Milling cutters are rotary tools used to shape and remove material from workpieces during machining processes. Milling cutters are essential in various industries, such as manufacturing, metalworking, and woodworking. Each type of milling cutter is designed to serve specific purposes and achieve precise results. These tools play a crucial role in shaping, grooving, slotting, and contouring workpieces with accuracy and efficiency, from simple end mills to complex form cutters.

This discussion shall traverse readers through types of Milling Cutters and their Applications. This topic is important for your upcoming examinations like SSC JE ME and RRB JE Mechanical Engineering.

What Are Milling Cutters?

Milling cutters are crucial components of milling machines, serving as the cutting tools used to remove excess material from the workpiece. Each milling machine incorporates a specific cutter for precise machining operations.

Significance of Milling Cutters

During a typical milling operation, the cutter in a milling machine moves perpendicular to its axis, effectively removing excess material from the workpiece at the cutter's perimeter. The milling machine is highly versatile, capable of performing multiple machining operations, and is used to machine and manufacture parts of diverse shapes and sizes. Milling cutters play a vital role in executing these tasks with precision and efficiency.

Milling cutters are the tools that are used in machines to perform various operations like cutting, shaping and other operations. There are various types of milling cutters PDF as plain milling cutters, face milling cutters and others. The milling cutters in industry are selected based on the machining requirement and material. For more information, candidates can refer to the table provided below. 

Types of Milling Cutting Tools

The various types of milling cutters available in the industries. The following types of milling cutters PDF and their uses are described below in detail.

• Plain Milling Cutters 
• Face Milling Cutter
• Side milling cutter
• Angle Milling Cutters
• 'T' Slot Milling Cutter
• Form Relieving Cutter
• Gang Milling Cutter
• Peripheral Milling cutter
• Straddle Milling cutter
• Cylindrical Milling cutter
• Hollow milling cutter
• Dovetail cutter
• Formed Milling Cutter
• End Mill Cutter
• Metal Slitting Saw
• Fly Cutter
• Inserted Tooth Milling Cutter 
• Woodruff Key Slot Milling Cutter
• Tap and Reamer Cutter
• Solid Cutter
• Tipped Solid Cutter
• Thread mill Cutter
• Ball cutter
• Hobbing cutter

Fig 1: Types of milling cutters

Plain Milling Cutters

Plain milling cutters possess a cylindrical shape and feature teeth solely on the periphery surface. These versatile milling cutters are specifically employed for creating flat, plane, and horizontal surfaces in various machining operations. Plain milling cutters can be further classified into the following types:

• Light Duty Plane Milling Cutters
• Heavy Duty Plane Milling Cutters
• Helical Milling Cutter

Fig 2: Types of milling cutters

Light-Duty Plane Milling Cutters:

• Have a face width of less than 20 mm with straight teeth parallel to the axis.
• Large-size cutters have helical teeth with a helix angle of less than 25°.

Heavy-Duty Plane Milling Cutters:

• Feature helical teeth and are designed for heavy-duty work.
• Helix angle ranges from 25° to 45°.

Helical Milling Cutters:

Possess a coarse pitch and a tooth helix angle ranging from 45° to 60°.

Face Milling Cutter

Fig 3: Face milling cutter

The face mill cutter comprises a sizable cutter body featuring multiple securely attached insert tools, allowing for substantial material removal through radially deep and axially narrow cuts. The cutter body's diameter is determined by the workpiece length and the available clearance on both sides of the workpiece. Face mill cutters find application in downward milling. Their inherent rigidity contributes to the surface finish, influenced by the feed rate and the tooth count.

Side Milling Cutter

• A side milling cutter is a type of cutting tool with teeth on its side circumference. It is designed for removing material from the side of a workpiece.
• Side milling cutters are used in various machining operations, including slotting, contouring, and angular surface machining, making them versatile tools for different applications.
• These cutters have multiple teeth distributed around their circumference, allowing for efficient and rapid material removal as the cutter rotates.
• Side milling cutters come in different widths, allowing machinists to choose the appropriate cutter width based on the width of the cut they need to make, enabling precise and controlled machining processes.

Angle Milling Cutters

• Angle milling cutters are specialised cutting tools with angled teeth designed to create chamfers, bevels, and angles on workpiece edges, enhancing their visual appeal and functionality.
• These cutters come in various angles, allowing machinists to achieve different chamfer or bevel angles on the workpiece edges, contributing to design versatility.
• They are commonly used in applications where angled edges are required, such as in the creation of bevelled edges on metal components, woodworking, and other industries that demand precise edge finishing.

T-Slot Milling Cutter

• T-Slot Milling Cutter is a specialised tool designed for machining T-slots in workpieces.
• It features a unique design with a T-shaped groove that matches the T-slot profile.
• T-Slot cutters come in various sizes to accommodate different T-slot dimensions.
• They are commonly used in the manufacturing of fixtures, jigs, and work holding devices.
• T-Slot milling cutters create precise T-slots with accurate dimensions for inserting T-nuts or other components.

Fig 4: T-slot milling cutter

Form Relieving Cutter

• A form relieving cutter is a specialised tool used to create intricate profiles on workpieces.
• These cutters can be tailored to match specific profiles or forms required in the machining process, making them ideal for producing unique components with intricate details.
• Form relieving cutters efficiently remove material from workpieces, resulting in faster production times and reduced machining costs, especially for parts with complex shapes.
• Due to their precision and ability to follow intricate profiles, form relieving cutters often produce superior surface finishes, minimising the need for additional finishing processes.

Gang Milling Cutter

• Gang milling cutters consist of two or more individual cutters mounted on the same arbor, allowing simultaneous cutting of multiple surfaces or features on a workpiece.
• This setup enables increased productivity as multiple cuts are performed in a single pass, reducing overall machining time and increasing efficiency.
• Gang milling cutters are often used for machining complex profiles, contours, and slots where multiple cutting actions are required on the same workpiece.
• The synchronised action of multiple cutters ensures uniform material removal and dimensional accuracy across the workpiece, resulting in consistent finished parts.

Peripheral Milling cutter

• A peripheral milling cutter is a type of cutting tool used for removing material from the external surface of a workpiece. It operates by cutting along the periphery of the cutter's circumference.
• These cutters feature multiple cutting teeth distributed around their outer edge, allowing for efficient material removal with each rotation, resulting in faster machining times.
• Peripheral milling cutters are versatile and can be used for various machining operations, including facing, contouring, slotting, and producing grooves on the outer surface of the workpiece.

Fig 5: Peripheral milling cutter

Cylindrical Milling Cutter

• A cylindrical milling cutter is one of the cutting tools characterised by its cylindrical shape, with cutting teeth located along the length of the cylinder. It resembles a rotating cylinder with cutting edges.
• These cutters are used for machining surfaces that are parallel to the cutter's axis. They excel in creating flat surfaces, slots, and grooves on workpieces.
• They come in various sizes, diameters, and tooth configurations, catering to different machining requirements and workpiece materials, from metals to plastics.

Fig 6: Cylindrical milling cutter

Hollow milling cutter

• A hollow milling cutter is designed to cut within the interior contours of a workpiece, creating voids or hollow areas with precise shapes and dimensions.
• These cutters are commonly used for machining internal profiles, such as pockets, recesses, and channels, where other tools might have difficulty accessing or achieving the required geometry.
• Hollow milling cutters provide accurate and efficient material removal in internal cavities, helping to achieve consistent dimensions and surface finishes within complex workpiece features.

Fig 7: Hollow milling cutter

Dovetail cutter

• A dovetail cutter is characterised by its unique triangular profile, resembling the shape of a dovetail joint. This profile is ideal for creating dovetail grooves or slots in workpieces.
• These cutters are specifically designed for producing dovetail grooves used for fitting sliding or mating components, such as machine tool slides or fixtures.
• Dovetail cutters ensure precise machining of dovetail grooves with tight tolerances, resulting in well-fitting components that have secure and accurate mating surfaces.

Fig 8: Dovetail milling cutter

Formed Milling Cutter:

• Formed milling cutters are designed with specialised profiles that match the desired shape or contour to be machined on the workpiece, enabling precise replication of intricate shapes.
• These cutters are ideal for creating complex features such as gears, splines, flutes, and other intricate geometries that may be challenging to achieve using standard cutters.
• They can be crafted from various tool materials tailored to the workpiece material being machined, enhancing durability and efficiency in the cutting process.
• Machinists skilled in utilising formed milling cutters can achieve remarkable results with minimal post-machining adjustments, thanks to the cutter's precision and compatibility with the desired design.

End Mill Cutter:

• An end mill cutter is a versatile rotary cutting tool with multiple flutes that can be used for various milling operations, including contouring, slotting, and pocketing.
• End mills come with different flute configurations, such as two, four, or more flutes, each offering specific advantages for different types of materials and cutting tasks.
• Unlike drills, end mills have cutting edges on the end and sides, allowing for both peripheral and face milling and enabling the creation of detailed shapes and profiles.

Metal Slitting Saw:

• A metal slitting saw is a thin, circular cutting tool designed for making narrow cuts or slots in metal workpieces, ensuring minimal material removal and efficient use of the material.
• These saws have a high number of teeth per inch, enabling precise and clean cuts with reduced chip load and improved surface finish.
• Metal slitting saws primarily cut on their periphery, making them suitable for slotting, grooving, and parting operations in metalworking applications.

Fly Cutter:

• A fly cutter is a single-point cutting tool used in machining operations, featuring a large, flat cutting surface that rotates to remove material from the workpiece.
• The design of a fly cutter is straightforward, consisting of a cutting tool, a tool holder, and a rotating mechanism. This simplicity makes them easy to set up and use.
• When used with proper feeds and speeds, fly cutters can achieve excellent surface finishes, making them popular for creating smooth, flat surfaces on materials like metal and plastics.

Inserted Tooth Milling Cutter:

• Teeth made from alloy tool steel or carbide, mechanically added or brazed to the correct location by screws.
• Suitable for expensive cutter materials like carbide.

Woodruff Key Slot Milling Cutter:

• A Woodruff Key Slot Milling Cutter is a specialised tool designed to create precise keyways or slots in shafts, hubs, and other components to accommodate Woodruff keys, ensuring secure mechanical connections.
• These cutters produce keyways with a half-moon or crescent-shaped cross-section, matching the profile of Woodruff keys, which have a matching shape for optimal engagement.
• These cutters are designed for efficient chip evacuation and minimal tool deflection during machining, contributing to precise and consistent keyway production in a range of materials, including metals and plastics.

Fig 9: Woodruff Key Slot Milling Cutter

Tap and Reamer Cutter:

• A tap is a cutting tool used for threading holes in materials. It has flutes that help remove material while creating internal threads, allowing screws or bolts to be securely threaded into the hole.
• A reamer is a precision cutting tool used to refine and enlarge drilled holes, ensuring accuracy in size, shape, and surface finish. It helps achieve tight tolerances and smooth surfaces.
• By using a tap and reamer in sequence, the threaded hole's dimensions are controlled accurately, enhancing the thread's fit and engagement with screws, bolts, or other threaded components.

Fig 10: Tap and Reamer Cutter

Solid Cutter

• A solid cutter, also known as a solid end mill, is a cutting tool with a single-piece construction made from solid material. It doesn't have any replaceable inserts or components.
• Solid cutters are versatile tools used for a wide range of machining operations, including milling, drilling, contouring, and profile machining in various materials.
• The absence of insert junctions in a solid cutter enhances its overall rigidity and stability during cutting operations, contributing to improved tool life and precision.

Fig 11: Solid milling cutter

Tipped Solid Cutter

• A tipped solid cutter, also referred to as an indexable insert cutter, combines a solid shank with replaceable carbide or ceramic inserts. This design allows for efficient tool replacement and extended tool life.
• Tipped solid cutters feature replaceable inserts on the cutting edges. When a cutting edge becomes dull or worn, only the insert needs to be replaced, reducing downtime and cost.
• These cutters are suitable for a wide range of machining tasks, from roughing to finishing, and are often chosen for high-speed and high-feed operations due to the advantages of indexable inserts.

Fig 12: Tipped solid cutter

Thread mill Cutter

• A thread mill cutter is a specialised tool used for machining threads in workpieces, creating internal or external threads with precision and accuracy.
• Thread mill cutters employ a helical motion to create threads, producing a continuous and smooth thread profile along the entire length of the cut.
• Thread mill cutters are versatile tools that can be used for threading different materials and thread profiles, offering flexibility in producing threads of various sizes and pitches.

Fig 13: Thread mill cutter

Ball cutter

• A ball cutter is a specialised tool with a rounded cutting end, resembling a sphere. It is used for machining curved surfaces, contours, and intricate three-dimensional shapes.
• Ball cutters are particularly useful for 3D machining operations, as they can create smooth and rounded features on workpieces, providing a visually appealing and tactile surface finish.
• Ball cutters excel in finishing operations where achieving a polished surface or complex shape is essential, such as in mould-making, sculpting, and producing decorative features.

Fig 14: Ball cutter

Hobbing cutter

• A hobbing cutter is a tool used for manufacturing gears. It employs a cutting action to generate gear teeth with accuracy and consistency.
• Hobbing cutters have multiple cutting teeth arranged around their circumference, allowing them to create multiple gear teeth simultaneously during the machining.
• The cutter rotates while the workpiece is gradually rotated and fed into the cutter's teeth. This process shapes the gear's teeth, resulting in precise gear profiles and dimensions.

Fig 15: Hobbing cutter

Geometry of the Milling Cutter

The geometry of the Milling cutter involves five angles:

• Radial Rake Angle: The milling cutter's radial rake angle corresponds to the side rake of a single-point tool.
• Axial Rake: Similarly, the axial rake angle of the cutter matches the back rake of a single-point tool.
• Radial Relief: It involves the creation of a small angle to prevent the tool's interference with the workpiece during machining.
• Axial Relief: In cases where the cutter's radius aligns along the face of the milling cutter, it is designated as having a zero rake.
• Clearance Angle: This angle is formed between a line extending through the land's surface and a tangent drawn to the periphery at the cutting edge.

Milling Cutter Material

The materials used in milling cutters comprise Steel and Carbide. The same has been discussed below:

Steel

• High-speed steel, a type of tool steel, incorporates various alloying elements to enhance heat and wear resistance beyond that of standard carbon steel. As the miller cutter's lifespan increases, so does the cost. It's categorised into general-purpose and special-purpose HSS, with the following attributes.
• Abundant tungsten, chromium, molybdenum, and vanadium alloy content, achieving hardness levels of HRC62-70, maintaining this hardness even at 600°C.
• Robust edge strength, toughness, and vibration resistance, suitable for medium-speed cutting applications. High-speed miller cutters can still facilitate easy cutting even in less robust machinery, such as low-grade steel machines.
• Efficient forging, machining, and sharpening processes, enabling the creation of intricate tool designs.
• Nonetheless, it presents drawbacks compared to carbide materials, such as lower hardness, reduced red hardness, and wear resistance.

Carbide

• Carbide mill cutters surpass high-speed steel in toughness, although their strength is inferior. Greater stiffness offers improved wear resistance, yet its lower strength renders it somewhat more susceptible to cracking and chipping.
• Comprising metal carbide, like tungsten carbide and titanium carbide, along with cobalt-based metal binders in powder and non-metallic processes, carbide boasts the following attributes:
• Endures high temperature and maintains cutting efficiency at approximately 800–1000°C.
• Allows cutting speeds 4-8 times faster than HSS.
• Exhibits commendable room temperature abrasion resistance and hardness. However, its bending strength and toughness are relatively lower, and its blades are less easily sharpened.
• The materials used for cutter production include high carbon steel, high-speed steel, sintered carbide tips, and Stellite. High carbon steel sees less use due to its sluggishness under high cutting speeds and feeds.
• Different grades of high-speed steel are widely employed for cutter fabrication, as they retain a robust cutting edge even at elevated temperatures, enabling high-speed applications.

Applications of Types of Milling Cutters:

The various applications include:

• Plain Milling Cutters: Used for producing flat, plane, and horizontal surfaces.
• Helical Milling Cutters: Ideal for coarse pitch applications and cutting at high helix angles.
• Face Milling Cutters: Used for face milling operations to produce flat surfaces.
• Side Milling Cutters: Suitable for side milling, strand milling, and cutting deep and narrow slots.
• Angle Milling Cutters: Applied for angular milling operations other than 90°.
• T Slot Milling Cutter: Specifically used for making T slots.
• Form Relieving Cutter: Primarily used for cutting gears with irregular profiles.
• Gang Milling Cutter: Employed for machining multiple surfaces on the workpiece simultaneously.
• Metal Slitting Saw: Used for parting off operations or slotting with narrow width.
• Fly Cutter: Utilized in tool room work for simple cutting operations.
• Inserted Tooth Milling Cutter: Suitable for more expensive cutter materials like carbide.
• Woodruff Key Slot Milling Cutter: Used for making Woodruff 'key' slots.
• Tap and Reamer Cutter: Specifically designed for making grooves or flutes in taps or reamers.
• Solid Cutter: Applied for general milling operations.
• Tipped Solid Cutter: Ideal for high-speed machining with cemented carbide or stellite tips.

Also, learn about the Milling Machine.

This article elaborated on different Types of Milling cutters and their various applications. We recommend our readers they should appear in the SSC JE Mechanical mock tests and SSC JE ME Previous Years Papers. Also, get enrolled in the AE/JE Mechanical coaching to get a firm grip on the subject.

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