Brahmos Aerospace Thiruvananthapuram Limited

8/7/2019 Brahmos Aerospace Thiruvananthapuram Limited

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Denny Thomas

Roll No. 15S8 Mechanical

MBCET


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Brahmos Productsy Gas bottles for rockets(for ISRO).

y

Propellant tank(for ISRO).

y Ring shaped water tank(for ISRO).

y Liquid Engine components(for ISRO) &

y Components of BrahMos missile.

y Other precision components for DRDO, BARC & ISRO.


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General Machine Shop


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General Machine Shopy The main metal used for machining in the machine shop

are titanium and marine steel.

y Titanium alloy metal is mainly used for manufacturing air-craft and space-craft components. Marine steel is used formaking parts of submarine missile called Sagarika which islaunched under water.

y All initial machining operations are done in generalmachine shop.

y The main machining operations are turning, milling ,boring , grinding etc. using both conventional and non-

conventional machines.


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Properties of Titanium.

y Strong and light weight.

y High resistance to corrosion.

y

High melting point.

y Low coefficient of linear expansion.


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Machining of Titanium Alloyy Titanium alloy is difficult to machine because its a

poor conductor of heat.

y Heat generated by cutting action does not dissipatequickly. Therefore most of the heat is concentrated onthe tool face and cutting edge.

y Titanium has a strong alloying tendency or chemicalreactivity with materials in the cutting tools at tooloperating temperatures. This causes rapid destructionof cutting tool.


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Machining of Titanium Alloy

y Titanium alloys demonstrate a complete absence of

built -up edge. Because of the lack of a stationary massof metal (built-up edge) ahead of the cutting tool, ahigh shearing angle is formed. This causes rapid toolbreakdown.


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Machining procedure for Titanium

y Use of low cutting speeds to minimize heat built-up.

y Use of a large flow of cutting fluid to increase thecooling effect.

y Use of tools with controlled sharpening and theirreplacement as soon as they become worn.


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Machining procedure for Titanium

y Maintaining stability of the whole machining system(machine, spindle, tool holder and tool) tocompensate for the elasticity of the material and toreduce vibrations to a minimum level.

y

No stopping on travel whilst the work piece and thetool are in Contact. Leaving the tool in position causesthe material to be immediately hardened and over-heated causing breakage of the tool.


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Conventional Machinesy Conventional Lathe.

y Boring Lathe.

y Drilling machine.y SurfaceGrinding Machine.

y CylindricalGrinding Machine.

y Shaping Machine.

y Slotting Machine.

y Tool and cutter grinding Machine.

y Milling Machine.


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CNCMachinesy CNC means computerized numerical control.

y The part design and the tool path program are done by

the CAD/CAM process, and the resulting file isuploaded to the CNC machine.

y Conveyor belt at the bottom to carry coolant.

y Bed length is 3m.

y Job holder can hold 12 different tools.

y At a time one tool acts on the job which can beselected by computer codes.


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CNCMachinesy Job rotates on chuck and tool on tool post acts on it.

y Turning of gas bottles to store fuel in rockets andsatellites are done on these lathes.

y There are 4 CNC machines in the General machine

shop and all are sponsored by ISRO.

y Costs about 80 lakhs.


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Non-Conventional Machine


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Electrical Discharge Machining

y Used to remove metal by using the heat from theelectric discharge(non-conventional machining).

y The dielectric discharge medium used is Rustlick oil.

y Cathode used isGraphite or copper.

y Anode is the metal to be machined.

y Computer programmed motion for tool & work-piece.y Mainly used to produce holes which are not uniform

throughout the thickness.

y Costs about ten lakhs.


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Manufacturing ofGas Bottles.y Initially titanium alloy sheets are pressed on hydraulic

press using hemispherical die.

y Then initial machining is done in the general machineshop.

y After the initial machining the hemispheres are taken forheat treatment to improve the structural properties.

y Final machining and finishing is done in precision machineshop. Then two hemispheres are joined by TIG welding toproduce a gas bottle.


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Precision Machine Shopy Final finishing of the products are done in the

precision machine shop.

y The temperature of air inside the precision machineshop is maintained at 20 degrees.

y Invar steel which is an alloy of iron is the material forverniers inside the Precision machine shop due to itsvery low cofficient of linear expansion.


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Precision Machine Shopy All the machines inside the precision machine shop

are CNC type.

y Majority the equipments have ATC (Automatic ToolChanger) and some have APC (Automatic PalletChanger) technology.

y The part design and the tool path program are done bythe CAD/CAM process, and the resulting file isuploaded to the CNC machine.


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Precision Machine Shopy The CAD/CAM laboratory is inside the precision

machine shop and the access to it is restricted.

y The operators inside the precision machine shop arehighly skilled as all the operations inside are finishingworks.

y Majority of the machines have four and three axesindex.


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Precision Machine Shopy Wide variety of machines are used in Precision

machine shop and in all machines inclined machiningis possible in four axis index machines.

y Some of the machines include CNC milling machine,drilling machine, boring machine, wire cuttingmachine etc.

y Majority of the machines are German and Swiss made

and are imported.y All machines can run at very high spindle speeds and

variety of tools are available. Drill bits as small as0.3mm is available.


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WireCutting Machiney It is a four axes machine.

y The four axes are X,Y,U and V.

y U and V are axes along which work-piece slides parallelto X & Y axes of machine.

y Brass wire is used to produce electric discharge whichvapourizes away the metal to form cut in workpiece.


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WireCutting Machiney De-ionized water is used as the di-electric.

y The wire which is used for cutting can be used only once.

y It is a very slow process but complex shapes can be madeusing computer controlled process.

y Material is removed from the work-piece by a series ofrapidly recurring current discharges between twoelectrodes, separated by a dielectric liquid and subject toan electric voltage. One of the electrodes is called the tool-electrode while the other is called the work-piece-electrode.


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Thank You

Brahmos Aerospace Thiruvananthapuram Limited

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