Mastering Turning Insert Nomenclature: A Clear Guide for CNC Operators

General Turning Insert Nomenclature for CNC Dummies

General turning inserts come in variety of shapes and sizes. One thing is important to remember and understand is that every turning insert has a nomenclature associated with it. These general turning inserts nomenclature tells us lot about these general turning inserts.
The turning inserts nomenclature is a list of some letters and numbers, but lot more data is hidden inside them.

Note: The following explanations are according to metric inserts.

General Turning Insert Nomenclature

The above turning insert nomenclature is CNMG 120408.

1 = Turning Insert Shape

General Turning Insert Nomenclature Shape

The first letter in general turning insert nomenclature tells us about the general turning insert shape, turning inserts shape codes are like C, D, K, R, S, T, V, W. Most of these codes surely express the turning insert shape like

• C = C Shape  Turning Insert
• D = D Shape  Turning Insert
• K = K Shape  Turning Insert
• R = Round Turning Insert
• S = Square Turning Insert
• T = Triangle Turning Insert
• V = V Shape Turning Insert
• W = W Shape Turning Insert

The picture tells us more about turning inserts shapes.The general turning insert shape play a very important role when we choose an insert for machining.Not every turning insert with one shape can be replaced with the other for a machining operation.As C, D, W type turning inserts are normally used for roughing or rough machining. As a cnc machinist I will use C type turning insert with Roughing Cycle (G71 G72 for Fanuc cnc control), And I will choose D type turning insert for Finishing Cycle(G70 for Fanuc ).

2 = Turning Insert Clearance Angle

General Turning Insert Nomenclature Clearance-Angle

The second letter in general turning insert nomenclature tells us about the turning insert clearance angle.The clearance angle for a turning insert is given as

• B = Turning Insert with 5° clearance angle
• C = Turning Insert with 7° clearance angle
• E = Turning Insert with 20° clearance angle
• N = Turning Insert with 0° clearance angle
• P= Turning Insert with 11° clearance angle

Turning insert clearance angle plays a big role while choosing an insert for internal machining or boring small components, because if not properly chosen the insert bottom corner might rub with the component which will give poor machining.On the other hand a turning insert with 0° clearance angle is mostly used for rough machining.

3 = Turning Insert Tolerances

The third letter of general turning insert nomenclature tells us about the turning insert tolerances.

These are the turning insert tolerances in different insert sizes, like the tolerance in turning insert length, height etc. I personally think that they are not of any use for a cnc machinist, because theses tolerances are minor.

 

4 = Turning Insert Type

General Turning Insert Type

The fourth letter of general turning insert nomenclature tells us about the turning insert hole shape and chip breaker type.

 

•  A = Turning insert with Cylindrical hole
• G = Turning insert with Cylindrical hole and Double-Sided Chipbreaker
• M = Turning insert with Cylindrical hole and Single-Sided Chipbreaker
• N = Turning insert with no hole                   and no Chipbreaker
• P = Turning insert with Cylindrical hole and Hi-Double-Positive Chipbreaker
• Q = Turning insert with 40-60° Double Countersink Hole
• R = Turning insert with no-hole and Single-Sided Chipbreaker
• T = Turning insert with 40-60° Double Countersink Single-sided Chipbreaker
• W =  Turning insert with 40-60° double countersink
• X = Turning insert with Special Design

5 = Turning Insert Size

This numeric value of general turning insert tells us the cutting edge length of the turning insert.

General Turning Insert Cutting Edge Length

 

6 = Turning Insert Thickness

This numeric value of general turning insert tells us about the thickness of the turning insert.

7 = Turning Insert Nose Radius

General Turning Insert Nose Radius

This numeric value of general turning insert tells us about the nose radius of the turning insert.

• Code     =         Radius Value
• 04           =         0.4
• 08           =         0.8
• 12           =          1.2
• 16           =          1.6

 

 

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