ISCAR TIP TALK - Parameters for choosing the correct turning insert

Introduction

In this tutorial, we will explore how to choose the right turning insert for machining applications. This choice is crucial for achieving optimal performance and efficiency in your metal cutting processes. We will cover the key parameters to consider, including application requirements, machine stability, workpiece clamping stability, and raw material hardness.

Step 1: Assess the Application and Conditions

To select the appropriate turning insert, start by evaluating these parameters:

• Application Type: Identify if the operation is finishing, semi-finishing, or rough cutting.
• Machine Stability: Determine how stable your machine is during operation.
• Workpiece Clamping Stability: Ensure that the workpiece is firmly clamped to prevent vibrations and improve cutting accuracy.
• Raw Material Hardness: Understand the hardness of the material you will be machining, as this significantly influences insert selection.

Step 2: Choose the Insert Geometry

Select the insert geometry based on the type of operation:

• Finishing and Semi-Finishing Operations:

  • Use positive inserts with a small corner radius of 0.2mm or 0.4mm.

• Continuous Medium Cuts:

  • Opt for negative inserts with an average corner radius of 0.8mm to 1mm.

• Interrupted Cuts or Higher Depths of Cut:

  • Increase the corner radius to strengthen the cutting edge for better durability.

• Unstable Conditions:

  • For low clamping stability or machining with low power consumption, use a positive insert with a small corner radius to reduce cutting forces.

Step 3: Select Based on Raw Material Hardness

Different materials require specific insert grades:

• Low Hardness Materials (20 HRC to 45 HRC):

  • Use PVD (Physical Vapor Deposition) and CVD (Chemical Vapor Deposition) grades.

• Medium Hardness Materials (45 HRC to 60 HRC):

  • Choose ISCAR’s Ceramic grades for effective cutting.

• Hard Part Turning (55 HRC to 70 HRC):

  • Utilize ISCAR’s PCBN (Polycrystalline Cubic Boron Nitride) grades for optimal performance on hardened materials.

Conclusion

Choosing the right turning insert is essential for efficient machining. By assessing application requirements, selecting the appropriate insert geometry, and considering the raw material hardness, you can enhance your machining processes significantly. For further learning, consider exploring ISCAR's catalogs and online resources to deepen your understanding and expertise in metal cutting tools.