What are Lathe Cutting Tools?
Lathe-cutting tools are called “lathe tools” or “turning tools.” They are used in lathes to remove material from a rotating workpiece, machining cylindrical, end plane, threads, bore, slotting, cutting, etc.
Therefore these tools can be categorized into two main classes based on their operational stage:
Roughing Tools: Designed for initial material removal, these tools work quickly to shape the workpiece.
Finishing Tools: These tools focus on achieving a smooth surface finish, refining the workpiece to meet specific standards.
Lathe Cutting Tools Types and Materials
The effectiveness of lathe-cutting tools is largely dependent on their types. Here are the main types of turning tools utilized in the industry:
Types and Uses of Turning Tools
a) Integral Type
b) Welded Type
c) Machine-clamped Indexable Type
Common Materials Used for Lathe-cutting
The selection of materials for lathe-cutting tools plays a vital role in their performance. Here’s a closer look at the most popular materials:
High-Speed Steel (HSS)
Property: HSS offers excellent strength and toughness, can withstand impact, and is easy to sharpen. However, it’s not suitable for high-speed cutting.
Application: Manufacturing tools such as drills, milling cutters, broaches, threading tools, gear cutters, and other complex shapes.
Carbide (Tungsten carbide)
Property: Carbide is much harder, more wear-resistant, and heat-resistance than HSS. It can maintain a sharp edge even under high-speed and high-temperature conditions. But carbide is brittle and sensitive to shock and vibration.
Applications: Carbide tools are typically for high-precision and high-speed machining of hard materials. Including turning tools, planer cutters, face milling cutters
Ceramic
Properties: Ceramic materials offer superior hardness and wear resistance compared to carbide but are more brittle. so they are mainly for finishing the operation
Superhard material
Properties: This category includes diamond and CBN (Cubic Boron Nitride), which exhibit extreme hardness and wear resistance.
The Importance of Tensile Strength in Cutting Tool Materials
Tensile strength is a crucial property that dictates the performance and durability of turning tools. It is crucial to ensure that the tools can endure the mechanical stresses during machining. Tools made from materials with higher tensile strength tend to last longer and perform better under demanding conditions.
FAQs on Rake Angles for Cutting Tools
Should I choose a large or small rake angle for strong and tough tool materials? And how to choose brittle tools?
Strong and Tough Tool Materials:
- A smaller rake angle increases the tool’s cutting-edge strength and helps to withstand the forces generated during machining. This minimizes the risk of tool failure and chipping, making it suitable for tough materials where durability is crucial.
Brittle Tool Materials: - For brittle tool materials, like certain ceramics or hard metals, a negative rake angle may be used. A negative rake angle increases the cutting edge’s strength and resistance to chipping, which helps prevent breakage. This is because the cutting forces are directed more toward the workpiece rather than toward the tool, reducing the stress on the cutting edge.
How to select rake angle when machining plastic materials?
Machining Plastic Materials:
When machining plastic materials, such as in the processing of plastic parts or soft non-ferrous metals, typically use a large rake angle. Below shows the larger rake angle helps in:
- First, reducing cutting forces and friction, is beneficial when machining soft materials.
- Additionally, improving the surface finish by providing a more aggressive cutting action.
- In addition, minimizing heat generation, which is crucial for plastics as they can deform under high temperatures