Choose from our selection of lathe tools, indexable turning tools, and more. In stock and ready to ship. Difference Between Capstan and Turret Lathe; Working of Shaper Machine. The workpiece is usually mounted on the table. The table is rigid as well as box-shaped and it placed in front of the machine or just near to the machine. We can easily adjust the height of the table. The table is adjusted in such a way that it suits the workpiece. Controls the chip flow direction and strength of the tool tip. Positive rake angles. Theless, lathes have limitations in handling heavy and/or non-cylindrical workpiece. Popular Lathe Parts $ 11.72. Switch W/ Key (8) Fix Number FIX10325609 Manufacturer Part Number 489105-00 This Switch is an OEM approved replacement part for various tools and models manufactured by Delta, Black and Decker, and Porter Cable. For full compatibility, please see the 'Model Cross Reference List' below. Integrated software controls the process and communicates the contents of the CD to the computer. Robotics is the application of mechatronics to create robots, which are often used in industry to perform tasks that are dangerous, unpleasant, or repetitive.

1. Lathe Controls The Mechanical
2. Lathe Mechanic

After reading this article you will learn about:- 1. Meaning of Cutting Tool 2. Types of Cutting Tools 3. Angles 4. Signature.

Meaning of Cutting Tool:

A cutting tool in metal working can be defined as “any tool that is used to remove metal from the work piece by means of shear deformation”. Frequently, it also refers as a tool bit. In order to perform effective cutting operation, the cutting tool must be made of a material harder than the work material to be cut. Also, the tool must be able to withstand the heat generated during machining process.

The tool must have a specific geometry (known as tool geometry) for effective cutting and smooth surface finish. According to the tool geometry, the cutting tools can be classified into solid cutting tools and carbide tipped tools.

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There are two surfaces adjacent to the cutting edge of the tool:

(a) Rake surface.

(b) Flank surface.

(a) Rake Surface:

Rake surface directs the flow of newly formed chip. It is oriented at a certain angle is called the rake angel ‘a’. It is measured relative to the plane perpendicular to the work surface. The rake angle can be positive or negative.

(b) Flank Surface:

The flank surface of the tool provides a clearance between the tool and the newly formed work surface, thus protecting the surface from abrasion which would degrade the finish. This angle between work surface and the flank surface is called the relief or clearance angle.

Types of Cutting Tools:

Various cutting operations require various types of cutting tools. To achieve good surface quality, proper cutting tool selection is very important.

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Following are some important parameters to be considered while selecting a cutting tool for particular machining operation:

i. Geometry.

ii. Material to be machined.

iii. Shape and Size of part.

iv. Type of operation required.

v. Machine tool quality.

vi. Surface finish required.

vii. Holding facility.

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viii. Machining parameters such as feed speed and depth of cut selected.

The various types of cutting tools are shown in Fig. 9.11.

The major classifications of cutting tools are following:

(i) According to Construction:

(a) Solid tool.

(b) Carbide tipped tool.

(ii) According to Number of Cutting Edges:

(a) Single point tool.

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(b) Multipoint tool.

(c) Formed (Tailor designed) tool.

(iii) According to Shape:

(a) Square.

(b) Circular.

(c) Left hand.

(d) Right hand.

(e) Round nose.

(f) Straight nose.

(iv) According to Operations:

(a) Turning.

(b) Drilling.

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(c) Threading.

(d) Knurling.

(e) Boring.

(f) Forming.

(g) Parting-off.

(h) Reaming.

(v) According to Type of Cutting Tool Material:

(a) H.S.S.

(b) Carbide.

(c) Ceramics.

(d) Diamond.

Cutting Tool Angles:

The face and the flank are pain surfaces, the cutting edge can be assumed to be a line. These surfaces and the edges are inclined with respect to some reference plan or line. The inclinations are called tool angles.

These angles are defined by various names. They are provided for various purposes. Consider the case of the face abgf, as shown in Fig. 9.12. It is a plane surface no doubt, but can have some inclinations. This surface may be parallel to the base or say to horizontal surface, or it can be inclined upward or downward with respect to the horizontal plane. Again it may have inclination sideward also. So in general the face can have two inclinations simultaneously, backward and sideward. Similarly the flank (Principal flank abed or auxiliary flank adef) can have two inclinations.

For efficient machining operation, the cutting tool must be provided with necessary tool angles. A tool with proper geometry (cutting edge and tool angles) cuts the metal effectively. Therefore reducing the chattering, breaking of the tool with less heat generation. Fig 9. 14. (a) and (b) shows a single point cutting tool with various cutting edges and tool angles.

From the geometry of cutting tool the various cutting tool angles are:

Rake Angle (α):

(a) Black rake angle.

(b) Side rake angle.

Clearance or Relief Angle (γ):

(a) End clearance relief angle.

(b) Side clearance relief angle.

Cutting Edge Angle:

(a) End cutting edge angle.

(b) Side cutting edge angle.

(i) Back Rake Angle:

It is the angle between the face of the tool and plane parallel to its base. It is also known as front rake angle or top rake angle.

(ii) Side Rake Angle:

It is the angle between the face of the tool and the shank of the tool.

(iii) End Clearance (Relief) Angle:

It is the angle between the front surface of the tool and a line normal to the base of the tool. It is also known as front clearance angle.

(iv) Side Clearance (Relief) Angle:

It is the angle between the side surface of the tool and a line normal to the base of the tool.

(v) End Cutting Edge Angle:

It is the angle between the end cutting edge of the tool and a line perpendicular to its shank.

(vi) Side Cutting Edge Angle:

It is the angle between the side cutting edge of the tool and shank of the tool.

(vii) Nose Radius:

Nose radius is one which connects the side and end cutting edge. Now, we will discuss the functions and effects of cutting tool angles on cutting process.

Functions of Back Rake Angle:

(a) It helps to control the chip flow in a convenient direction.

(b) It reduces the cutting force required to shear the metal and consequently helps to reduces power requirements and increase tool life.

(c) It also helps counteract the pressure against the cutting tool from the work by pulling the tool into the work.

(d) It provides keenness to the cutting edge and improves the surface finish.

Functions of Side Rake angle:

(a) It performs similar functions as performed by back rake angle.

(b) Side rake angle along with back rake angle controls the chip flow direction.

(c) It partly counteracts the resistance of the work to the movement of the cutter.

(d) For example, brass requires a back and side rake angle of almost 0°, while aluminum uses a back rake of 35° and a side rake of 15°.

Functions of End Clearance (relief) Angle:

(a) It allows the tool to cut freely without rubbing against the work surface.

(b) This angle varies from 0° to 15°, and usually 8°.

(c) Excessive relief angle reduces strength of the tool.

Functions of Side Clearance (relief) Angle:

i. It avoids the rubbing of flank against the work piece when the tool is fed longitudinally.

ii. This angle is 6° to 10° for steel, 8° for aluminum.

iii. It maintains that no part of the tool besides the actual cutting edge can touch the work.

Functions of End Cutting Edge Angle:

i. It avoids rubbing between the edge of the tool and workspace.

ii. It influences the direction of chip flow.

Functions of Side Cutting Edge Angle:

i. Increase in side cutting edge angle tends to widen and thin the chip.

ii. An excessive side cutting edge angle redirects feed forces in radial direction which may cause chatter.

Functions of Nose Radius:

i. A sharp point at the end of tool is undesirable, because it is highly stressed, short lived and leaves groove in the path of cut.

ii. Therefore Nose Radius is favourable for long tool life and good surface quality.

iii. It affects the tool life, radial force, and surface quality of work piece.

iv. If nose radius is too large chatter will occur.

v. There is an optimum value of the nose radius at which the tool life is maximum.

vi. If the nose radius exceeds optimum value, the tool life decreases.

vii. Larger nose radius means larger area of contact between tool and work piece. Resulting more frictional heat is generated. Also, cutting force increases due to which the work part may start vibrating and chattering, if work part holding is not very tight.

viii. The recommendations for use of more nose radius are.

R= 0.4 mm for delicate components.

R = 0.4 mm to 1.2 mm for disposable carbide inserts for common use.

R = 1.2 mm to 1.5 mm for heavy duty inserts.

R ≥ 1.5 mm for heavy depth of cut, interrupted cuts and heavy feeds.

Significance of Rake Angle:

1. The rake angles may be positive, zero or negative.

2. An increased rake angle will reduce the strength of the cutting edge.

3. Rake angle affects the values of cutting angle and the shear angle.

4. Larger the rake angle, smaller the cutting angle (and larger the shear angle).

5. In general, the small rake angle is used for cutting hard metals and a larger rake angle is used for cutting soft and ductile metals.

6. The use of negative rake angle started with the employment of carbide cutting tools. When positive rake angle is used, the force on the tool is directed towards the cutting edge, tending to chip or break it, as shown in Fig. 9.15(a).

7. Since the carbide material is brittle and lacks shock resistance, it will fail if positive rake angles are used with it. Using negative rake angles, directs the force back into the body of the tool away from the cutting edge, which protects to the cutting edge, as shown in Fig. 9.15 (b).

8. The use of negative rake angle increases the cutting force. This can compensate by higher cutting speeds. Therefore, high cutting speeds are always used with negative rake angles. High cutting speeds require high power of the machine tool.

9. The use of index able inserts also need the use of negative rake angles.

10. A negative rake angle insert has twice life than an equivalent positive rake angle insert.

11. Negative rake angle increases cutting edge strength, because the cutting force acts on the middle of cutting edge.

12. Positive rake angle decreases cutting edge strength, because the cutting force acts on the end or corner of the cutting edge.

13. Positive rake angle recommendations are:

(a) When machining low strength metals and alloys, such as aluminum and copper alloys, mild steel, etc.

(b) Where cutting at low speeds.

(c) When set up has low strength and rigidity.

(d) When low power machines used.

(e) When tool materials are H.S.S. and cast alloys.

14. Negative rake angle recommendations are:

(a) When machining high strength metal and alloys, such as stainless steel, alloy tool steel, titanium alloys, etc.

Table 9.4. Gives the recommended rake angles for various combinations of work and tool materials:

Tool Signature:

Tool signature is the specification or nomenclature of the tool which provides information regarding various tool angles and nose radius.

It includes seven parameters in specified order as given below:

(i) Back rake angle.

(ii) Side rake angle.

(iii) End relief (clearance) angle.

(iv) Side relief angle,

(v) End cutting edge angle.

(vi) Side cutting edge angle.

(vii) Nose radius.

For example:

(a) If the tool signature is 12, 15, 7, 6, 10, 15, 0.8

Means,

Lathe Controls The Mechanical

Back rake angle (degree): 12

Side rake angle: 15

End relief angle: 07

Side relief angle: 06

End cutting edge angle: 10

Side cutting edge angle: 15

Nose radius (mm): 0.8

(b) If the tool signature is -10, 15, 8, 6, 8, 5, 0.5

Here, also the meaning is back rake angle is negative 10 degree, side rake angle is 15 degree, End relief angle is 08 degree, side relief angle is 06 degree, End cutting edge angle is 08 degree, side cutting edge angle is 05 degree and nose radius is 0.5 mm.

Automotive service technicians inspect, maintain, and repair automobiles and light trucks that run on gasoline, electricity, or alternative fuels, such as ethanol. They perform basic care maintenance, such as oil changes and tire rotations, diagnose more complex problems, and plan and execute vehicle repairs.
Automotive service technicians' and mechanics' responsibilities have evolved from simple mechanical repairs to high-level technology-related work. Today, integrated electronic systems and complex computers regulate vehicles and their performance while on the road. This increasing sophistication of automobiles requires workers who can use computerized shop equipment and work with electronic components while maintaining their skills with traditional hand tools. Technicians must have an increasingly broad knowledge of how vehicles' complex components work and interact. They also must be able to work with electronic diagnostic equipment and digital manuals and reference materials.
When mechanical or electrical troubles occur, technicians first get a description of the problem from the owner or, in a large shop, from the repair service estimator or service advisor who wrote the repair order. To locate the problem, technicians use a diagnostic approach. First, they test to see whether components and systems are secure and working properly. Then, they isolate the components or systems that might be the cause of the problem. For example, if an air-conditioner malfunctions, the technician might check for a simple problem, such as a low coolant level, or a more complex issue, such as a bad drive-train connection that has shorted out the air conditioner. As part of their investigation, technicians may test drive the vehicle or use a variety of testing equipment, including onboard and hand-held diagnostic computers or compression gauges. These tests may indicate whether a component is salvageable or whether a new one is required. Accuracy and efficiency are critical in diagnosing and repairing vehicles, as parts are increasingly expensive, and timely repairs allow shops to take on more business.
During routine service inspections, technicians test and lubricate engines with lubricants and other major components. Sometimes, technicians repair or replace worn parts before they cause breakdowns or damage the vehicle. Technicians usually follow a checklist to ensure that they examine every critical part. Belts, hoses, plugs, brakes, fuel systems, and other potentially troublesome items are watched closely.
Service technicians use a variety of tools in their work. They use power tools, such as pneumatic wrenches, to remove bolts quickly; machine tools like lathes and grinding machines to rebuild brakes; welding and flame-cutting equipment to remove and repair exhaust systems; and jacks and hoists to lift cars and engines. They also use common hand tools, such as screwdrivers, pliers, and wrenches, to work on small parts and in hard-to-reach places. Technicians usually provide their own hand tools, and many experienced workers have thousands of dollars invested in them. Employers furnish expensive power tools, engine analyzers, and other diagnostic equipment.
Computers are also commonplace in modern repair shops. Service technicians compare the readouts from computerized diagnostic testing devices with benchmarked standards given by the manufacturer. Deviations outside of acceptable levels tell the technician to investigate that part of the vehicle more closely. Through the Internet or from software packages, most shops receive automatic updates to technical manuals and access to manufacturers' service information, technical service bulletins, and other databases that allow technicians to keep up with common problems and to learn new procedures.
High technology tools are needed to fix the computer equipment that operates everything from the engine to the radio in many cars. In fact, today, most automotive systems, such as braking, transmission, and steering systems, are controlled primarily by computers and electronic components. Additionally, luxury vehicles often have integrated global positioning systems, accident-avoidance systems, and other new features with which technicians will need to become familiar. Also, as more alternate-fuel vehicles are purchased, more automotive service technicians will need to learn the science behind these automobiles and how to repair them.
Automotive service technicians in large shops often specialize in certain types of repairs. For example, transmission technicians and rebuilders work on gear trains, couplings, hydraulic pumps, and other parts of transmissions. Extensive knowledge of computer controls, the ability to diagnose electrical and hydraulic problems, and other specialized skills are needed to work on these complex components, which employ some of the most sophisticated technology used in vehicles. Tune-up technicians adjust ignition timing and valves and adjust or replace spark plugs and other parts to ensure efficient engine performance. They often use electronic testing equipment to isolate and adjust malfunctions in fuel, ignition, and emissions control systems.
Automotive air-conditioning repairers install and repair air-conditioners and service their components, such as compressors, condensers, and controls. These workers require special training in Federal and State regulations governing the handling and disposal of refrigerants. Front-end mechanics align and balance wheels and repair steering mechanisms and suspension systems. They frequently use special alignment equipment and wheel-balancing machines. Brake repairers adjust brakes, replace brake linings and pads, and make other repairs on brake systems. Some technicians specialize in both brake and front-end work.
Work Environment
While in 2008, most automotive service technicians worked a standard 40 hour week, 24 percent worked longer hours. Some may work evenings and weekends to satisfy customer service needs. Generally, service technicians work indoors in well-ventilated and well-lighted repair shops. However, some shops are drafty and noisy. Although many problems can be fixed with simple computerized adjustments, technicians frequently work with dirty and greasy parts and in awkward positions. They often lift heavy parts and tools. As a result, minor workplace injuries are not uncommon, but technicians usually can avoid serious accidents if safe practices are observed.
Education & Training Required
Most employers regard the successful completion of a vocational training program in automotive service technology as the best preparation for trainee positions. High school programs, while an asset, vary greatly in scope. Graduates of these programs may need further training to become qualified. Some of the more extensive high school programs participate in Automotive Youth Education Service (AYES), a partnership between high school automotive repair programs, automotive manufacturers, and franchised automotive dealers. All AYES high school programs are certified by the National Institute for Automotive Service Excellence. Students who complete these programs are well prepared to enter entry-level technician positions or to advance their technical education. Courses in automotive repair, electronics, physics, chemistry, English, computers, and mathematics provide a good educational background for a career as a service technician.
Postsecondary automotive technician training programs usually provide intensive career preparation through a combination of classroom instruction and hands-on practice. Schools update their curriculums frequently to reflect changing technology and equipment. Some trade and technical school programs provide concentrated training for 6 months to a year, depending on how many hours the student attends each week, and upon completion, award a certificate. Community college programs usually award a certificate or an associate degree. Some students earn repair certificates in a particular skill and leave to begin their careers. Associate degree programs, however, usually take 2 years to complete and include classes in English, basic mathematics, computers, and other subjects, as well as automotive repair. Recently, some programs have added classes on customer service, stress management, and other employability skills. Some formal training programs have alliances with tool manufacturers that help entry-level technicians accumulate tools during their training period.
Various automobile manufacturers and participating franchised dealers also sponsor 2-year associate degree programs at postsecondary schools across the Nation. Students in these programs typically spend alternate 6-week to 12-week periods attending classes full time and working full time in the service departments of sponsoring dealers. At these dealerships, students work with an experienced worker who provides hands-on instruction and timesaving tips.
Those new to automotive service usually start as trainee technicians, technicians' helpers, or lubrication workers, and gradually acquire and practice their skills by working with experienced mechanics and technicians. In many cases, on-the-job training may be a part of a formal education program. With a few months' experience, beginners perform many routine service tasks and make simple repairs. While some graduates of postsecondary automotive training programs often are able to earn promotion to the journey level after only a few months on the job, it typically takes 2 to 5 years of experience to become a fully qualified service technician, who is expected to quickly perform the more difficult types of routine service and repairs. An additional 1 to 2 years of experience familiarizes technicians with all types of repairs. Complex specialties, such as transmission repair, require another year or two of training and experience. In contrast, brake specialists may learn their jobs in considerably less time because they do not need complete knowledge of automotive repair.
Employers increasingly send experienced automotive service technicians to manufacturer training centers to learn to repair new models or to receive special training in the repair of components, such as electronic fuel injection or air-conditioners. Motor vehicle dealers and other automotive service providers may send promising beginners or experienced technicians to manufacturer-sponsored technician training programs to upgrade or maintain employees' skills. Factory representatives also visit many shops to conduct short training sessions.
Other Skills Required (Other qualifications)
The ability to diagnose the source of a problem quickly and accurately requires good reasoning ability and a thorough knowledge of automobiles. Many technicians consider diagnosing hard-to-find troubles one of their most challenging and satisfying duties. For trainee automotive service technician jobs, employers look for people with strong communication and analytical skills. Technicians need good reading, mathematics, and computer skills to study technical manuals. They must also read to keep up with new technology and learn new service and repair procedures and specifications.
Training in electronics is vital because electrical components, or a series of related components, account for nearly all malfunctions in modern vehicles. Trainees must possess mechanical aptitude and knowledge of how automobiles work. Experience working on motor vehicles in the Armed Forces or as a hobby can be very valuable.
Automotive Service Technicians and Mechanics - What They Do - Page 2

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