

In this screen shot, IMSpost shows the machine model, the automatically programmed tool from the CAM software and the resulting G code.

For example, when 5-axis drilling, instead of a series of G0/G1 moves with a defined working plane, a user can employ a standard G81 canned cycle. Profile contouring in planes other than the standard X-Y, Y-Z and X-Z can use the controller’s built-in cutter-compensation functions.

An effective post-processor, such as IMSpost from IMS Software Inc., defines the working plane based on a variety of different inputs from the CAM system and outputs the correct code based on the specifications of the CNC. The result of using IMSpost to support working planes is easy-to-read, concise G code that leverages the controller features for efficient operation.