Overview

A good CAD/CAM system is one of the most important tools in a modern machine shop, and will provide enough control to confidently drive any multiaxis CNC equipment. The three major things that need to be controlled are:

• Cut Pattern - This pattern guides the tool s cutting directions.

• Tool Axis Control - The orientation of the tool s center axis in 3D space as it follows the cut pattern.

• Tool Tip Control - The geometry that the tool tip is compensated to follow.

In addition to those three major controls, which are defined in more detail in this chapter, good-quality CAD/CAM systems also provide additional collision-avoidance. This insurance will recognize the tool s cutter, shank, and holder. Different avoidance behaviors can be invoked when any of these components comes into proximity with the work-piece or a fixture. Different near-miss tolerances can be assigned to each of these tool components.

Cut Patterns

Cut Patterns guide the tool along specified paths. These patterns can be simple 2D or 3D wireframe, or solid primitives (for example, box, cylinder, and sphere.) Cut Patterns can also be complex multi-surface grids.

Some examples of cut patterns are shown in Figures 6-1 through 6-17

Figure 6-1: Tool motion following a 3D curve projected on to the face of a workpiece.

Figure 6-2: Tool motion following the rib s bottom edge.

Figure 6-3: A Cut Pattern is selected to slice the part in any given plane, for example, patterns 3 or 4.

Figure 6-4: Impeller...