LATHE MACHINE IMS ENGINEERING COLLEGE,GHAZIABAD Submitted by Ankit Chauhan ( ) Introduction Lathe is a machine, which removes the metal from a piece of work to the required shape &size Working Principle; The lathe is a machine tool which holds the work piece between the two rigid and strong supports called centres or in a chuck which revolves. The cutting tool is rigidly held and supported in a toolpost which is feed against the revolving work. Types of Lathe Engine Lathe The most common form of lathe, motor driven and comes in large variety of sizes and shapes. Bench Lathe A bench top model usually of low power used to make precision machine small work pieces. Automatic Lathe A lathe in which the work piece is automatically fed and removed without use of an operator. Cutting operations are automatically controlled. Turret Lathe lathe which have multiple tools mounted on turret either attached to the tailstock or the cross-slide, which allows for quick changes in tooling and cutting operations. Computer Controlled Lathe A highly automated lathe, where both cutting, loading, tool changing, and part unloading are automatically controlled by computer coding. Component Description 8 Lathe Size 9 Lathe Bed 10 Lathe Bed Heavy, rugged casting Made to support working parts of lathe Guide and align major parts of lathe 11 Headstock Clamped on left-hand end of bed Hollow cylindrical shaft supported by bearings Provides drive through gears to work-holding devices 12 Headstock 13 Quick-Change Gearbox Contains number of different-size gears Provides feed rod and lead-screw with various speeds for turning and thread- cutting operations Feed rod advances carriage when automatic feed lever engaged 14 Quick-Change Gearbox Top View 15 Carriage Used to move cutting tool along lathe bed Consists of three main parts Saddle H-shaped casting mounted on top of lathe ways, provides means of mounting cross-slide and apron Cross-slide Apron 16 Carriage 17 Carriage 18 Cross-slide Mounted on top of saddle Provides manual or automatic cross movement for cutting tool Compound rest (fitted on top of cross- slide) Used to support cutting tool Swiveled to any angle for taper-turning 19 Apron Fastened to saddle Houses gears and mechanism required to move carriage or cross- slide automatically Apron handwheel turned manually to move carriage along lathe bed 20 Apron 21 Tailstock Provides support for right-hand end of work 22 Shear Pins and Slip Clutches Prevents damage to feed mechanism from overload or sudden torque Shear pins Made of brass Found on feed rod Spring-loaded slip clutches Found only on feed rods When feed mechanism overloaded, shear pin will break or slip clutch will slip causing feed to stop 23 Shear pin in end gear train prevents damage to the gears in case of an overload Lathe Operations Turning:produce straight, conical, curved, or grooved workpieces Facing: to produce a flat surface at the end of the part or for making face grooves. Boring: to enlarge a hole or cylindrical cavity made by a previous process or to produce circular internal grooves. Drilling: to produce a hole by fixing a drill in the tailstock Threading: to produce external or internal threads Knurling: to produce a regularly shaped roughness on cylindrical surfaces Work Holding Devices Fig : (a) and (b) Schematic illustrations of a draw-in-type collets. The workpiece is placed in the collet hole, and the conical surfaces of the collet are forced inward by pulling it with a draw bar into the sleeve. (c) A push-out type collet. (d) Workholding of a part on a face plate. Three jaw chuck - For holding cylindrical stock centered. - For holding cylindrical stock centered. Four-Jaw Chuck - This is independent chuck generally has four jaws, which are adjusted individually on the chuck face by means of adjusting screws Thin jobs can be held by means of magnetic chucks. Collet Chuck Collet chuck is used to hold small workpieces Simple formula