11 An Introduction to CNC Milling
11.6 Sharpening the Tools
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11.5.4.
Engraving Tools
An engraving tool has a single sharp cutting tip. The engraving tool is used to produce very shallow, narrow, and
fine cuts into the workpiece face.
11.5.5.
Roughing and Finishing Tools
Two-tooth tools are generally used for roughing operations. These tools can be moved very quickly to
cover a large surface area.
A tool with a small number of teeth has relatively little contact with the workpiece in a single revolution.
The material is removed from the workpiece in chunks, leaving an imperfect surface scattered with
ridges. This is acceptable for roughing operations, as these imperfections will be removed during
finishing.
For finishing operations, four-tooth tools are usually used. These tools remove a greater amount of
material in a single revolution and provide a smooth finish. This finish comes at the expense of speed.
The cutting speed must be reduced as the number of tool sides grows, to compensate for the additional
heat generated during cutting.
11.6.
SHARPENING THE TOOLS
Cutting tools will dull over time and need to be sharpened or replaced. Sharpened tools will have a
smaller diameter so be sure to measure them and adjust the tool offsets accordingly.
