58348385 Hydro Forming of T JOINT

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HYDROFORMING FOR T-JOINT

Hydroforming(or hydramolding) is a cost-effective way of shaping

malleable metalssuch as aluminumorbrassinto lightweight, structurallystiff and strong pieces. One of the largest applications of hydroforming isthe automotive industry, which makes use of the complex shapes possibleby hydroforming to produce stronger, lighter, and morerigid unibodystructures for vehicles. This techniue is particularly popularwith the high-endsports carindustry and is also freuently employed in theshaping of aluminium tubes for bicycle frames.

!ydroforming is a speciali"ed type of dieforming that uses a high

pressure hydraulicfluidto press room temperature working material into adie. To hydroform aluminum into a vehicle#s frame rail, a hollow tube of

aluminum is placed inside a negative mold that has the shape of the

desired end result. !igh pressure hydraulic pistons then in$ect a fluid at

very high pressure inside the aluminum which causes it to expand until it

matches the mold. The hydroformed aluminum is then removed from the

mold.

!ydroforming allows complex shapes with concavities to be formed, which

would be difficult or impossible with standard solid die stamping.!ydroformed parts can often be made with a higher stiffness to weight ratio

and at a lower per unit cost than traditional stamped or stamped and

welded parts.

This process is based on the %&'s patent for hydramolding by red

*euthesser, +r. and +ohn ox of the chaible ompany of incinnati, O!. t

was originally used in producing kitchen spouts. This was done because in

addition to the strengthening of the metal, hydramolding also produced less

/grainy/ parts, allowing for easier metal finishing.
http://en.wikipedia.org/wiki/Metalhttp://en.wikipedia.org/wiki/Aluminumhttp://en.wikipedia.org/wiki/Brasshttp://en.wikipedia.org/wiki/Unibodyhttp://en.wikipedia.org/wiki/Sports_carhttp://en.wikipedia.org/wiki/Die_(manufacturing)http://en.wikipedia.org/wiki/Hydraulichttp://en.wikipedia.org/wiki/Fluidhttp://en.wikipedia.org/wiki/Cincinnati,_OHhttp://en.wikipedia.org/wiki/Metalhttp://en.wikipedia.org/wiki/Aluminumhttp://en.wikipedia.org/wiki/Brasshttp://en.wikipedia.org/wiki/Unibodyhttp://en.wikipedia.org/wiki/Sports_carhttp://en.wikipedia.org/wiki/Die_(manufacturing)http://en.wikipedia.org/wiki/Hydraulichttp://en.wikipedia.org/wiki/Fluidhttp://en.wikipedia.org/wiki/Cincinnati,_OH


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Animated model of hydroforming.

In the above image, we can replace the w-shape with any shapes.

IN THIS CAS ! TA" T-SHA#$

Sheet hydroforming

n sheet hydroforming there is 0ladder forming (where there is a bladder

that contains the liuid, no liuid contacts the sheet) and hydroforming

where the fluid contacts the sheet (no bladder). 1 work piece is placed on a

draw ring (blank holder) over a male punch then a hydraulic chamber

surrounds the work piece and a relatively low initial pressure seats the work

piece against the punch. The punch then is raised into the hydraulic

chamber and pressure is increased to as high as %' psi which forms

the part around the punch. Then the pressure is released and punch

retracted and hydraulic chamber lifted and the process is complete.


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Tube hydroforming

n tube hydroforming (T!) there are two ma$or practices2 high pressureand low pressure. 3ith the high pressure process the tube is fully enclosed

in a die prior to pressuri"ation of the tube. n low pressure the tube isslightly pressuri"ed to a fixed volume during the closing of the die (thisused to be called the 4ariform process). n tube hydroforming pressure isapplied to the inside of a tube that is held by dies with the desired crosssections and forms. 3hen the dies are closed, the tube ends are sealed byaxial punches and the tube is filled with hydraulic fluid. The internalpressure can go up to a few thousands of bars and it causes the tube tocalibrate against the dies. The fluid is in$ected into the tube through one ofthe two axial punches. 1xial punches are movable and their action isreuired to provide axial compression and to feed material towards thecenter of the bulging tube. Trasverse counterpunches may also beincorporated in the forming die in order to form protrusions with smalldiameter5length ratio. Trasverse counterpunches may also be used topunch holes in the work piece at the end of the forming process. 6anyindustrial applications of the process can be found, especially in theautomotive sector

Explosive hydroforming

or large parts, explosive hydroforming can generate the forming pressureby simply exploding a charge above the part (complete with evacuatedmold) which is immersed in a pool of water. The tooling can be muchcheaper than what would be reuired for any press-type process. Thehydroforming-into-a-mold process also works using only a shock wave inair as the pressuring medium. 7articularly when the explosives are close tothe workpiece, inertiaeffects make the result more complicated than

forming by hydrostatic pressure alone.

Typical tools

One advantage of hydroforming is the savings on tools. or sheet metalonly a draw ring and punch (metalworking)or male die is reuired. The
http://en.wikipedia.org/wiki/Inertiahttp://en.wikipedia.org/wiki/Punch_(metalworking)http://en.wikipedia.org/wiki/Inertiahttp://en.wikipedia.org/wiki/Punch_(metalworking)


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bladder of the hydroform itself acts as the female die eliminating the needto fabricate a matching female die. This allows for changes in materialthickness to be made with usually no necessary changes to the tool.!owever, dies must be highly polished and in tube hydroforming a two-piece die is reuired to allow opening and closing.

Geometry produced

1nother advantage of hydroforming is that complex shapes can be made in

one step. n sheet hydroforming (!) with the bladder acting as the

female die almost limitless geometries can be produced. !owever,

process is limited by the very high closing force reuired in order to

seal the dies, especially for large panels and thick hard materials.

mall concave corner radii are difficult to be completely calibrated, i.e.

filled, because too large a pressure would be reuired. *imits of the

! process are due to risks of excessive thinning, fracture, wrinkling

and are strictly related to the material formability and to a proper

selection of process parameters (e.g. hydraulic pressure vs. time

curve). Tube hydroforming (T!) can produce many geometric options

as well, reducing the need for tube welding operations. imilar

limitations and risks can be listed as in !8 however, the maximum

closing force is seldom a limiting factor in T!.

Tolerances and surface nish

Hydroforming is capable of prod%cing parts within tight tolerances

incl%ding aircraft tolerances where a common tolerance for sheet

metal parts is within thirty tho%sandths of an inch. Sheet metal

hydroforming also allows for a smoother &nish as draw mar's

prod%ced by the traditional method of pressing a male and femaledie together are eliminated.


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!ect on "or# $aterial

!hen a blan' is hydroformed the metal (ows aro%nd the dierather than stretching, which prod%ces less material thinning, andalso red%ces the rate of wor' hardening which helps eliminate the

need for an annealing process on some parts that mightotherwise re)%ire f%rther forming operations

HYDROOR!"#G O T$%O"#T&

There are many metal-forming processes which are well-established, such

as deep drawing, which is used in the manufacture of billions of cans forconsumable drinks. n press forming, flat sheets are formed between dies.The die set usually has a static face on which the sheet (blank) is securedand the mating die(T-!179:) is depressed - this latter die is calledthepunch. The ma$or advantage of forming processes is that they avoid thewaste of material as happens in machining. 7roductivity can also be veryhigh compared with machining. The final properties of the metal in theformed state may also be superior to those in the blank.

!ydroforming is a relatively new process, popularised by design studies

which suggest that automobiles can be made much lighter by usinghydroformed components made of steel. tructural strength and stiffnesscan be improved and the tooling costs reduced because severalcomponents can be consolidated into one hydroformed part. omponentsmanufactured by forming can springback, meaning that the undergo elasticdistortion on removing the component from the die(T-!179:). This effectis apparently smaller in hydroformed components.

The process is uite simple - a blank with a closed-form, such as a cylinder,is internally pressurised using fluid. The fluid is freuently water. Theapplied pressure is usually in the range ;-


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heet metal can also be hydroformed but the sealing of the sheet to the dieprior to pressurisation can be problematic, making the process too costly formass production.

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O>61TO? O T-+O?T

*INA+ T-SHA#$ C#NNT


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1lmost all the curvaceous body panels on the olstice are produced viasheet metal hydroforming C a first for a production vehicle(T-!179:). 1relatively new process which uses water pressure to help form thedesired panel shapes, sheet metal hydroforming is used to create theolsticeDs uniue clamshell hood, outer door panels, rear deck lid anduarter panels.

heet metal hydroforming of exterior body panels has seen limited use inother markets around the world, but predominantly for small runs ofspecialty aftermarket panels. olsticeDs body panels represent the firstexterior application of the technology, which enables the transfer oforiginal concept vehicle design without compromises, in a mass-produced automobile.

6ore precise than conventional body panel stamping, sheet metalhydroforming (also known as hydromechanical deep drawing) allows themuch deeper draw C or depth of the component C necessary for creatingpanels with complex curves. The process allows the body curves of theoriginal olstice concept to be reproduced on a mass production scale.6any of the olstice body panels, in fact, such as the uniue clamshellhood and its compound curves, could not have been formed byconventional stamping methods. The only conventionally stampedportion of the olstice exterior is a small, almost flat panel between thefront wheel well and door edge.

1lthough more time-consuming than conventional draw stamping, sheetmetal hydroforming offers reduced tooling costs, as only a singleEpositiveF die is reuired for each panel. n the conventional stampingprocess, both EpositiveF and EnegativeF dies are reuired to form a singlepanel. The sheet metal hydroforming process uses hydrauliccounterpressure to press a blank panel onto the die(T-!179:).ounterpressure builds as the die presses the blank downward into thewater tank. The compressed water forces the blank onto the die, forming

the shape of the panel.

0ecause pressure is spread more evenly onto the blank, sheet metalhydroforming offers the additional advantages of excellent finish uality,uniform panel thickness and precise dimensional accuracy whencompared with conventional draw stamping. 6ore uniform panel


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thickness improves the chances for successful forming, particularly whencreating complex shapes, such as the olsticeDs clamshell hood.

1chievement of the olsticeDs curvaceous contours was aided byhydroforming in other ways. The strength of the lower-dominantfoundation of the vehicleDs hydroformed chassis freed engineers fromhaving to use body panels as structural members, thus eliminatingrestrictions to applying the concept vehicle design to the productionmodel.Thus by this method we can not only form T-+O?T but also manycomponents of vehicles

SOME OF THE COMPONENTS FORMED BY HYDROFORMING

A%tomobile component tarting shape cylindrical. !oles hydro-pierced

!ydroformed bellows, beginning with cylinders !andle bar is hydroformed aluminium


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INNATI /I


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INNOVATIVE II


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INFO INSTITUTE OF ENGINEERING

%&ppro'ed (y &I)T * Ne" Delhi + &,liated to &nna

ni'ersity * )oi$(atore.

INT0NA+ TIAT$ ST1$2 0C0$

3"

NA- 4 R.SATHISH KUMAR

05IST0 N1-30 4 090111109023

DEGREE & SEMESTER : B.E & III

BRANCH & SECTION : MECHANICAL

SUBJECT & CODE : MANUFACTURING TECHNOLOGY-I

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58348385 Hydro Forming of T JOINT