This video will give you the step by step procedure of doing taper turning operation in Lathe
Facing and Plain turning operation in Lathe • Facing and Plain Turni...
Thanks to Mr. Radha Krishnan, Technician, National Engineering College, Kovilpatti
College website www.nec.edu.in
The machine tools used for machining are broadly classified into three types
General purpose - (used for general machining like turning, drilling etc.)
Example: Lathe. drilling machine
Special purpose - (used for special machining like gear cutting) Example: Capstan and turret lathe„ gear hobbing machine.
Automatic machine tools - (used for mass production of components) Example: CNC (Computer Numerical Control) lathe, CNC milling machine.
Simple Turning:
Simple machining like turning is carried out in a lathe. A general-purpose lathe may be used to produce cylindrical, flat or curvilinear surface and also to drill holes.
Components of a Lathe
Headstock: The headstock supports spindle and spindle bearing and houses the speed changing mechanisms. The spindle holds the chuck that holds the work piece. Lathe Bed: The lathe bed is the base of the machine: the headstock, tailstock, compound rest and carriage are mounted on the bed. The lathe bed is rigid and absorbs vibrations while machining.
Tailstock: The tail stock supports the long size work piece that is held in the headstock. It is also used to hold the drilling tool.
Carriage: The carriage moves over the lathe bed. It consists of two parts: saddle and apron. The saddle carries the cross-slide over which the
compound rest is fitted. The cross-slide is used to produce a transverse movement fbr the cutting tool.
Compound rest: The compound rest carries the tool post on a swivel base. "Ibis arrangement helps cutting tool movement at an angle to the lathe axis in taper turning. Tool post: The tool post that is located on top of the compound rest holds the tool. The tool post can he adjusted to a convenient working position.
Work Holding Devices
Work holding devices are used to hold the work piece firmly during the operation. Following are the commonly used work holding devices in lathe.
Three-jaw Chuck: It is a self-centering chuck. A chuck key is engaged and rotated in one of the jaws, which simultaneously moves the other jaws to grip the work piece.
Mandrel: It is used for holding a work piece with pre-drilled holes. The work piece is inserted in the mandrel by force-fit and then held firmly in a chuck.
Feed Mechanism
Feed refers to the movement of the tool during metal cutting operation. The tool movement may be longitudinal, transverse or angular. The tool movement parallel to the lathe axis is called longitudinal movement; the movement perpendicular to the lathe axis is called transverse or cross movement; the movement at specified angle to the lathe axis is called angular movement. Angular movement is used for taper turning operation. Metal removal rate is high in larger feed rate but the surface finish will be poor. Usually high feed is given for rough turning and less feed is given to get smooth surface finish. Feed is expressed in mm/revolution or mm/minute.
Operations using Lathe
Simple machining operations that can be done in a lathe are as follows.
Turning: Turning is the process of removing excess material from a work piece to produce a cylindrical surface
Facing: Facing is done to remove material at the ends of a work piece to produce at surface. Taper turning: Taper turning is the process of removing excess material fr6m a work piece to produce a conical surface.
Drilling: Drilling is done to produce a hole in a work piece. The work piece is held in the chuck and the drilling tool is held in the tailstock. Feed is given by rotating the wheel slowly in the tailstock.
Tools:
A single-point cutting tool is commonly used for turning and taper turning. A knurling tool is used to produce a rough surface with diamond cuts. The knurling tool has knurled rollers that will be pressed against the cylindrical surface to be knurled. A drill bit is used to drill a hole in the work piece. EISS (high speed steel) cutting tool is a general-purpose tool made from the alloy of steel, tungsten, chromium and vanadium.
28 дек 2020
