CHOOSING THE CORRECT TURNING INSERT

Choosing the Correct Turning Insert

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There are many variables that go into choosing the correct insert for your turning operations: insert shape, geometry, grade, and more. The goal is to select an insert that meets your requirements for quality and performance, while providing good chip control, and a reasonable combination of wear resistance and toughness.

Choose the insert style (shape and size) based on the features of the part and the desired depth of cut. A larger nose radius is stronger, but requires more machine power, and increases the tendency for vibration. A smaller nose radius increases the access to fine part features, but has a weaker cutting edge.

Choose the chip breaker (geometry) based on the selected machining operation: finishing, medium, or roughing. Roughing with high depths of cut and feedrates requires an insert with a stronger cutting edge.

Finishing operations with light depths of cut and lower feedrates produce lower cutting forces, so cutting-edge strength is not as important. Medium turning operations, with a wide range of depths of cut and feedrate, require a more versatile geometry.

Choose the insert grade (coatings) based on the type of material being cut, the specific machining operation (finishing, medium, roughing), and the cutting conditions (smooth, lightly interrupted, heavily interrupted). The insert grade and the chip breaker complement each other to provide specific performance characteristics. A tougher grade can compensate for a cutting edge with less strength, while a more wear resistant grade can provide longer tool life on a stronger cutting edge.

INSERT STYLES

Insert Styles

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C-Style Inserts – 80° Rhombic

For external machining and facing. The large point angle is very rigid, and good for rough machining. This is the most commonly used insert.

D-Style Inserts – 55° Rhombic

The smaller point angle of this insert is more versatile for finishing and detail work, but it has less cutting-edge strength than other geometries.

V-Style Inserts – 35° Rhombic

The smaller point angle of this insert is more versatile for finishing and detail work, but it has less cutting-edge strength than other geometries.

T-Style Inserts – 60° Triangle

For internal machining. The 60° cutting angle provides medium cutting-edge strength that allows for both ID roughing and finishing applications.

W-Style Inserts – 80° Trigon

This insert has 3 cutting edges per side. The 80° cutting angle provides high cutting-edge strength for roughing, but the depth of cut is limited by the short cutting edge.

LARGE NOSE ANGLE
• Stronger cutting edge
• Higher cutting forces
• More vibration
• Higher feedrates

SMALL NOSE ANGLE
• Better access to features
• Lower cutting forces
• Weaker cutting edge
• Lower vibrations

Chip Breaker Types

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HFF

HFF – Fine Finishing
For finish turning, producing smooth, accurate surfaces. Very good chip control, especially at low depths of cut

HFP

HFP – Finishing Positive (Single-Sided)
For finishing to medium turning operations, with optimal chip control over a wide range of cutting conditions and workpiece materials.

HFS

HFS – Finishing High-Temp
For finishing applications. Ground periphery with positive cutting edge. Ideally suited for high-temp alloys. Micro-finished edge on the ground periphery adds just a slight hone for improved edge integrity and reliability.

HKR

HKR – Flat Top
Flat top geometry for machining cast iron. For finishing and roughing applications.

HML

HML – Medium Light
For finishing to medium machining, with a negative, stable cutting edge. 

HMP

HMP – Medium Positive (Single-Sided)
For medium to rough turning, with reduced cutting forces and improved chip control for high feedrates. Suitable for high metal removal rates.

HMR

HMR – Light to Medium Roughing
For light to medium roughing of steels, difficult-to-machine high-alloy titanium, and aluminum materials. High strength to deal with heavy chip deformation. 

HMS

HMS – Medium High-Temp
For medium machining in high-temp materials. Utilizes a micro-finished edge preparation to increase edge toughness.

HMU

HMU – Medium Universal
A medium universal geometry with a soft cutting action due to its positive geometry. Has a versatile application range, and is suited for turning unstable components and for boring applications.

HRH

HRH – Roughing Heavy
For medium-duty to roughing. Outstanding chip control. High edge strength for interrupted cuts, forging skin, or scale. Preferred for all cast iron, such as gray, malleable, and nodular.

HUF

HUF – Ultra-Fine Finishing
For finishing, with a positive cutting edge for reduced cutting forces and superior surface quality.

HUM

HUM – Universal Medium
For medium-duty turning operations. Soft-cutting chip breaker. Used in applications producing varying chip sections, such as profile or copy turning. Good dimensional accuracy. For soft steel materials and stainless steels.

HUR

HUR – Universal Roughing
Roughing geometry, with smooth chip forming and improved coolant flow for increased tool life. Positive geometry reduces cutting forces, and improves depth-of-cut notching resistance. Ideally suited for stainless steel applications, and for smooth machining of steel.

HUR

CCET – Finishing Positive (Single-Sided)
For finishing turning operations, with optimal chip control over a wide range of cutting conditions and workpiece materials.

Insert Grades

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Choose the grade that best matches your application and workpiece material.

DECODING HAAS GRADES: HTP15

BRAND

H

Haas

APPLICATION

T

Turning

PRIMARY WORKPIECE MATERIAL

P

  P – Steel

  M – Stainless Steel

  K – Cast Iron

  N – Non-Ferrous

  S – High-Temp Alloys

  H – Hardened Materials

  U – Universal Machining

APPLICATION RANGE

15

10 – Uninterrupted

15 – Light Interrupted

20 – Medium Interrupted

25 – Medium Interrupted

35 – Heavy Interrupted

WEAR RESISTANCE

10

15

20

TOUGHNESS          

25

30

35

SMOOTH
SURFACE

MEDIUM TO
ROUGH SURFACE

ROUGH
SURFACE

Smooth Cut
Pre-Turned

Lightly
Interrupted

Heavily
Interrupted

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CCET Insert Grades