Machines have many important components, but perhaps none matter more than the parts where the machine and the rest of the world meet. With cars, this point is the tires, which contact the road. When it comes to CNC routers, it means router bits.
Please read on to learn more about the geometry of CNC router bits so you can appreciate their diversity and select the right one for your machine.
Background Comparison
Before considering CNC router bits, imagine the bits of a more common tool: the power drill. With power drills, the bits are designed to fit into variously shaped screws or to pierce through various materials, like wood or metal.
Power drill bits are shaped according to function. A drill bit that can cut through wood can’t pierce stone or metal, so you’d need a differently sized bit. CNC router bits work on more or less the same principle.
Single, Double, and Triple Fluting
The phrase “fluting” refers to the number of threads, which look like something like coiled braids, on a CNC router bit. Single fluting gives you faster feed rates for softer materials, like plastics. Single-flute cutters typically have more room for chips, but their single cutting edge limits their feed rate or the hardness of materials.
Double and triple-fluting are much more suited to harder materials. Their smaller chip load provides a smoother cutting action. The materials you plan to cut will largely dictate which type of fluting you need.
Upcut and Downcut Spirals
CNC router bits are often spiraled but will cut very differently depending on whether the blade is on the upper or lower part. Upcut spirals are great for slotting and grooving. They’re perfect for use on the bottom side of the piece part, as they cut rapidly since the tool itself removes the chips from the material.
They’re ideal for harder materials, not softer ones, like MDF. Upcut spirals are excellent when you need a nice finish on the bottom side of a part. On the flip side, CNC bits with downcut spirals are ideal for downward chip flow when you need the best finish on the cut part’s topside. Because the chips get pushed back into the material, you should reduce the cutting speed.
You’ll need both geometries in your arsenal, along with when to use each one.
Compression Spiral
Finally, compression spiral CNC router bits are used for double-laminated material. They provide the best finish on the part’s top and bottom sides. They create a very clean cut on the top and bottom edges because the spiral forces the chips back into the material, so long as you reduce the cutting speed.
You can often find all these CNC router bits for sale at the same stores that sell the machines themselves.
It doesn’t matter how powerful the engine is in your car; when roads have ice on them in winter, you need snow tires. Just so, get the CNC router bit that matches the materials you use, and you’ll enjoy productive use of your machine for years to come.
