1 Flute DOWN CUT Carbide End Mill - downcut end mill

InsertEnd Mill Cutter

About the Authors: Edmund Isakov, Ph.D., is a consultant, writer, and frequent CTE contributor. He is the author of four books “Mechanical Properties of Work Materials” (Modern Machine Shop Publications, 2000); “Engineering Formulas for Metalcutting” (Industrial Press, 2004); “Cutting Data for Turning of Steel” (Industrial Press, 2009); “International System of Units (SI)” the CD-ROM (Industrial Press, 2013); and the software “Advanced Metalcutting Calculators” (Industrial Press, 2005). For more information, call (561) 369-4063, or email: edmundisakov9701@comcast.net. Shi ‘Steve’ Chen is Manager Product Engineering Turning at Kennametal Inc. For more information, call (724) 539-5321, or email: Shi.Chen@Kennametal.com

American National Standard ANSI B212.4-2002 covers the identification system for indexable-type inserts for both single-point and multiple-point cutting tools. It was published on October 29, 2002. The earlier editions of the standard are:

In case of a facet, two letters are used. The first letter designates the facet angle: A – 45°; D – 60°; E – 75°; G – 87°; P – 90°; Z – Any other facet angle. The second letter designates the facet clearance angle:

The 10th position is only used if there are letters in the seventh position. It will be a significant number representing the nominal sixty-fourths of an inch in length of the primary facet: 1 – 1 ⁄ 64"; 2 – 1 ⁄ 32"; 3 – 3 ⁄ 64"; 4 – 1 ⁄ 16"; 5 – 5 ⁄ 64"; 6 – 3 ⁄ 32"; 7 – 7 ⁄ 64"; 8 – 1 ⁄ 8"; 9 – 9 ⁄ 64"; 10 – 5 ⁄ 32".

Space provided behind a tool’s land or relief to prevent rubbing and subsequent premature deterioration of the tool. See land; relief.

Nine relief angle values have been described in ANSI B212.12-1991 standard. These angles are the difference from 90° measured in a plane normal to the cutting edge generated by the angle between the flank and top surface of the insert. Each relief angle is denoted by a capital letter as follows:

Milling insertnomenclature

The seventh position indicates the cutting point configuration: a radius or a facet. In the case of a radius, the number indicates how many of 1 ⁄ 64 of an inch in the radius: 0 – sharp corner (0.002" max. radius); 0.2 – 0.004"; 0.5 – 0.008"; 1 – 1 ⁄ 64"; 2 – 1 ⁄ 32"; 3 – 3 ⁄ 64"; 4 – 1 ⁄ 16"; 5 – 5 ⁄ 64"; 6 – 3 ⁄ 32"; 7 – 7 ⁄ 64"; 8 – 1 ⁄ 8"; 10 – 5 ⁄ 32"; 12 – 3 ⁄ 16" 14 – 7 ⁄ 32" = 14; 16 – 1 ⁄ 4"; X – Any other corner radius.

Due to the magazine’s space limitations, the authors provide the following tables showing most popular Kennametal’s indexable inserts only for general turning of steel, cast iron, and nonferrous alloys. These tables don’t cover all Kennametal chip breakers. (Figure 4 and Figure 5 also show Kennametal Inc. insert identification system and chip breaker identification system respectively.)

ANSI B212.4-2002 standard added one more capital letter O, which denotes other relief angles for new designs of indexable inserts.

The mathematical expression denoting one of several parameters that describe surface texture (same as average roughness Ra). Average roughness is the arithmetic average height deviation of the measured surface profile from the profile centerline. See surface texture.

Tolerances on dimensions (± from nominal) are denoted by letters A, B and T. Dimension A is the nominal inscribed circle (I.C.) of the insert. Dimension T is the thickness of the insert. For pentagon, triangle and trigon shapes, dimension B is the insert height, i.e., the distance between one side and the opposite corner (Figure 2).

It will be a two-digit number carried to one decimal place when it is not a whole number: 1.2 – 5 ⁄ 32"; 1.5 – 3 ⁄ 16"; 1.8 – 7 ⁄ 32"; 2.5 – 5 ⁄ 16".

Edmund Isakov, Ph.D., is a consultant, writer and frequent CTE contributor. He is the author of the books “Mechanical Properties of Work Materials” (Modern Machine Shop Publications, 2000); “Engineering Formulas for Metalcutting” (Industrial Press, 2004); “Cutting Data for Turning of Steel” (Industrial Press, 2009); the CD-ROM “International System of Units (SI)” (Industrial Press, 2012); and the software “Advanced Metalcutting Calculators” (Industrial Press, 2005). For more information, call (561) 369-4063 or visit www.edmundisakovphd.com.

There are 14 tolerance classes that control the indexability of the inserts. Each class is denoted by a capital letter. Letters for tolerances are A, B, C, D, E, F, G, H, J, K, L, M, U and N.

Tool that cuts a sloped depression at the top of a hole to permit a screw head or other object to rest flush with the surface of the workpiece.

Long edgemillingcutter

There are 16 standard shapes of indexable inserts, and each shape is identified by a capital letter as follows (Figure 1):

The fifth position is a significant one- or two-digit number indicating the size of the inscribed circle (I.C.) for all inserts having a true I.C. such as Round, Square, Triangle, Trigon, Pentagon, Hexagon, Octagon, and Diamond. This position designates the number of eighths of an inch in the nominal size of the I.C. It will be a one-digit number when the number of eighths of an inch in the I.C. is a whole number: 1 – 1 ⁄ 8"; 2 – 1 ⁄ 4"; 3 – 3 ⁄ 8"; 4 – 1 ⁄ 2"; 5 – 5 ⁄ 8"; 6 – 3 ⁄ 4"; 7 – 7 ⁄ 8";

Angle of inclination between the face of the cutting tool and the workpiece. If the face of the tool lies in a plane through the axis of the workpiece, the tool is said to have a neutral, or zero, rake. If the inclination of the tool face makes the cutting edge more acute than when the rake angle is zero, the rake is positive. If the inclination of the tool face makes the cutting edge less acute or more blunt than when the rake angle is zero, the rake is negative.

Insertcuttermilling

In PVD, the sacrificial material is vaporized or gasified into a charged plasma gas by applying a high-power electricity source for a short time. The vaporized source material will then condense onto the substrate, creating the desired layer. No chemical reactions take place during this process unless the PVD vapour is coloured by the addition of noble gases, which is typically done for aesthetic purposes only.

Any machining process used to part metal or other material or give a workpiece a new configuration. Conventionally applies to machining operations in which a cutting tool mechanically removes material in the form of chips; applies to any process in which metal or material is removed to create new shapes. See metalforming.

Physical Vapor Deposition (PVD) and Chemical Vapor Deposition (CVD) are commonly used techniques for depositing ultra-thin films of metals or ceramics onto substrates. Both methods are highly reliable and have been widely adopted in many industries, from semiconductors to architectural projects. However, while both processes are used to create thin films, the methods used to achieve this goal differ significantly.

Milling insertspecification

It is a two-digit number carried to one decimal place when it is not a whole number: 1.2 – 5 ⁄ 64"; 1.5 – 3 ⁄ 32"; 2.5 – 5 ⁄ 32"; 3.5 – 7 ⁄ 32".

Space provided behind the cutting edges to prevent rubbing. Sometimes called primary relief. Secondary relief provides additional space behind primary relief. Relief on end teeth is axial relief; relief on side teeth is peripheral relief.

Imaginary circle that touches all sides of an insert. Used to establish size. Measurements are in fractions of an inch and describe the diameter of the circle.

Conditioning of the cutting edge, such as a honing or chamfering, to make it stronger and less susceptible to chipping. A chamfer is a bevel on the tool’s cutting edge; the angle is measured from the cutting face downward and generally varies from 25° to 45°. Honing is the process of rounding or blunting the cutting edge with abrasives, either manually or mechanically.

For all other polygons, dimension B is the distance, measured along the bisector of the rounded off corner angle and a gage roll of nominal I.C. size tangent to the two sides opposite the corner (Figure 2). For example, if a tolerance letter is H, tolerances on dimensions (± from nominal) are: 0.0005" on dimension A, 0.0005" on dimension B and 0.001" on dimension T.

On rectangular and parallelogram inserts, the width and length dimensions are used in place of the I.C. A two-digit number designates the sizes of these inserts. The first digit indicates the number of eighths of an inch in the width and the second digit indicates the number of fourths of an inch in the length of the insert.

In summary, the main differences between PVD and CVD are the method used, the source material, and the environmental impact. PVD uses physical processes and pure source material, while CVD uses chemical processes and mixed source material. CVD is also considered to be more environmentally harmful than PVD. Both techniques are widely used and have similar end goals, but the choice of technique will depend on the industry's specific application and requirements.

Although PVD and CVD are different processes, they both produce the same result: an extremely thin layer of the desired material coating at the desired coating thickness. PVD and CVD belong to a large family of techniques, with many more specific techniques used to produce hundreds of coatings. The choice of technique will depend on factors such as cost, ease of use, and environmental impact. CVD is considered to be more environmentally harmful due to the nature of the chemicals used in the process.

Replaceable tool that clamps into a tool body, drill, mill or other cutter body designed to accommodate inserts. Most inserts are made of cemented carbide. Often they are coated with a hard material. Other insert materials are ceramic, cermet, polycrystalline cubic boron nitride and polycrystalline diamond. The insert is used until dull, then indexed, or turned, to expose a fresh cutting edge. When the entire insert is dull, it is usually discarded. Some inserts can be resharpened.

Inserts selection depends on workpiece material, chip control, surface finish, tool life, and the machine tool’s power and torque requirements. One of the commonly used indexable inserts for general turning is CNMG 432.

Workpiece is held in a chuck, mounted on a face plate or secured between centers and rotated while a cutting tool, normally a single-point tool, is fed into it along its periphery or across its end or face. Takes the form of straight turning (cutting along the periphery of the workpiece); taper turning (creating a taper); step turning (turning different-size diameters on the same work); chamfering (beveling an edge or shoulder); facing (cutting on an end); turning threads (usually external but can be internal); roughing (high-volume metal removal); and finishing (final light cuts). Performed on lathes, turning centers, chucking machines, automatic screw machines and similar machines.

Tungaloymillinginserts

According to ANSI B212.4-2002 standard, identification of the indexable insert includes 10 positions denoted by a capital letter. Each position (from 1 to 10) defines a characteristic of the insert in the following order:

The sixth position is a significant one- or two-digit number indicating the number of sixteenths of an inch in the thickness of the insert. It is a one-digit number when the number of sixteenths of an inch in the thickness is a whole number: 1 – 1 ⁄ 16"; 2 – 1 ⁄ 8"; 3 – 3 ⁄ 16"; 4 – 1 ⁄ 4"; 5 – 5 ⁄ 16"; 6 – 3 ⁄ 8"; 7 – 7 ⁄ 16"; 8 – 1 ⁄ 2"; 9 – 9 ⁄ 16"; 10 – 5 ⁄ 8".

Properties of a material that reveal its elastic and inelastic behavior when force is applied, thereby indicating its suitability for mechanical applications; for example, modulus of elasticity, tensile strength, elongation, hardness and fatigue limit.

Substances having metallic properties and being composed of two or more chemical elements of which at least one is a metal.

PVD is a physical process that uses purely physical forces, such as the application of electricity, to produce the desired vapour. This vapour is then deposited onto the substrate, creating the desired coating. In contrast, CVD is a chemical process that uses various chemicals to produce the same result. In addition, the source material used in PVD is pure, whereas CVD uses a mixed source material. Both processes typically take place in vacuum chambers, but PVD is exclusively performed in this type of environment.

The fourth position is a capital letter denoting differences in design of insert, such as the existence of fixing holes, countersinks and special features on rake surfaces. There are 15 standard types in design as follows (Figure 3):

In CVD, the source material is mixed with a volatile precursor that acts as a carrier vapour. The chemical mixture is then injected into the vacuum chamber that contains the substrate to be coated. The gas produced by this chemical reaction is then deposited onto the surface of the substrate, creating the desired thin film. When the chemical mixture has adhered to the substrate, the volatile precursor will, over time, start to decompose, leaving behind the desired layer of source material on the substrate. The volatile precursor can then be removed from the chamber using gas flow or other industrial methods, and the process can be accelerated by the application of heat.