US 3371404 A
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United States Patent 3,371,404 METHOD OF SIMULTANEOUSLY CLADDING AND DEFORMING MATERIAL BY INTENSE PRESSURE Jerome H. Lemelson, 85 Rector St., Metu-chen, NJ. 08840 Filed Oct. 22, 1965, Ser. No. 501,395
6 Claims. (Cl. 29-421) This invention relates to an improved method for simultaneously cladding and deforming material, such as sheet material and is a continuation-in-part of copending application Ser. No. 668,561, filed June 27, 1957, now abandoned, for Wave Generating Apparatus.
Various methods of forming material are known in the art and include such techniques as die pressing or stamping, bending, stretch forming, spinning, etc. While each of these techniques may form sheet metal such as the Widely used ferrous and non-ferrous metals, large and heavy sheets and plates of same and a variety of other metals are difiicult to form by same. Explosive forming has been applied with success to form heavy plates of difiicult to form metal but suffers a number of shortcomings as it requires an explosive charge, substantial labor to prepare for each forming operation and is time-consuming. Furthermore, all forming is generally performed by means of a single, expensively-formed high explosive pulse limiting the application of the process to the forming of simple deformations in heavy sheets or plates.
It is an object of this invention to provide an improved method for cladding and working material by means of high pressure waves such as shock waves generated in a fluid in an enclosed or confined volume.
Another object is to provide a new and improved method for cladding and forming sheet material by intermittently applying to said sheet a plurality of intense pressure pulses operative to progressively deform same info or against a die.
With the above and such other objects in view as may hereafter more fully appear, the invention consists of the novel constructions, combinations and arrangements of parts as will be more fully described and illustrated in the accompanying drawings, but it is to be understood that changes, variations and modifications may be resorted to which fall within the scope of the invention as claimed.
In the drawings:
FIG. 1 is a cross sectional view of a sheet forming apparatus employing high-intensity pressure waves such as shock waves and operative to perform other functions as well, and
FIG. 2 is a sectional view of a fragment of an apparatus similar to FIG. 1 for having modifications thereto.
FIG. 1 is a partly sectioned partial view of apparatus for shaping metal sheet or plate by means of multiple, intermittently produced shock waves. By clamping sheet material such as metal or plastic sheet in a die having a cavity protrusion or otherwise shaped portion disposed adjacent a first face of said sheet, and directing high intensity pressive waves such as shock waves against the other face of said sheet, the forces due to the intense pressure or shock waves directed against the unsupported portion of the sheet and/or the intense heat of the shock waves intersecting said sheet, may be operative to cause said sheet to deform against and conform to the walls of said die cavity or protrusion. Depending on the intensity of the shock waves, the sheet may be gradually or rapidly worked by each successive wave directed thereagainst to force said sheet to conform to the forming section of the die. Materials normally difiicult to form by conventional press means may be so worked.
'FIG. 1 shows details of fluid pressure forming apparatus 10 which comprises a reaction chamber 12 which may comprise or terminate a shock tube in which intermittent shock waves are generated by any suitable means such as the arcing of high intensity electrical sparks discharged across said chamber, intermittent explosions generated therein by chemical or electrical means, etc. Reaction chamber 12 may also be provided in any suitable configuration or shape of chamber having means for generating shock waves of a desired intensity. Such waves or pressure pulses may be generated singly or in rapid succession as described. The chamber or tube 12 is provided with means 141 for raising and lowering said chamber against a bed 13 comprising a rigid platen or bench 15 in which is secured a die 16 shown having a cavity 17 into which a member 18 such as a sheet of metal is to be deformed by pressure and heat applied to one face thereof. The cavity 17 may be replaced with a flat platen if it is desired to work the surface of the member 18 such as in flattening or straightening said member, heat treating or work-hardening same. It is noted that by placing material such as metal powders or abrasive grit particles on the surface of member 18 they may be worked into or bonded onto said surface or operate to abrade said surface by the action of the shock Waves thereon. A steel die (not shown) placed on said member 18 and free to move towards the die 16 may also be urged by the impact pressure of the pressure or shock waves generated in chamber 12 to shape or penetrate the surface of sheet 18. Such a die may be slidably engaged in the bore of chamber 12 or on sliding guides therein and may, when impacted by the shock waves generated in chamber 12, coact with the die 16 to shape or cut the sheet 18'. Means 14 for raising and lowering the chamber 12 is provided and comprises at least two hydraulic or air cylinders 20 and 21 which are supported on the frame 19 of the press, the rams 20', 21' of which cylinders engage a flange 22 of the chamber 12 and preferably are attached thereto for cooperating in raising as well as lowering the chamber 12 and forcing its lower rim into clamping engagement against the press bed and/ or work 18. In FIG. 1, a circumscribing ridge-like protrusion or lip 23 projects from the open end-face 12' of the chamber and is adapted to be forced against the sheet 18 to efiect a fluid pressure seal therewith. The lip or ring shaped rim 23 may be replaced by a sealing ring such as a metal seal or O-ring to effect such a circumscribing pressure seal. Upon clamping engagement of the face 22 of the chamber 12 against the press bed 15, shock waves may be produced such as by exploding chemicals in said chamber 12 or electrical discharge means to effect the desired work forming, coating or cutting action on the member 18.
If work member 18 is metal or other thermoplastic material it is noted that, by producing a plurality of intermittent shock waves in the chamber volume 12V, sufficient heat from said shock waves may be transferred thereto to raise its temperature a degree whereby it will become softened or rendered malleable and more easily workable by the forces of the subsequent pressure or shock waves directed thereagainst. The degree of softening or increase in workability will be a function of the intensity of the shock waves generated, their frequency of appearance at the surface of member 18 and the physical characteristics as well as dimensions of the material 18 being worked or formed. By producing fluid pressure in excess of 10 p.s.i. or shock waves of an intensity greater than Mach 2 and at a frequency in excess of 25 per second, most plastic or thin metal non-ferrous sheets may be formed or worked as described. As the intensity and frequency of the shock waves are increased, the time required to work the member 18 will be decreased. Many materials not easily formed or worked by conventional means may be formed using fluid pressures or shock waves in excess of Mach 3 produced at frequencies in excess of 50 per second.
Notation 25 refers to one or more conduit or nozzle inlet means connected to the shock tube 12 for blowing or otherwise injecting a fluid or flowable particles into said tube and/or against the surface of the sheet or plate 18 while the shock waves are directed thereagainst. The heat and/ or pressure of said shock waves may be used in coaction with the fluid or material injected through conduit 25 to eflect one or more physical and/ or chemical reactions on member 18. Material injected through duct 25 may be used to perform one or more of the functions of abrading or roughening the surface of the work, coating or cladding said surface (which may or may not have been previously abraded by said action) with a protective coating or other material per se or during and in coaction with the forming action, effecting a chemical or physical reaction on said member 18 such as softening or cleaning said surface, etching or other chemical reaction which occurs with and is enhanced by said shock waves directed thereagainst. In certain of these fabrication or processing actions, the die 16 may be replaced by a fiat platen and the rest of the illustrated structure may remain for merely processing sheets, plates or other shaped solids with shock waves and chemicals while said shapes are held stationary.
Flexible conduit 25 which terminates at a small opening 25' provided at the lower end of the side wall 12" of the elongated reaction chamber 12 may also be utilized for admitting a working fluid to the volume 12V of the reaction chamber 12 which working fluid may be utilized as a transmitting means for the shock Waves generated in the upper portion of the chamber and/ or may contain one or more explosive chemicals for generating said shock Waves as well as particulate material, when utilized, to be clad or otherwise used in affecting the surface of the work piece. In one form of the operation of the apparatus 10, the working fluid may comprise air in which shock waves are generated and transmitted to the work piece from the wave generating means. In other forms of the invention, liquid such as water or oil may be pumped through conduit 25 from a reservoir supply 26 thereof connected to said conduit after the chamber 12 has been moved to a downward position to effect a fluid pressure seal between the circumscribing lip 23 and the upper surface of the sheet or plate 18. After the sheet or plate 18 has been worked such as deformed to conform the wall of the cavity 17 or die 16, automatic control means to be described hereafter are operated to either control lineal actuator cylinders 20 and 21 to either lift the chamber immediately, if the workin fluid contained therein is air, or to effect operation of the pump 26 for removing working fluid, if liquid, from volume 12V prior to controlling the operation of cylinders 20 and 21 to lift said chamber. Notation 16 refers to a passageway in the wall of the die 16 leading to cavity 17 which may be utilized for evacuating air therefrom either prior to the wave forming action or as the result of deformation of sheet 18 into said cavity. a
The means illustrated in FIG. 1 for generating a succession of shock waves in the volume 12V of the reaction chamber 12 include a plurality of pairs of electrodes defined by notations 27, 28 and 30, 31 which are illustrated as being disposed in respective diametrically opposite portions of the upper end 12a of the chamber 12 and across which high intensity electrical discharges or sparks are generated which are operative to generate shock waves. Each shock wave so generated has a first component which travels down chamber 12 in the fluid therein and intersects the surface of the work piece 12 exposed thereto. A second component of the shock wave travels up the chamber and reflects off the spherical or parabolic end wall 12b of the chamber and thence downward in the direction of the work.
One or more additional pairs of electrodes such as the illustrated electrodes 30, 31 may be operative to generate shock waves interposed between those generated by the upper electrodes 27 and 28 and, in a preferred form of the invention, are all generated in timed relation to those generated by the other electrodes so as to amplify or reinforce the resultant shock wave resulting in a greater force being applied to the work piece. Further pairs of similar electrodes may also be provided and so energized as to increase the reinforcement or amplification of one or a group of shock waves traveling along the tube towards the work to provide the desired force and temperature for operating on and deforming said work. As stated, in a preferred form of the invention, the shock wave not only transmits a force of substantial magnitude to the work which is operative to deform, clad, heat treat or otherwise physically affect the work or the material thereof in a predetermined manner to improve same, but also transmits substantial heat to the surface of the work which may be utilized to render same more easily worked by the force of the shock wave.
The reaction chamber 12 may be produced of a material which is not electrically conducting such as a ceramic or may be lined or coated therewith on the inside for serving a plurality of functions including protecting the main chamber wall from heat distortion and corrosion and for insulating the electrodes across which high intensity spark discharges are generated. In FIG. 1, the electrodes are each shown supported'in a tubular member 29 which is held in a boss portion 12] extending from the reaction chamber and serves not only to insulate said electrode but to protect same from the vibration and shock. The formation 29 may be made of any suitable ceramic or high temperature polymer. A suitable material from which the entire wall or lining of the reaction chamber 12 may be fabricated is so-called Pyroceram, a shockresistant ceramic material manufactured by the Corning Glass Works of Corning, N.Y. If the entire wall is fabricated of such a material or if such a material lines the wall of a metal reaction chamber the interior surface of the ceramic may be coated or lined with a further material such as silicone carbide, boron nitride, aluminum oxide, tungsten carbide, titanium carbide or the like. These materials may be also utilized to directly coat the inside of a steel or stainless steel reaction chamber wall for heat resistance and electrical insulation purposes.
Also shown in FIG. 1 are means for controlling the operation of the various described mechanical and electrical devices. A master controller 44 such as a digital computer or multi-circuit sequential controller has a plurality of outputs 45 extending to controls for the various described servo devices as well as to means for generating and controlling the discharge of electrical sparks across the chamber wall for generating shock waves within the apparatus. In its simplest form, the controller 44 may comprise a multi-circuit, self-resetting timer which is adjusted to effect the following operations by gating signals or power to the devices to be described. The first signal generated by controller 44 closes a bi-stable switch 39 connecting a source of line current PS to. energize a high voltage generator 38. The generator 38 is connected to a multi-pole switch 35 having a plurality of outputs 36 extending to the positive electrodes 28 and 31 of the described electrode pairs. Switch 36 is operated when a wiper arm thereof 37 or other suitable contact making means is operated by a servo 40'such as a constant speed, controllable motor 40 having a control input 41 which itself is controlled by a signal or signals generated by the controller 44. Lines 32 and 33 extend to positive electrodes 28 and 31 whereas a ground line 34 extends to electrodes 27 and 30 and connects to the source of'high voltage through switching device 35. Thus the device 35 is operated to generate the desired number of shock waves in the volume 12V for a predetermined period of time which occurs during a predetermined interval in a controlled production cycle. Other outputs 45 from the controller 44 extend to forward and reverse control inputs PR of control means 42 which are operative to projecting and retracting the shafts 20' of actuators 20 and 21 which lower and raise the reaction chamber 12. Other outputs of the master controller 44 extend to controls F, S and R for operating, stopping and reversing the described fluid pump 26 for admitting and removing fluid to the chamber 12V for the purposes described. Still other outputs of the master controller 44 extend to forward and reverse controls F and R of a servo operating a device 43 for transferring the work piece 18 to the die 16, prepositioning same and, when controller R is operated, for removing said work piece from said die and replacing same with a new work piece.
Thus master controller 44 is preprogrammed or adjusted to aflect the sequence of operations which include the operation of transfer device 43 to preposition a work piece 18 across the face of die 16; operation of actuators 20 and 21 to move the chamber 12 downwardly to sealingly compress the lip or seal 23 thereof against the work 18; operation of pump 26 to admit fluid or particulate material (in those production operations where applicable) to the chamber 12V; connection of a source of power PS to the high voltage generator 38; operation thereafter of the switching device 35 to generate one or more high voltage sparks across the combustion chamber by energizing one or more of the described pairs of electrodes; reverse operation of pump 26 (where applicable) to remove fluid from volume 12V; reverse operation of fluid cylinders 20 and 21 to lift the chamber 12 to clear the Work piece; operation of transfer device 43 to remove the formed work piece from the surface of the die; and further operation of transfer device 43 to replace the old work piece with a new work piece. Not mentioned in the above cycle, though applicable in certain instances, would be the application of suction pressure to the line 16' extending to the die cavity volume 17 following the step of engaging a sealing lip 23 of chamber 12 against the surface of work piece 18.
It is noted that the apparatus of FIG. 1 may be operated to receive work in other forms than individual pieces of plate or sheet. For example, articles of a suitable shape may be disposed within the chamber against a flat platen or block replacing die 16 or against the upper surface of the plate 18 for the purposes of coating, abrading or eroding same or effecting the welding of a plurality of the components disposed within the chamber by pressure and heat applied as a result of the generation of one or more shock waves therein. For example, a plurality of components may be secured or otherwise predeterminedly positioned on plate 18 to be welded to each other and/or to the plate itself.
FIG. 2 illustrates modifications to the apparatus of FIG. 1 permitting the feeding of material to the wave forming apparatus wherein said material is in the form of a continuous sheet or plate. The material 18' is shown being fed to the reaction chamber 12 along an input conveyor 46 which includes a plurality of cooperating powered rolls 47, 48 powered by a servo (not shown) which is controlled by master control 44 to position new lengths of said sheet in alignment with the forming die 16. The sheet 18 is shown deformed at portion 18" to the cavity of the die 16' as the result of pressure or wave action within the chamber 12. The sealing lip 23 of FIG. 1 has been modified in FIG. 2 to define, in addition to means for sealingly engaging that portion of the sheet extending across the chamber 12, further means in the form of a sharp edge 23' or knife operative to die cut a predetermined portion of said sheet including the deformed portion 18" thereof. Notation 52 refers to one or more resilient or rigid wear resistant inserts secured to die block 16 which cooperate with the knife edge or sharp rim 23' extending from the flange 22' or end of the chamber 12. Thus, prior to or immediately after forming the central portion 13" of each portion of sheet disposed across the die 16', chamber 12 is compressively forced by the operation of the actuators 20 and 21 to die cut sheet 18 into individual sections which include a portion thereof which is worked or formed to shape by means of the pressure or wave action generated in the volume 12V.
After the portion of sheet 18' has been shaped or otherwise predeterminedly worked, the master controller 44 generates signals for lifting chamber 25 and/ or retracting the die 16" to permit the article or deformed portion of sheet 18' to be removed from the die. Such removal may be affected by operating a take-off conveyor 49 which includes a plurality of power operated rollers 50 and 51 engaging the border areas of the deformed portion of the sheet 18' for removing same from alignment with chamber 12 provided that said deformed portion is not totally severed from that portion of the sheet driven by conveyor 49. A 'blast of air ejected through passageway 16' in the die may also be used to blow the sheet or severed portion thereof out of the die cavity. The sequence of actions controlling the modified form of the wave generating apparatus of FIG. 2 which are described in the description of FIG. 1, are also assumed to be controlled by master controller 44 where applicable.
While the apparatus hereinbefore described may employ a plurality of shock waves generated in the confined liquid or gas disposed in the reaction chamber to predeterminedly deform, weld, clad, erode, coat or otherwise process material such as sheet metal or other shapes of metal or non-metallic materials, it is noted that one or a plurality of successively generated shock waves or pressure pulses of lesser intensity may be formed within the reaction chamber by other means. For example, the sudden generation of an intense beam of radiant energy such as that generated by an electron gun or a so-called laser may be directed into the liquid or gas defining the Working fluid through a transparent portion of the Wall of the chamber such as a high temperature glass or ceramic window or wall itself and may be utilized to generate said shock waves by the sudden transfer of heat thereto or to increase the fluid pressure by heating the gas or vaporizing a portion of the liquid. Chemical combustion or explosive reaction means employing a solid, particulate, gaseous or liquid combustible or explosive chemical or chemicals may also be continuously or intermittently fed to the reaction chamber in a controlled manner by a conveying means operated or controlled by a servo which is controlled by the described master controller 44 and may be rapidly burned or exploded by a controlled spark, intense laser or electron beam, radio frequency energy or other suitable means to generate one or more pressure waves within the chamber for the purposes described.
1. A method of cladding and shaping a member comprising:
(a) supporting a member to be clad adjacent a shaping means of predetermined shape,
(b) disposing a cladding material on the surface of said member to be clad and providing a working fluid medium above said cladding material,
(0) generating an intense pressure in said fluid medium against said cladding material at sufficient intensity to cause said cladding material to become molecularly bonded to the surface of said member and simutaneously causing said cladding material and member to be deformed to said predetermined shape.
2. A method of cladding metal plate and simultaneously working said plate and cladding to deform same to a predetermined shape comprising:
(a) supporting a metal plate member to be clad and shaped with one surface thereof in alignment With a forming die of predetermined shape,
(b) disposing a cladding material against the other surface of said metal plate,
(c) generating a shock wave and directing said shock wave against said cladding material at sufiicient intensity to cause said cladding material to become molecularly bonded to the surface of said plate and to simultaneously deform and change the shape of said cladding material and plate and cause same to conform to said predetermined shape as defined by the shape of said forming die.
3. A method in accordance with claim 1 wherein said member to be clad is metal and said cladding material is a particulate material.
4.. A method in accordance with claim 1, whereby said intense fluid pressure is composed of a shock wave, said method further comprising directing said shock wave against material disposed on said member to effect the cladding of said member as it is simultaneously deformed to said predetermined shape.
5. A method in accordance with claim 2, including generating a plurality of shock Waves to clad and deform said plate.
6. A method in accordance with claim 2, whereby said forming die has a curved shape and the force of said shock wave is operative to cause said clad metal plate to conform to said curved shape.
References Cited UNITED STATES PATENTS THOMAS H. EAGER, Primary Examiner.