What Is Milling Cutter?
Milling cutters are an essential component of a milling machine. As the name suggests, it is the cutting tool responsible for scraping the material outside the workpiece. All milling machines have a cutter.
During a typical milling operation, the Cutter moves perpendicular to its axis, allowing it to remove material from the workpiece at the perimeter of the Cutter. To learn more about milling cutters and how they work, keep reading. A milling machine is a versatile machine on which we can perform most machining operations.
It is used to machine various shapes & sizes. Milling cutters are used to perform these tasks. There are different types of cutters that are responsible for proper machining on a milling machine. A short description of them all is given below.
Types of the Milling Cutters:
A variety of milling cutters available help make millings versatile machining process. Cutters are made in a larges range of sizes. Milling cutters are made from high-speed steel (HSS), other carbides are tipped, and many are replaced or indexed inserts.
#1. End Milling Cutter
It has teeth on either side, so it can be used very successfully in drilling operations. The term “end mill” is commonly used for flat bottom cutters. The basic difference between a drill bit and an end mill cutter is that the drill bit can only cut in the axial directions, but this Cutter can cut in all directions. This Cutter consists of one or more flutes and is ultimately used in milling operations. It is made of high-speed steel or hardened material. This Cutter is mainly available in two variants. The first one is known as centers cutting, which has cutting edges on both sides of the Cutter, and the second one is a non-center cutting edge with the cutting edge on only one side.
#2. Roughing End Milling Cutter
Roughing mills are also known as “Pippa” cutters. These cutters give a great performance under the toughest operating conditions. As names themselves suggest, it is used to extract large amounts of material. A wavy tooth is used from such cutters. These cutters make very small chips that result in a rough surface finish.
#3. Periphery Milling Cutter
When the cuttings’ teeth are present on the circumference of the circular disc, it is known as a circumference mill cutter. Perimeter mill cutters can only be used for horizontal mill machines.
#4. Side Milling Cutter
A side mill cutter is a type of Cutter in which the cutting teeth are present on the periphery and also on the face or end. This Cutter is mostly used in strand milling operations and face milling operations. It is also used to cut slots and mix deep and narrow slots.
#5. Face Milling Cutter
Face mill cutters have a large diameter cutter body with several mechanically fastened insertion tools. A large amount of material is removed by making radially deep and axially narrow cuts. The diameter of the cutter body depends on the length of the workpiece and the available clearance on either side of the workpiece.
Face mill cutters are used in down milling. The face mill cutter is very rigid, and the surface finish depends on the feed rate and the number of teeth.
#6. Gang Milling Cutter
It is the type of Cutter in which peripheral milling cutters of different sizes are cut together to remove material from the workpiece simultaneously.
#7. Staggered Mill Cutter
Staggered mill cutters are staggered at the periphery with optional right and left-hand helix angles and are made to a relatively narrow width.
#8. Concave Milling Cutter
A concave cutter is a type of formed Cutter. The form cutter is designed to have a specific shape on the workpiece.
A concave milling cutter is a type of Cutter shaped to match a convex surface of a circular contour equal to half a circle or less.
#9. Cylindrical Milling Cutter
A cylindrical mill cutter is a type of Cutter that has a cylindrical shape and has teeth only on the perimeter surface.
#10. Hollow Milling Cutter
It resembles a pipe that has thick walls. The bites of hollow surfaces are on the inside surfaces. This Cutter is used in screw machines.
#11. Woodruff Cutter
This tool is used to cut keyways for a wooden key. It is slightly hollow at the edges for relief, and the teeth are not side cuttings. Teeth come in both straight & staggered varieties.
#12. Thread Mill Cutter
The thread is produced by a helical projectile. The cutting process enables the productions of threads with a multi-profile from M2 to a nominal diameter of 1 mm (single profile).
#13. Hobbing Cutter
It is also a cutting tool that is used to cut teeth. It is cylindrical in shape with helical bite teeth.
#14. Dovetail Cutter
The dovetail cutter is a final mill whose form protrudes behind a dovetail slot.
#15. Ball Cutter
It is also called a ball-nosed cutter. Ball cutters as their end are hemispherical in shape. It is used to reduce the concentration of stress. It is also used to cut three-dimensional shapes.
#16. Fly Cutter
It is a cutting tool that transits and rotates with the argon of a lathe and acts on the work fed into its circular path. A fly cutter is made of a body into which one or two tool bits are inserted. As the entire unit rotates, the tool bits take wider, shallow cuts. Face mills are more ideal in various cases, but it is expensive, while fly cutters are very inexpensive.
Overview of Milling Cutters:
The purpose of milling cutters is to remove material from a workpiece. According to that saying, milling cutters do not have a single blade. Operations commissioned using a lathe typically feature a single-blade cutting tool, with milling cutters having multiple blades.
Since the milling cutter rotates against a stationary workpiece, it ejects the material. The milling cutter is often made of hard, strong material that can withstand significant stress without breaking or otherwise suicide to damage. For example, it is not uncommon to combines cutters to facilitate the coating of polycrystalline diamonds (PCD).
According, PCD-coated milling cutters last 100 times longer than their untouched counterparts. The download for using PCD-coated milling cutters is that they cannot be used in applications where temperatures are higher than 1,112 degrees Fahrenheit.
Milling Cutter Material:
#1. Steel (HSS, FSS)
High-speed steel, a tool steel grade, has several alloy additives to provide better heat and wear response than ordinary carbon steel; as the life cycle of the mill cutter increases, the cost increases. It is divided into general purpose and special purpose HSS. It has the following characteristics.
Tungsten, chromium, molybdenum, and vanadium alloying elements have high contents, and the hardness can reach HRC62-70, which can hold high hardness at 6000 ° C. Good mill cutting edge strength and toughness, strong vibration resistance, can be used to make tool medium cutting speed cutting machine, in case of low steel machine tool, use high-speed mill cutter, still easily Can be cut.
Good process efficiency, forging, machining, and sharpness are relatively easy, and more complex tool shapes can be created. There are still disadvantages compared to carbide materials, such as lower hardness and worse red hardness, and wear resistance.
Carbide mill cutters are tougher than high-speed steel, but their strength is not as good. Higher stiffness provides greater protection against wear, but lower strength makes it slightly more susceptible to cracking and peeling. It is composed of metal carbide, tungsten carbide, titanium carbide, and cobalt-based metal binders in powders and non-metallic processes. Its main features are the following.
It can withstand high temperatures and maintain good cutting efficiency at around 800–10000C. When cutting with a carbide mill cutter, the cutting speed can be 4-8 times faster than the HSS. Good room temperature abrasion resistance and hardness. Low bending strength, low toughness, blades are not easy to sharpen, very fast.
The materials used for making milling cutters are: –
- High Carbon Steel.
- High-Speed Steel.
- Sintered Carbide Tip.
Of all the above four materials used to make cutters, the use of high carbon steel is the least because cutters made from it quickly become sluggish when using high cutting speeds and feeds. Various grades of high-speed steel are used extensively for the manufacture of cutters because they maintain a deep cutting edge even at high temperatures and thus can be easily used at high speeds.