Method for multi-phase radial forming of a workpiece using a machine radial press

Abstract

A process for the multi-phase radial forming of a workpiece using a machine-driven radial press comprises placing the workpiece in a workpiece holding chamber, closing the radial press tool by means of a drive unit in a first process phase (I) until all press jaws are in contact with the workpiece, and continuing to close the radial press tool by means of the drive unit in a second process phase (II) with increasing pressing force (F), resulting in initial elastic and then plastic deformation of the workpiece. In a third process phase (III), the drive unit is controlled by a control unit such that the pressing force (F) pulsates according to a pulsation profile, whereby in the secondary sub-phases (β) of each pulsation cycle, characterized by a renewed increase in pressing force, a greater degree of plastic deformation of the workpiece occurs compared to the preceding secondary sub-phase (β).This is followed by opening the radial press tool and removing the workpiece from the workpiece holding chamber.

Description

[0001] The present invention relates to a method for the multi-phase radial forming of a workpiece using a machine radial press, which comprises a base, a drive unit, a control unit controlling the drive unit, and a radial press tool with at least four, preferably at least six, press jaws that are radially movable towards and away from a press axis by means of the drive unit. The present invention further relates to a radial press suitable and configured for carrying out the method in question.

[0002] Radial forming of workpieces using machine-driven radial presses is a long-established and proven technology. This technology is widely used, for example, in connection technology, specifically for attaching fittings to both ends of a high-pressure hose during the production of hydraulic lines. Radial presses specifically designed and suitable for such processes, comprising a base, a drive unit, a control unit, and a radial press tool with typically eight press jaws that are movable radially relative to the base by the drive unit towards and away from a press axis, are available in a variety of designs and configurations from Uniflex-Hydraulik GmbH, Karben, and other suppliers.

[0003] The usual processes for radial forming of workpieces using known radial presses typically proceed as follows: The workpiece is placed in a workpiece holding chamber located between the press jaws with the radial press tool open; the radial press tool is closed by means of the drive unit until all press jaws are in contact with the workpiece; the radial press tool is continuously closed by means of the drive unit with increasing pressing force, initially elastically and then plastically deforming the workpiece until an end point of the pressing is reached – defined by an end force or an end dimension; if necessary, the tool is held in a holding phase; the radial press tool is opened by means of the drive unit with the pressing force decreasing to zero and beyond, to an open position in which at least part of the press jaws are out of contact with the workpiece; the workpiece is removed from the workpiece holding chamber.

[0004] The present invention aims to provide an improved method for the radial forming of a workpiece using a machine radial press, such that, at least in selected, demanding application areas, the workpiece produced using the method meets higher quality requirements with a lower manufacturing tolerance.

[0005] This problem is solved by the method specified in claim 1. This method is characteristically multi-stage, in that the actual pressing, i.e., the actual forming of the workpiece, extends over several successive phases with fundamentally different pressing characteristics. Following the closing of the radial press tool by means of the drive unit with increasing pressing force, initially elastic and then plastic deformation of the workpiece, a phase with a characteristically pulsating pressing force is performed before the press tool is reopened to remove the finished workpiece. In this phase, the drive unit is controlled by the control unit in such a way that the pressing force pulsates according to a pulsation profile, namely – either with permanent contact of the press jaws with the workpiece or with the press jaws temporarily lifting from the workpiece (su) - repeatedly decreases and increases again, whereby the decrease in pressing force occurs in corresponding primary sub-phases and the subsequent increase in pressing force occurs in corresponding secondary sub-phases, and in each of the secondary sub-phases a more extensive plastic deformation of the workpiece takes place compared to the preceding secondary sub-phase.

[0006] The targeted discontinuous application of a repeatedly decreasing and increasing pressing force to the workpiece in the third process phase, with progressively greater plastic deformation from pulsation cycle to pulsation cycle, results in a number of practically relevant advantages. A particularly significant advantage lies in the adherence to exceptionally tight tolerances by the finished workpiece; because workpieces produced using the process according to the invention typically exhibit less variation in their characteristic properties than analogous workpieces produced using conventional radial pressing techniques. Furthermore, the application of the process according to the invention can have a positive effect on the final strength of the workpiece (su).In particular, when these advantages are combined, workpieces produced in accordance with the present invention prove to be especially suitable for applications with particularly high quality requirements.

[0007] The advantageous effects described above can be achieved regardless of whether, in a specific case – according to a first embodiment of the method according to the invention – there is permanent contact between the press jaws and the workpiece in the third process phase, or whether – according to a second, alternative embodiment of the method according to the invention – there is intermittent contact between the press jaws and the workpiece in the third process phase, by repeatedly lifting the press jaws from and placing them back on the workpiece according to the pulsation profile. The favorable results of this second method are particularly pronounced when the workpiece is rotated about the pressing axis (by a predetermined amount) while the press jaws are lifted; because the stepwise rotation of the workpiece about its axis, i.e.,The press axis – for example, 22.5° in a press tool with eight press jaws – results in a spatially significantly more homogeneous machining of the workpiece compared to conventional radial pressing technology, with the consequence of a significantly more homogeneous stress distribution in the finished workpiece.

[0008] In the first-mentioned process, where in the third process phase the press jaws do not lift off the workpiece, but rather – utilizing the workpiece's elasticity, namely its springback as the pressing force decreases in the respective primary sub-phase – maintain permanent contact between the press jaws and the workpiece, a particularly advantageous embodiment allows the pressing force amplitude – the difference between minimum and maximum pressing force determined during each complete pulsation cycle – to be varied, at least in a portion of the third process phase, specifically by decreasing the said pressing force amplitude. This is especially advantageous if the frequency of the pressing force pulsation is simultaneously varied to increase it. A relationship (dependency) can be established or...The relationship between the instantaneous mean pressing force, namely the average between the maximum and minimum pressing force during a complete pulsation cycle, and the pressing force-pulsation amplitude must be taken into account, in particular by varying the pressing force-pulsation amplitude such that it decreases as the instantaneous mean pressing force increases. Conversely, within the third process phase (or the relevant sub-phase thereof), a continuous increase in the instantaneous mean pressing force can be specified via the control unit.

[0009] However, targeted manipulation, i.e., variation of the frequency of the press force pulsation within at least a sub-area of ​​the third process phase (specifically in the sense of increasing the frequency), also opens up excellent possibilities for optimizing the process with regard to the individual boundary conditions of the respective application, even outside the specific advanced training described above. This applies regardless of whether the press jaws lift off the workpiece in the third process phase or not.

[0010] The process according to the invention, characterized by a pulsating pressing force in the third forming phase, can – depending on the individual boundary conditions, such as in particular the workpiece material and the pulsation frequency and pulsation force amplitude – lead to significant changes in the microstructure of the workpiece material, specifically to work hardening (in the case of radial forming below the recrystallization temperature of the workpiece material). The corresponding positive effects are particularly pronounced in the process variant with stepwise rotation of the workpiece during the pulsation phase with the press jaws raised (so); because here, effects resulting from the multidimensional dislocations come into play that cannot be achieved with conventional radial pressing technology.Such cold working can prove extremely advantageous with regard to the operational behavior of the manufactured end product, for example, by enabling the same strength of a workpiece to be achieved using less material, thus resulting in material savings. In this respect, advantages are to be expected, particularly in the field of lightweight construction technology, when implementing the present invention.

[0011] If radial forming is carried out at a correspondingly increased temperature, i.e., with a heated workpiece, targeted heat strengthening (with the associated specific advantages) can be achieved.

[0012] According to another preferred embodiment of the invention, at least in the third process phase, the actual dimension of the press is measured, and the change in the average press force is dependent on the actual dimension amplitude that develops in response to the predetermined press force pulsation. The actual dimension amplitude that develops at a specific press force amplitude represents a characteristic parameter for properties inherent in the workpiece, such as, in particular, its springback elasticity. Considering this parameter when controlling the press force pulsation by changing the average press force allows for targeted adaptation (optimization) of the respective process to the specific situation of each individual case.

[0013] According to yet another particularly preferred embodiment of the method according to the invention, a pulsation-free intermediate phase takes place between the third and fourth process phases. In this intermediate phase, force-controlled final pressing can be performed with a continuously increasing pressing force, or displacement-controlled final pressing can be performed with a continuously decreasing actual workpiece dimension. Alternatively, with or without a preceding final pressing phase, a holding phase can precede the fourth process phase, in which the radial press is, in effect, "frozen" for a predetermined time at a constant pressing force.

[0014] In terms of the apparatus, the present invention manifests itself particularly in a corresponding embodiment of the control unit controlling the drive unit. In this sense, a radial press designed for carrying out the inventive method described above, which comprises a base, a drive unit, a control unit controlling the drive unit, and a radial press tool with at least four press jaws that are radially movable relative to the base in the direction of and away from a press axis by means of the drive unit, is characterized in that the radial press further comprises a press force pulsation unit for generating press force pulsations.In a hydraulically operated drive unit, a hydraulically actuated pressing force pulsation unit is particularly preferably provided, which can in particular comprise a vibration volume that communicates with the hydraulic path between the hydraulic pressure transmitter (pump) and the hydraulic pressure sensor (cylinder). This vibration volume can in particular be adjustable, specifically volume-variable.

[0015] If, on the other hand, the radial press has a mechanically operated drive unit, an electromechanically operated press force pulsation unit is particularly preferred. This can, in particular, include a piezoelectric transducer connected in the mechanical path between the force transmitter and the press jaws.

[0016] To carry out the preferred embodiment of the method according to the invention described above, the radial press according to the invention preferably has a workpiece rotating device suitable for rotating the workpiece about the press axis. This device can, in particular, comprise a rotary table rotatably mounted about the press axis with workpiece gripping elements arranged thereon, wherein a rotary table drive – controlled by the control unit – and a gripping element adjustment drive – also controlled by the control unit – are provided.

[0017] The present invention will now be explained in more detail with reference to an embodiment illustrated in the drawing. Fig. 1 in a partially schematic representation a preferred embodiment of a radial press prepared and suitable for carrying out the method according to the invention; further illustrated Fig. 2. Using a diagram illustrating the pressing force and the movement of the press jaws over time, describe the process of a complete pressing in the radial press according to Fig. 1. radial press forming process according to a first preferred embodiment; and Fig. Figure 3 illustrates, also using a diagram showing the pressing force and the movement of the press jaws over time, the process of a complete pressing in the radial press according to Fig. 1. radial press forming process according to a second preferred embodiment.

[0018] The in Fig. 1. An exemplary radial press – other known radial press designs, such as so-called “yoke presses,” e.g., according to DE 41 35 465 A1, are equally suitable for implementing the present invention – comprises, in a manner known as such, a radial press tool 1 with eight press jaws 4 arranged evenly distributed around a press axis X, each having a base jaw 2 and a replaceable press jaw head 3 attached thereto. The press jaws 4 are supported radially on the outside by sliding surfaces 5 inclined to the press axis X against corresponding control surfaces 6 of a housing 7. Furthermore, they are supported by sliding guide blocks 8 against an annular pressure plate 9, which is movable along the press axis X relative to the housing 7. As the pressure plate 9 approaches the housing 7, the press jaws 4 move radially inwards, i.e.,in the direction of the press axis X; however, as the pressure plate 9 moves away from the housing 7, the press jaws 4 move radially outwards, i.e., away from the press axis X. The base jaws 2 are thereby pre-tensioned, also in a known manner, by spreading springs arranged between them (not shown) to bear against the control surfaces 6 of the housing 7.

[0019] The movement of the pressure plate 9 and the housing 7 relative to each other is effected by a hydraulic drive unit 10. This unit comprises an annular cylinder 11 located in the housing 7, with which an annular piston 13, mounted on a cup-shaped piston element 12 and immersed in the cylinder, interacts. The piston element 12 is coupled to the pressure plate 9 via axially parallel tie rods 14, which extend through the housing 7, slidably guided within it, and are rigidly connected at their ends to the pressure plate 9 on one side and to the base 15 of the piston element 12 on the other. The hydraulic drive unit 10 also includes a hydraulic pump 18 (serving to actuate the annular cylinder-annular piston unit 16 and supplied from the reservoir 17), which is controlled by the control unit 19 according to the respective pressing process to be carried out.

[0020] Depending on the individual design, either the housing 7 or the assembly comprising the pressure disc 9 and the piston element 12 can be stationary, i.e., firmly connected to a (not shown) base of the radial press.

[0021] A return stroke device 20 that causes the radial press to open comprises several return stroke elements 21, each of which acts between a first arm 22 arranged on the housing 7 and a second arm 23 arranged on the pressure plate 9.

[0022] To the extent set out above, the Fig. Figure 1 illustrates the prior art of a mechanical radial press, so that further explanations are unnecessary and reference is made instead to DE 10 2011 015 706 A1, the entire content of which is incorporated by reference into the disclosure content of the present patent application. The modification in Figure 1 is based on the prior art of DE 10 2011 015 706 A1. Fig. The radial press shown in 1 differs from DE 10 2011 015 706 A1 in that the return stroke elements 21 (each housed in a telescopic spring housing 24) comprise mechanical return springs instead of hydraulic return cylinders.

[0023] The radial press also features a hydraulically actuated pressing force pulsation unit 25 for generating pressing force pulsations. This unit comprises a pulsation chamber 26 connected in the hydraulic path between the hydraulic pump 18 (hydraulic pressure transmitter) and the ring cylinder-ring piston unit 16 (hydraulic pressure sensor). The volume of this chamber filled with hydraulic fluid (vibration volume) can be changed via a piston 27, the position of which is adjustable by means of an actuator 28 controlled by the control unit 19. A piezoelectric element 29 also acts on the hydraulic fluid in the vibration volume, and its volume—displacing the hydraulic fluid present in the pulsation chamber 26—can be changed by means of a control voltage applied to it.To generate defined pressure pulsations in the hydraulic path, the piezoelectric element 29 is subjected to a pulsating voltage by the control unit 19, whereby the pulsation frequency and the pulsation amplitude of the pressure pulsation in the hydraulic path can be specifically varied via the individual voltage pulsation. The change in the vibration volume via the piston 27 can be used to change the natural frequency of the hydraulic system, in particular to utilize advantageous amplifying resonance effects.

[0024] The radial press after Fig. In addition, unlike known radial presses, instrument 1 includes a workpiece rotating device 32 suitable for rotating the workpiece 31 – illustrated by way of example as a round bar 30 – about the press axis X. This rotating device has a rotary table 33 which is rotatably mounted about the press axis X by means of the bearing ring 34 on a support ring 35, which is attached to the end face of the pressure plate 9. The rotary table 33 can be rotated by means of a rotary table drive 36, which is supported on the support ring 35 and controlled by the control unit 19 (see double arrow A). Several workpiece gripping elements 37 are arranged on the rotary table 33. The workpiece gripping elements 37 can be radially displaced by means of a gripping element adjustment drive 38, which is supported on the rotary table 33 and controlled by the control unit 19 (see double arrow B).

[0025] A first using the in Fig. The multi-phase radial forming of a workpiece, exemplified by the machine radial press shown in Figure 1, is shown in Figure 1. Fig. Figure 2 illustrates this. In this figure, three superimposed diagrams (not to scale for visibility reasons) show, each over time t, the course of the pressure p in the hydraulic working space 39 limited by the ring cylinder 11 and the ring piston 13, the course of the pressing force F acting on the workpiece, and the course of the movement r of the press jaws 4 from their maximum open position inwards towards the press axis X.

[0026] After the workpiece 31 is inserted into the workpiece holding chamber 40 between the press jaws 4 of the fully opened radial press tool, the radial forming process is initiated, i.e., the press program is started. During an initiation phase a, pressure is built up in the system by the starting hydraulic pump 18. As long as the force generated in the hydraulic working chamber 39 remains less than the restoring force applied by the return stroke device 20, the position of the ring cylinder 11 and the ring piston 13 relative to each other does not change; the press jaws 4 remain in their fully open position.

[0027] If, during a further pressure increase, the force generated in the hydraulic working chamber 39 exceeds the restoring force exerted by the return stroke device 20, the annular piston 13 is extended from the annular cylinder 11. During this idle-stroke closing phase b, the press jaws 4 approach the workpiece 31 and, at the end of this phase, contact the workpiece surface. This idle-stroke closing phase b, sometimes also referred to as "rapid traverse," constitutes the "first process phase" I as defined in the present invention.

[0028] Under a further increasing pressure p in the hydraulic working chamber 39, the annular piston 13 extends further from the annular cylinder 11, and consequently the press jaws 4 move further towards the press axis X, deforming the workpiece 31 as a result of a pressing force F acting upon it. This force is approximately proportional to the pressure p in the hydraulic working chamber 39. Depending on the individual material properties of the workpiece 31, namely its elasticity, a first part of the radial deformation (corresponding to a first part r1 of the movement of the press jaws 4) is elastic (reversible component) and a second part of the radial deformation (corresponding to a second part r2 of the movement of the press jaws 4) is plastic (irreversible component).This closing phase – sometimes also referred to as the “power phase”, comprising the two sub-phases c and d – in which a first radial forming of the workpiece 31 takes place, represents the “second process phase” II within the meaning of the definition of the present invention.

[0029] This is followed by the “third process phase” III according to the invention, in which the drive unit 10 is controlled by the control unit 19 such that the pressing force F pulsates according to a pulsation profile, namely repeatedly decreasing and increasing again, with the decrease of the pressing force F occurring in corresponding primary sub-phases α and the subsequent increase of the pressing force F occurring in corresponding secondary sub-phases β. The reduction of the hydraulic pressure p prevailing in the hydraulic working chamber 39 (and accordingly the pressing force F) in the respective primary sub-phase α is brought about by the control unit 19 applying pressure to the piezoelectric element 29 housed in the pulsation unit 25, thereby reducing the volume of the piezoelectric element 29.As the pressure p decreases in the respective primary phase α, the press jaws 4 are retracted by a spring-back effect of the workpiece 31 due to its elasticity. In the subsequent secondary phase β of each pulsation cycle γ, the relationships and processes are reversed. The drawing illustrates the effect of work hardening of the workpiece 31 caused by the press force pulsation, such that the transition from elastic to plastic deformation only occurs at a higher pressure p (or a higher press force F) than before the respective pulsation cycle γ. The pressure and thus press force increase in the respective secondary phase β is controlled by the control unit 19 in such a way that a greater degree of plastic deformation of the workpiece 31 occurs compared to the preceding secondary phase β.However, it should be emphasized once again as a precaution that the presentation is based on... Fig. Figure 2 is not to scale, but rather – for the sake of illustrating the relationships – significantly distorted. Furthermore, in reality, considerably more than three pulsation cycles (γ) regularly occur in the third process phase.

[0030] The third procedural phase III is followed in the case of the Fig. In the embodiment shown in Figure 2, an intermediate phase e is introduced, which is designed as a holding phase such that the pressure p, and thus the pressing force F, remains constant at the value existing at the end of the third process phase III over a predetermined time interval. Accordingly, the press jaws 4 also remain essentially in their position at the end of the third process phase III during this time interval.

[0031] After the time interval specified for the intermediate phase e has elapsed, the radial press tool is opened – in a fourth process phase IV – by means of the drive unit 10 while the pressure p prevailing in the hydraulic working chamber 39 is continuously reduced. Here, mirroring the processes that take place at the beginning of the press cycle, two sections f and g can be distinguished. Initially, the press jaws 4 are still in contact with the workpiece 31, which springs back due to its elasticity in accordance with the decreasing pressing force p. Once the stress-free final dimension of the formed workpiece 31 is reached, the press jaws 4 lift off the workpiece 31. The pressing force F is zero. During the further opening stroke (free-stroke opening) of the press jaws 4 until they reach their maximum open position, the pressure p prevailing in the hydraulic working chamber 39 decreases according to the spring force of the return stroke device 20.

[0032] Finally, a last phase h follows, in which the hydraulic working chamber 39 is depressurized. This completes the pressing program, and the unformed workpiece 31 is removed from the workpiece holding chamber 40.

[0033] In Fig. 3 is a different embodiment compared to the exemplary embodiment according to Fig. 2. Modified procedure illustrated. Whereas in the procedure according to Fig. 2 in the third process phase III, i.e. during the pulsation phase, a permanent contact of the press jaws 4 with the workpiece 31 exists, according to the process guidance Fig. 3 In the third process phase III, intermittent contact occurs between the press jaws 4 and the workpiece 31, as the press jaws 4 repeatedly lift off and re-place on the workpiece 31 according to the pulsation profile. This temporary lifting of the press jaws 4 from the workpiece 31 is achieved by reducing the pressure p in the hydraulic working chamber 39 – in the respective primary sub-phase α of each pulsation cycle γ – to a level such that the closing force induced by the corresponding actuation of the ring cylinder-ring piston unit 16 falls below the restoring force of the return stroke device 20 in the position of the press jaws 4 that they assume when the workpiece 31 is stress-free and fully rebounded.By means of the workpiece turning device 32 explained in detail above, the workpiece 31 - with the press jaws 4 lifted from it in this way - is rotated by a predetermined angle around the press axis X, at which in . Fig. The press tool shown in Figure 1, comprising eight press jaws 4, rotates, for example, by 22.5° before, as a result of renewed pressurization of the hydraulic working chamber 39 and a corresponding pressure increase therein, the press jaws 4, in the respective secondary phase β, re-contact the workpiece 31 and a renewed (initially elastic, then plastic) radial deformation ensues. The rest is explained in Fig. 3 forming processes illustrated can be readily derived from the preceding explanations of the forming process according to Fig. 2.

[0034] By appropriately modifying the press program stored in the machine control 19, various modifications of the forming processes according to the Fig. 2 and Fig. Three possibilities exist. This includes, in particular, varying the frequency of the pressing force pulsation in the third process phase III. Furthermore, the process can be carried out according to Fig. 2. The amplitude of the press force pulsation, namely the difference between minimum press force and maximum press force determined during each complete pulsation cycle 'γ', is varied. The further specific modifications of the forming processes according to the dependent claims are also included. Fig. 2 and Fig. 3 can be easily implemented by a specialist by appropriately modifying the underlying pressing program.

Claims

[1] Method for multi-phase radial forming of a workpiece (31) by means of a machine radial press, which comprises a base, a drive unit (10), a control unit (19) controlling this, and a radial press tool (1) with at least four, preferably at least six press jaws (4) which are movable radially towards and away from a press axis (X) by means of the drive unit (10), with the following features: - Inserting the workpiece (31) into a workpiece receiving space (40) located between the press jaws (4) with the radial press tool (1) open; - Closing of the radial press tool (1) by means of the drive unit (10) in a first process phase (I) until all press jaws (4) are in contact with the workpiece (31); - continued closing of the radial press tool (1) by means of the drive unit (10) in a second process phase (II) with increasing pressing force (F) under first elastic and then plastic deformation of the workpiece (31); - Controlling the drive unit (10) by the control unit (19) in a third process phase (III) such that the pressing force (F) pulsates according to a pulsation profile, namely repeatedly decreasing and increasing again, wherein the decreasing of the pressing force (F) takes place in corresponding primary sub-phases (α) and the subsequent increasing of the pressing force (F) takes place in corresponding secondary sub-phases (β) and in the secondary sub-phases (β) a more extensive plastic deformation of the workpiece (31) takes place compared to the preceding secondary sub-phase (β); - Opening of the radial press tool (1) by means of the drive unit (10) in a fourth process phase (IV) with the pressing force (F) decreasing to zero and beyond to an opening position in which at least part of the press jaws (4) come out of contact with the workpiece (31); - Removing the workpiece (31) from the workpiece receiving area (40). [2] Method according to claim 1, characterized by , that in the third process phase (III) the frequency of the pressing force pulsation is varied. [3] Method according to claim 1 or claim 2, characterized by , that in the third process phase (III) there is intermittent contact of the press jaws (4) with the workpiece (31) by repeatedly lifting the press jaws (4) off the workpiece (31) and placing them back on it according to the pulsation profile, whereby the workpiece (31) is rotated around the press axis (X) when the press jaws are lifted. [4] Method according to claim 1 or claim 2, characterized by , that in the third process phase (III) there is permanent contact between the press jaws (4) and the workpiece (31). [5] Method according to claim 4, characterized by , that in the third process phase (III) the amplitude of the pressing force pulsation, namely the difference (ΔF) between minimum pressing force (Fu) and maximum pressing force (Fo) determined during each complete pulsation cycle (γ), is varied. [6] Method according to claim 5, characterized by that the variation of the pressing force pulsation amplitude in at least one sub-area of ​​the third process phase (III) takes the form of a continuous decrease over time (t). [7] Method according to claim 5 or claim 6, characterized by, that the variation of the pressing force pulsation amplitude depends on the instantaneous mean pressing force, namely the mean value between maximum pressing force (Fo) and minimum pressing force (Fu) during a complete pulsation cycle' (γ). [8] Method according to any one of claims 1 to 5, characterized by , that in the third process phase (III) the mean pressing force, namely the mean value between maximum pressing force (Fo) and minimum pressing force (Fu) during a complete pulsation cycle' (γ), is changed over time (t). [9] Method according to claim 8, characterized by , that at least in one part of the third process phase (III) the average pressing force is controlled in the sense of a continuous increase. [10] Method according to claim 8, characterized by, that an actual measurement of the press dimension is carried out and the change in the average press force value is carried out depending on the actual dimension amplitude that results in response to the specified press force pulsation. [11] Method according to any one of claims 1 to 10, characterized by , that a pulsation-free intermediate phase (e) occurs between the third process phase (III) and the fourth process phase (IV). [12] Method according to claim 11, characterized by , that during the intermediate phase (e) a force-controlled final pressing takes place with a steadily increasing pressing force. [13] Method according to claim 11, characterized by , that during the intermediate phase (e) a path-controlled final pressing takes place with a continuously decreasing actual workpiece dimension. [14] Radial press for carrying out the method according to claim 1, comprising a base, a drive unit (10), a control unit (19) controlling the drive unit and a radial press tool (1) with at least four press jaws (4) which can be moved radially towards and away from a press axis (X) by means of the drive unit (10), wherein the radial press has a press force pulsation unit (25) for generating press force pulsations. [15] Radial press according to claim 14, characterized by , that in a hydraulically operating drive unit (10) a hydraulically acting press force pulsation unit (25) is provided, which in particular includes a vibration volume communicating with the hydraulic path between hydraulic pressure transmitter and hydraulic pressure sensor. [16] Radial press according to claim 14, characterized by, that in a mechanically operating drive unit (10) an electromechanically acting press force pulsation unit is provided, which in particular includes a piezoelectric transducer connected in the mechanical path between force generator and press jaws. [17] Radial press according to one of claims 14 to 16, characterized by that it includes a workpiece rotating device (32) suitable for rotating the workpiece (31) about the press axis (X).

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