208:. With the high pressure process the tube is fully enclosed in a die prior to pressurization of the tube. In low pressure the tube is slightly pressurized to a fixed volume during the closing of the die (this used to be called the Variform process). Historically, the process was patented in the '50s, but it was industrially spread in the 1970s for the production of large T-shaped joints for the oil and gas industry. Today it is mostly used in the automotive sector, where many industrial applications can be found. With the rise of the electric bicycle it is now a method of choice for e-bicycle manufacturers. Especially down tubes and top tubes are favorably made with hydroforming in order to fit the battery for the electric bicycle. Newest applications in the bicycle industry are now hydroformed handlebars to improve aero dynamics and ergonomics. In tube hydroforming pressure is applied to the inside of a tube that is held by dies with the desired cross sections and forms. When the dies are closed, the tube ends are sealed by axial punches and the tube is filled with
251:
for large panels and thick hard materials. Small concave corner radii are difficult to be completely calibrated, i.e. filled, because too large a pressure would be required. in fact, the die closing force can be very high, both in tube and sheet hydroforming and may easily overcome the maximum tonnage of the forming press. In order to keep the die closing force under prescribed limits, the maximum internal fluid pressure must be limited. This reduces the calibration abilities of the process, i.e. it reduces the possibility of forming parts with small concave radii. Limits of the sheet hydroforming 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 can produce many geometric options as well, reducing the need for tube welding operations. Similar limitations and risks can be listed as in sheet hydroforming; however, the maximum closing force is seldom a limiting factor in tube hydroforming.
221:
sequentially along the length of the tube, with the tube being bent around bending discs (or dies) as the tube length is fed in. Bending can be done with or without mandrels. This additional complexity of process further increases the reliance on FEM for designing and evaluating manufacturing processes. The feasibility of a hydroforming process must take into consideration the initial tube material properties and its potential for variation, along with the bending process, hydraulic pressure throughout the forming process, in inclusion of axial feed or not, in order to predict metal formability.
212:. The internal pressure can go up to a few thousand bars and it causes the tube to calibrate against the dies. The fluid is injected into the tube through one of the two axial punches. Axial punches are movable and their action is required to provide axial compression and to feed material towards the center of the bulging tube. Transverse counterpunches may also be incorporated in the forming die in order to form protrusions with small diameter/length ratio. Transverse counter punches may also be used to punch holes in the work piece at the end of the forming process.
264:
geometries. Tube
Hydroformed sections by the nature of their closed sections are very rigid and do not display high degrees of elastic deformation under load. For this reason it is likely that negative residual stress induced during tube hydroforming might be insufficient to deform the part elastically after the completion of forming. However, as more and more tubular parts are being manufactured using high strength steel and advanced high strength steel parts, springback must be accounted for in the design and manufacture of closed section tube hydroformed parts.
122:) or with a female solid die. In hydro-mechanical deep drawing, a 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 100 MPa (15000 psi) which forms the part around the punch. Then the pressure is released and punch retracted, hydraulic chamber lifted, and the process is complete.
225:
118:
that contains the liquid; no liquid contacts the sheet) and hydroforming where the fluid contacts the sheet (no bladder). Bladder forming is sometimes called flexforming. Flexforming is mostly used for low volume productions, as in the aerospace field. Forming with the fluid in direct contact with the part can be done either with a male solid punch (this version is sometimes called hydro-mechanical
259:
Hydroforming is capable of producing parts within tight tolerances including aircraft tolerances where a common tolerance for sheet metal parts is within 0.76 mm (1/30th of an inch). Metal hydroforming also allows for a smoother finish as draw marks produced by the traditional method of pressing
241:
or male die is required. Depending on the part being formed, the punch can be made from epoxy, rather than metal. The bladder of the hydroform itself acts as the female die eliminating the need to fabricate it. This allows for changes in material thickness to be made with usually no necessary changes
117:
in the United States. It was originally used in producing kitchen spouts. This was done because in addition to the strengthening of the metal, hydromolding also produced less "grainy" parts, allowing for easier metal finishing. In sheet hydroforming there are bladder forming (where there is a bladder
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Another advantage of hydroforming is that complex shapes can be made in one step. In sheet hydroforming with the bladder acting as the male die almost limitless geometries can be produced. However, the process is limited by the very high closing force required in order to seal the dies, especially
263:
While springback has long been a topic of discussion for sheet metal forming operations it has been far less of a topic of research for tube hydroforming. This may in part be a result of the relatively low levels of springback naturally occurring when deforming the tubes into their closed section
74:
working material into a die. To hydroform aluminium into a vehicle's frame rail, a hollow tube of aluminium is placed inside a negative mold that has the shape of the desired result. High pressure hydraulic pumps then inject fluid at very high pressure inside the aluminium tube which causes it to
220:
simulations must be performed in order to find a feasible process solution and to define the correct loading curves: pressure vs. time and axial feed vs. time. In the case of more complex tube hydroformed parts the tube must be pre-bent prior to loading into the hydroforming die. Bending is done
183:
For large parts, explosive hydroforming can generate the forming pressure by simply exploding a charge above the part (complete with evacuated mold) which is immersed in a pool of water. The tooling can be much cheaper than what would be required for any press-type process. The
215:
Designing the process has in the past been a challenging task, since initial analytical modeling is possible only for limited cases. Advances in FEA and FEM in recent years has enabled hydroform processes to be more widely engineered for varieties of parts and materials. Often
20:
50:
into lightweight, structurally stiff and strong pieces. One of the largest applications of cost-effective hydroforming is the automotive industry, which makes use of the complex shapes made possible by hydroforming to produce stronger, lighter, and more rigid
129:
of sheet material by distinctive stretching operations and provides better shape accuracy for complex parts. Hence, by selecting proper material and the forming parameters for hydraulic sheet bulging study one can determine
Forming Limit Curves (FLCs).
139:
Hydraulic bulge testing is more appropriate for sheet metal forming operations as deformation mode is bi-axial rather than uniaxial. Also it provides flow curves for the materials with extended range of plastic strain levels up to 70% before bursting
158:
The use of only single form surface tooling, which saves time and expense in the manufacture of tooling. Absence of rigid tool contact on one surface also reduces surface friction and thus surface defects, resulting in a good surface
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expand until it matches the mold. The hydroformed aluminium is then removed from the mold. Hydroforming allows complex shapes with concavities to be formed, which would be difficult or impossible with standard
143:
It is helpful to generate the FLCs which will be reliable sense of reference input to the explicit solver like LS-DYNA. These obtained FLCs are used as load curve input for such solvers for analysis.
149:
Hydraulic bulge testing would be helpful to calculate the Strain hardening coefficient- "n" (i.e. Work hardening coefficient) of the material, to determine the ability of the material to be formed.
298:
Many motor vehicles have components manufactured using hydroformed tubing, with the first mass-produced automotive component being the instrument panel support beam for the 1990 Chrysler
Minivan.
348:
The process has recently become popular for the manufacture of aluminium wheelchair frames and wheelchair hand rims, making wheelchair more rigid and lightweight and hand rims more ergonomic.
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The technique is widely used in the manufacture of engine cradles. The first mass-produced one was for the Ford
Contour and Mystique in 1994. Others from a long list include the
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422:
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FLCs also serve the best for identifying the exact zone for forming operations without getting affected with localized necking and other possible defects while forming.
237:
Tools and punches can be interchanged for different part requirements. One advantage of hydroforming is the savings on tools. For sheet metal only a draw ring and
184:
hydroforming-into-a-mold process also works using only a shock wave in air as the pressuring medium. Particularly when the explosives are close to the workpiece,
582:
Hydroforming technology. (conference report): Advanced
Materials & Processes (Refereed) : May 1, 1997: ASM International: v151 : n5 : p50(4)
456:
Hatipoğlu, H. Ali; Polat, Naki; Köksal, Arif; Tekkaya, A.Erman (1 January 2007). "Modeling
Flexforming (Fluid Cell Forming) Process with Finite Element Method".
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A controlled pressure distribution over part surface during forming can be used to “control” the sheet thickness and postpone localized necking.
996:
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The process has become popular for the manufacture of aluminium bicycle frames. The earliest commercially manufactured one being that of the
242:
to the tool. However, dies must be highly polished and in tube hydroforming a two-piece die is required to allow opening and closing.
989:
958:
619:
Strano, Matteo; Jirathearanat, Suwat; Shr, Shiuan-Guang; Altan, Taylan (2004). "Virtual process development in tube hydroforming".
691:. 5th International symposium on reducing the cost of spacecraft ground systems and operations. Pasadena, CA: NASA. Archived from
205:
113:
This process is based on the 1950s patent for hydramolding by Fred
Leuthesser, Jr. and John Fox of the Schaible Company of
1017:
951:
903:"Evaluation of Two Wheelchair Hand Rim Models: Contact Pressure Distribution in Straight Line and Curve Trajectories"
796:
491:
Strano, M (2006). "Optimization under uncertainty of sheet-metal-forming processes by the finite element method".
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316:
Other significant automotive applications for hydroforming include suspension components, and radiator supports.
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323:. A selection from many examples are the current versions of the three major United States pickup trucks—the
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Proceedings of the
Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture
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Dachang, Kang; Yu, Chen; Yongchao, Xu (2005). "Hydromechanical deep drawing of superalloy cups".
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industry and is also frequently employed in the shaping of aluminium tubes for bicycle frames.
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uses electrodes to vaporize the fluid explosively in an arc to deform the working material.
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Hydroforming for advanced manufacturing, Ed. by M, Koç, 2009 Woodhead
Publishing Limited
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can be hydroformed, including aluminium, brass, carbon and stainless steel, copper, and
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than traditional stamped or stamped and welded parts. Virtually all metals capable of
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effects make the result more complicated than forming by hydrostatic pressure alone.
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structures for vehicles. This technique is particularly popular with the high-end
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Various vehicle frame components, the earliest mass-produced one being the 1997
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Satellite antennas up to 6 meters in diameter, such as those used in the
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Among these techniques hydraulic bulge testing allows for an increased
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Process sequence in tube hydroforming of a t-shape with counterpunch
592:
Asnafi, Nader (1999). "Analytical modelling of tube hydroforming".
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Low cost microwave ground terminals for space communication
853:"2006 Pontiac Solstice Sheetmetal Hydroforming Technology"
901:
Silva, D. C.; Paschoarelli, L. C.; Medola, F. O. (2019).
773:"Tier 1 supplier builds four-stage competitive strategy"
164:
Alternative names, other variants and similar processes
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In tube hydroforming there are two major practices:
79:. Hydroformed parts can often be made with a higher
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16:Method of shaping metal through pressurized water
260:a male and female die together are eliminated.
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335:—which all have hydroformed frame rails, 2006
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959:
877:"Utility Vehicle has hydroformed steel frame"
8:
1004:
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621:Journal of Materials Processing Technology
528:Journal of Materials Processing Technology
748:"2001 Pontiac Aztek - First Drive Review"
23:A plate being shaped through hydroforming
818:
816:
390:
169:Hydromec (Hydromechanical deep drawing)
470:10.4028/www.scientific.net/KEM.344.469
355:Revive bicycle first marketed in 2003.
288:Lighting fixture housing and reflector
62:Hydroforming is a specialized type of
7:
830:. 13 September 2004. Archived from
797:"2009 Harley Davidson V-Rod Muscle"
309:and the perimeter frame around the
682:Weinreb, Sander (8–11 July 2003).
66:forming that uses a high pressure
14:
540:10.1016/j.jmatprotec.2004.08.024
311:Harley Davidson V-Rod motorcycle
152:A simple and versatile approach.
339:and the steel frame inside the
206:high pressure and low pressure
30:is a means of shaping ductile
1:
919:10.1080/00140139.2019.1660000
662:"Great Designs in Steel 2015"
633:10.1016/S0924-0136(03)00853-7
606:10.1016/S0263-8231(99)00018-X
255:Tolerances and surface finish
771:Eric Lundin (24 July 2003).
722:Fundamentals of Hydroforming
824:"Hydroformed Frame Repairs"
1332:
399:"The Hydroforming Process"
343:HPX Gator Utility Vehicle.
272:Notable examples include:
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458:Key Engineering Materials
81:stiffness-to-weight ratio
1075:Electrohydraulic forming
719:Harjinder Singh (2003).
660:Hertell (May 11, 2015).
98:Electrohydraulic forming
1080:Electromagnetic forming
746:Tony Swan (July 2000).
1065:Casting (metalworking)
828:I-Car Advantage Online
594:Thin-Walled Structures
505:10.1243/09544054JEM480
229:
24:
1286:Tools and terminology
444:U.S. patent 2,713,314
283:Allen Telescope Array
227:
104:Main process variants
93:high strength alloys.
22:
1115:Progressive stamping
403:Jones Metal Products
239:punch (metalworking)
1191:Finishing processes
353:Giant Manufacturing
329:Chevrolet Silverado
276:Sheet Hydro Forming
83:and at a lower per
834:on 21 October 2012
725:. SME. p. 4.
554:"first thf patent"
358:The brass tube of
321:Chevrolet Corvette
293:Tube Hydro Forming
230:
194:Rubber pad forming
109:Sheet hydroforming
77:solid die stamping
25:
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1154:Joining processes
1085:Explosive forming
1053:Forming processes
913:(12): 1563–1571.
883:. 5 December 2003
801:thekneeslider.com
732:978-0-87263-662-0
423:"first HF patent"
246:Geometry produced
200:Tube hydroforming
179:Explosive forming
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777:The Fabricator
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647:"Hydroforming"
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135:Significance
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1145:Tube bending
1100:Hydroforming
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975:Metalworking
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885:. Retrieved
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693:the original
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376:Blow molding
307:Honda Accord
271:
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120:deep drawing
112:
96:
89:cold forming
61:
42:, low alloy
28:Hydroforming
27:
26:
1256:Fabrication
1204:Galvanizing
1044:Sheet metal
1034:Fabrication
1018:fabrication
464:: 469–476.
1276:Metallurgy
1219:Patination
1039:Piece work
907:Ergonomics
887:2008-12-05
862:2008-12-05
838:2008-12-05
806:2008-12-05
782:2008-12-05
757:2008-12-05
702:2008-11-21
408:2011-06-21
386:References
363:saxophones
341:John Deere
325:Ford F-150
313:'s engine.
57:sports car
1271:Machining
1266:Jewellery
1234:Polishing
1199:Anodizing
1176:Soldering
1090:Extrusion
935:201748187
881:ThomasNet
513:108843522
478:137151717
85:unit cost
70:to press
36:aluminium
1310:Category
1281:Smithing
1171:Riveting
1166:Crimping
1135:Spinning
1120:Punching
1105:Stamping
927:31446854
370:See also
268:Examples
172:Aquadraw
34:such as
1291:Welding
1261:Forming
1251:Casting
1229:Plating
1224:Peening
1181:Welding
1161:Brazing
1140:Swaging
1130:Sinking
1125:Rolling
1095:Forging
1070:Drawing
1060:Coining
1027:General
1014:Forming
559:17 July
428:17 July
186:inertia
159:finish.
140:occurs.
53:unibody
933:
925:
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511:
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378:, for
360:Yamaha
331:, and
305:, the
46:, and
32:metals
931:S2CID
696:(PDF)
689:(PDF)
665:(PDF)
509:S2CID
474:S2CID
44:steel
40:brass
923:PMID
727:ISBN
561:2012
430:2012
915:doi
629:doi
625:146
602:doi
536:doi
532:166
501:doi
497:220
466:doi
462:344
333:Ram
218:FEM
64:die
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