Central Institute of Hand Tools

Central Institute of Hand Tools

Introduction

Central Institute of Hand Tools was established in 1983 with assistance from United Nations development program (UNDP), government of India and government of Punjab.CIHT aim is to provide technology support services and trained manpower to engineering industry in general and the hand tools industries in particular to achieve global standards.Service offered at CIHTHeat Treatment ForgingHammer blowMechanical PressTool RoomLathe machineCNC Wire cut.CNC EDM.Test and Quality ControlEquipment for chemical testing for iron, steel brass and bronze etc.Profile projector.Rockwell hardness tester.

ForgingForging is the working of metal into a useful shape by hammering or pressing.The oldest of the metalworking arts (primitive blacksmith).Replacement of machinery occurred during early the Industrial revolution.Forging machines are now capable of making parts ranging in size of a bolt to a turbine rotor.Most forging operations are carried out hot, although certain metals may be cold-forged.Forging operationsEdging is used to shape the ends of the bars and to gather metal. The metal flow is confined in the horizontal direction but it is free to flow laterally to fill the die.Drawing is used to reduce the cross-sectional area of the work piece with concurrent increase in length.Punching are used to produce holes in metals.Swaging is used to produce a bar with a smaller diameter (using concave dies).Swaging at the ends, ready for next forming process.Swaging provides a reduced round cross section suitable for tapping, threading, upsetting or other subsequent forming and machining operations.Classification of forging processes Forging hammer or drop hammer. Press forging.Hammer and press forging processes

Forging hammers: There are two basic types of forging hammers used; Board hammer Power hammer

Forging presses: There is one basic type of forging press available; Mechanical presses

Board hammer The upper die and ram are raised by friction rolls gripping the board.After releasing the board, the ram falls under gravity to produce the blow energy.The hammer can strike between 60-150 blows per minute depending on size and capacity.The board hammer is an energy restricted machine. The blow energy supplied equal the potential energy due to the weight and the height of the fall. Potential energy = mghBoard hammer

Forging HammerThe process is done with a ram, delivering intermittent blows to the section to be forged, applying tremendous pressure, shaping the material, by an instantaneous application of pressure to a relatively small area.The hammer is forced from its maximum height, by air pressure.

Provide rapid impact blows to the surface of the metal.Dies are in two halves - Lower : fixed to anvil - Upper : moves up and down with the TUP.Energy (from a gravity drop) is adsorbed onto the metal, in which the maximum impact is on the metal surface.Dies are expensive being accurately machined from special alloys (susceptible to thermal shock).Drop forging is good for mass production of complex shapes.Forging Hammer

MechanicalpressAmechanicalpressis a device designed to apply very high force to form, shape, or cut materials, to compress solids, or to extract liquids.Mechanicalpresses range in size from very small units that are operated by hand, to large powered industrial units used in manufacturing and assembly line applications. For example, a simple hand-presscan be used to remove a bearing from a machine assembly, or a largepressmay be used to stampsheet metalinto the curved shapes used to construct automobile bodies.Mechanical press

CNC wire cut Principle: It puts impulse voltage between electrode wire and work piece through impulse source, controlled by servo system, to get a certain gap, and realize impulse discharging in the working liquid between electrode wire and work piece. Numerous tiny holes appears due to erosion of impulse discharging, and therefore get the needed shape of work piece.

Electrode wire is connecting to cathode of impulse power source, and workpiece is connecting to anode of impulse power source.

When workpiece is approaching electrode wire in the insulating liquid and gap between them getting small to a certain value, insulating liquid was broken through; very shortly, discharging channel forms, and electrical discharging happens. And release huge high temperature instantaneously, up to more than 10000 degree centigrade, the eroded work piece is cooling down swiftly in working liquid and flushed away.

Conditions that wire cut EDM work correctlyThe gap between electrode wire and work piece should be certainly maintained in a required range.The procedure should happen in the liquid with insulate capacity.Electrical discharging should be short time impulse discharging.