Method of forming parts of moulded-welded shells of spherical and elliptical shape
FIELD: process engineering.
SUBSTANCE: invention relates to metal forming. Proposed method consists in consecutive local clampings in several passes. In first pass, spherical surface is produced with curvature radius equal to maximum preset radius on entire surface of sheet billet. Here, used is round female die and spherical male die. In second pass, sheet billet section with smaller curvature radius is drawn using annular female die and spherical made die. Working radius of said male die varies with drawing radius, with due allowance for spring back of billet and its thickness and depends upon Gauss curvature of part surface: Note here that where Rd is drawing radius, m; R1 is preset transverse radius of billet central surface, m; R2 - is preset lengthwise radius of sheet billet central surface, m; K is double Gauss curvature of billet central surface, 1/m2. In third pass, spherical make die is used with working surface radius proportional to preset transverse radius R1 with due allowance for spring back and thickness, as well and prismatic female die.
EFFECT: reduced residual strain and thinning.
2 cl, 2 dwg
The invention relates to the forming of metal parts pressure, in particular to the production of a torispherical and ellipsoidal elements of stamped shells with double curvature surface.
Known methods of forming double curvature components based on application of methods of hot stamping and cold flexible method of successive local taps (PLN) using universal or special stamps (Moshnin E.N. Flexible, stretch-forming and straightening presses, Meters, motor cycle", 1959; Kuklin O.S, Brooke MB Technology and equipment for forming thick-walled shells and their elements, L, CRI "RUMB", 1986).
A known method of forming products of double curvature of the sheet metal by A.S. 1616746, including shaping for the two transitions, the first of which impart a curvature in one direction, and the second final shape, and forming on the first transition is carried out in the direction of maximal curvature of the product, providing a curvature equal to the difference between the largest and smallest curvature of the product, and the second transition get the final shape. Shaping produce a spherical tool, having a curvature corresponding to the smallest curvature of the product. However, to use the above method of forming the mu who needs to have a lot of large stamping equipment, and in some cases to apply the hot bending operation.
Closest to the claimed technical solution to the technical essence and the achieved result is a method of forming the double curvature components items torispherical shells under the patent of the Russian Federation No. 2194587, including the shaping of the workpiece consecutive mouse clicks for the two transitions, the first transition on the sheet blank to receive the spherical surface and tore part of the surface with a given radius of curvature in the latitudinal direction, and the second tore a part of the surface with a given radius of curvature in the meridional direction, with both transitions formation starting from the wide end edge of the workpiece.
However, as demonstrated by work experience in the use of this method of forming the item, acquiring the specified form, has a high level of residual stresses and thinning, which requires a subsequent heat treatment after bending or forming in a hot state that the complexity of the process and the accuracy of the details give the worst 3-4 times the results than when cold bending.
The present invention is to develop a method of forming double curvature components, allowing to obtain high quality items while snizeni the complexity and intensity, as well as reducing the metal snap.
The use of the invention will provide the technical result consists in a greater uniformity of deformation of the sheet during bending and, consequently, to reduce the level of residual stresses and thinning.
The task can be solved, when in accordance with the proposed method of forming parts of stamped torispherical shells and elliptical forms the sheet-metal part formed by the method of successive taps for multiple transitions. However, unlike the prototype on the first transition receive the spherical surface with radius of curvature equal to the greater of the specified radii across the surface of the workpiece, which use a punch with a working surface of the spherical shape (hereinafter - spherical punch) and the matrix in the form of a ring with a working surface of a spherical or conical shape (hereinafter - ring matrix). On the second transition are stretching the part of the sheet-metal part, which has a smaller radius of curvature, while the use of the ring matrix and spherical punch, the radius of the working surface of which is proportional to the radius of the drawing with regard to the springback of the material and thickness of the workpiece and depends on the Gaussian curvature of a given surface details:
inis the radius of the drawing, m;
R1- set the radius of the middle surface of the plate part in the meridional direction, i.e. in the direction of the generatrix (hereinafter transverse radius), m;
R2- set the radius of the middle surface of the plate part in the circumferential direction (hereinafter longitudinal radius), m;
K is the Gaussian curvature of the middle surface of the plate part, 1/m2.
On the third transition for bended form neognathae part of the sheet-metal part in the meridional direction using spherical punch with the radius of the working surface, is proportional to a given transverse radius R1considering springback, and the matrix in the form of a prism with a cylindrical recess (hereinafter referred to prismatic matrix).
In the particular case of the proposed method for final finishing details on the fourth transition use a stamp, comprising a punch and die working surface which corresponds to the internal and external surface details with regard to the springback of sheet blanks in the circumferential direction, as well as its thickness. However, as shown by experimental work, for parts, wall thickness over 40 mm, subject to the technology in the first three transitions fourth transition may not be necessary.
Thus, in the proposed method, the surface plate part receives the specified double (Gauss is Wu) curvature* after the second transition and does not require further extraction. The third transition is brought to a specified radius, only tore a part of the sheet-metal part in the meridional direction, i.e. they perform the bending curvature in one direction without changing the dual (Gaussian) curvature of the surface plate part. Therefore, the curvature of the surface plate part in the circumferential direction becomes a desired value while receiving a given curvature in the meridional direction, which significantly reduces the complexity of the process while improving the quality of the finished product, and the implementation of formation for several transitions makes it possible to reduce deformations and thinning of the sheet workpiece in the process of its formation.
* The curvature is the reciprocal of the curvature radius.
The whole process is flexible on the most time-consuming the first and second stages of morphogenesis can be implemented on a single die for forming spherical parts, comprising a spherical punch with interchangeable nozzles and annular matrix. This allows to solve the problem of reducing the complexity of the process of forming and metal bending (die) snap-in.
The invention is illustrated by the scheme shown in figure 1 and 2.
1 shows a diagram of forming torispherical details on the second transition, i.e. when drawing the torus sleeve part foxes the OIC procurement. Leaf harvesting (petal) torispherical shape 1 is specified radii: the same radii Rmaxin the latitudinal (district) and the meridional direction in the spherical part of the plate part and the radius Rminin the meridional direction in the torus sleeve side plate part. Radius values in the latitudinal direction in spherical and torus sleeve parts differ slightly.
The forming plate part 1 (figure 1) on the first and second transition is carried out in a universal stamp, including the punch 2 (figure 1) with a spherical surface and an annular matrix 3 (in figure 1 the matrix has a working surface of a spherical shape). The radii of curvature of the working surface of the punch Rpand the matrix Rmless than the specified radius of the sphere of procurement of Rmaxon the first transition and range hoods RBon the second transition by an amount equal to pruginin (elastic aftereffect) workpiece material with regard to its thickness.
Figure 2 shows the scheme of forming torispherical details on the third transition, when do pogibko the torus sleeve side plate part in the meridional direction, i.e. in only one direction using a stamp, comprising a spherical punch 2 (figure 2) and prismatic matrix 4. Pogibko sheet 1 exercise local serial pressed the s to achieve a given radius R minin the meridional direction. In the circumferential direction sheet item is straight and gets the specified radius of curvature in the circumferential direction while receiving a given radius of curvature in the meridional direction.
It should be noted that the radius of curvature of the working surface of the spherical punch on the second transition is chosen smaller than the first and the third transition is smaller than the second, i.e. decreases as the forming plate part.
In the particular case on the latter, as a rule, the fourth transition adjustments are performed shaped sheet-metal part in the bulk are specially manufactured for forming this sheet details the stamp, consisting of a punch and die working surface which repeats the specified form of the sheet-metal part with regard to the springback and the thickness of the sheet stock to adjust the degree of drawing and correcting any skew in the sheet-metal part. Note that this step is not required if flexible sheets developed by the company.
Experimental verification of the proposed method of forming carried out on a regular torispherical petals of steel AK-SU thickness 45-80 mm in OJSC "sevmashpredpriatie". The proposed method is carried out on a hydraulic press with a force of 1500 cu 2000 cu. The sheet-metal part was molded in a cold state, PR is more than three transition. After the second transition plate stock received the required hood, the corresponding dual (Gaussian) curvature of the surface, and after the third transition is finalized. At the first transition of the received spherical surface, the second surface with a given dual (Gaussian) curvature, the third transition tore a part of the surface with a given radius of curvature in the Meridian and at the same time the circumferential direction. With proper operation of all three transitions of the form sheet parts after the third transition met.
Forming at all transitions in successive local presses. All transitions were performed in the cold state of the metal and, as a rule, without heat treatment.
Compared to another possible method of manufacture of such parts - hot stamping, the proposed method allows to reduce in 3-4 times the complexity and cycle parts manufacturing, to ensure harmless and less dangerous working conditions of gershikov, to eliminate or substantially reduce metal loss due to intoxication. The measured strain values in 2-2,5 times lower than during the hot forming, which allows to increase the dimensions of the molded parts and to perform image forming in a cold state without subsequent heat treatment or with mini the actual displacement of the heat treatment in the form of high holidays.
1. Method of forming parts of stamped torispherical shells or elliptical shape by successive local presses a few transitions, characterized in that the first transition receive the spherical surface with radius of curvature equal to the greater of the specified radii on the entire surface of the sheet workpiece, using the ring matrix and spherical punch, the second transition carry out the hood part of the sheet stock, having a smaller radius of curvature, using the ring matrix and spherical punch, the radius of the working surface of which is proportional to the radius of the drawing with regard to the springback of the workpiece material and its thickness and depends on the Gaussian curvature of a given surface details:
where RBis the radius of the drawing, m;
R1- set transverse radius of the middle surface of the plate part, m;
R2- given the longitudinal radius of the middle surface of the plate part, m;
K - dual of the Gaussian curvature of the middle surface of the plate part, 1/m2on the third transition for bended form neognathae part of the sheet-metal part using a spherical punch with the radius of the working surface, is proportional to a given transverse radius R1with regard to spring the Oia and the thickness of the sheet, and prismatic matrix.
2. The method according to claim 1, characterized in that for final finishing sheet parts for the fourth transition use a stamp, comprising a punch and die working surface which corresponds to the internal and external surface details with regard to the springback of sheet parts in the circumferential direction.
SUBSTANCE: formation of parts is performed with pressure and support elements in the form of puncheon and matrix with creation of plastic contact at interaction points of the tool with the workpiece. Pressure is created and allows reaching the workpiece material yield point in sections of the part with single curvature owing to non-tight contact of working surfaces of pressure and support elements. Excess pressure is created in sections of the part with double curvature owing to tight contact of pressure and support elements till the required thinning of those sections is obtained.
EFFECT: increasing intensification of the deformation process.
5 cl, 4 dwg
FIELD: process engineering.
SUBSTANCE: set of invention relates to metal forming and may be used in producing bicurved surface shells. Separate parts are preformed. Here, to compensate for welding strains from welding seam shrinkage, parts made from titanium or steel are produced with undercurved edge while parts from aluminium are made with fluted edges all over their edges in the zone of post-welding deformation with width making 8-10 S where S is part thickness.
EFFECT: higher quality of bicurved surface shells.
8 cl, 6 dwg
FIELD: process engineering.
SUBSTANCE: invention relates to metal forming and can be used in producing bicurved surface sheet structures. Structure surface is divided into separate parts formed by straining the billet. Then produced parts are welded together to produce preset structure. Note here that structure is divided into separate parts to ensure identical thinning of said parts in their deformation. Said thinning in distributed along parabola with its branches starting from the part points located on opposite edges and at the distance of bending and assembling allowances with apex in the zone of the smallest thinning with ordinate equal to least thinning.
EFFECT: higher quality of sheet structures.
6 cl, 5 dwg
FIELD: process engineering.
SUBSTANCE: invention relates to metal forming, particularly, to tube bending. Proposed method comprises the stage of computing, at least, one cycle of instructions related to, at least, one parametre of tube production process depending upon set of data on a tube and set of process data. At least, one 3D geometrical model of, at least, one tube bending machine and appropriate tools is produced governed by, at least, one production parametre derived from cycles of computed bending instructions. To comply with thus computed bending instructions, 3D and kinematic simulation of tube bending is performed, the tube being described by set of data on tube and bending performed by bending machine and appropriate mechanical tools described by appropriate 3D geometrical model. Possibility of producing tube by, at least, one bending machine and appropriate tools is checked up.
EFFECT: higher quality of tube bending.
14 cl, 6 dwg
FIELD: machine building.
SUBSTANCE: device consists of bed plate, of two supports mounted on bed plate and of replaceable puncheons. The bed plate rotates around its axis, is installed in a case and performs vertical travels. The case travels in horizontal plane. The supports are mounted on the bed plate, they converge and rock to centre of the bed plate and back under control. A bracket-shaped frame is rigidly tied with the case. A beam rotating around axis of the bed plate in mounted on the frame. The beam has slots, wherein there are installed lengthwise or two cross puncheons. The puncheons are equipped with shank ends corresponding to slots.
EFFECT: simplification of design avoiding usage of additional mechanisms for hoisting, turn and overturn of treated panel; control over dimension of bend section; upgraded quality of parts.
FIELD: machine building.
SUBSTANCE: form block is made of interconnected sections attached to single platform. A template jig is mounted on guide elements from the side of working surface of the form block; the template jig determines arrangement of base orifices in a sheet work-piece. Removable fixing pins are inserted into base orifices in the sheet work-piece and into corresponding orifices in the form block. Blank-holders fixing a part are positioned on working surface of the form block. The blank-holders are attached by adjusting screws screwed into a threaded fitting, mounted into a body of the form block behind both internal and external contour of the part. A sheet work piece is first fabricated on the form block of the press of cross fringe, and further with mechanical treatment of a machine with programme numerical control using the same form block as process equipment.
EFFECT: upgraded quality of parts.
2 cl, 5 dwg
SUBSTANCE: proposed male die comprises carcass with stiffness ribs. Said carcass represents a frame. Stiffness ribs are support assemblies mounted on the frame and tied by lengthwise stiffness sections. Male die working surface is made from longitudinal set of planks made from wood laminar plastics attached to support assemblies.
EFFECT: higher quality.
SUBSTANCE: invention refers to metal forming operations, particularly to process of shaping metal sphere-toroid or elliptic coating of doubled curvature or shaping their elements from sheet work-pieces. The sheet work-piece is shaped by the procedure of successive local pressing per several passes with specified thinning depending on a grade of work-piece material. At the first pass there is shaped a sphere of the biggest specified radius along total bent surface of the work-piece, then surface of the work-piece is shaped with smaller specified radii of curvature, particularly elliptic and toroid part of coating. The facility consists of a matrix with shaping sections and tapered working surfaces designed to transfer in vertical and flat parallel planes; also the facility consists of a puncheon. Working surfaces of shaping sections are arranged to facilitate projections of width generatrices of the component under the puncheon running along their middle with the puncheon positioned at equal space from working surfaces of central opposite sections.
EFFECT: reduced labour input at shaping hardly deformed components of double curvature.
3 cl, 4 dwg, 1 ex
FIELD: technological processes.
SUBSTANCE: invention pertains to metal forming, particularly to bending of sheet materials having structures that promote bending. Sheet of material has multiple structures that promote bending, which are configured and arranged so that the bending is carried out along the bending line. Structures that promote bending have arched return parts stretched from the opposite ends backwards along structure that promotes bending in direction towards other return part, and each return part has length and radius of curvature that reduce stress concentrations. Length of arched return part exceeds double thickness of sheet. Side distance, for which the structures promoting bending are shaped from the bending line, is minimised by small radiuses of arches, which join return parts with remaining parts of structures that promote bending. The method is also described for shaping of structure from sheet of material, so that it resists cyclic load, as well as method to increase resistance of structure fatigue developed by bending of material sheet along bending line, having multiple structures that promote bending.
EFFECT: quality improves as a result of better configuration and improved resistance to fatigue.
32 cl, 8 dwg
SUBSTANCE: invention relates to metal deformation process, particularly to methods of bending and finishing of bended flat-pattern parts and can be used in different branches of mechanical engineering and construction during the manufacturing of box-like and tubular parts. At the first pass it is implemented shaping by means of mandrel with receiving of required necking of blank section, at the second pass it is implemented bending of blank by generatrix of detail, starting from its edges, and then by middle line of part. At the third pass there are removed unavoidable at the first and the second pass undesirable warpings of part ensured by changing of pressure-bearing and bearing deformation element, approximating radius of pressure-bearing element to specified radius in cross direction of part.
EFFECT: there are extended process capabilities, provided reduction of material- and energy intensity of bending prociesses.
2 dwg, 1 tbl
FIELD: plastic working of metals, namely processes for bending, finishing and controlling contour of bent sheet parts.
SUBSTANCE: method comprises steps of shaping double-curvature sheet parts by two transitions; at first transition forming cylindrical or cone curvature across blank without thinning it while under-bending blank by value equal to 1/3 of predetermined curvature of part in the same direction; at second transition further deforming blank and thinning it in direction normal relative to direction of blank deforming at first transition during process of rotary local or successive local deforming; selecting upper deforming member whose curvature is less than predetermined one in cross and longitudinal directions at least by springing value; controlling contour by means of gages in cross sections of blank.
EFFECT: lowered time period of bending piece blank, reduced labor consumption and bending effort, lowered power consumption of process.
4 cl, 4 dwg, 1 tbl
FIELD: plastic working of metals.
SUBSTANCE: method is realized due to applying successive local bending efforts during one or several transitions along bending lines and performing rotary local deforming between engaging deforming members. At least one pressure member is in the form of roller with curvature radius in cross direction less than curvature radius of part in the same direction. Axis for applying bending efforts is directed along lines normal relative to bending lines in plane and to plane of bent blank. Bending efforts are applied beginning from shortest butt cross edge of blank. Above mentioned bending lines divide cross section of blank by even number of pieces whose length is equal to bending pitch or proportional to it. Lengthwise edges of grooves are selected as near as possible to curvature lines of part surface with maximum and minimum curvature radius in each point.
EFFECT: lowered labor consumption of process for shaping sheet parts.
3 cl, 3 dwg
FIELD: plastic working of metals.
SUBSTANCE: method for making welded structure with curvilinear surface having metallic sheets with parts welded to them comprises steps of shaping by successive or rotary application of local bending efforts during one or several transitions along surface area of structure; initially welding sheets one to other and welding parts arranged on sheet surface to said sheets; then performing formation of structure while by-passing welded joints and starting such motion of upper deforming member that it is to be in position being the nearest relative to welded parts in edges and ends of sheet; using pressure roller or punch as upper deforming member; using roller or double-support beam as lower deforming member; welding parts adjoined to curved surface of structure.
EFFECT: enhanced accuracy of preset curvilinear surfaces of structure, simplified manufacturing process due to reduced number of transitions.
4 cl, 3 dwg
FIELD: plastic working of metals, possibly shaping portions of main pipelines, making metallic columns with round or polyhedral cross section.
SUBSTANCE: method comprises steps of bending blank by rotary local deforming of it in parallel relative to its lengthwise edges; beginning bending of blank by alternatively bending up its lengthwise edges; then performing next step of bending of blank from each bent-up lengthwise edge until mean part of blank. Apparatus for performing the method includes mutually engaging upper and lower deforming units. Upper deforming unit is in the form of pressure roller type device and it is mounted on rod of power drive with possibility of reciprocation motion in vertical plane. Lower deforming unit is in the form of drive roller or two -support beam. Pressure roller type device is joined with rod of power drive through cutter-like yoke that is formed according to condition of closing lengthwise edges of sheet blank with it.
EFFECT: lowered labor consumption of manufacturing process.
7 cl, 1 tbl, 5 dwg
FIELD: plastic working of metals, possibly manufacture of double-curvature articles in creep mode.
SUBSTANCE: apparatus includes shaping chamber with working organs forming single-row modules; hydraulic drives; units for providing differential degree of said drives; normalizing devices. The last include screw gages with step motors mounted in single-row modules of working organs. Communication circuits of hydraulic drive include phase mains of power hydraulic cylinders, phase mains of return hydraulic cylinders and mains for communicating four-phase systems with pressure and drainage source. Constant-pressure main lines and phase main lines are mutually communicated through hydraulic distributors and other aggregates of hydraulic systems.
EFFECT: enhanced reliability of controlling, simplified program control, enlarged assortment of shaped products.
5 cl, 19 dwg
FIELD: plastic working of metals.
SUBSTANCE: method comprises steps of controlling combined process of bending and tensioning shaped parts along path corrected while taking into account mechanical parameters of blank material determined according to pickups readings received during process of preliminary tension.
EFFECT: enhanced accuracy of article shape, improved recurrence of results of shaping parts.
FIELD: plastic metal working: manufacture of shell members for welded structures.
SUBSTANCE: proposed method of forming double curvature sheet parts by application of successive local bending forces at one or several passes includes preliminary cutting out of middle part of blank is place of expected maximum thinning. Then parts of blank are formed separately after which integrity of part is restored by welding.
EFFECT: improved quality of parts owing to reduction of thinning.
4 cl, 6 dwg
FIELD: plastic metal working.
SUBSTANCE: invention can be used for manufacture of single and double curvature sheet parts. Proposed method includes series or rotary-local deformation of blank on support deforming member with simultaneous displacement of blank or forming tool relative to each other. Contact compression stresses are created in pattern of plastic contact of tool and blank, stresses are to reach yield point of blank material. Invention reduces number of passes which provides decrease of production expenses and optimization of applied forces at which contact compressing forces reach yield point of blank material.
EFFECT: enhanced operation reliability.
5 cl, 3 dwg
FIELD: plastic metal working.
SUBSTANCE: invention can be used for bending and straightening of rolled sections and strips. According to proposed method of bending, blank is moved longitudinally, and bending forces and counteracting forces spaced relative to bending forces are applied square to flange of blank determining outer radius of bending and parallel to its free walls. Hindering forces are applied in place of action of bending force square to free walls of blank to decrease buckling. Device provided with pressure and support deforming members made in form of rollers whose shape corresponds to cross section of parts under bending has slots in pressure roller with widening from roll axis for free walls of blank.
EFFECT: improved quality of product owing to reduced buckling of free walls of section and specific consumption of material and power.
10 cl, 1 tbl, 3 dwg
FIELD: plastic metal working, namely processes for making double-curvature parts by stretching sheet blanks.
SUBSTANCE: method comprises steps of combined deforming of blank with cover plate on punch of stretching press and then removing cover plate; using cover plate in the form of two flexible sheets preliminarily placed onto punch of stretching press with possibility of moving on its surface; fixing one end of each sheet of cover plate in clamps of press together with sheet blank; after removal of cover plate finally deforming sheet blank for forming target contour part. Method allows form double-curvature parts with highly uniform elongation deformation of blank.
EFFECT: enhanced efficiency of process at keeping physical and mechanical properties of material and at maximally using deformation capability of material.
2 dwg, 1 ex