Choosing the right bit makes all the difference. It’s the difference between your result being perfect and just being okay. It’s the difference between cutting down on waste and increasing material costs. In the most extreme cases, it’s the difference between operating your CNC machine safely and setting something on fire.
Do you primarily use your router with wood? Is it hardwood, soft wood, or plywood? Do you use your CNC for composites such as MDF, particle board or laminate? What about phenolic materials? Maybe your shop depends on your CNC for manufacturing large amounts of plastic, acrylic, or aluminum.
You might be cutting solid surfaces, fiberglass, or stainless steel. CNC machines can even etch glass.
Unfortunately, bit selection is not “one size fits all.” There are even different grades of carbide used for different materials. Choosing the wrong bit for the type of material you are processing may deteriorate or even destroy the bit, your material and, in the worst case, even your machine. Remember, the goal is to cut the material, not grind it.
Cutting bits specifically designed for plastic will help avoid melting the material you are processing. Bits for aluminum will clear the chips so they do not fuse to the bit at high operating temperatures. Compression bits are used to avoid chipping or tearing materials such as melamine and plywood.