SE516734C2 - Material is molded using an impact machine having an upper ram unit and lower ram unit which move towards each other at velocities such that their respective momentums are about equal - Google Patents

Abstract

Material is cavity molded on an impact machine in which an upper ram unit and punch and a lower ram unit and punch move towards each other with respective velocities such that their momentums (mass x velocity) are about equal. The total kinetic energy developed by each ram unit is transferred to the material in the mold cavity, causing the material to plasticise and flow, and fill the cavity.

Description

ven »~ wav» u- v u u-u »v ~. n 10 15 20 25 30 35.: I. šPIESU tool inserts in the tool unit, adjusting the height of the percussion unit above the tool unit, etc. The purpose of the invention is to address the above problem complex. More specifically, the invention aims to achieve primarily the following advantages: - to achieve that the kinetic energy of cheerleaders can essentially be used for efficient work in the processing of a working material instead of being lost in tools and peripherals, such as in stands and foundations, which in in turn can create improved opportunities to process and / or shape materials that previously could not be processed and / or formed to the desired degree - to counteract shock waves from the blow via machine stands, which in turn provides the opportunity to have significantly lighter stands and to eliminate heavy platforms , which according to the prior art had the task of dealing with shock waves, - to reduce the total mass of the machine compared to known, comparable percussion machines, including reducing the sizes of the percussion units, while lower percussion speeds can be used to achieve the desired processing, - ability to compact metal powder or other moldable powder, such as ceramic powder or composite take powders consisting mainly of powders of metal, ceramic and / or polymer, to a higher and more even density than has been possible with prior art due to energy losses in tools and peripherals, and - the possibility of designing the percussion units so that superimposition of shock waves occurs , which increases the effect of the impact units on the working material.

The characteristic of the method according to the invention is that the upper cheerleader and the lower cheerleader are simultaneously made to perform a single stroke at such a speed against an upper impactor, which is integrated with or pressed against the upper punch, and against a lower impactor, which is integrated with or pressed against the lower punch, that the masses moving downwards, including the upper punch, have a downward speed v1 and the masses moving upwards, including the lower punch, have an upward speed V2, the movable parts having such masses and the velocities are so great that the impulses of the downwardly moving masses and the upwardly moving masses become substantially equal, i.e. so that the following relation applies: mjXVlzmgXVg 10 15 20 25 30 35 516 734 3 '..' J .. 2P125l7 where m; is the total mass of the downwardly moving masses during the stroke and m2 is the total mass of the upwardly moving masses during the stroke, 2 2 ... . . . m vi m V2 ._. that the kinetic energies of the turbulent masses, i.e. ïl-q and å *, respectively, are substantially transferred to the working material in the mold cavity and are so large that the working material is plasticized and fl expands and fills all parts of the mold cavity, when the punches are maximally joined, to form said body of desired shape, and the matrix is substantially stationary during the said kind.

Preferably, before the impact, the upper punch and the lower punch are pressed with a static pressure from above and below against the working material in the forming cavity by a downward force exerted on the upper impact body and by an upward force fl exerted on the lower impact body.

What is particularly characteristic of the percussion machine according to the invention is that the upper and lower percussion units can be adjustably raised and lowered by means of elevator means relative to the central, stationary unit for setting predetermined stroke lengths of the upper hoist and of the lower hoist before the forming operation.

Due to the short duration of the pressure pulse, when according to the invention the material in the forming cavity is processed in a symmetrical manner with the addition effect with impulses from two directions, the risk of the high pressure deflating the tool due to the mass inertia of the tool material is reduced. This allows a higher pressure in the forming cavity than can be allowed in known techniques with high kinetic energy forming, thereby increasing the possibility of plasticizing the machining material in the forming cavity. Due to the fast material processing, when the tool geometry allows such, there is also significantly less friction between tool and machining material, and, in the case where the machining material consists of powder, also less friction between powder commas, which means that you can get significantly better yield in the formation and consolidation process, ie that more energy can be made to act on the processing material. In an uncontrolled process and with incorrect tool geometry, there is a great risk that the tool will break due to large frictional forces.

Characteristic of the method according to the invention is thus that a very high forming pressure is applied symmetrically from two directions and is allowed to act on the material to be formed or consolidated with minimal losses due to friction, mass scars and high frequency 10 15 20 25 30 35 516 734 4 '. .J .. 2P1§517 wave propagation caused by impact-initiated resonances in tool details and surrounding machine and stand. Thus, a very high forming pressure can be allowed to operate in the tool chamber / forming cavity without failing the tool parts, due to extremely short duration of forming impulse and mass inertia of the included tool parts.

A preferred embodiment of the percussion machine is characterized in that the upper percussion unit comprises an upper percussion unit, that the lower percussion unit comprises a lower percussion body, that the upper punch and the lower punch are arranged to be brought into contact with the working material in the forming cavity in the matrix. the upper impactor and the lower impactor have, or are arranged to be brought into direct or indirect mechanical contact with the upper punch and with the lower punch at the latest in the operating positions of the impactors before the forming operation, then said stroke lengths of the cheerleaders are the upper impact body in the latter's operating position, and the distance of the lower impactor to the lower impact body in the latter's operating position, respectively.

Said lifting means are suitably hydraulically operating and can thus help to dampen any shock waves arising during the forming operation and may comprise at least two upper hydraulic lyne cylinders and associated vertical upper piston rods, which are included in an upper frame unit and support an upper carrier for the upper the percussion unit, and at least two upper, hydraulic lifting cylinders and associated vertical lower piston rods, which can be included in a lower frame unit to support a lower carrier for the lower percussion unit. The piston rods form pillars in the frame, which can be made very slender. The number of such pillars / piston rods and associated hydraulic cylinders may be increased to more than two, but not more than four to enhance the stability of the machine. Alternatively, special guides can be provided to increase stability, especially laterally. The hydraulic cylinders can either be stationary and fixedly connected to the foundation, the piston rods / pillars being height-adjustable relative to the foundation or being stationary. In the latter case, the piston rods are suitably designed as continuous piston rods in hydraulic cylinders, which are mechanically connected to said carrier, which carries the impact units, as according to the principle described in Swedish patent application no. 0001560-2 by the same applicant, which is hereby incorporated into the present patent application by reference.

The geometry of the tool cavity in the tool can be of significant importance to allow rapid material processing. If, for example, the forming cavity narrows in the direction of movement of the punches, very high frictional forces can occur between the walls of the forming cavity and the material being processed. The forming can, however, continue in other parts of the tool during the duration of the impulse, due to the law of least resistance, until high frictional forces have built up in the remaining tool parts and thereby counteracted the forming forces. In some cases of powder material, frictional forces between the powder grains can cause sintering with inappropriate tool geometry. In an uncontrolled process and with incorrect tool geometry, there is also a risk that the tool will break due to large frictional forces. In the embodiment which will be shown in the following, the forming cavity has a cylindrical geometry, a geometry which may be desirable for the manufacture of products with a final or near final shape, but from a material processing point of view a forming cavity which widens in the direction of punching is more ideal. , since the frictional forces of such a geometry can be minimized. In addition, when forming solid blanks, the blank should have a smaller radial extent than the tool cavity to enable the blank to be plasticized, before contact occurs with the side walls of the mold cavity. If an annular product is to be made of a solid substance, the substance should be in the form of a ring, the outer diameter of which is smaller than the diameter of the tool cavity and the inner diameter of which is greater than the diameter of the mandrel in the center of the tool, all to eliminate friction against the side wall of the forming cavity and against the mandrel initially.

Additional features and aspects and advantages of the invention will also be apparent from the dependent claims and from the following description of a preferred embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS In the following description of a preferred embodiment, reference will be made to the accompanying drawing figures, of which Fig. 1 is a side view, partly schematic, of the percussion machine according to the preferred embodiment of the invention, Figs. 2A and Fig. 2B show parts of the percussion units and a central, stationary, functional unit during two different steps before the work stroke / mold operation, Fig. 3 is a perspective view of a central, functional unit included in the machine, and Fig. 4 shows the functional unit in cross-section along a views IV-IV in Fig. 3. 10 15 20 25 30 35 516 734 6 '..' J .. 2PlZ517 DESCRIPTION OF PREFERRED EMBODIMENT Referring first to Fig. 1, a percussion machine is generally designated by the number 1. Its main parts consist of a upper percussion unit 2, a lower percussion unit 3, a middle unit 4, an upper frame 6 consisting of a pair of upper rods 8, which consist of a pair of piston rods, and a lower frame 7 consisting of a pair of lower rods 9, which also consists of a pair of piston rods. A foundation has been designated 5.

The upper striking unit 2 comprises a yoke 10 on the piston rods 8 and can be raised and lowered with a pair of upper, hydraulic ly-cylinders 12, which are connected to the foundation 5 and whose hydraulic chambers are filled with and emptied of hydraulic fluid via hydraulic lines extending through the piston rods 8 and yoke 10 from and to pressure source and tank respectively.

The yoke 10 carries an upper hydraulic percussion cylinder 13 connected to the yoke, which contains an upper pusher in the form of a percussion piston 14. An upper percussion body is designated 15. This is movable in an upper percussion cylinder 16. An upper punch 17 is interchangeably connected to the impact body 15. The upper impact cylinder 16 is fixedly connected to the upper impact cylinder 13.

The lower striking unit 3 comprises a lower yoke 20, which hangs in the rods 9, which consist of a pair of piston rods, which can be raised and lowered with a pair of lower, hydraulic ly-cylinders 12, which are also connected to the foundation 5 and which are filled and emptied. on hydraulic fluid via hydraulic lines through the piston rods 9 and the yoke 20 from and to the pressure source and tank respectively. The yoke 20 carries a lower, hydraulic percussion cylinder 23 associated with the yoke, which contains a lower pusher in the form of a percussion piston 24. A lower percussion body is designated 25. This is movable in a lower percussion cylinder 26.

The middle unit 4 comprises a table 30, which may be movable in the horizontal plane but in principle immovable in the vertical direction; however, that means are provided to allow a certain fi resilience in the vertical direction. The means for movements in the horizontal plane and for suspension in the vertical direction have been shown only symbolically in Fig. 1 and are designated 31.

The table 30 contains and carries a number of identical, functional units 32. Such a functional unit is shown in detail in Fig. 3 and Fig. 4 and more schematically in Fig. 1. The main parts of the functional unit 32 shown in Fig. 1 comprise a lower, tubular punch 27, a die 34, a sub-punch holder 36 slidably movable in a punch holder guide 37, and a mandrel 35.

The base holder 36, Fig. 3 and Fig. 4, consists of two identical halves 36a and 36b, which are pressed almost into abutment against each other in a vertical dividing plane, 10 15 20 25 30 35 5167734 '..' J .. 2Pl25l7 dels in the area of the upper part of the punch, which comprises almost half of the length of the punch, partly in a lower part with a short vertical extent. Between these upper and lower parts, both halves of the punch holder are milled out to form a vertical, continuous groove 39 with a substantial extent in the vertical direction. There is also a vertical, central groove in each punch half 36a and 36b, such as the groove 40a in the punch half 36a.

The opposite groove 40b in the punch holder half 36b is not shown in fi gur. Together, the grooves 39 and 40a / 40b allow the punch 36 to move in a vertical direction relative to the mandrel 35. In their upper part, each punch half 36a and 36b has an outwardly facing end 41 and a central recess 42 which widens in its bottom part for to accommodate a correspondingly shaped skull 43 in the lower end of the lower punch 27. Together, the two punch holder halves 36a and 36b hold the lower punch 27.

The illustrated example relates to the manufacture of products with a through hole, such as gears. The mandrel 27 is therefore tubular, and the mandrel 35 extends through the mandrel. In the matrix 34 there is a continuous, cylindrical hole 45, the walls of which correspond to the external shape of the desired product, e.g. a gear. The shape of the hole 45 also corresponds to the outer shape of the lower punch 27 over the skull 43 and of the upper punch 17, which, like the lower punch 27, has the shape of a tubular sleeve.

The mandrel 35 has an elongate cylindrical upper part extending through the lower punch and up into the forming cavity 46 defined by the hole 45 in the die 34 between the two punches 17 and 27. In its lower part the mandrel has a thicker portion, here called grip part 47, showing a circumferential indentation 48.

The punch guide 37 consists of an upper part 37a and a lower part 37b. The two parts 37a and 37b are internally cylindrical. The upper part 37a has a larger diameter than the lower part 37b. The parts 37a and 37b constitute guides for the end portion 41 and the main part of the base holder 36, respectively, which have corresponding cylindrical outer shapes. The lower part 37b also functions in combination with the end portion 41 of the base holder also as a retainer of the base holder. The two parts 37a and 37b are connected to each other by bolted joints 55.

In the lower part of the lower part 37b of the punch guide guide there are a pair of opposite recesses for a pair of opposite wedges 49, which are pressed into the indentation 48 in the grip part 47 of the mandrel 35.

The pressing-in collar is obtained by means of a locking ring 50 and a bushing ring 51 of polyurethane or other material with a certain flexibility. The wedges 49 allow a certain suspension 10 15 20 25 30 35 516 8734: Pfsiv due to frictional forces that can be exerted on the mandrel 35 during the working of the machine.

From the locking ring 50, a number of guide pins 52 extend up through the punch holder guide 37 to hold the locking ring in its rotational position relative to the punch holder guide, as the locking ring 50 is loosened and displaced axially for pulling out the wedges 49 in connection with replacement and / or lower punch 27. There are also a number of upper guide pins 53 extending up from the punch guide 37 and further up the table 30. Finally, there are also bolts 54 for clamping the entire unit 32 in the table 30 fi 'on the underside.

The upper strut body 15 consists of a continuous cylindrical piston rod 60 with a fixed ring 61. The piston rod 60 is sealed slidably in an opening in an upper end wall 62 in the upper strut cylinder 16. In a lower end wall 63 there is a further opening 64, through which the cylindrical piston rod 60 of the impactor 15 can be moved without sealing. The fixed ring 61 has a diameter which is slightly smaller than the inner diameter of the impactor cylinder 16, i.e. the fixed ring 61 does not abut sealingly against the inside of the cylinder. Above the fixed ring 61, on the other hand, there is a movable ring 65, which can move relative to the piston rod 60 and which seals against the inside of the impactor cylinder 16, either directly or via one or more of its sealing rings. The inside of the movable ring 65 is also sealed against the piston rod 60, either by direct sealing abutment or via some sealing ring (not shown). Above the movable ring 65 is a hydraulic chamber 66, which is connected to a pressure source for hydraulic fluid via a hydraulic line 67, in which there is a non-return valve 68 and a pressure-reducing valve, not shown, and to the tank or accumulator via a hydraulic line 69. , in which there is a pressure relief valve (not shown).

The lower percussion body 25 and its percussion cylinder 26 are designed in an identical manner to the upper percussion body 15 and the percussion cylinder 16, respectively, except that the lower punch 27 is not directly attached to the percussion body, as is the case with the upper punch 17 in the upper percussion body. In Figs. 2A and 2B, the various details of the impactor 25 and the impactor cylinder 26 have been given the same reference numerals as in the upper impactor 15 and the impactor cylinder 16 with the extension '. No further description of these parts is made here but reference is made to the above description of the upper impact body 15 and its impact body cylinder 16. Regarding the terminology, however, it should be mentioned that the end walls 62 'and 63' in the lower impact cylinder 26 shall be referred to as the lower end wall. respective upper end wall.

The equipment also includes control and operating means for the described, movable units, including position sensors 80, 80 "for the impact cylinders 13, respectively 23 and 10 15 20 25 30 35 5169 734" ': P1: 517 thus also for the brakes 14 and 24 respectively and position sensors 81 and 81 'for the percussion bodies 15 and 25, respectively. These are connected to and convey information about the position of said units to a central control unit, which comprises computers and associated means, which will not be described here.

The equipment described works as follows. In a previous operation, the space 46 in the die hole 45, Fig. 4, has been filled with working material 90 around the mandrel 35.

The working material 90 can consist of e.g. a ring of metal, polymer or of a composite material, which may comprise ceramic or other malleable material, but in the example it is assumed that the working material consists of a metal powder, possibly a composition of metal and ceramic powder. Initially, the lower yoke 20 is raised by means of the lower ly cylinders 22, and the piston rods 9, carrying the lower impact cylinder 23 and its impact body 25, until the impact body 25 is brought into contact with the underside of the base holder 36, Figs. 1 and Fig. 2A. Thereafter, the upper yoke 10 is lowered by means of the upper lifting cylinders 12 and the piston rods 8, causing the upper impact body cylinder 16 and its impact body 15 so far that the upper tubular punch 17 is lowered into contact with the metal powder 90 in the mold cavity 46 and begins compress the powder, until the pressure in the hydraulic chamber 66 reaches a predetermined value.

The movement is stopped and the position is maintained. The lower punch 27 settles at this moment in the position shown in Fig. 2A, positioned by the lower punch unit 7 and creates the abutting force.

The yoke 24 now begins to move upwards by means of the ly-cylinders 22, the lower punch being pressed upwards against the powder 90. The movement continues until the pressure in the hydraulic chamber 66 'has reached a certain, predetermined value. This pressure has then also been transmitted via the powder 90 to the hydraulic chamber 66 of the upper percussion unit. The powder 90 is thus pre-compressed and centered in the mold cavity 46 in the die 34. The percussion bodies 15/25, the hydraulic cylinders 16/26 and the punches 17/27 are now located in de i F ig. 2A showed the positions.

The next operation involves setting the stroke lengths S1 and S2 of the cheerleaders 14 and 24, ie the distance between the upper cheerleader 14 and the upper striker body 15, and between the lower striker 24 and the lower striker body 25 before the stroke, respectively. This can be done simultaneously for the upper 2 and the lower 3 impact unit by pressing the yokes 10 and 20 further downwards and upwards by means of the hydraulic cylinders 12 and 22, respectively. The pre-compressed powder 90 exerts a back pressure on the punches 17 and 27, whereby the pressure in the hydraulic chambers 66 and 66 'increase further. The overpressure is relieved by the hydraulic lines 69 and 69 '. The punches 17 and 27 will thereby 10 15 20 25 30 35 51 6 73 4; §§; ¿§;.; ':; == 10 Pl5l7 retain their positions, while the percussion pistons / hejama 14 and 24 approach the percussion bodies 15 and 25, respectively. , until its correct strokes S1 and S2, Fig. 2B, have been obtained, which is registered by the upper and lower position sensors 80, 81 and 80 ', 81', respectively. The difference in pressure between the lower and upper hydraulic chambers 66 'and 66 is chosen so small that this does not affect the strokes to any negligible degree.

Thus, when the intended strokes S1 and S2 have been reached, the rings 61 and 65 of the upper striker 15 are in an upper position and the two rings 61 'and 65' of the lower striker 25 are in a lower position in the hydraulic cylinders 16 and 26, respectively, Fig. 2B, The beating machine is now ready to consolidate the powder 90 into a single, simultaneous stroke of the two brackets 14 and 24 to form the desired article.

The distances S1 and S2 constitute the acceleration distances of the hammers / percussion pistons 14 and 24 and are so selected, taking into account mainly the masses of the cheerleaders and the impact bodies, that the total mass m1 of the upper impactor 14, the upper impact body 15 and the upper punch 17 obtains a downward velocity vi, when the cheerleader 14 hits the impact body 15, and the total mass m2 of the lower cheerleader 24, the lower impact body 25, the lower punch 27 and the lower punch holder 36 has an upward velocity V2 when the cheerleader hits the impact body, the masses and velocities being so large that the impulses (amounts of movement) of the masses moving downwards, respectively moving upwards, are substantially equal, ie. so that the following relationship applies: III | XV1ZITI2XV2 The upper cheerleader 14, which has substantially greater mass than the upper impactor 15, thus strikes the upper impactor 15 at a very high speed, while the lower cheerleader 24, which also has a much larger mass than the lower impact body 25, strikes the lower impact body 25 at a very high speed. The kinetic energies of the moving masses, which are very large, are transmitted via the upper punch 17 and the lower punch 27 to the powder 90. Hi ama 14 and 24 performs only one stroke, but the kinetic energies which are substantially transferred to the metal powder 90 in the mold cavity 46 are so large that the powder is plasticized, whereby it expands and fills the mold cavity to form a consolidated body of the desired shape in a few milliseconds.

The pressure pulse which occurs in the forming cavity due to the only impact of the cheers against the impact bodies has a duration which is less than 0.001 sec but has a magnitude in the range 1-10 GPa, typically in the range 1.5-5 GPa. Due to the high pressure and the plasticization caused as a result, the friction between the working material is also reduced / 10 15 20 25 30 35 516 7 s 4 - i? ëë - ll Pl5l7 the powder and the walls of the forming cavity, and between the powder cups, which contributes to or is a prerequisite for the material to be able to surface and fulfill all parts of the mold cavity. During the stroke, the mandrel 35 is substantially stationary relative to the die 34, as well as during the pre-compression of the powder, which is possible in that the lower punch holder is movable relative to the mandrel held by the wedges 49 in the groove 39 in the punch holder.

At the same time as the desired body is formed almost instantaneously by striking masses of substantially equal impulse from opposite directions towards the working material, shock waves of such magnitude are prevented that they can damage components in the machine and substantially prevent kinetic energy of the moving masses from spreading. to and lost in machine and foundation. This is due to the fact that the shock waves that can occur are counter-directed and that they can therefore significantly cancel each other out. In addition, the hydraulic medium in the lifting cylinders 12 and 22 dampens the shock waves which may remain and which propagate via the direction of the machine frame towards the foundation 5. By superimposing the shock waves generated by the two simultaneously acting impact units, the impact and compaction effect of the impact also increases. These conditions make it possible to design the whole machine as easily as illustrated by the example.

At high speed strokes of the impact members 15 and 25, respectively, the cylindrical piston rods 60 and 60 'of the impact members move freely relative to the movable rings 65 and 65', respectively, which during the impact remain substantially in the positions they had before the impact, Figs. 2B. A smaller gap occurs between on the one hand the remaining movable rings 65 and 65 'and on the other hand the fixed rings 61 and 61', corresponding to the final compression of the powder 90 in the vertical direction during the stroke.

As soon as the brackets 14 and 24 have performed their simultaneous strokes, they are returned to their initial positions in the upper 13 and in the lower stroke cylinder 23, respectively. The yokes 10 and 20 are returned to their initial positions by means of ly cylinders 12 and 22. Pressure both hydraulic chambers 66 and 66 ', so that the movable rings 65 and 65' are pressed downwards and upwards, respectively, into contact with the fixed rings 61 and 61 ', after which the movable rings press the entire impact bodies 15 and 25 to their initial positions, in which the fixed rings 61 and 61 "have contact with the end wall 63 and 63", respectively. The work cycle has thus been completed, after which the functional unit 32 can be moved to a new station, in which the molded product is ejected from the mold cavity 46.

Claims (16)

10 15 20 25 30 35 516 734 l2 PATENT CLAIMS A method of forming a body of a moldable working material in a percussion machine comprising an upper percussion unit (2) with an upper percussion unit (14), a lower percussion unit (3) with a lower percussion unit (24) and a middle unit (4). ) with a matrix (34) with a through hole (45) which together with an upper punch (17) and a lower punch (27) form a found cavity for the working material, characterized in that the upper and the lower cheerleaders simultaneously is made to perform a single stroke at such a speed against an upper percussion body (15), which is integrated with or pressed against the upper punch, and against a lower percussion body (25), which is integrated with or pressed against the lower punch, that the masses moving downwards, including the upper punch (17) has a downward velocity (V1) and the masses moving upwards, including the lower punch (27) have an upward speed (V2), the movable parts having such masses and the velocities are so great that the impulses of the downwardly moving masses o ch the upwardly moving masses become substantially equal, i.e. so that the following relationship applies: IIHXWIITIZXV; where m, is the total mass of the downwardly moving masses during the stroke and m2 is the total mass of the upwardly moving masses during the stroke, ... . . . m, v12 m2 v22 ._. that the disturbing energies of the masses, i.e. -2--, respectively 7-, vasenthgen are transferred to the working material in the forming cavity and are so large that the working material is plasticized and flows out and fills all parts of the forming cavity, when the punches are maximally joined, to form said body of desired shape, and that the matrix is stationary during said type. 2. A method according to claim 1, characterized in that the upper punch and the lower punch are pressed before the impact with a static pressure from above and below against the working material in the mold cavity by a downward force exerted on the upper percussion body (15) and by an upward force exerted on the lower impact body (25). 3. A method according to claim 1, characterized in that the distance (S1) between the upper cheerleader (14) and the upper striker (15) and the distance (S2) between the lower cheerleader (24) and the lower striker (25) is set to certain predetermined distances, which constitute the strokes of the cheers during the stroke, after the upper punch and the lower punch have been brought into contact with the working material in the forming cavity. 4. A method according to claim 3, characterized in that the upper striker (15) and the lower striker (25) are arranged in an upper, hydraulic striker cylinder (16), respectively in a lower, hydraulic striker cylinder (26), that said impactor cylinders have an upper and a lower hydraulic core core (66, 66 '), respectively, containing a hydraulic fluid which, during an initial pressing of the upper punch and the lower punch against the working material in the pouring cavity, exerts a force on the impact bodies (15, 25). , which is transmitted via the upper punch (17) and the lower punch (27) as a pressure exerted on the working material in the mold cavity. 5. A method according to claim 1, characterized in that the lower percussion body (25) abuts against a sub-punch holder (36) before the stroke, and that the sub-punch is attached to the sub-punch holder. 6. A method according to claim 4, characterized in that the strokes are adjusted by means of hydraulic lifting means (12, 8, 22, 9), which support the upper and the lower striking unit, respectively, which hydraulic lifting means are also included as supporting elements of a stand (6, 7). Percussion machine for forming a body of moldable working material by percussion action in a forming operation, comprising a machine frame (6, 7), an upper percussion unit (2) with an upper pusher (14), a lower percussion unit (3) with a lower pile (24) and a central unit (32) stationary during molding with a forming tool between the upper and lower percussion units, the forming tool comprising a die (34) having a through hole (45) which, together with an upper punch (17), ) and a lower punch (27) form a forming cavity (46) for the working material (90), characterized in that the upper and lower percussion units are adjustably height-adjustable by means of elevator means (12, 8, 22, 9) relative to the central , the stationary unit for setting predetermined strokes (S1, S2) of the upper boom, and of the lower boom, respectively, before the founding operation. Percussion machine according to claim 7, characterized in that the upper percussion unit comprises an upper percussion body (15), that the lower percussion unit comprises a lower percussion body (25), that the upper punch (17) and the lower punch (27) are arranged that before the forming operation is brought into contact with the working material (90) in the forming cavity (46) in the die (34), that the upper impact body and the lower impact body have, or are. .c.-. ~ - now 10 15 20 25 30 35 516 734; æ¿.šíæïíä%ßbbeï@^ 14 P15l7 arranged to be brought into direct or indirect mechanical contact with the upper punch and with the lower punch at the latest in the functional positions of the impact bodies before the forming operation, that said stroke lengths (S1, S2) of the cheerleaders consist of the distance of the upper cheerleader to the upper impactor in the latter position of operation, and of the distance of the lower cheerleader to the lower impactor in the mode of operation of the latter. Impact machine according to claim 8, characterized in that - the stroke length (S1) of the upper cheerleader is so great that the upper cheerleader is accelerated by means of the cheerleader movement means (13) to such a speed that the upper parts which are movable during the forming operation and which include the upper cheerleader the upper impact body and the upper punch, and has a certain total mass (m1), obtains a certain predetermined speed (v1), - that the stroke of the lower cheerleader (S2) is so large that the lower cheerleader by means of the cheerleader's moving means (23 ) is accelerated to such a speed that the upper parts which are movable during the forming operation and which include the lower lever, the lower impact body and the lower punch, and have a certain total mass (m2), obtain a certain predetermined speed (v2), - that said masses (m1, m2) and velocities (v1, v2) are so large that the impulses of the downwardly moving masses (m1) and the upwardly moving masses (m2) become substantially equal, i.e. so that the following relationship applies: IT11 X V1 In m2 X V2 where m1 is the total mass of the downwardly moving masses during the stroke and m2 is the total mass of the upwardly moving masses during the stroke, 2 2 ._. . . . m vi m v2 ._. that the kinetic energies of the moving masses, i.e. ï'- and -22--, respectively, are substantially transferred to the working material (90) in the forming cavity (46) and are so large that the working material is plasticized and fl surfaces and fills all parts of the forming cavity, when the punches are maximally joined, to form said body with desired shape. Percussion machine according to any one of claims (7-9), characterized in that said lifting means are hydraulically operating and comprise at least two upper, hydraulic lifting cylinders (12) and associated vertical, upper piston rods (8), which are included in an upper frame unit (6) and supports an upper carrier (10) for the upper impact unit (2), partly at least two upper, hydraulic lifting cylinders (22) and associated vertical, lower 10 15 20 25 516 734 15 Pl5l7 piston rods (9), which is part of a lower frame unit (7) and carries a lower carrier (20) for the lower striking unit (3). Percussion machine according to any one of claims 7-10, characterized in that the upper percussion body (15) is arranged in an upper hydraulic percussion cylinder (16), which is fixedly connected to said upper carrier (10) and that it the lower impact body (25) is arranged in a lower, hydraulic impact body cylinder (26), which is fixedly connected to the lower carrier (20). A percussion machine according to any one of claims 7 to 1 for the manufacture of an annular body, characterized in that the two punches are tubular, in that a mandrel (47) extends up into the mold cavity through the lower punch, and in that the mandrel is substantially stationary during the forming operation. Percussion machine according to claim 12, characterized in that the lower punch is attached to a punch holder (36), that the lower punch holder is vertically movable in a punch holder guide (37), which is stationary, and that the mandrel is interchangeably mounted in the punch holder guide. Percussion machine according to one of Claims 7 to 13, characterized in that the forming cavity has a cylindrical geometry. Percussion machine according to one of Claims 7 to 13, characterized in that the forming cavity widens in the direction of movement of the punches during the stroke. Percussion machine according to claim 13, characterized in that the base holder (36) is divisible in a vertical center plane.