the many tools available for CNC milling

What Are Chamfer Mills?
Chamfer mills do not have blades along the edges, only at the tip. These are used to cut angled edges. The cutting blades on each chamfer mill are called “flutes.” The more flutes on the mill, the more delicate the cut. But fewer flutes on the mill remove more material each turn, for faster production. Balancing speed and finish is essential when selecting a chamfer mill with two, three or four flutes.
What Are End Mills?
End mills come in several types used for different cutting. All end mills cut at 90-degree angles, which distinguishes them from the angle-creating chamfer mills. To cut straight down, you use a center cutting end mill. These mills cut both in the middle and on the sides.
Non-center cutting end mills have a hole in the center and only have cutting edges along the sides of the mill. Roughing end mills are used to make the initial cuts because these have fewer flutes and remove more material at first. To create the finely cut finished product, you’ll use finishing end mills, which have more flutes to achieve a closer design to the desired part.
Aside from the number of flutes, the material used for the end mill will also make a difference in the tool used for a project. Cobalt, high-speed steel, and carbide are common materials used to create end mills. Each of these materials has its benefits, but they cannot be used interchangeably. Here’s what to know:
Cobalt: Cobalt mills are only comprised of eight percent cobalt , with the remainder of the construction made of steel. Thanks to the reinforcement of cobalt, cobalt mills run 10 percent faster compared to high-speed steel mills. This increased speed removes more metal, more quickly, than HSS without sacrificing the finish.
Carbide: While carbide is harder and can be turned faster than high-speed steel, it also tends to chip. Don’t use carbide mills for rough work. These end mills are best suited for finishing processes.
High-Speed Steel: High-speed steel, or HSS, is the standard material used for many mills. It carefully balances longevity and tool cost. Though end mills made of high-speed steel cannot turn as fast as those made from carbide or cobalt, the lower price makes HSS a better option for many. Additionally, HSS has enough flexibility to be used in the cutting of iron and non-iron materials.
End mills have numerous means of cutting into a material. How you will cut determines the tool used:
Side milling: When you want to produce beveled edges with chamfer mills, you perform side milling. This process moves the mill along the corner of the material to cut into it and smooth it to the desired angle.
Face Milling: When you simply cut into one surface of a material, it’s called “face milling.” The surface is the face of the material.
Ramping: Ramping cuts directly down into a surface and at an angle, creating a slanted cut down through the material.
Plunge: As the name suggests, plunge milling makes the end mill dive straight down into the material being cut. Like ramping, plunge milling requires a center cutting end mill to remove material from the center and edges of the hole produced.
Slot Milling: Slot milling produces slots through a material, cutting edges on two sides at once as the end mill makes a groove.
What Are Ball End Mills?
Ball end mills have rounded tips. As the name suggests, these mills produce clean and rounded bases at the bottom of the holes they create. Do not confuse ball end mills with bull nose mills, however. Although both create rounded cuts, bull end mills produce straight bottoms and sides with softened corners. Ball end mills are ideal for carving because they produce spherical bases.
What Are Straight Flute Mills?
Mills usually have twisted flutes. But in straight flute mills, the cutting teeth are vertical. The straight sides are best suited for cutting delicate or easily frayed substances, such as plastics or epoxy composite materials.
What Are Down Spiral End Mills?
Most end mills have up-spiral designs, which pull the cut material up and out of the hole produced. But down-spiral end mills push the cut material downward. These mills do not work well for drilling through an element, but the end mills work well for cutting thin materials while keeping the top clean.
What Are Drill Bits?
Drill bits cut holes in a material. Occasionally, a machinist must drill a hole first before adding threads with taps or widening the hole with reamers. Twist drill bits are commonly encountered in general repairs. These bits create small holes.
As with end mills, drill bits can be made from different materials that influence their strength and performance. Coatings on the exterior of the bits may increase longevity. Here are some common materials:
Carbide: Like end mills, carbide drill bits increase the bit’s longevity. But this delicate metal requires secure and straight positioning to prevent the bit from breaking.
High-Speed Steel: The same HSS used for end mills may also be used to create drill bits. These bits have a quality that makes them suitable for general use without breaking the bank.
Titanium Nitride Coating: Titanium nitride, or TiN, coating makes the drill bit appear gold on the cutting surface. TiN increases the hardness and longevity of the bit. Additionally, the bit operates more smoothly because the TiN coating slightly lubricates the surface.
Titanium Aluminum Nitride Coating: The most common coating for end mills and bits is titanium aluminum nitride, or TiAlN. While TiN makes a bit appear gold, TiAlN gives the exterior of the part a bluish color. The longevity of the element increases while the speeds at which you can use the bit rise by 20 percent when the bit has a TiAlN coating.
What Are Flycutters?
Flycutters are used to create a smooth, flat surface from a large piece of material. Think of table tops and counters. While they get a lot of material off the surface quickly, the design of flycutters can make the engine of the CNC mill work harder. Some people refer to flycutters as “spoilboards.”