Objective :This unit provides students with the fundamental knowlege and skills necessary for the various maching and various welding processes. It cover from the industrial safety in workshop practice to precision measurement in manufacturing processes.Workshop practice forms an important part of this unit.
Syllabus
1Industrial Safety
Mechanical and other accidents.Safety devices.Electrical accidents.Care and Order in the worksop. Safety Precautions
Occupational Safety and Health act 1994
2Fitting
Marking out, sawing , clamping , drilling and use of jig saw
3Checking and measurement of surface
Accuracy of measuring instruments, traceability of standard for measuring instrument.
Working principles and applications for one dimensional , digital tools and two measuring instrument instruments
concept of straightness , parallelism , flatness.
concept of cylindricity , concentricity , roundness coaxiallity.
Introduction to three dimensional coordinating measuring machine.
4principles of cutting tools
Rake angle , clearance angle. Cutting tool materials , Force acting on cutting tool , type of chips ,heat produced during cutting operation , functions of coolant
5Drilling
Drill bit: types , their features (ie angle) and functions ,grinding of drill
Drilling process :Drilling of an ordinary hole , countersinking , counterboring , spotfacing .
Drilling machines; types ,parts and functions
Drilling process parameters :Cutting speed and feed
cutting fluid ; types and uses
Safety precautions
set up and holding of work piece while drilling
6Shaping machine
Main features and driving meechanism. How to use clapper box and tools to machine inclined surface.
7Milling machine
Type and functions of main parts .
Various milling operation, gang milling , face milling, profiling, indexing , how to make a step and to make a slot
Milling cutters
Maching parameter; feeds and cutting speed .
8Grinding machine
Types of grinding machine and their uses
Grinding wheel : types and uses , specification
Balancing , dressing ,fixing and truing of wheels
9Lathe machine
Types of lathe machine
Functions of parts of lathe machine
Different method of holding workpiece : between centre , with face plate , with chucks
Cutting tool : materials , angle , shape
Other operations: Cutting of external thread , boring , drilling , knurling .
Machining parameters; Cutting speed , feed , depth of cut
10 Surface texture measurement
Concept of roughness and profiles .
Signifance of roughness
Allowable torelance for different types of process
Different types of expression of roughness; ie Average roughness ,RMs roughness , Bearing area curve
11Welding processes
Principle of oxyacetylene welding
oxyacetylene welding equpment
set up of oxyacetylene equipment
Oxyacetylene flames .
Welding techniques
Gas cutting
Weld testing and inspection
Arc welding machine
Polarity of welding machine
Types of weld and preparation
Terminology in welding
Electrodes
Weld defect , distortion
Weld symbol
MIG and TIG welding; characteristics of arc
shielding gas
advantage and disadvantages
2009年1月4日 星期日
आर क welsding
Arc welding uses a welding power supply to create an electric arc between an electrode and the base material to melt the metals at the welding point. They can use either direct (DC) or alternating (AC) current, and consumable or non-consumable electrodes. The welding region is sometimes protected by some type of inert or semi-inert gas, known as a shielding gas, and/or an evaporating filler material.
Safety issues
Welding can be a dangerous and unhealthy practice without the proper precautions; however, with the use of new technology and proper protection the risks of injury or death associated with welding can be greatly reduced.
Heat and sparks
Because many common welding procedures involve an open electric arc or flame, the risk of burns is significant. To prevent them, welders wear protective clothing in the form of heavy leather gloves and protective long sleeve jackets to avoid exposure to extreme heat, flames, and sparks.
[edit] Eye damage
The brightness of the weld area leads to a condition called arc eye in which ultraviolet light causes inflammation of the cornea and can burn the retinas of the eyes. Goggles and helmets with dark face plates are worn to prevent this exposure and, in recent years, new helmet models have been produced featuring a face plate that self-darkens upon exposure to high amounts of UV light. To protect bystanders, transparent welding curtains often surround the welding area. These curtains, made of a polyvinyl chloride plastic film, shield nearby workers from exposure to the UV light from the electric arc, but should not be used to replace the filter glass used in helmets.[26]
In 1970, a Swedish doctor, Åke Sandén, developed a new type of welding goggles that used a multilayer interference filter to block most of the light from the arc. He had observed that most welders could not see well enough, with the mask on, to strike the arc, so they would flip the mask up, then flip it down again once the arc was going: this exposed their naked eyes to the intense light for a while. By coincidence, the spectrum of an electric arc has a notch in it, which coincides with the yellow sodium line. Thus, a welding shop could be lit by sodium vapor lamps or daylight, and the welder could see well to strike the arc. The Swedish government required these masks to be used for arc welding, but they were not used in the United States. They may have disappeared.[27]
[edit] Inhaled matter
Welders are also often exposed to dangerous gases and particulate matter. Processes like flux-cored arc welding and shielded metal arc welding produce smoke containing particles of various types of oxides. The size of the particles in question tends to influence the toxicity of the fumes, with smaller particles presenting a greater danger. Additionally, many processes produce various gases (most commonly carbon dioxide and ozone, but others as well) that can prove dangerous if ventilation is inadequate. Furthermore, the use of compressed gases and flames in many welding processes pose an explosion and fire risk; some common precautions include limiting the amount of oxygen in the air and keeping combustible materials away from the workplace.[28]
[edit] Interference with pacemakers
Certain welding machines which use a high frequency AC current component have been found to affect pacemaker operation when within 2 meters of the power unit and 1 meter of the weld site[29].
Safety issues
Welding can be a dangerous and unhealthy practice without the proper precautions; however, with the use of new technology and proper protection the risks of injury or death associated with welding can be greatly reduced.
Heat and sparks
Because many common welding procedures involve an open electric arc or flame, the risk of burns is significant. To prevent them, welders wear protective clothing in the form of heavy leather gloves and protective long sleeve jackets to avoid exposure to extreme heat, flames, and sparks.
[edit] Eye damage
The brightness of the weld area leads to a condition called arc eye in which ultraviolet light causes inflammation of the cornea and can burn the retinas of the eyes. Goggles and helmets with dark face plates are worn to prevent this exposure and, in recent years, new helmet models have been produced featuring a face plate that self-darkens upon exposure to high amounts of UV light. To protect bystanders, transparent welding curtains often surround the welding area. These curtains, made of a polyvinyl chloride plastic film, shield nearby workers from exposure to the UV light from the electric arc, but should not be used to replace the filter glass used in helmets.[26]
In 1970, a Swedish doctor, Åke Sandén, developed a new type of welding goggles that used a multilayer interference filter to block most of the light from the arc. He had observed that most welders could not see well enough, with the mask on, to strike the arc, so they would flip the mask up, then flip it down again once the arc was going: this exposed their naked eyes to the intense light for a while. By coincidence, the spectrum of an electric arc has a notch in it, which coincides with the yellow sodium line. Thus, a welding shop could be lit by sodium vapor lamps or daylight, and the welder could see well to strike the arc. The Swedish government required these masks to be used for arc welding, but they were not used in the United States. They may have disappeared.[27]
[edit] Inhaled matter
Welders are also often exposed to dangerous gases and particulate matter. Processes like flux-cored arc welding and shielded metal arc welding produce smoke containing particles of various types of oxides. The size of the particles in question tends to influence the toxicity of the fumes, with smaller particles presenting a greater danger. Additionally, many processes produce various gases (most commonly carbon dioxide and ozone, but others as well) that can prove dangerous if ventilation is inadequate. Furthermore, the use of compressed gases and flames in many welding processes pose an explosion and fire risk; some common precautions include limiting the amount of oxygen in the air and keeping combustible materials away from the workplace.[28]
[edit] Interference with pacemakers
Certain welding machines which use a high frequency AC current component have been found to affect pacemaker operation when within 2 meters of the power unit and 1 meter of the weld site[29].
कॉम्पोनेन्ट ऑफ़ ऑफ़ मिल्लिंग machine
• Column: Vertical structure made of gray cast iron that support knee and allow it to move vertically up and down.
• Knee: Supported by column and which in turn provide guide way for saddle to move along it.
• Saddle : supported by knee which in turn provide guide way for table to move along it.
• Table :supported by saddle is provided with T slots to facilitate the clamping of work piece.
Over arm can be adjusted to accommodate arbor of different length
Basic Steps of Milling
• Get the detail information of work piece from drawing
• Select the appropriate types of side cutters and plain milling cutter
• Select appropriate type of arbor
• Mount cutters on arbor ,tighten the over-arm
• Select the table feed speed and RPM according to work piece type and accuracy required
• Knee: Supported by column and which in turn provide guide way for saddle to move along it.
• Saddle : supported by knee which in turn provide guide way for table to move along it.
• Table :supported by saddle is provided with T slots to facilitate the clamping of work piece.
Over arm can be adjusted to accommodate arbor of different length
Basic Steps of Milling
• Get the detail information of work piece from drawing
• Select the appropriate types of side cutters and plain milling cutter
• Select appropriate type of arbor
• Mount cutters on arbor ,tighten the over-arm
• Select the table feed speed and RPM according to work piece type and accuracy required
प्रोसेस परमेते
Paraneter to be considered in machining include
RPM , Feed rate depth of Cur , surface finish and material removal rate
Cutting Speed = (22/7 * Diameter of work piece * RPM)/1000
RPM , Feed rate depth of Cur , surface finish and material removal rate
Cutting Speed = (22/7 * Diameter of work piece * RPM)/1000
अवताम्सका Cutting fluids
Cutting fluids are various fluids that are used in machining to cool and lubricate the cutting tool. There are various kinds of cutting fluids, which include oils, oil-water emulsions, pastes, gels, and mists. They may be made from petroleum distillates, animal fats, plant oils, or other raw ingredients. Depending on context and on which type of cutting fluid is being considered, it may be referred to as cutting fluid, cutting oil, cutting compound, coolant, or lubricant.
Every kind of machining (e.g., turning, boring, drilling, milling, broaching, grinding, sawing, shaping, planing, reaming, tapping) can potentially benefit from one kind of cutting fluid or another, depending on workpiece material. (Cast iron and brass are usually machined dry. Interrupted cuts such as milling with carbide cutters are usually recommended to be used dry due to damage to the cutters caused by thermoshock.)
The properties that are sought after in a good cutting fluid are the ability to:
keep the workpiece at a stable temperature (critical when working to close tolerances). Very warm is OK, but extremely hot or alternating hot-and-cold should be avoided.
maximize the life of the cutting tip by lubricating the working edge and reducing tip welding.
ensure safety for the people handling it (toxicity, bacteria, fungi) and for the environment upon disposal.
prevent rust on machine parts and cutters.
Mechanisms of action
[edit] Cooling
Metal cutting operations involve generation of heat due to friction between the tool and the pieces and due to energy lost deforming the material. The surrounding air alone is a rather poor coolant for the cutting tool, because the rate of heat transfer is low. Ambient-air cooling is adequate for light cuts with periods of rest in between, such as are typical in maintenance, repair and operations (MRO) work or hobbyist contexts. However, for heavy cuts and constant use, such as in production work, more heat is produced per time period than ambient-air cooling can remove. It is not acceptable to introduce long idle periods into the cycle time to allow the air-cooling of the tool to "catch up" when the heat-removal can instead be accomplished with a flood of liquid, which can "keep up" with the heat generation.
[edit] Lubrication at the tool-chip interface
Besides cooling, the other way that cutting fluids aid the cutting process is by lubricating the interface between the tool's cutting edge and the chip. By preventing friction at this interface, some of the heat generation is prevented. This lubrication also helps prevent the chip from being welded onto the tool, which interferes with subsequent cutting.
EP additives are often added to cutting fluids.
[edit] Delivery methods
Every conceivable method of applying cutting fluid (flooding, spraying, dripping, misting, etc.) can be used, with the best choice depending on the application and the equipment available. For many metalcutting applications the ideal would be high-pressure, high-volume pumping to force a stream of fluid directly into the tool-chip interface, with walls around the machine to contain the splatter and a sump to catch, filter, and recirculate the fluid. This type of system is commonly employed, especially in manufacturing. It is often not a practical option for MRO or hobbyist metalcutting, where smaller, simpler machine tools are used. Fortunately it is also not necessary in those applications, where heavy cuts, aggressive speeds and feeds, and constant, all-day cutting are not vital.
[edit] Types of cutting fluid
[edit] Liquids
There are generally three types of liquids: mineral, semi-synthetic, and synthetic. Semi-synthetic and synthetic cutting fluids try to blend the best properties of oil into the best properties of water. They basically achieve this by allowing oil to emulsify into water. Some of these properties are: rust inhibition, tolerance of a wide range of water hardness (maintain pH stability around 9 to 10), ability to work with many metals, resist thermal breakdown, and environmental safety.[1]
Water is a great conductor of heat but has drawbacks as a cutting fluid. It boils easily, promotes rusting of machine parts, and does not lubricate well. Therefore, other ingredients are necessary to create an optimal cutting fluid.
Mineral coolants, which are petroleum-based, began in the late 1800s. They vary from the thick, dark, sulfur-rich cutting oils used in heavy industry to light, clear oils.
Semi-synthetic coolants are an emulsion or microemulsion of water with mineral oil. They began in the 1930s. A typical CNC usually uses emulsified coolant. One way to understand it is to think of "pots-and-pans dishwater". It is a fair amount of oil emulsified into a larger amount of water using a detergent. Therefore it is roughly analogous to your dishwater after you have washed the vegetable oil off your pans (although more oily and less soapy).
Synthetic coolants originated in the late 1950s and are usually water-based.
A hand-held refractometer is used to determine the mix ratio (also called strength) of water soluble coolants to verify effectiveness. Numerous other test equipment are used to determine such things as acidity, and amount of conductivity.
[edit] Pastes or gels
Cutting fluid may also take the form of a paste or gel when used for some applications, in particular hand operations such as drilling and tapping.
[edit] Mists
Some cutting fluids are used in mist (aerosol) form and some of them are used in drilling aluminium
[edit] Other fluids used (present and past)
[edit] Present
Kerosene, rubbing alcohol, and 3-In-One Oil often give good results when working on aluminium.
Lard is suitable for general machining and also press tool work.
Mineral oil
WD-40
Dielectric fluid is the cutting fluid used in Electrical discharge machines (EDMs). It is usually deionized water or a high-flash-point kerosene. Intense heat is generated by the cutting action of the electrode (or wire) and the fluid is used to stabilise the temperature of the workpiece, along with flushing any eroded particles from the immediate work area. The dielectric fluid is nonconductive.
Liquid- (water- or petroleum oil-) cooled water tables are used with the plasma arc cutting (PAC) process.
[edit] Past
In 19th-century machining practice, it was not uncommon to use plain water. This was simply a practical expedient to keep the cutter cool, regardless of whether it provided any lubrication at the cutting edge–chip interface. When one considers that high-speed steel (HSS) had not been developed yet, the need to cool the tool becomes all the more apparent. (HSS retains its hardness at high temperatures; other carbon tool steels do not.) An improvement was soda water, which better inhibited the rusting of machine slides. These options are generally not used today because better options are available.
Lard was very popular in the past. It is used less often today, because of the wide variety of other options, but it is still a fine option.
Old machine shop training texts speak of using red lead and white lead, often mixed into lard or lard oil. This practice is obsolete. Lead is a health hazard, and excellent non-lead-containing options are available.
From the mid-20th century to the 1990s, 1,1,1-trichloroethane was used as an additive to make some cutting fluids more effective. In shop-floor slang it was referred to as "one-one-one". It has been phased out because of its ozone-depleting and CNS-depressing properties.
[edit] Safety concerns (toxicity, bacteria, fungi)
Cutting fluids have been associated with skin rashes, dermatitis, esophagitis, lung disease, and cancer. These problems result from either toxicity or bacterial or fungal contamination.
Metalworking fluids often contain substances such as biocides, corrosion inhibitors, metal fines, tramp oils, and biological contaminants. Inhalation of cutting fluid aerosols may cause irritation of the throat, nose, and lungs and has been associated with chronic bronchitis, asthma, hypersensitivity pneumonitis (HP), and worsening of pre-existing respiratory problems. Skin exposure may result from touching contaminated surfaces, handling parts and equipment, splashing fluids, and aerosol mist settling on the skin. Skin contact with cutting fluids may cause allergic contact dermatitis, irritant contact dermatitis, and occupational ("oil") acne.[2]
Safer formulations provide a natural resistance to tramp oils allowing improved filtration separation without removing the base additive package. Ventilation, splash guards on machines, and personal protective equipment can mitigate hazards related to cutting fluids.[3]
Bacterial growth is predominant in semi-synthetic and synthetic fluids. Tramp oil along with human hair or skin oil are some of the debris during cutting which accumulates and forms a layer on the top of the liquid, anaerobic bacteria proliferate due to a number of factors. An early sign of the need for replacement is the "Monday-morning smell" (due to lack of usage from Friday to Monday). Antiseptics are sometimes added to the fluid to kill bacteria. Such use must be balanced against whether the antiseptics will harm the cutting performance, workers' health, or the environment. Maintaining as low a fluid temperature as practical will slow the growth of microorganisms.[3]
[edit] Environmental impact
Old, used cutting fluid must be disposed of when it is fetid or when it is chemically degraded and has lost its performance. As with used motor oil or other wastes, its impact on the environment should be mitigated. Legislation and regulation specify how this mitigation should be achieved. Enforcement is the most challenging aspect. Modern cutting fluid disposal may involve techniques such as ultrafiltration using polymeric or ceramic membranes which concentrates the suspended and emulsified oil phase.
In conclusion cutting fluid play the following important role
i)Cool work piece and tool
ii) Wash away chips
iii) Improve cutting efficiency
iv) Prevent rust
v) Impart good surface finish
Every kind of machining (e.g., turning, boring, drilling, milling, broaching, grinding, sawing, shaping, planing, reaming, tapping) can potentially benefit from one kind of cutting fluid or another, depending on workpiece material. (Cast iron and brass are usually machined dry. Interrupted cuts such as milling with carbide cutters are usually recommended to be used dry due to damage to the cutters caused by thermoshock.)
The properties that are sought after in a good cutting fluid are the ability to:
keep the workpiece at a stable temperature (critical when working to close tolerances). Very warm is OK, but extremely hot or alternating hot-and-cold should be avoided.
maximize the life of the cutting tip by lubricating the working edge and reducing tip welding.
ensure safety for the people handling it (toxicity, bacteria, fungi) and for the environment upon disposal.
prevent rust on machine parts and cutters.
Mechanisms of action
[edit] Cooling
Metal cutting operations involve generation of heat due to friction between the tool and the pieces and due to energy lost deforming the material. The surrounding air alone is a rather poor coolant for the cutting tool, because the rate of heat transfer is low. Ambient-air cooling is adequate for light cuts with periods of rest in between, such as are typical in maintenance, repair and operations (MRO) work or hobbyist contexts. However, for heavy cuts and constant use, such as in production work, more heat is produced per time period than ambient-air cooling can remove. It is not acceptable to introduce long idle periods into the cycle time to allow the air-cooling of the tool to "catch up" when the heat-removal can instead be accomplished with a flood of liquid, which can "keep up" with the heat generation.
[edit] Lubrication at the tool-chip interface
Besides cooling, the other way that cutting fluids aid the cutting process is by lubricating the interface between the tool's cutting edge and the chip. By preventing friction at this interface, some of the heat generation is prevented. This lubrication also helps prevent the chip from being welded onto the tool, which interferes with subsequent cutting.
EP additives are often added to cutting fluids.
[edit] Delivery methods
Every conceivable method of applying cutting fluid (flooding, spraying, dripping, misting, etc.) can be used, with the best choice depending on the application and the equipment available. For many metalcutting applications the ideal would be high-pressure, high-volume pumping to force a stream of fluid directly into the tool-chip interface, with walls around the machine to contain the splatter and a sump to catch, filter, and recirculate the fluid. This type of system is commonly employed, especially in manufacturing. It is often not a practical option for MRO or hobbyist metalcutting, where smaller, simpler machine tools are used. Fortunately it is also not necessary in those applications, where heavy cuts, aggressive speeds and feeds, and constant, all-day cutting are not vital.
[edit] Types of cutting fluid
[edit] Liquids
There are generally three types of liquids: mineral, semi-synthetic, and synthetic. Semi-synthetic and synthetic cutting fluids try to blend the best properties of oil into the best properties of water. They basically achieve this by allowing oil to emulsify into water. Some of these properties are: rust inhibition, tolerance of a wide range of water hardness (maintain pH stability around 9 to 10), ability to work with many metals, resist thermal breakdown, and environmental safety.[1]
Water is a great conductor of heat but has drawbacks as a cutting fluid. It boils easily, promotes rusting of machine parts, and does not lubricate well. Therefore, other ingredients are necessary to create an optimal cutting fluid.
Mineral coolants, which are petroleum-based, began in the late 1800s. They vary from the thick, dark, sulfur-rich cutting oils used in heavy industry to light, clear oils.
Semi-synthetic coolants are an emulsion or microemulsion of water with mineral oil. They began in the 1930s. A typical CNC usually uses emulsified coolant. One way to understand it is to think of "pots-and-pans dishwater". It is a fair amount of oil emulsified into a larger amount of water using a detergent. Therefore it is roughly analogous to your dishwater after you have washed the vegetable oil off your pans (although more oily and less soapy).
Synthetic coolants originated in the late 1950s and are usually water-based.
A hand-held refractometer is used to determine the mix ratio (also called strength) of water soluble coolants to verify effectiveness. Numerous other test equipment are used to determine such things as acidity, and amount of conductivity.
[edit] Pastes or gels
Cutting fluid may also take the form of a paste or gel when used for some applications, in particular hand operations such as drilling and tapping.
[edit] Mists
Some cutting fluids are used in mist (aerosol) form and some of them are used in drilling aluminium
[edit] Other fluids used (present and past)
[edit] Present
Kerosene, rubbing alcohol, and 3-In-One Oil often give good results when working on aluminium.
Lard is suitable for general machining and also press tool work.
Mineral oil
WD-40
Dielectric fluid is the cutting fluid used in Electrical discharge machines (EDMs). It is usually deionized water or a high-flash-point kerosene. Intense heat is generated by the cutting action of the electrode (or wire) and the fluid is used to stabilise the temperature of the workpiece, along with flushing any eroded particles from the immediate work area. The dielectric fluid is nonconductive.
Liquid- (water- or petroleum oil-) cooled water tables are used with the plasma arc cutting (PAC) process.
[edit] Past
In 19th-century machining practice, it was not uncommon to use plain water. This was simply a practical expedient to keep the cutter cool, regardless of whether it provided any lubrication at the cutting edge–chip interface. When one considers that high-speed steel (HSS) had not been developed yet, the need to cool the tool becomes all the more apparent. (HSS retains its hardness at high temperatures; other carbon tool steels do not.) An improvement was soda water, which better inhibited the rusting of machine slides. These options are generally not used today because better options are available.
Lard was very popular in the past. It is used less often today, because of the wide variety of other options, but it is still a fine option.
Old machine shop training texts speak of using red lead and white lead, often mixed into lard or lard oil. This practice is obsolete. Lead is a health hazard, and excellent non-lead-containing options are available.
From the mid-20th century to the 1990s, 1,1,1-trichloroethane was used as an additive to make some cutting fluids more effective. In shop-floor slang it was referred to as "one-one-one". It has been phased out because of its ozone-depleting and CNS-depressing properties.
[edit] Safety concerns (toxicity, bacteria, fungi)
Cutting fluids have been associated with skin rashes, dermatitis, esophagitis, lung disease, and cancer. These problems result from either toxicity or bacterial or fungal contamination.
Metalworking fluids often contain substances such as biocides, corrosion inhibitors, metal fines, tramp oils, and biological contaminants. Inhalation of cutting fluid aerosols may cause irritation of the throat, nose, and lungs and has been associated with chronic bronchitis, asthma, hypersensitivity pneumonitis (HP), and worsening of pre-existing respiratory problems. Skin exposure may result from touching contaminated surfaces, handling parts and equipment, splashing fluids, and aerosol mist settling on the skin. Skin contact with cutting fluids may cause allergic contact dermatitis, irritant contact dermatitis, and occupational ("oil") acne.[2]
Safer formulations provide a natural resistance to tramp oils allowing improved filtration separation without removing the base additive package. Ventilation, splash guards on machines, and personal protective equipment can mitigate hazards related to cutting fluids.[3]
Bacterial growth is predominant in semi-synthetic and synthetic fluids. Tramp oil along with human hair or skin oil are some of the debris during cutting which accumulates and forms a layer on the top of the liquid, anaerobic bacteria proliferate due to a number of factors. An early sign of the need for replacement is the "Monday-morning smell" (due to lack of usage from Friday to Monday). Antiseptics are sometimes added to the fluid to kill bacteria. Such use must be balanced against whether the antiseptics will harm the cutting performance, workers' health, or the environment. Maintaining as low a fluid temperature as practical will slow the growth of microorganisms.[3]
[edit] Environmental impact
Old, used cutting fluid must be disposed of when it is fetid or when it is chemically degraded and has lost its performance. As with used motor oil or other wastes, its impact on the environment should be mitigated. Legislation and regulation specify how this mitigation should be achieved. Enforcement is the most challenging aspect. Modern cutting fluid disposal may involve techniques such as ultrafiltration using polymeric or ceramic membranes which concentrates the suspended and emulsified oil phase.
In conclusion cutting fluid play the following important role
i)Cool work piece and tool
ii) Wash away chips
iii) Improve cutting efficiency
iv) Prevent rust
v) Impart good surface finish
6Cutting tool materials
Two common types of cutting tool are i) High speed tool steel and ii) Carbide Tool
High Speed is cheap , commonly available , can be reground however has short tool life .
On the other hand Carbide tool has a much longer tool life , however it is expensive and can not be reground.
High Speed is cheap , commonly available , can be reground however has short tool life .
On the other hand Carbide tool has a much longer tool life , however it is expensive and can not be reground.
स्पेसिफिकेशन of a lathe machine ,इट्स maintenance
Size of a lathe machine is specified according to i) Length between centers
ii) The maximum diameter of work piece that can be turned,iii) The power of motor
To ensure the smoothnessss of the movement of the carriage assembly of a lathe machine is maintained , the bed need to be protected to avoid damage on its surface , tool should not be placed over the bed upon completion of jobs, iii) Bed should be oiled regulary,iv)Covered with cloth during holidays
Straight turning a cutting tool moves parallel to the rotating axis of work piece to produce a true cylindrical work piece
Taper turning. , a cutting tool moves at an angle to the rotating axis of work piece to produce a tapered work piece
Facing a cutting tool moved perpendiculary to the rotating axis of a work piece to produce a flat surface on one end of the work piece.
ii) The maximum diameter of work piece that can be turned,iii) The power of motor
To ensure the smoothnessss of the movement of the carriage assembly of a lathe machine is maintained , the bed need to be protected to avoid damage on its surface , tool should not be placed over the bed upon completion of jobs, iii) Bed should be oiled regulary,iv)Covered with cloth during holidays
Straight turning a cutting tool moves parallel to the rotating axis of work piece to produce a true cylindrical work piece
Taper turning. , a cutting tool moves at an angle to the rotating axis of work piece to produce a tapered work piece
Facing a cutting tool moved perpendiculary to the rotating axis of a work piece to produce a flat surface on one end of the work piece.
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