Indexable inserts are cutting tools used in machining operations, designed to be replaceable when worn rather than requiring the entire tool to be replaced. They come in a variety of shapes, materials, and coatings, tailored to different machining applications. Here are the different types of indexable inserts, categorized by shape, material, and application:
1. Types by Shape
- Square (S): Square inserts offer four cutting edges and are commonly used for general-purpose turning and facing operations.
- Triangle (T): Triangle inserts have three cutting edges, used in high-feed turning and light to medium-duty operations.
- Diamond (D, C): Diamond-shaped inserts (rhomboid) typically have two or four cutting edges, allowing for more precision in turning, boring, and facing applications.
- Round (R): Round inserts are used for heavy-duty turning and milling, excelling at operations that require smooth finishes and high resistance to shock.
- Hexagonal (H): These inserts have six cutting edges and are used for fine finishing operations where multiple cutting edges are required.
- Parallelogram (P): Parallelogram inserts have a sharp angle for finishing operations and are designed for unique approaches to workpieces.
- Trigon (W): Trigon-shaped inserts, with three large cutting edges, are used for high-feed turning operations due to their strength and durability.
2. Types by Material
- Carbide: The most common material for indexable inserts, carbide inserts provide an excellent balance between hardness and toughness, allowing for high-speed cutting and long tool life. Carbide is suitable for cutting a wide range of materials.
- Ceramic: These inserts are highly wear-resistant and suitable for high-speed finishing operations, especially on cast iron and hardened materials. Ceramic inserts are ideal for hard turning but are less tolerant to shock and vibration.
- Cermet: Cermet inserts combine ceramic and metal, offering excellent wear resistance and a high-quality surface finish. These are mainly used in finishing operations.
- Polycrystalline Diamond (PCD): PCD inserts are extremely hard and wear-resistant, making them ideal for cutting non-ferrous materials like aluminum, copper, and plastics. They provide excellent surface finishes.
- Cubic Boron Nitride (CBN): CBN inserts are second only to diamond in hardness and are ideal for machining hardened steels, cast irons, and superalloys. They excel in finishing hardened materials.
- High-Speed Steel (HSS): Though less common in modern indexable inserts, HSS inserts are still used for lower-speed operations where toughness is required, like in some milling and threading applications.
3. Types by Application
- Turning Inserts: Used in lathe operations, turning inserts are designed for external and internal turning. They come in various shapes and sizes, depending on the specific turning application.
- Milling Inserts: Used in face and peripheral milling, these inserts are designed to withstand higher radial and axial forces. They come in round, square, or triangular shapes.
- Boring Inserts: Boring inserts are used in precision boring operations and are designed for internal turning or boring bars.
- Grooving Inserts: Specifically designed for grooving or parting operations, these inserts have unique geometries that facilitate material removal in grooving or cutting off workpieces.
- Threading Inserts: Designed for threading operations, these inserts have pre-formed thread profiles and are available in different pitches to cut both internal and external threads.
- Drilling Inserts: These inserts are used in drilling applications, particularly in indexable drills, where the insert is mounted on the drill body for cutting.
4. Types by Coating
- TiN (Titanium Nitride): A general-purpose coating that provides hardness and lubricity, ideal for light to medium-duty applications and improving wear resistance.
- TiCN (Titanium Carbonitride): This coating is harder than TiN and is used in more abrasive materials, offering enhanced toughness and tool life.
- TiAlN (Titanium Aluminum Nitride): TiAlN provides excellent heat resistance, making it ideal for high-speed machining in dry or semi-dry conditions. The aluminum content increases its oxidation resistance.
- AlTiN (Aluminum Titanium Nitride): A more advanced coating than TiAlN, AlTiN is ideal for high-temperature machining operations and provides superior hardness and wear resistance.
- Diamond Coatings: Applied to inserts for non-ferrous cutting, diamond coatings offer extreme hardness and wear resistance, particularly when machining aluminum, copper, and composite materials.
5. Specialty Inserts
- Wiper Inserts: These inserts have specially designed geometries to improve surface finish at higher feed rates, commonly used in finishing operations.
- Chip Breaker Inserts: Inserts with chip breaker geometries are designed to control the shape and flow of chips, preventing entanglement and improving machining performance in materials that form long chips.
- High-Feed Inserts: These inserts are designed for high-feed machining applications, allowing for increased material removal rates while maintaining surface quality.
Each of these types of indexable inserts is designed for specific machining requirements, making it essential to choose the right insert type based on the material being machined, the machining process, and the desired surface finish.
