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8CNC Router Essentials

3 : Toolpath Essentials

cause you to lose control of the tool. With a CNC, this is not a concern, Image 3.11, and you can reap the primary benefit of climb cuing, which is that it reduces grain chipping when cuing solid wood. Conventional cuing is commonly used for other materials or as a finishing pass aer climb cuing. Sometimes determining the best cuing direction requires running a test cut and then examining both sides of the cut and choosing the one with the best edge quality. Whichever cuing direction you use, the goal is a smooth edge that’s best for your project. On projects with exposed edges, you can expect to do about the same amount of sanding as you would when using a handheld router or router table.

Offset and raster

Achieving a smooth surface at the boom of a pocket cut can be a challenge. First, make sure you are using a bit designed for boom cuing in your material. Generally, this will be some a type of end mill bit. Then give some thought to the pocket clearing direction for the cut. Two common ones include offset and raster, Image 3.12. Think of offset cuing as a spiral motion, and raster as a straight-line motion. Raster can be set up to cut in the X or Y direction or at an angle. Think about machining a piece of wood. You typically get the best cut quality by going with the grain, or at an angle. So, when you’re concerned about the quality of the finished cut, seing the raster cut parallel to the

Image 3.10: The Profile Toolpath is used to cut around a shape or on a line. Any bit can be used with a Profile Toolpath, although a straight bit works best when cutting out around a project.

Image 3.11: As a general practice, use climb cutting for solid wood and conventional cutting for other materials, but run some tests to determine which feed direction produces the best edge quality for your particular material and bit. Sometimes a combination of the two feed directions is used to produce the desired results.

Conventional Cut