2D Toolpath Terminology

Though the terminology and ways of working vary widely, all CAD/CAM software needs the same basic information to function. Figure 7.6 shows parameters common to 2D tool paths.

Figure 7.6: 2D Tool Path Terminology

Clearance Height is the first height the tool rapids to on its way to the start of the tool path. It is usually set 1.000 in above the top of stock because this makes it easier to see if the tool length offset register was set properly.

Rapid Height is the second height the tool rapids to, and the height the tool retracts to between moves (unless set higher to clear clamps). It is usually set to .250 in above the top of the finished part face.

Feed Height is the last height the tool rapids to before starting to feed into the cut. It is usually set to .1000 in above top of stock. No rapid motion occurs below this height.

Top of Stock is the top of the finished face of the part. This value is used as the reference plane for depths.

Stepdown is the depth of material removed with each cutting pass. This illustration shows one pass, but for deeper cuts or harder materials, many passes may be required to cut to the final depth.

Depth is the final cutting depth of the machining operation.

Stepover sets how much material the tool removes with each pass in the XY direction.

XY Stock Allowance is the material remaining on the finished wall of the part to be removed by subsequent operations.

Z Stock Allowance is the material remaining on the finished floor of the part to be removed by subsequent operations.

Toolpath Centerline represents the actual coordinates in the CNC program. In this book, rapid moves are shown as dashed lines and feed moves as solid.