Basic Mechanisms Of Tool Wear

The various mechanisms that contribute to wear process are as below .

• Mechanical overload causing micro breakages (attrition). 

• Abrasion
• Adhesion
• Diffusion

Attrition :
The grains of the various components of the tool material hold together at grain boundaries. Those on the rake face and on the flank are supported on at least half of their surfaces and can therefore be rather easily broken out, embedded in the machined surface and in the underside of the chip, and dragged over the tool surface. Some of them may then break out other grains and produce a kind of chain effect.
 

Abrasion :
Abrasion is the commonly known wear process in which a harder material scratches a softer material over which it is sliding under normal pressure. This mechanism is significant for tool wear only in those instances where the workpiece material is very hard or contains hard particles: cast iron with grains of cementite, various metal containing hard inclusions like hypereutectic aluminum with SiC grains, steel killed with aluminum and containing Al2O3 , and so on. The machined surface is cooler than the tool flank, and it may happen that tool material is softened more than some of the constituents of the workpiece materials, which creates the conditions for abrasion.
 

Adhesion :
In the conditions of the intimate contact between the tool and the freshly created surfaces on the workpiece and on the underside of the chip, welding of the workpiece surface and of the chip to the tool can often be observed. The extreme case is the built-up edge, which is formed in the low and middle speed range. Layers of workpiece material welded to the tool are found in ductile materials like in ferritic and Tehran International Congress on Manufacturing Engineering  Tehran, Iran austenitic steels, titanium alloy, and nickel-based alloys. The welded layers and points are periodically sheared away. This mechanism contributes to flank wear as well as to the formation of the crater.
 

Diffusion:
Diffusion is an important mechanism and plays a significant role at higher cutting speeds in some workpiece/tool material combinations. The diffusion rate, that is, the amount of atoms of material penetrating into another material, depends on the affinity of the two, very strongly on temperature, and on the gradient of concentration of the penetrating atoms in the solvent material. The latter aspect is very special in cutting, because the chip materials that absorbs the atoms of the tool material is continuously being carried away, and all the time new, virgin, unsaturated material is always arriving.

Orthogonal and Oblique Cutting

Orthogonal Cutting: 

The cutting condition when chip is expected to flow along the orthogonal plane is known as orthogonal cutting.pure orthogonal cutting is orthogonal cutting when principle cutting angle is 90 degree.

Oblique Cutting:

 When the chip does not flow on orthogonal plane i.e chip deviates from orthogonal plane then it is called oblique cutting.

Basic Difference Between Orthogonal and Oblique Cutting: 

 In oblique cutting inclination angle(lamda) have some value but in orthogonal cutting there is no lamda i.e lamda=zero.

Causes of orthogonal cutting:

• Restricted cutting effect.
• tool nose radius-ing.
• inclination angle (Lamda not equal to zero).

Cutting Processes

Cutting processes work by causing fracture of the material that is processed. Usually, the portion that is fractured away is in small sized pieces, called chips. Common cutting processes include sawing, shaping (or planing), broaching, drilling, grinding, turning and milling. 

Although the actual machines, tools and processes for cutting look very different from each other, the basic mechanism for causing the fracture can be understood by just a simple model called for orthogonal cutting. In all machining processes, the workpiece is a shape that can entirely cover the final part shape. The objective is to cut away the excess material and obtain the final part. This cutting usually requires to be completed in several steps – in each step, the part is held in a fixture, and the exposed portion can be accessed by the tool to machine in that portion. 

Common fixtures include vise, clamps, 3-jaw or 4-jaw chucks, etc. Each position of holding the part is called a setup. One or more cutting operations may be performed, using one or more cutting tools, in each setup. To switch from one setup to the next, we must release the part from the previous fixture, change the fixture on the machine, clamp the part in the new position on the new fixture, set the coordinates of the machine tool with respect to the new location of the part, and finally start the machining operations for this setup. Therefore, setup changes are time-consuming and expensive, and so we should try to do the entire cutting process in a minimum number of setups; the task of determining the sequence of the individual operations, grouping them into (a minimum number of) setups, and determination of the fixture used for each setup, is called process planning

TOOLCHIP INTERFACE TEMPERATURE IN TURNING PROCESS

The cutting temperature is a key factor which directly affects cutting tool wear, workpiece surface integrity and machining precision according to the relative motion between the tool and workpiece. The amount of heat generated varies with the type of material being machined, cutting parameters, contact length between tool and chip, cutting forces and friction between tool and workpiece material. 

The temperatures which are of major interests are: average shear zone temperature, average (and maximum) temperature at the chip-tool interface, temperature at the work-tool interface (tool flanks), average cutting temperature. Temperature on the chip-tool interface is important parameters in the analysis and control of machining process. Total tool wear rate and crater wear on the rake face are strongly influenced by the temperature at chip-tool interface. Much research has been undertaken into measuring the temperatures generated during cutting operations.

To measure the tool temperature at the tool chip interface many experimental methods have been developed. The main techniques used to evaluate the cutting temperature during machining are tool-work thermocouple, embedded thermocouple and thermal radiation method. Design and develop control system to control the temperature lead to decrease tool wear and better surface finish. Production research activities in a real production environment supported by statistical experimental procedures enable continuous improvement of control processes and further cost .

Milling Cutter Nomenclature

As far as metal cutting action is concerned, the pertinent angles on the tooth are those that define the configuration of the cutting edge, the orientation of the tooth face, and the relief to prevent rubbing on the land.

Outside diameter — The diameter of a circle passing through the peripheral cutting edges. It is the dimension used in conjunction with the spindle speed to find the cutting speed (SFPM).

Root diameter — This diameter is measured on a circle passing through the bottom of the fillets of the teeth.

Tooth — The tooth is the part of the cutter starting at the body and ending with the peripheral cutting edge. Replaceable teeth are called inserts.

Tooth face — The tooth face is the surface between the fillet and the cutting edge, where the chip slides during its formation.

Land — The area behind the cutting edge on the tooth that is relieved to avoid interference is called the land.

Flute — The flute is the space provided for chip flow between the teeth.

Gash angle — The gash angle is measured between the tooth face and the back of the tooth immediately ahead.

Fillet — The fillet is the radius at the bottom of the flute, provided to allow chip flow and chip curling.

The terms defined above apply primarily to milling cutters, particularly to plain milling cutters. In defining the configuration of the teeth on the cutter, the following terms are important.

Peripheral cutting edge — The cutting edge aligned principally in the direction of the cutter axis is called the peripheral cutting edge. In peripheral milling, it is this edge that removes the metal.

Face cutting edge — The face cutting edge is the metal removing edge aligned primarily in a radial direction. In side milling and face milling, this edge actually forms the new surface, although the peripheral cutting edge may still be removing most of the metal. It corresponds to the end cutting edge on single point tools.

Relief angle — This angle is measured between the land and a tangent to the cutting edge at the periphery.

Clearance angle — Is provided to make room for chips, thus forming the flute.

Radial rake angle — The angle between the tooth face and a cutter radius, measured in a plane normal to the cutter axis.

Axial rake angle — Measured between the peripheral cutting edge and the axis of the cutter, when looking radially at the point of intersection.

Blade setting angle — When a slot is provided in the cutter body for a blade, the angle between the base of the slot and the cutter axis is called the blade setting angle.

Milling Cutters

Milling is a process of generating machined surfaces by progressively removing a predetermined amount of material from the workpiece, which is advanced at a relatively slow feed rate to a milling cutter rotating at a comparatively high speed. The characteristic feature of the milling process is that each milling cutter tooth removes its share of the stock in the form of small individual chips.

Types of milling cutters
The variety of milling cutters available helps make milling a versatile machining process. Cutters are made in a large range of sizes. Milling cutters are made from High Speed Steel (HSS), others are carbide tipped and many are replaceable or indexable inserts.

Periphery milling cutters — Periphery milling cutters are usually arbor-mounted to perform various operations. Common high-speed steel milling cutters include the staggered tooth cutter, side-milling cutter, plain-milling cutter, single-angle milling cutter, double-angle milling cutter, convex milling cutter, concave milling cutter, and corner-rounded milling cutter.

Light-duty plain mill — A general-purpose cutter for peripheral milling operations. Narrow cutters have straight teeth, while wide ones have helical teeth.

Heavy-duty plain mill — Similar to the light duty mill except that it is used for higher rates of metal removal. To aid it in this function, the teeth are more widely spaced and the helix angle is increased to about 45 degrees.

Side milling cutter — Has a cutting edge on the sides as well as on the periphery. This allows the cutter to mill slots.

Half-side milling cutter — Same as the one previously described except that cutting edges are provided on a single side. It is used for milling shoulders. Two cutters of this type are often mounted on a single arbor for straddle milling.

Stagger-tooth side mill — Same as the side-milling cutter except that the teeth are staggered so that every other tooth cuts on a given side of the slot. This allows deep, heavy-duty cuts to be taken.

Angle cutters — The peripheral cutting edges lie on a cone rather than on a cylinder. A single or double angle may be provided.

Drilling In Tool Engineering

The geometry of the common twist drill tool (called drill bit) is complex; it has straight cutting teeth at the bottom – these teeth do most of the metal cutting, and it has curved cutting teeth along its cylindrical surface .The grooves created by the helical teeth are called flutes, and are useful in pushing the chips out from the hole as it is being machined. Clearly, the velocity of the tip of the drill is zero, and so this region of the tool cannot do much cutting. 

Therefore it is common to machine a small hole in the material, called a center-hole, before utilizing the drill. Center-holes are made by special drills called center-drills; they also provide a good way for the drill bit to get aligned with the location of the center of the hole. There are hundreds of different types of drill shapes and sizes; here, we will only restrict ourselves to some general facts about drills. 

• Common drill bit materials include hardened steel (High Speed Steel, Titanium Nitride coated steel); for cutting harder materials, drills with hard inserts, e.g. carbide or CBN inserts, are used.
• In general, drills for cutting softer materials have smaller point angle, while those for cutting hard and brittle materials have larger point angle.
• If the Length/Diameter ratio of the hole to be machined is large, then we need a special guiding support for the drill, which itself has to be very long; such operations are called gun-drilling. This process is used for holes with diameter of few mm or more, and L/D ratio up to 300. These are used for making barrels of guns.
• Drilling is not useful for very small diameter holes (e.g. < 0.5 mm), since the tool may break and get stuck in the workpiece.
• Usually, the size of the hole made by a drill is slightly larger than the measured diameter of the drill – this is mainly because of vibration of the tool spindle as it rotates, possible misalignment of the drill with the spindle axis, and some other factors.

Metal Cutting

Metal cutting applications span the entire range from mass production to mass customization to high-precision, fully customized designs. The careful balance between precision and efficiency is maintained only through intimate knowledge of the physical processes, material characteristics, and technological capabilities of the equipment and workpieces involved. The  Metal Cutting Theory and Practice provides knowledge, integrating timely research with current industry practice. This brilliant reference enters its later concepts with fully updated coverage, new sections, and the inclusion of examples and problems.

Supplying complete, up-to-date information on machine tools, tooling, and work holding technologies, it stresses a physical understanding of machining processes including forces, temperatures, and surface finish. This provides a practical basis for troubleshooting and evaluating vendor claims. In addition to updates three new areas on cutting fluids, agile and high-throughput machining, and design for machining. Rounding out the treatment, an entire thing is devoted to machining economics and optimization.

Endowing you with practical knowledge and a fundamental understanding of underlying physical concepts, Metal Cutting Theory and Practice is a necessity for designing, evaluating, purchasing, and using machine tools.

Techniques To Combat Chatter

Following are some of the techniques commonly used to combat chatter. Use these guidelines to establish a good foundation for optimizing your moldmaking processes. 

1.The Right Tool holder: 

 Common tool holders (side-lock, double-angle collets and standard ER collets) do not provide the accuracy or stiffness needed for high-performance machining. Better options are tool holder shanks that incorporate face and taper contact to deliver high accuracy and rigidity. This type of holder engages the precision ground face of the spindle with simultaneous contact with the taper, which provides the additional rigidity required, and also aids in damping. All tooling should be evaluated for balancing, which provides improvements in surface finish even at lower RPMs. 

2.Cutter Tooling Selection: 

Cutter tooling can greatly influence chatter. Considerations include correct substrate, geometry, coating and length-diameter ratio. Programmers often gravitate to using the largest tool that can fit, but that may not be the ideal tool size. Incorporating multiple tools with variable flute geometries is an effective way to reduce vibrations.

3.Proper Work holding:

 If the part is not properly secured, the part itself can vibrate and induce chatter. There are many excellent systems available to clamp your workpieces. Criteria to look for include high precision, high clamping force, ease of use and flexibility (allowing use across multiple CNC machine tool platforms).

4.Machine Maintenance:

If you’re trying to hold fine finishes and tight tolerances on a poorly maintained machine, you’ll need to overcome mechanical challenges well beyond the issues listed here. Keep your equipment on a regular maintenance schedule to ensure the best performance.

5.Control Solution: 

The above can correct some causes of chatter, but there are limitations to these methods. The use of new control technology—smart control systems—that navigates processes and eliminates potentials for costly surface finish problems is another method. One such technology1 is designed to eliminate chatter and take the guesswork out of the trial-and-error process typically used to find the correct spindle speed, allowing the cutting tool and machine tool to continuously operate at the highest performance. It uses a single processor intelligent numerical control2 and vibration sensors to monitor chatter noise and automatically adjust spindle speed. No longer does an operator need to babysit a cut. With this technology in place, your mold shop can be more profitable and gain a competitive advantage.

Optimization Of Machining Techniques

First of all, machining models are required to determine the optimum machining parameters including cutting speed, feed rate and depth of cut, in order to minimize unit production cost. Unit production cost can be divided into four basic cost elements:

• Cutting cost by actual cut in time
• Machine idle cost due to loading and unloading operation and idling tool motion cost
• Tool replacement cost
• Tool cost

For the optimization of unit production cost, practical constraints which present the state of machining processes need to be considered. The constraints imposed during machining operations are:

 
• Parameter constraint – Ranges of cutting speed, feed rate and depth of cut.
• Tool life constraint – Allowable values of flank wear width and crater wear depth.
• Operating constraint – Maximum allowable cutting force, power available on machine tool and surface finish requirement.

An optimization model for multi-pass turning operation can be formulated. The multipass turning model is a constrained nonlinear programming problem with multiple variables(machining variables). The initial solution for SS is picked in a random way. The user-specified parameters have to be given. The experimentation can be run on a PC with Pentium800Mhz processor. The computational results validate the advantage of SS in terms of solution quality and computational requirement.

Future as a machinist looks bright

Everything you see that is not natural is manufactured and we need machinists to manufacture,Machinists use machine tools that are either conventionally controlled or by computer numerical controls (CNC), such as lathes, milling machines and grinders, to produce precision metal parts.The parts range from simple bolts of steel or brass and titanium bone screws for orthopedic implants to hydraulic parts, anti-lock brakes and automobile pistons.

Opportunities are vast for graduate. It's a high demand area and companies want people who are trained in the technology but still have the basics of the manual work and a foundation of safety.Machinists typically work from blueprints, sketches or computer aided design (CAD) or computer aided manufacturing (CAM) files; set up, operate and tear down CNC machine tools; install, align, secure, and adjust cutting tools and work pieces; monitor the feed and speed of machines; turn, mill, drill, shape and grind machine parts to specifications; and examine and test completed products for defects and ensure all products conform to specifications.Because the technology of machining is changing rapidly, machinists must learn to operate a wide range of machines, and as engineers create new types of machine tools, machinists must learn new machining properties and techniques.As jobs come back to the U.S.,we need to train a well-prepared workforce for the industry and that's where junior college comes into play.

There are many ways to become a skilled machinist, but as the trade evolves, so does the training required.Courses result in several levels of qualification, from a certificate to an associate of applied sciences degree and can take from two semesters to two years to complete, depending on full- or part-time commitment and level of education desired.There is tremendous opportunity and the greater the education, the more opportunities that will be available to graduates.And varied experience the will allow them to move up. Even after completing a formal training program, machinists still need years of experience to become highly skilled.But it is getting hard to get on-the-job-training because of production schedules - there is little or no down time in order to train.

Thinks to Remember while designing Jigs and Fixtures

Important considerations while designing Jigs and Fixtures are based on certain parameters and design factors. These factors are analysed to get design inputs for jigs and fixtures. The list of such factors is mentioned below :

1.Study of workpiece and finished component size and geometry.

2.Type and capacity of the machine, its extent of automation.

3.Provision of locating devices in the machine.

4.Available clamping arrangements in the machine.

5.Available indexing devices, their accuracy.

6.Evaluation of variability in the performance results of the machine.

7.Rigidity and of the machine tool under consideration.

8.Study of ejecting devices, safety devices, etc.

9.Required level of the accuracy in the work and quality to be produced.

Purpose of Jigs and Fixtures

Following are the purpose and advantages of jigs and fixtures,

• It reduces or sometimes eliminates the efforts of marking, measuring and setting of workpiece on a machine and maintains the accuracy of performance.
• The workpiece and tool are relatively located at their exact positions before the operation automatically within negligible time. So it reduces product cycle time.
• Variability of dimension in mass production is very low so manufacturing processes supported by use of jigs and fixtures maintain a consistent quality.
• Due to low variability in dimension assembly operation becomes easy, low rejection due to les defective production is observed.
• It reduces the production cycle time so increases production capacity. Simultaneously working by more than one tool on the same workpiece is possible.
• The operating conditions like speed, feed rate and depth of cut can be set to higher values due to rigidity of clamping of workpiece by jigs and fixtures.
• Operators working becomes comfortable as his efforts in setting the workpiece can be eliminated.
•  Semi-skilled operators can be assigned the work so it saves the cost of manpower also.
•  There is no need to examine the quality of produce provided that quality of employed jigs and fixtures is ensured.

Jigs and Fixtures Design

Although many people have their own definitions for a jig or fixture, there is one universal distinction between the two. Both jigs and fixtures hold, support, and locate the workpiece. A jig, however, guides the cutting tool. A fixture references the cutting tool. The differentiation between these types of work holders is in their relation to the cutting tool.

Jigs

The most-common jigs are drill and boring jigs. These tools are fundamentally the same. The difference lies in the size, type, and placement of the drill bushings. Boring jigs usually have larger bushings. These bushings may also have internal oil grooves to keep the boring bar lubricated. Often, boring jigs use more than one bushing to support the boring bar throughout the machining cycle.

In the shop, drill jigs are the most-widely used form of jig. Drill jigs are used for drilling, tapping, reaming, chamfering, counterboring, countersinking, and similar operations. Occasionally, drill jigs are used to perform assembly work also. In these situations, the bushings guide pins, dowels, or other assembly elements.

Jigs are further identified by their basic construction. The two common forms of jigs are open and closed. Open jigs carry out operations on only one, or sometimes two, sides of a workpiece. Closed jigs, on the other hand, operate on two or more sides. The most-common open jigs are template jigs, plate jigs, table jigs, sandwich jigs, and angle plate jigs. Typical examples of closed jigs include box jigs, channel jigs, and leaf jigs. Other forms of jigs rely more on the application of the tool than on their construction for their identity. These include indexing jigs, trunnion jigs, and multi-station jigs.

Specialized industry applications have led to the development of specialized drill jigs. For example, the need to drill precisely located rivet holes in aircraft fuselages and wings led to the design of large jigs, with bushings and liners installed, contoured to the surface of the aircraft. A portable air-feed drill with a bushing attached to its nose is inserted through the liner in the jig and drilling is accomplished in each location.

Fixtures

Fixtures have a much-wider scope of application than jigs. These work holders are designed for applications where the cutting tools cannot be guided as easily as a drill. With fixtures, an edge finder, center finder or blocks position the cutter. Examples of the more-common fixtures include milling fixtures, lathe fixtures, sawing fixtures, and grinding fixtures. Moreover, a fixture can be used in almost any operation that requires a precise relationship in the position of a tool to a workpiece.

Fixtures are most often identified by the machine tool where they are used. Examples include mill fixtures or lathe fixtures. But the function of the fixture can also identify a fixture type. So can the basic construction of the tool. Thus, although a tool can be called simply a mill fixture, it could also be further defined as a straddle-milling, plate-type mill fixture. Moreover, a lathe fixture could also be defined as a radius-turning, angle-plate lathe fixture. The tool designer usually decides the specific identification of these tools.

Single Point Cutting Tool

Single point cutting fits in the category of machining as a manufacturing process. It involves the removal of metal from a workpiece using cutting tools that only have one primary cutting edge. Single point cutting using standard tools and equipment is a good option for the production of small batches and 1 off items such as prototypes. Machines are flexible and can be used for the production of a large range of components without the need for dedicated tooling. Basic set up costs are relatively low.

Characteristics of Single Point Cutting Tools

• Hardness even at high temperatures
• Toughness
• Chemical
• Resistant to wear

These characteristics have traditionally been found through the adoption of carbon and low alloy steels, although they did have a tendency to wear a little too easily. Being relatively easy to sharpen offset this problem to an extent but there was a clear need for further development  of tooling which could perform better.
High speed steels provided an initial solution to the wear problem, which was mainly brought about as a result of high temperatures being present while machining that would have an adverse affect on the low alloy steels. The high speed steels are still considered to be an affordable and effective choice for cutting most materials, but more recently there has been an adoption of cemented carbide inserts.
Cemented carbide tips are used in conjunction with tool holders and are normally supplied in a triangular geometry which can now be rotated in the holder to provide a new cutting tip when it does wear simply by loosening a retaining screw and clamp. Early designs used brazing to secure the carbide tip in its holder which, for obvious reasons, made continued use of the tip after wear impractical.
Further improvements in wear resistance came in the form of ceramic coatings that could be used on both high speed steels and cemented carbide tools. Diamond is another cutting tool material but is pretty much limited to low temperature applications, despite it being the hardest known material available.

Nomenclature of Single Point Cutting Tool

The single point cutting tool has only one cutting point or edge. These tools used for turning, boring, shaping or planning operations. These tools used on lathe, boring and shaper machines.

A single point cutting tool consists of a sharpened cutting part and the shank and main parts or elements which are:
1: Shank
It is the main body of the tool.
2: Flank:
The surface or surfaces below the adjacent to the cutting edge is called flank of the tool.
3: Face
The surface on which the chip slides is called the face of the tool.
4: Heel
It is the intersection of the flank and the base of the tool.
5: Nose
It is the point where the side cutting edge and end cutting edge intersect.
6: Cutting Edge
It is the edge on the face of the tool which removes the material from the work piece. The cutting edge consists of the side cutting edge(major cutting edge) and cutting edge(minor cutting edge) and the nose.

Single Point Cutting Tool Angles

The single point cutting tool mainly focus at their angles. The angle in cutting tool is following

• Side rake angle :This angle has major effect on the power efficiency as well as on the tool life. The value of this angle lies between 15° to 25°.
• Back rake angle : This angle controls the flow of chips, thrust force of the cut and the power of cutting tool edge. The value of this angle lies between 4° to 8°.
• Side cutting edge angle :This angle can reduce the thickness of chips. The value of this angle lies between 10° to 15° and is also called as lead angle.
• True rake angle :This angle has prime importance in metal removal process. All three angles which are discussed above are directly affected by this angle. If we have high positive true rake angle then less force, power and heat generate. The value of true rake angle can either be positive or negative but it totally depends upon the cutting tool material, machine rigidity and some other variables.
• End cutting edge angle :This angle provides us some clearance between cutter and finished surface of the work piece. If the value of angle is very close to zero then the tool strength will increase and if we take a larger value then it weakens the tool. The value of this angle lies between 8° to 15°.
• Nose radius:This angle gives us the strength to cutting edge, improves finish and also put some stress on the life factor of the tool. If we take a large value then it produces large radial force .But if we take too small value then it stops proper distribution of heat and reduces cutting tool material properties.
• Primary clearance angle :This angle is below cutting edge angle and is used to prevent tool from rubbing.
• Secondary clearance angle :This angle is on the tooth forms of shank and has a large value so it can permit chips to escape easily. But if we take too large value then it weakens the tool, so to avoid this problem we take economical value.

Tool Engineering Elements and work Area

Tool engineering is a division of industrial engineering whose function is to plan the processes of manufacture, develop the tools and machines, and integrate the facilities required for producing particular products with minimal expenditure of time, labours, and materials.
Tool engineers can find job opportunities in Product Drafters, Entry - Level Tool Designers, CAD Operators and Other Technical - related positions. Well trained and qualified tool engineers occupy important positions of responsibility with good scope for career enhancement in manufacturing industries. Tool Engineering Graduates an opportunity to acquire advanced skills and knowledge relating to Tool Design and Manufacturing with extensive exposure to CAD / CAM / CAE and GD&T to meet the growing demands of the industries

Tool Engineering Elements:

The basic elements of tool engineering are single point cutting tool and multiple point
cutting tool.

• Single Point Cutting Tool

The cutting tool, which has only one cutting edge, is termed as single point cutting tool.
Single point cutting tools are generally used while performing turning, boring, shaping
and planing operation. The important elements in single point cutting tools are rake
angle, principle cutting edge, nose etc.

• Multi Point Cutting Tool

A cutting tool which has more than one cutting edge is multipoint cutting tool. Multi
point cutting tools are generally used while performing drilling, milling, broaching,
grinding etc. Important elements are cutting edge, helix angle, the number of teeth. The
cutting edge is the only element that comes in direct contact with the work. The axial 8
Fundamentals of CIM angle corresponds to side rake angle in single point tool and similar angle with respect to the cutting axis, i.e. the radial angle is same as the back rake angle.

Work Areas:

Some of the common job profiles for tool makers are as follows:

• Tool and die makers
• Mold maker
• Tool fitter
• Jig maker
• Designers