Roughing toolpaths: Introduction to hobby CNC?

[SweetJustice]

I'm ready to start milling my first 3d-modeled part, an aluminum block with a vertical L-shaped protrusion.

I tend to assume that the coders know more than I, but with default settings, the roughing paths I've generated in pycam, Pro/NC at work, and mCodeGenerator all seem wrong. They want to plunge randomly into the workpiece, slot straight along X and/or Y, lift up over the protrusion, and plunge back down on the other side and keep cutting along the same line.

Shouldn't I be cutting with the side of the tool where ever possible? The entire part could be cut without a single plunge or slot, just a gradual 2D spiral around the outside of the protrusion.

This is a very basic question, but because it's CNC, it's beyond the scope of my intro texts, Tabletop Machining and Home Machinist's Handbook. Everything in the library seems targeted to professionals with Bridgeports, who already know this stuff. I'm obviously lacking a lot of background. What do I read next?

[JoeBean]

I'm not familiar with any of the specific software packages you're using, but typically CAM software will give various options to control entry/exit as well as whethr to do all areas to each "step" depth at once, or one area to full depth at a time. Entry/exit controls would allow ramping with various parameters (ie. the line, or curve as it may be, of the cutter, as well as feeds) or directly plunging. But the paths of the tool, once entry has been made, will typically contain themselves to a single plane, ie. not complex spirals. In the case of contouring the contouring action would typically be confined in a single plane at any given time, either the XY, or XZ, or YZ, while it moves a step at a time along the other axis (Z, Y or X, respectively) as one plane's contour is complete.

Watch some youtube vids of contouring to get the idea.