Chapter 22

Name the four categories of cutting fluids according to chemistry

1. cutting oils 2. emulsified oils 3. chemical fluids 4. semi-chemical fluids

Name the three modes of tool failure in machining

1. fracture failure 2. temperature failure 3. gradual wear

What are some of the tool life criteria used in production machining operations?

As identified in the text, tool life criteria used in production include 1. complete failure of the tool 2. visual observation of flank or crater wear by the machine operator 3. changes in the sound emitted by the tool 4. degradation of surface finish 5. power increase 6. workpiece count 7. length of cutting time for the tool

Why are ceramic cutting tools generally designed with negative rake angles?

Ceramics posses low shear and tensile strength but good compressive strength. During cutting, this combination of properties is best exploited by giving the tool a negative rake angle to load the tool in compression.

Why can diamond cutting tools not be used to machine steel and other ferrrous metals?

Machining steel and other ferrous metals with SPD tools is not practical because of the chemical affinity that exists between these metal and carbon, because diamond is carbon.

What is the chemical formula of the ceramic material used in almost all ceramic cutting tools?

The chemical formula is Al3O3 for aluminum oxide.

Identify some of the common compounds that form the thin coatings on the surface of coats carbide inserts.

The common coatings are: TiN, TiC, and Al_2O3

Identify the mechanisms by which cutting tools wear during machining

The important tool wear mechanisms are 1. abrasion 2. adhesion 3. diffusion 4. chemical reactions 5. plastic deformation of the cutting edge

What is the physical interpretation of the parameter C in the Taylor tool life equation?

The parameter C is the cutting sped corresponding to a one-minute tool life. C is the speed-axis intercept on the log-log plot of the tool life data.

What is the physical interpretation of the parameter n in the Taylor tool life equation?

The parameter n is the slope of the log-log plot of the tool life data. It indicates how strongly tool life is affected by cutting speed.

Name the seven elements of tool geometry for a single-point cutting tool.

The seven elements of single-point tool geometry are 1. back rake angle 2. side rake angle 3. end relief angle 4. side relief angle 5. end cutting edge angle 6. side cutting edge angle 7. node radius

What is the difference between cemented carbides and cermets used as cutting tools in machining?

The term cermet in cutting tool technology refers to ceramic-and binder combinations other than WC-Co and WC-TiC-TaC-Co, which are known as cemented carbides, although technically, cemented carbides satisfy the general definiation of a cermet.

Name the two main categories of cutting fluid according to function

The two function categories of cutting fluids are 1. coolants 2. lubricants

What are the two principal aspects of cutting-tool technology?

The two principals aspects of cutting tool technology are 1. tool material 2. tool geometry

Identify the three alternative ways of holding and presenting a cutting edge for a single-point cutting tool during machining.

There are three principal ways: 1. solid shank, in which the cutting edge is an integral part of the tool shank, an example being high speed steel tooling 2. brazed inserts, used for some cemented carbides 3. mechanically clamped inserts, used for most hard tool materials including cemented carbides, coats carbides, cermets, ceramics, SPD, and CBN

What are the principal lubricating mechanisms by which cutting fluids work?

There are two lubricating mechanisms that are believed to be effective in metal cutting 1. boundary lubrication, which involved the formation of a thin fluid film to help

Identify three desireable properties of a cutting-tool material

Three desirable properties are 1. toughness to resist fracture failure 2. hot hardness to resist temperature failure 3. wear resistance to prolong the life of the tool during gradual wear 4. carbon Some grades of HSS also contain cobalt