Highly automated milling is a versatile machining process that is capable of producing components in almost any shape. There are a wide variety of CNC milling operations adopted for different manufacturing purposes. End milling mainly differs from other processes due to the type of tooling it is used for cutting materials. In this article, we’ll outline the types of end mills, what is end milling, and also figure out the difference between end mill and drill bit.
End milling is a type of milling process that can be used to produce slots, shoulders, die cavities, contours, profiles, and other milling parts. End milling uses the end mill which is a cylindrical cutter with multiple cutting edges on both its periphery and its tip, permitting end cutting and peripheral cutting.
The end mill is a type of milling cutter designed to be able to cut axially and applicable in end milling, profile milling, tracer milling, face milling, and plunging. End mills and other cutting tools can be made from a host of materials, such as the carbide inserts (suitable for high production milling), high-speed steel (when a special tool shape needed), ceramics inserts (for high-speed machining with high volume), and diamond inserts (offer tight tolerances). High-speed steel (HSS) and tungsten carbide are two of the most common materials for making the end mill. End mills allow precision cutting to manufacture milled parts for broad applications, including jewelry, sign making, mold making, circuit boards, wood engravings, machine parts, and more. Endmills are available in varying lengths, diameters, flutes, and types.
End mills can be classified based on the number of flutes, helix angle, shapes, materials, coating, and more. Here we talk about some common types of end mills.
1. End mills in different shapes
– Ball nose end mill: with a radius at the bottom which makes for a greater surface finish, produces a rounded pass, ideal for 3D contour work, shallow slotting, pocketing, and contouring applications.
– V-bits: with small angles and tips, produce a V-shaped pass, used for engraving, narrow cuts, and small, delicate engraving of lettering and lines, particularly for making signs, it’s also available for exceptionally sharp edges. The v-bit end mill comes in two forms- 60°or 90°V-bit.
– Fishtail end mill: with cutting edges on one end, which may be much thinner than the other end, fishtail end mills can plunge directly into your material and produce a flat surface, prevent any splintering or breakout, create clean edges on thin material and make pockets with flat bottoms, suitable for plunge routing and producing precise contours, like signs. With fishtail end mills, you can also have nice square corners at the bottom of any inset section of geometry.
– Square end mill: also known as flat end mills, are general-purpose mills that generate flat-surfaced cuts with perfect 90° corners in the workpiece, involves milling operations like side milling, face milling, and more. Square endmills can be used in the roughing or finishing stage.
– Bull-nose end mills: also called corner radius end mills, this type of cutter is a combination of fishtail and ball-nose, also a flat bottom but with rounded corners. Bull-nose end mills are often used to mill molds (plastic injection molds, die cast molds, etc.)
2. End mills in different number of flutes
The spiral-shaped cutting teeth on the end mill are flutes, which offer an empty path for cutting chip removal during the machining process. End mills available in 2, 3, or 4 flutes, 2 and 4 flutes end mill are more common. More flutes create a smoother surface finish, while fewer flutes are best at chip clearing and keep heat from building up.
– 2 Flute end Mill: suitable to work with wood and aluminum because they produce large chips
– 4 Flute end Mill: used to machine most other materials, cut harder materials than 2 flutes
3. End mills in different materials
– High-speed steel (HSS): cheaper than carbide tools but dull faster as well
– Carbide: is brittle and can shatter, provide better wear resistance and toughness. Carbide end mills are extremely heat-resistant and used for high-speed applications on some of the hardest materials.
– Solid Carbide end mills: considerably harder, rigid, and more wear-resistant than other types.
Endmills also come in different coatings and helix angles.
End mill is similar to a drill bit in appearance, what is the difference between end mill and drill bit, drill bits vs end mills, when to use an end mill?
1. Rotary end mills cut side to side or in the horizontal direction, lots of mills can cut both axially and laterally, while drill bits that plunged directly into the material only move up and down and cut in vertically.
2. End mills are versatile milling cutters used to machine slots, profile, cavities, and more features, a drill bit is used to cutting or producing round holes
3. End mills can also be used to machine a hole, but it requires an already drilled hole, you can use a drill bit working with the material directly for processing a hole.
4. The tip of drill bits is often ground in cone-shape, the exception is diamond drill bits which have a flat end, end mills are available in various shapes and specifications, a regular end mill has a flat tip, and a ball nose end mill with a profile at the cutting end. You can choose a proper end mill according to the materials to be cut and surface finish required.