MET 103 Lathe module 4

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MET 103 Lathe module 4

  1. 1. safety regulations which should be observed when operating a lathe. p g• Always wear approved glasses.• Never attempt to run a lathe until you are familiar with its operation operation.• Never wear loose clothing, rings or watches when operating a lathe.• Remove the chuck key before starting the spindle.• Always stop the lathe before taking measurements of any kind.• Always use a brush to remove chips.• Before mounting or removing accessories, always shut of the power supply to the motor.• Do not take heavy cuts on long lender piece. G I NE ER I NG• Do not lean on the machine. EN T AL EC MECH NIC HNOLOGY A MET E N T D P A R T ME
  2. 2. TYPES OF LATHE 1. ENGINE 2 . MANUFACTURING 3 . PRODUCTION LATHE LATHE LATHE1. BENCH LATHE2. SPEED LATHE 1. 1 TURRET LATHE3. TOOL ROOM / PRECISION LATHE 2. SINGLE SPLINDLE A.L4.4 GAP BED LATHE 3. NC LATHES EN G I NE ER I NG T AL EC MECH NIC HNOLOGY A MET E N T D P A R T ME
  3. 3. TYPES OF LATHE1. Engine l th1 E i lathes,2 Manufacturing lathes,3. Production lathes.1 . Engine Lathes :(a) Bench lathe(b) Speed lathe(c) Precision lathe / Tool room lathe(d) Gap bed latheBENCH LATHE :# A small lathe mounted on bench# Small in size# Used for light machining on small work pieces. EN G I NE ER I NG T AL EC MECH NIC HNOLOGY A MET E N T D P A R T ME
  4. 4. SPEED LATHE# C b mounted on a bench or cabinet. Can be t d b h bi t# The fast setup , ease of operation, & low main-tenance.# Used for light machining operations, turning, polishing, & finishing on g g p , g, p g, g small precision work. TOOL ROOM LATHE # Is equipped with special attachments and accessories to allow a variety of precision operations to be performed. # It is generally used to produce tools and gauges which are used in tool and die work.GAP BED LATHE# The bed can be removed to increase the maximum work diameter that can be revolved EN G I NE ER I NG T AL EC MECH NIC HNOLOGY A MET E N T D P A R T ME
  5. 5. 2 . MANUFACTURING LATHE # Are basically engine lathes which have been modified by the addition of a tracer attach-ment or a digital readout system.# Tracer lathes are used to duplicate parts which may be too difficult or costly to produce on other types of lathes. tl t d th t f l th 3 . PRODUCTION LATHES # Are generally used when a large number of duplicate parts must be produced. TYPES OF PRODUCTION LATHES (a) Turret lathes, (b) Single-spindle automatic lathes, (c) Numerically controlled lathes. EN G I NE ER I NG T AL EC MECH NIC HNOLOGY A MET E N T D P A R T ME
  6. 6. TURRET LATHE# Used to produce a large number of duplicate parts which may require operations such as turning, drilling, boring, reaming, facing, & threading.# On some turret lathes, as many as 20 different tools can be mounted# Each tool may be rotated into position quickly and accurately.# Once the tools have been set, each part is quickly and accurately producedSINGLE SPINDLE AUTOMATIC LATHE# designed to automatically mass produce parts which require mass-produce primarily turning and facing operations.# Automatic lathes generally have two tool slides mounted on the carriage. g# The front-slide tooling is used for turning and boring operations.# The rear-slide tooling is used for facing, undercutting, chamfering, and necking operations EN G I NE ER I NG T AL EC MECH NIC HNOLOGY A MET E N T D P A R T ME
  7. 7. NUMERICALLY CONTROLLED LATHE # One of the latest modifications of the basic engine lathe lathe. # This lathe, controlled by numerical tape, is used primarily for turning operations and can economically and automatically produce shafts of almost any shape shape.# This lathe can perform most types of lathes and provides saving in tooling, setup, and cycle time Size of the Engine Lathes # The size of an engine lathe is determined by the maximum diameter of work which may be revolved over the bed.# The length of a lathe is stated by the length of the bed.The size of a lathe is measured by :1. Length of bed2. Swing, the largest diameter that can be rotated EN G I NE ER I NG T AL EC3. Maximum useable distance between centers MECH NIC HNOLOGY A MET E N T D P A R T ME
  8. 8. LATHE……………….# A support for the lathe accessories or the work piece.# A way of holding and revolving the work piece.# A means of holding and moving the cutting tool. MAIN PARTS OF ENGINE LATHE AND ACCESSORIES EN G I NE ER I NG T AL EC MECH NIC HNOLOGY A MET E N T D P A R T ME
  9. 9. EN G I NE ER I NG T AL ECMECH NIC HNOLOGY A MET E N T D P A R T ME
  10. 10. MAIN PARTS OF ENGINE LATHE1. BED2. HEADSTOCK3. TAILSTOCK4. CARRIAGE1. BEDThe bed is a heavy ruggedcasting made to support theworking parts of lathe. BED EN G I NE ER I NG T AL EC MECH NIC HNOLOGY A MET E N T D P A R T ME
  11. 11. 2. HEADSTOCKThe headstock is clamped on the left-hand side ofthe bed.The headstock spindle, a hollow cylindrical shaftsupported by bearings, provides a drive from themotor to work-holding devices. EN G I NE ER I NG T AL EC MECH NIC HN Headstock (A gear-drive) OLOGY A MET E N T D P A R T ME
  12. 12. 3. TAILSTOCKThe tailstock is made up of two units.The top half can be adjusted on the base by twoadjusting screws for aligning the dead and livecenters for parallel turning.The tailstock hand wheelmoves the tailstock spindle inor out of tailstock casting. EN G I NE ER I NG T Tail Stock AL EC MECH NIC HNOLOGY A MET E N T D P A R T ME
  13. 13. 4. CARRIAGEThe carriage supports the cutting tool and used tomove it along the bed of the lathe for turningoperations. tiMain parts of the carriageare1.SADDLE,2.APRON,2 APRON3.CROSS-SLIDE4. TOOLPOST5. COMPOUND REST EN G I NE ER I NG T AL EC MECH NIC HNOLOGY A MET E N T D P A R T ME
  14. 14. CUTTING TOOLS ANGLES EN G I NE ER I NG T AL EC MECH NIC HNOLOGY A MET E N T D P A R T ME
  15. 15. TYPES OF LATHE CUTTING TOOLS# Left and Right-Cut Roughing Tools# Finishing Tools# Boring and Inside Threading Tools# Facing Tools# Round-Nose Turning Tools# Threading Tool# Parting Tool EN G I NE ER I NG T AL EC MECH NIC HNOLOGY A MET E N T D P A R T ME
  16. 16. Tool MaterialsThe hardness of a t l must b greater th th t of the material being machined.Th h d f tool t be t than that f th t i lb i hi d# Nature of the finished product.# Type of operation operation.# Volume of production.# Tool design details.# Condition of tool.# Type of material being machined.CARBON STEEL TOOLS# Are characterized by low hot hardness and poor hardenability.# Carbon contents range from 0.8 percent to 1.3 percent.# Tools of this type can be used for light work where temperatures produce do not exceed 204°C (400°F). EN G I NE ER I NG T AL EC MECH NIC HNOLOGY A MET E N T D P A R T ME
  17. 17. Medium-Alloy Steels# These steels are not satisfactory for operations where high temperatures are encountered, as in high production.# In finishing operations, they can be used successfully High-Speed Steels # Are characterized by superior wear resistance and hot hardness. # It contain up to 18 percent tungsten and 51.5 percent chromium as the principal alloying elements. # Other alloying elements such as Mo & Co give special qualities. # These cutters will retain keen cutting edges at temperatures up to 593°C .Cast Alloys# A number of nonferrous alloys known as stellites have been developed for use as cutting tools, tools# These alloys usually contain 2 to 4 percent carbon, 14 to 29 percent tungsten, 27 to 32 percent chromium, 40 to 50 percent cobalt.# The tools must be used as cast and cannot be heat-treated. EN G I NE ER I NG T AL EC MECH NIC HNOLOGY A MET E N T D P A R T ME
  18. 18. Cemented Carbide# Are known by trade names such as Carboloy® Kenna-metal®, Vascoloy Carboloy®, Kenna metal® Vascoloy- Ramet®, and Pirthite®.There are two general grades cemented carbides in use: (1) The "C" grade is made up of tungsten carbide with cobalt as a binder. This grade is used in machining cast iron and nonferrous metals. (2) The "S" grade is made up of tungsten titanium and tantalum carbides with S tungsten, titanium, cobalt as a binder. This grade is used on steels.# The cobalt content may vary from 3 percent to 16 percent.Cemented carbides have the following characteristics: (1) High hardness over a wide range of temperatures. (2) High thermal conductivity (3) Low thermal expansion (4) Stiffness. # Cemented carbide should be used at much higher operating EN G I NE ER I NG T AL EC MECH NIC HN speeds than high-speed steel tools. OLOGY A MET E N T D P A R T ME
  19. 19. TOOL FAILUREThere are many factors that can contribute to the failure of a cutting tool The tool.following are a few of these factors: (1) Temperature failure. (2) Fracture of the tool point. (3) Tool wearTemperature FailureThe heat generated at the cutting edge of the tool may become excessive The excessive.heat will cause the tool to soften. Tool failure will occur. This type of failure occursquite rapidly after a certain temperature is reached.Fracture of Tool PointBecause of their hardness, carbide-tipped tools are mechanically brittle and weak.Cutting forces may be too great for a given tool. This will cause small portions ofthe tip to break away In some instances the whole tip may be destroyed If the away. instances, destroyed.tool or work is not properly supported, vibration and chatter may occur. These cancause tool point to fracture. EN G I NE ER I NG T AL EC MECH NIC HNOLOGY A MET E N T D P A R T ME
  20. 20. Tool WearTool wear can be attributed to two basic causes: (1) Wear due to plowing or abrasive action of the carbides or other hard particles in the work piece. (2) Wear resulting from instantaneous "welds" that occur when the chip and finished surface slide over the tool face LATHE TOOLHOLDERS AND TOOLPOSTS Lathe cutting tools are generally held by two methods: (1) In tool holders, which provide a means of rigidly holding the cutting tool. (2) In tool posts, which provide a means of holding either a tool holder or a cutting tool. The most common are the standard (round), turret, heavy-duty (open-side), and quick-change tool posts EN G I NE ER I NG T AL EC MECH NIC HNOLOGY A MET E N T D P A R T ME
  21. 21. Tool Holders TypesFollowing are the tool holders types:1. Tool holders for High Speed Steel (HSS) Tool bits2. Tool holders for Brazed Carbide Tipped Tool bits3. Cutting Off Tool holders4. Threading Tool holders5. Boring Tool holdersTool Posts TypesFollowing are the tool holders types:1. Standard (Round) Tool post2. Turret Type Tool post3. Quick Change3 Quick-Change Tool post a. Dovetailed tool post b. Boring Bar holder EN G I NE ER I NG T AL EC MECH NIC HNOLOGY A MET E N T D P A R T ME
  22. 22. WORK HOLDING DEVICES 1. 1 With the faceplate. faceplate 2. With the lathe dog. 3. With the lathe chuck 4. With the collet chuck. - This is independent chuck- For holding cylindrical generally has four jaws , which are- St k centered Stock t d adjusted individually on the chuck face by means of adjusting screws EN G I NE ER I NG T AL EC MECH NIC HN Three-Jaw Universal Chuck Four-Jaw Independent Chuck OLOGY A MET E N T D P A R T ME
  23. 23. iece # Work pieces can be bolted to the faceplate. Workpi WFaceplates Collet chuck is used to hold small work pieces EN G I NE ER I NG TCollet Chuck AL EC MECH NIC HNOLOGY A MET Work holding devices…. E N T D P A R T ME
  24. 24. Drill h k ith tapered shank t fit tailstockD ill chuck with a t d h k to t il t k LATHE DOG EN G I NE ER I NG T AL EC MECH NIC HNOLOGY A MET Work holding devices…. E N T D P A R T ME
  25. 25. CUTTING SPEED AND FEEDSCUTTING SPEEDCutting speed for lathe work may be defined as the rate at which a point on thecircumference of the work passes the cutting tool in a minute.Cutting speed may be expressed in feet per minute (ft/min) or meters per minute(m/min). Inch Calculations Metric C l l ti M t i Calculations CS ( ft ) x12 CS x 320 r / min  r / min   x work dia.(in.) D (mm) EN G I NE ER I NG T AL EC MECH NIC HNOLOGY A MET E N T D P A R T ME
  26. 26. Lathe FeedThe feed of a lathe is define as the distance the cutting tool advances alongthe length of the work for every revolution of the spindle. Cutting Time = length of cut l h f feed x r/min EN G I NE ER I NG T AL EC MECH NIC HNOLOGY A MET Speed, feed, and depth of cut in turning. E N T D P A R T ME
  27. 27. MACHINING OPERATIONS1.FACING1 FACING FACING2.TURNING3.BORING4.TAPER TURNING5.CHAMFERING TURNING6.THREADING7.DRILLING BORING8.REAMING9.TAPPING10.COUNTER SINKING11.COUNTER BORING12.PARTING EN G I NE ER I NG T AL EC MECH NIC HNOLOGY A MET13.KNURLING E N T D P A R T ME
  28. 28. TAPPING THREADINGTAPER TURNING DRILLING & REAMNING CSK & C’BORE EN G I NE ER I NG T AL EC MECH NIC HN KNURLING& PARTING OLOGY A MET E N T D P A R T ME

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