EP3010708A1

EP3010708A1 - Method for bending the machine bed of a stamping press, and stamping press

Info

Publication number: EP3010708A1
Application number: EP13736464.2A
Authority: EP
Inventors: Josef Thomas Hafner
Original assignee: Bruderer AG
Current assignee: Bruderer AG
Priority date: 2013-06-19
Filing date: 2013-06-27
Publication date: 2016-04-27
Anticipated expiration: 2033-06-27
Also published as: EP3010709A1; JP6192821B2; WO2014201576A1; JP6192820B2; JP2016524540A; EP3010709B1; EP3010708B1; SG11201510311QA; SG11201510310VA; US20160136710A1; ES2663233T3; WO2014201577A1; US20160144588A1; JP2016523715A

Abstract

The invention relates to a method for bending the machine bed (5) of a stamping press, which machine bed has an opening (6b) for leading away stamped parts and waste, in order to at least partially compensate a deflection of the machine bed (5) caused by stamping force during stamping operation. Forces acting perpendicularly to the stamping force direction are applied to the machine bed (5) and/or forces acting perpendicularly to the stamping force direction are produced in the machine bed (5), by means of which forces the machine bed (5) bends in a direction toward the press ram (2) in such a way that the machine bed is more greatly bent in the region adjacent to the opening (6b) than in the regions adjacent to the longitudinal sides of the machine bed. By means of the method according to the invention, machine beds (5) of stamping presses having openings can be spatially pre-deformed with very minimal system complexity for the purpose of at least partially compensating deflections caused by stamping force.

Description

Process for buckling the machine bed of a stamping press and stamping press

Technical area

The present invention relates to a method for buckling the machine bed of a stamping press for the at least partial compensation of a punching force-induced deflection in the punching operation and a punch press, in particular for carrying out the method, according to the preambles of the independent claims.

State of the art

For the industrial production of punched parts made of sheet metal strip today fast-running automatic stamping machines are used, in which an upper tool part with punches to a certain stroke on a lower tool part with dies is moved to and thus

Performs cuts and shaping on sheet metal strip. Today's so-called follow-cutting tools, which usually comprise a large number of modules that carry out various tasks such as cutting, bending, forming and embossing, require ever longer tool ^installation spaces.

Accordingly, in the last three decades, the length of the tool installation space of stamping machines has virtually doubled while maintaining the same tonnage, which leads to a corresponding increase in the moving and stationary masses due to the longer components and at the same time problems with the rigidity of the press senstruktur, as the Due to the increase in length typically decreasing stiffness of some critical components, in particular of the machine bed, due to limited space can not be compensated arbitrarily by corresponding cross-sectional enlargements.

This in turn gives rise to the problem that it increases with increasing length of the tool installation space is becoming increasingly difficult, the deformations of the press structure and in particular the deflection of the machine ^¬ betts under the stamping load which liehst for a high per ^¬ zesspräzision and low tool wear possible should be low to keep it within acceptable limits. In machine beds with a breakthrough for, removal of stamped parts and waste, as used in today's punching machines, resulting in punching operation, a spatial deflection of the machine bed, as more or less is punched over this breakthrough, causing the deflection in the area the breakthrough is greater than in the areas of the longitudinal sides of the machine bed. In particular, in the event that punching operations are carried out in the rather unusual punching direction from back to front, these deflections represent a major problem.

In order to reduce or compensate for the deflection due to the process load in the case of machine ^beds or tool ^mounting plates without breakthrough, it is known from the prior art to buckle the machine bed or the tool clamping plate against the direction of deflection, if possible in such a way that this bulging through the process load is just canceled, or support the platen dynamically with variable-height support elements so on under the load possibly bending support structure that the platen undergoes no significant deflection even under the punching load.

Thus, EP 0 653 254 A2 discloses a press in which supporting units are arranged between the press bed and the tool clamping plate and are adjustable in height. These support units can be mechanical, electromechanical or hydraulic type and operated by a controller such that a deformation of the platen is counteracted under the working pressure of the press. It is also possible, with these support units to cause a protrusion of the platen to compensate for tool types.

From DE 44 15 577 AI a machine table with a tool clamping plate for pressing in the field of metal forming is known in which a plurality of hy ^¬ draulischer compensation piston are arranged between a base plate and the platen. There are displacement and bending sensors and a suitable control present, for controlling the pressure in the compensation piston such that a deformation of the tool clamping plate is counteracted under the working pressure of the press.

From EP 0653254 A2 and DE 44 15 577 AI known systems generally have the disadvantage that they are mechanically complex and therefore expensive and kos ^¬ tenintensiv in the manufacture and maintenance, and that they are produced by the design with multiple selective ex support the tool clamping plate in the punching force direction on a support structure below it for the required height allow a relatively low structural rigidity. For the variants with hydraulic support units / compensation piston comes as a further disadvantage that the supporting oil cushion in the punching force direction has a low rigidity and the inevitable deformations of the entire hydraulic system under the oil pressure generated by the support pressure to a compression of the support under the punching load. For the variants in which a deflection of the platen is to be prevented by means of dynamic height adjustment of support elements, it should be said that these, if feasible at reasonable cost, at most suitable for very slow forming processes, but not for fast punching machines for processing Metal strips in the following cutting process.

From DE 100 10 197 AI a press is known in which the machine bed by biasing in the lower part of the machine bed in the longitudinal direction durch- settling tie rods can be warped in the direction of the press ram in order to correct a deflection of the press bed or to produce a protrusion in the load-free state. There is a control by means of which the pretensioning of the tie rods can be regulated as a function of determined deflections. This system largely avoids the aforementioned disadvantages of the two systems mentioned first.

However, none of the known systems solves the aforementioned problem of spatial deflection in machine beds with a breakthrough for the removal of stampings and waste.

Presentation of the invention

It is therefore the task of providing a technical solution which, in punch presses ^¬ with a machine bed with breakthrough for the removal of stampings and waste an at least partial compensation of a punching force induced spatial deflection of the machine bed both in the longitudinal and in the transverse direction of the Machine bed allows and thereby does not have the aforementioned disadvantages of the prior art or at least partially avoids.

This object is achieved by the method and the punch press according to the independent claims.

According to these, a first aspect of the invention relates to a method for buckling the machine bed of a stamping press, which has a breakthrough for the removal of stamped parts and waste, for the at least partial compensation of a punching force-induced deflection of the machine bed in the punching operation. In this ER be inventively transversely initiated acting to the punching force direction Strengthens ^¬ te in the machine bed and / or transversely generated to the punching direction of the force acting forces in the machine bed, by which to warped the machine bed in the direction of the press ram, in such a way that it is in the area adjacent to the more warped breakthrough than in the regions adjacent to its longitudinal ^¬ sides.

The inventive method is perforated machine beds of stamping presses can predeforming spatially with a very small investment outlay in order to ^¬ least partial compensation of punching force induced deflections.

In a preferred embodiment of the method, the machine bed is placed under compressive stress in its lower region under tensile stress in the longitudinal direction of the tie rods, and is then subjected to buckling in the direction of the press ram. This method of generating the deformation forces has the advantage that it is delay-free and the deformation forces and the resulting deformations are well controlled.

It is preferred that the tie rods are arranged such that they pass through the machine bed in its lower region. This has the advantage that virtually no additional space is needed.

Advantageously, in this particular form from guide symmetrically on both sides of the opening in each case a tie rod arranged in such a way that the Zugan ^¬ ker each having a smaller distance to the breakthrough as the respective longitudinal side of the machine bed. As a result, a greater warping in the area of the opening than in the area of the longitudinal sides can be achieved in a simple manner.

In a further preferred embodiment of the method, a temperature gradient is generated within the machine bed or within a support structure formed with the machine bed for the lower tool parts of the press tool, by means of which the machine bed, due to locally different thermal expansion or heat shrinkage of the machine bed and / or or different thermal expansion or heat shrinkage of components of the support structure formed therewith for the lower tool parts, to be arched in the direction of the press ram. This method of generating the deformation forces has the advantage that it can be used without having to deviate from existing and proven structural concepts. This is of particular importance in the field of high-speed, high-speed stamping presses, as it often requires years of detailed work to optimize the press structures with regard to their dynamic behavior and service life. In addition, this embodiment of the inventive method can be implemented with little effort even with existing presses.

In this case, in a preferred embodiment of the method, the temperature gradient causing the warpage is generated by heating the machine bed in the region of its side facing the press ram, wherein it is further preferred that heating is more intense in the vicinity of the boundaries of the opening than in the vicinity of the longitudinal sides of the press machine bed. Local heating represents a particularly simple and economical method of generating the temperature gradient, especially as waste heat is often available free of charge in production plants.

Alternatively or additionally, it is preferable to generate the temperature gradient by cooling the machine bed in the region of its side facing away from the press ram, wherein it is further preferred that more cooling is achieved in the vicinity of the boundaries of the opening than in the vicinity of the longitudinal sides of the machine bed. This method is particularly useful when these machine components are relatively warm during operation and can be locally cooled in this way, without leading to dew point falls with condensation on the machine parts. The introduction of heat and / or cold in the components can be done in various ways.

In a preferred embodiment of the method, flow channels arranged within the machine bed are flowed through by a heated or cooled, gaseous or liquid medium.

For this purpose, for example, heated lubricating oil of a lubricating oil circuit of the press can be used, which is guided through the flow channels prior to cooling. The latter method has the advantage that no additional energy is needed for heating.

In a further preferred embodiment of the method, electrical heating elements are arranged within the machine bed and supplied with electric current for generating heat. In this variant, there is the advantage that with very simple means a precise and adapted to the respective operation control of the temperature gradient is possible.

In yet another preferred embodiment of the method, the temperature gradient is generated by arranging on the machine bed a clamping plate which is heated.

In another preferred embodiment of the method, a clamping plate is arranged on the machine bed and a heating device is arranged between the machine bed and the clamping plate, which is heated.

While heating, according to a preferred variant of these two embodiments last mentioned, the machine bed by means of the heated platen or by means of on its side facing the Stös- sel facing between the machine bed and the chuck ^¬ plate arranged heater side, with the result that there is a Warping of the machine bed towards the press ram comes to.

According to another preferred variant of these two latter embodiments, the Platen rigidly connected to the machine bed, directly or indirectly via the heater. In this variant, the warping of the machine bed in the direction of the press ram can also occur exclusively as a result of an initiation of shear forces generated by a thermal expansion of the platen in the side facing the plunger of the machine bed, or due to a combination of shear forces generated by a thermal expansion of the platen in the side facing the plunger of the machine bed with a heating of the machine bed by the platen or the heater.

In still another preferred embodiment of the method, the warpage of the machine bed is adjusted in dependence on parameters of the stamping process, e.g. as a function of a previously calculated or product-specific punching force or of a maximum punching force measured during operation. Furthermore, it is preferred that the warping be adjusted during the intended operation of the press. In this way, the respective operating situation and any changes, for example due to increasing tool wear, are particularly well taken into account.

A second aspect of the invention relates to a punch press which is suitable for carrying out the method according to the first aspect of the invention. The punch press has a machine bed and a press ram working against the machine bed. The machine bed of the punch press has an opening for the removal of stamped parts and waste. Furthermore, the punch press comprises means for arching the machine bed in the direction of the press ram to the machine bed by introducing forces acting transversely to the punching force direction into the machine bed and / or by generating forces acting transversely to the punching force direction in the machine bed. In this case, these funds are designed such that they Machine bed in the area adjacent to the opening more pronounced warping than in the areas adjacent to the longitudinal sides of the machine bed.

The invention makes it possible to provide high-precision, high-speed, high-speed stamping presses with perforated machine beds at low cost.

In a preferred embodiment of the stamping press, the means for arching the machine bed in the longitudinal direction of the machine bed extending tie rods, with which the machine bed can be placed in its lower region under compressive stress, for buckling of the machine bed in the direction of the press ram to. This method of generating the deformation forces has the advantage that it is delay-free and the deformation forces and the resulting deformations are well controlled.

It is preferred that the tie rods are arranged such that they pass through the machine bed in its lower region. As a result, virtually no additional space is needed.

Advantageously, in these embodiments, on both sides of the opening, in particular in a symmetrical configuration, in each case a tie rod arranged such that the tie rods each have a smaller distance from the breakthrough than the respective longitudinal ^¬ side of the machine ^bed . This can be achieved in a simple manner, a greater warping in the area of the breakthrough than in the area of the longitudinal sides.

In a further preferred embodiment of the stamping press, the means for arching the machine bed are designed for selectively generating a temperature gradient within the machine bed or within a support structure formed with the machine bed for the lower tool parts, by means of which the machine bed, due to locally different thermal expansion or heat shrinkage of the machine bed and or different thermal expansion or heat shrinkage of components of the support structure formed therewith for the lower tool parts, can be warped in the direction of the press ram. This method of generating the deformation forces has the advantage that it can be realized without having to deviate from existing and proven structural concepts. As already mentioned, this is of particular importance in the field of high-speed, high-speed stamping presses, since it often takes years of detailed work to optimize the press structures with regard to their dynamic behavior and their service life. In addition, this embodiment can be implemented with little effort even with existing presses.

In a preferred embodiment of

Stamping press are the means for buckling of the machine bed designed such that with them the machine ^¬ bed in the region of the press ram facing side can be heated to cause the warping due to uneven heating with the same uneven spatial thermal expansion of the same. It is further preferred that with these means, the machine bed can be heated in the vicinity of the limits of the break through ^¬ stronger than in the vicinity of its longitudinal sides.

Alternatively or additionally, the means for buckling the machine bed are designed such that with them the machine bed in the region of the press ram facing away from the side can be cooled to the effect of warping due to uneven cooling with corresponding uneven spatial shrinkage of the same. It is further preferred that with these means, the machine bed can be cooled in the vicinity of the boundaries of the opening stronger than in the vicinity of its longitudinal sides. For introducing heat or cold, the punch press according to the invention can have a wide variety of devices:

In a preferred embodiment of the punch press flow channels are arranged within the machine bed, which can be flowed through during normal operation of the press with a heated or cooled, gaseous or liquid medium, for generating the temperature gradient.

Advantageously, according to a preferred variant of this embodiment, means are provided with which in the intended operation of the press heated lubricating oil of a lubricating oil circuit of the press can be guided through the flow channels, for generating the temperature gradient. This solution is energeti ^¬ sch particularly advantageous because virtually no heating energy is needed to provide the heat.

In a further preferred embodiment of the stamping press, fresh heating elements are arranged inside the machine bed, in particular resistance heating elements, which can be supplied with electrical current during intended operation of the press, for generating the temperature gradient causing the warping. This construction allows a particularly well controllable generation of the temperature gradient.

Preferably are on both sides of the passage of the machine bed, respectively arranged one or several Strö ^¬ mung channels and / or electrical heating elements within the machine bed, preferably such that each side of the sum of the distances of the flow channels and / or heating elements to the breakthrough is always smaller than the sum of the distances the flow channels and / or heating elements to the respective longitudinal side of the machine bed. It is further preferred that the flow channels and / or heating elements are arranged symmetrically to both sides of the opening. This can be on easy way to bring about the desired greater warping of the machine bed in the area of the breakthrough.

In yet another preferred embodiment, the punch press arranged on its machine bed on a platen, which during the best immungsgemäße operation of the press, in particular electrically, is heated.

In another preferred embodiment, the punch press on a arranged on its machine bed platen, wherein between the machine bed and the platen, a particular electric heating device is arranged, which can be operated during the best immung operation of the press.

In this case, according to a preferred variant of these two embodiments, the platen or arranged between platen and machine bed heater so connected to the machine bed that the platen when heated, or the heater when it is operated, the machine bed on his Heated tappet facing side, to produce the warping causing temperature gradient. It is further preferred that with the platen or the heater, the machine bed can be heated in the vicinity of the boundaries of the opening stronger than in the vicinity of its longitudinal sides.

According to a further preferred variant of these two embodiments, the platen is shear-stiffly connected to the machine bed, directly or indirectly via the heating device.

In this case, according to a first preferred sub-variant, the heatable clamping plate or the heating device arranged between the clamping plate and the machine bed is thermally decoupled essentially from the machine bed, so that it heats up during the heating of the machine

Platen or when operating the heater substantially to a heating and Auslass stretch the platen comes, which is due to the thrust-rigid coupling of the same to the machine bed, the warping of the machine bed in the direction of the press ram to causes.

The thermal decoupling may conveniently be realized by means of a disposed between the platen and the machine bed thermal insulation layer, which causes a reduction of the heat transfer from the platen to the machine bed.

In a preferred variant, this thermal insulation layer is present in the regions adjoining the longitudinal sides of the clamping plate or the machine bed, between the clamping plate and the machine bed, while in the regions adjoining the aperture a layer is present between the plate Platen and the machine bed is present, which has a much better thermal conductivity, to promote a heat transfer from the mounting plate on the machine bed in these areas. Also by this measure can be easily cause the desired greater warping of the machine bed in the breakthrough.

According to a second preferred subvariant the platen is such connected to the machine bed, that when it is heated, the Ma ^¬ schin bedded on its side facing the plunger side facing heated, or is arranged between clamping plate and the machine bed heater such the Up when operated, heats the platen and heats the machine bed on its side facing the plunger. As a result of this configuration, during heating of the clamping plate or during operation of the heating device, the warping of the machine bed by the shear forces introduced from the clamping plate into the machine bed in combination with that caused by the uneven Heating the machine bed resulting uneven thermal expansion of the same.

The use of heated platens or of heating devices arranged between the machine bed and a mounting plate is particularly suitable for the cost-effective retrofitting of existing stamping presses.

Advantageously, the means for buckling the machine bed are adjustable, preferably during the intended operation of the press, so that a targeted and adapted to the particular operating case setting the warping of the machine bed is possible.

For this purpose, the punch press preferably has a press control, with which the warpage of the machine bed, preferably automatically, depending on parameters of the punching process is adjustable, preferably in response to a calculated or product specific punching force or measured during operation maximum punching force, preferably during the intended operation of the press. As a result, a process management with automati ^¬ shear adaptation of the warping of the machine bed to the respective operating conditions is possible.

BRIEF DESCRIPTION OF THE DRAWINGS Further preferred embodiments of the invention emerge from the dependent claims and from the following description with reference to the figures. Show:

1 shows a sectional view through a stamping machine with upper drive.

2 shows a section through the machine base of the stamping machine along the line XX in Fig. 1. FIG. 3 shows a representation like FIG. 2 through the substructure of a first punching machine according to the invention; FIG.

FIG. 4 shows a representation like FIG. 2 through the substructure of a second punching machine according to the invention; FIG.

5 shows an illustration as in FIG. 2 through the substructure of a third stamping machine according to the invention; and

Fig. 6 is a section along the line A-A in

Figure 5.

Ways to carry out the invention

In FIG. 1, a punching machine with upper drive is shown, wherein the machine upper part with the drive 1, the plunger 2 and the slide guides 3 is shown cut longitudinally, while the machine base is not shown cut with the platen 4 and the machine bed 5.

Fig. 2 shows a section through the machine base of the stamping machine along the line X-X in Fig. 1, as it is formed according to the prior art. As can be seen, the clamping plate 4 is arranged on the machine bed 5 and has in the center an opening 6a, which opens in the direction of gravity in a centrally arranged in the machine bed 5 opening 6b. The openings 6a, 6b are used to carry away punched parts and waste from the punching zone.

As can also be seen, the machine bed 5 forms a closed cavity 7a, 7b on both sides of the opening 6b, which serves as a tank for the lubricating oil 8 of the lubricating oil circuit of the stamping machine. In operation, the machine bed 5 is heated more strongly by the warm lubricating oil 8 in its lower region than in its upper region, whereby it cambers already without punching force load by different thermal expansion downwards. Under the load due to the punching force causes an additional bending of the machine bed 5 during operation, and consequently a corresponding loss of precision and increased tool wear.

Fig. 3 shows a section through the machine base of the stamping machine along the line XX in Fig. 1, as it is formed according to a first embodiment of the invention. As can be seen, the outer contours of the clamping plate 4 and of the machine bed 5 are identical here as in the embodiment according to FIG. 2. However, the internal structure of the machine bed 5 differs significantly from that of FIG. 2. In the present case the machine bed 5 on both sides of the opening 6b in each case two closed cavities 9a, 9b arranged one above the other; 9c, 9d, of which only the upper 9a, 9c serve as a tank for the lubricating oil 8 of the lubricating oil circuit of the punching machine. Above the cavities 9a, 9b; 9c, 9d, the machine bed 5 has three flow channels 10a, 10b, 10c arranged side by side on both sides of the opening 6b; lOd, lOe, lOf, of which in each case the flow channels 10c, 10d closest to the aperture 6b have a significantly larger flow cross-section than the other flow channels 10a, 10b, 10e, 10f. The flow channels 10a-10f are flowed through in operation by the heated lubricating oil 8 of the lubricating oil circuit of the stamping machine, which is then passed into the cavities 9a, 9c, from where it with the lubricating oil pump of the lubricating oil circuit, possibly after passing through a cooler, again to the lubrication points the punching machine is performed. The warm lubricating oil 8 is first passed through the flow channels 10c, 10d closest to the opening 6b, then through the middle flow channels 10b, 10e and finally through the outer flow channels 10a, 10f, where it gives off heat to the machine bed 5. As a result, the machine bed 5 is in operation in its upper Warmer area warmed more than in its lower portion, causing it due to differential thermal expansion upwards and thus warped in the direction of the plunger 2.

In this case, the machine bed 5 due to the

Order of flow of the flow channels and the different flow channel cross sections in the areas adjacent to the opening 6 b heated more than in the areas of its longitudinal sides, which leads to a greater warping of the same upward in the areas adjacent to the opening 6 b than in the areas of its longitudinal sides ,

The clamping plate 4, which is fastened to the machine bed 5 with a multitude of screw connections, follows the warping of the machine bed 5. During operation, under the load due to the punching force, this warping-related warping is compensated, so that the machine bed 5 ideally under maximum punching force load both in the longitudinal and in the transverse direction flat, ie not warped or not bent, is. As a result, a loss of punching precision and increased tool wear can be effectively counteracted.

4 shows a section through the machine lower part of the stamping machine along the line XX in FIG. 1, as it is formed according to a second embodiment of the invention. As can be seen, here the outer contours of the platen 4 and the machine bed 5 are identical to those of the embodiment according to FIG. 2, and also the internal construction of the machine bed 5 is identical to that of the machine bed of FIG. 2. However, here is between the clamping plate 4 and the machine bed 5, an intermediate plate 11 with a plurality of flow channels 10a-101 arranged, which are flowed through in operation by a hot water circuit, for example, from a recooling device of the lubricating oil circuit of the punching machine. This is the warm water first through the flow channels 10d, 10e, 10h, 10i closest to the boundaries of the aperture 6b in the machine bed 5, then through the inner and middle flow channels 10c, 10f, 10g, 10j arranged next to these, and finally through the outer flow channels 10a, 10b, 10k, 101. In this case, the intermediate plate 11 is heated by the hot water circuit and in turn heats the adjoining them contact surfaces of the machine bed 5 and the platen 4. This in turn, the machine bed 5 is heated more in its upper region than in its lower region, where ^¬ by it due to differential thermal expansion upwards, ie in the direction of the plunger 2, warps.

Since the heating is greatest here by the flow channels 10d, 10e, 10h, 10i closest to the boundary walls of the opening 6b, the machine bed 5 curves more strongly upwards in the areas adjacent to the opening 6b than in the areas of the longitudinal sides , which are less strongly heated by the outer flow channels 10a, 10b, 10k, 101. The clamping plate 4, which is connected to the machine bed 5 in a shear-resistant manner via the intermediate plate 11 and is formed from a material with a greater coefficient of thermal expansion than the material of the machine bed 5, introduces additional thrust forces into the machine bed 5 which reinforce its upward warping , As in the case of the embodiment according to FIG

Punching force to compensate for this warping, which ideally leads to the fact that the machine bed 5 is flat under maximum punching load both in the longitudinal and in the transverse direction, that is not warped or not bent. This solution has the advantage that existing machines with a corresponding intermediate plate 11 can be easily converted to a punch press according to the invention. Fig. 5 shows a section through the machine base of the stamping machine along the line XX in Fig. 1, as it is formed according to a third embodiment of the invention. As can be seen, here, the outer contours of the platen 4 and the machine bed 5 are substantially identical to those of the embodiment of FIG. 2, and also the internal structure of the machine bed 5 is substantially identical to that of the machine bed of FIG. 2. However, here the machine bed 5 is penetrated in its lower region by two tie rods 19 extending in the longitudinal direction of the machine bed, with which the machine bed 5 is subjected to compressive stress in its lower region, in order to buckle the machine bed 5 in the direction of the press ram 2. The tie rods 19 are arranged symmetrically on both sides of the opening 6b of the machine bed 5, such that they each have a smaller distance from the opening 6b than to the respective longitudinal side of the machine bed 5.

Since, by this arrangement, the tie rod 19 is placed under compressive stress most strongly by the tie rods 19, the regions of the machine bed 5 closest to the boundary walls of the aperture 6b, the machine bed 5 buckles more strongly in the regions adjacent to the aperture 6b in the areas of the long sides. The clamping plate 4, which is connected via a plurality of screws to the machine bed 5, warps together with the machine bed 5. As in the embodiments according to Figures 3 and 4, it comes in operation under the load by the punching force to compensate for this Warping, which ideally leads to the machine bed 5 is flat under maximum punching load both in the longitudinal and in the transverse direction, ie not warped or not bent.

As can be seen in FIG. 6, which shows a longitudinal section through the substructure from FIG. 5 Line XX in Fig. 5, the tie rods 19 are each set between a nut 12 and an adjustable biasing device 13, 14, 15, 16, 17, 18 under tension. The biasing device 13, 14, 15, 16, 17, 18 comprises a clamping nut 13 with an actuating arm 16, which can be rotated by a hydraulic cylinder 15 by about 90 °, for adjusting the tension of the tie rod 19, and a discharge device with a hydraulic Piston / cylinder arrangement 14, 17, 18, by means of which the tie rod 19 can be preloaded temporarily hydraulically, to relieve the clamping nut 13 when setting the same. After adjusting the clamping nut 13, the hydraulic piston / cylinder assembly 14, 17, 18 is switched ineffective for the operation of the press.

On the underside of the machine bed 5, below each tie rod 19, a strain gauge 20 is arranged, by means of which the length shortening of the machine bed 5 in this area can be measured as a result of the pressure stress applied by the tie rods 19.

This third embodiment of the invention has the advantage that the adjustment of the warping of the machine bed 5 is instantaneous and that the deformation forces or the resulting deformations of the machine bed 5 are easily controllable.

Claims

claims

1. A method for buckling the machine bed (5) of a punch press for at least partially compensating a punching force-induced deflection in the punching operation, wherein the machine bed (5) has an opening (6b) for removing punched parts and waste,

characterized in that forces acting transversely to the punching force direction are introduced into the machine bed (5) or are produced in the machine bed (5), for arching the machine bed (5) in the direction of the press ram (2) such that the machine bed (5) in the area adjacent to the opening (6b) is more warped than in the areas adjacent to its longitudinal sides.

2. The method of claim 1, wherein the machine bed (5) is set with in its longitudinal direction extending tie rods (19) in its lower region under compressive stress, the same for buckling in the direction of the press ram (2).

3. The method of claim 2, wherein the tie rods (19) are arranged such that they pass through the machine bed (5) in its lower region.

4. The method according to any one of claims 2 to 3, wherein on both sides of the opening (6b) of the machine bed (5), in particular symmetrically to both sides of the opening (6b), in each case a tie rod (19) is arranged such that the tie rod (19 ) each having a smaller distance from the opening (6b) than the respective longitudinal side of the machine bed (5).

5. The method according to any one of the preceding claims, wherein within the machine bed (5) or

a support structure formed with the machine bed (5)

(4, 5, 11) for the lower tool parts, a temperature gradient is generated, through which the machine bed

(5) to buckle in the direction of the press ram (2).

6. The method of claim 5, wherein the temperature gradient is generated by heating the machine bed (5) in the region of the press ram (2) facing side.

A method according to claim 6, wherein the machine bed (5) is heated more near the boundaries of the aperture (6b) than near its longitudinal sides.

8. The method according to any one of claims 5 to 7, wherein the temperature gradient by cooling the machine bed (5) in the region of the press ram (2) facing away from the side is generated.

9. The method of claim 8, wherein the machine bed is cooled more near the boundaries of the aperture than near the longitudinal sides.

10. The method according to any one of claims 5 to 9, wherein within the machine bed (5) arranged flow channels (10a-10f) with a heated or cooled gaseous or liquid medium (8) are flowed through to generate the temperature gradient.

A method according to claim 10, wherein heated lubricating oil (8) of a lubricating oil circuit of the press is passed through the flow channels (10a-10f).

12. The method according to any one of claims 5 to

11, wherein disposed within the machine bed electrical heating elements are supplied with electric current, for generating the temperature gradient.

13. The method according to any one of claims 5 to

12, wherein there is a clamping plate arranged on the machine bed, which is heated, for buckling of the machine bed in the direction of the press ram, due to heating of the same by means of the clamping plate on its side facing the ram and / or buckling of the machine bed in the direction on the press ram to as a result of an introduction of by a thermal expansion of the platen generated thrust forces in the tappet side facing the machine bed.

14. The method according to any one of claims 5 to 11, wherein on the machine bed (5) arranged platen (4) is present and between the machine bed (5) and the clamping plate (4) arranged heating device (11) which is heated, for warping the machine bed (5) in the direction of the press ram (2) as a result of heating it by means of the

Heating device (11) on its side facing the plunger (2) and / or buckling of the machine bed (5) in the direction of the press ram (2) due to heating of the platen (4) by means of the heating device (11) and a Initiation of shear forces generated by a thermal expansion of the platen (4) in the side of the machine bed (5) facing the plunger (2).

15. The method according to any one of the preceding claims, wherein the warping of the machine bed in

Depending on parameters of the stamping process is set, in particular depending on a calculated or measured maximum punching force, and in particular, wherein the warpage during the intended operation of the press is set.

16. punching press, in particular for carrying out the method according to one of the preceding claims, with a machine bed (5) and with a against the machine bed (5) working press ram (2),

wherein means (8, 9a, 9c, 10a-10f; 10a-101,

11; No 12-19) are (for warping of the machine ^¬ bed 5) (in the direction of the press ram 5) to by introducing acting transversely to the cutting force direction forces in the machine bed (5) and / or by generating acting transversely to the cutting force direction forces in the machine bed (5), and wherein the machine bed (5) has an opening (6b) for removing punched parts and waste, and the means (8, 9a, 9c, 10a-10f; 10a-101, 11; 12-19) for warping the machine bed (5) are formed such that they more strongly warp the machine bed (5) in the area adjacent to the opening (6b) than in the areas adjacent to the longitudinal sides of the machine bed (5).

17, punching press according to claim 16, wherein the means (12-19) for buckling of the machine bed in the longitudinal direction of the machine bed extending tie rods (19), with which the machine bed (5) can be placed in its lower region under compressive stress, for Ver ^¬ arching the machine bed (5) in the direction of the press ram (2).

18. Punching press according to claim 17, wherein the tie rods (19) pass through the machine bed (5) in its lower region.

19. Punching press according to one of claims 17 to 18, wherein on both sides of the opening (6b) of the machine bed (5) each have a tie rod (19) is arranged, such that the tie rod (19) each have a smaller distance from the opening (6b) as the respective longitudinal side of the machine bed (5).

20. Punching press according to claim 19, wherein the two tie rods (19) are arranged symmetrically to both sides of the opening (6b).

21. Punching press according to one of claims 16 to 20, wherein the means (8, 9a, 9c, 10a-10f; 10a-101, 11) for buckling the machine bed (5) are designed to generate a temperature gradient within the machine bed (5). or a support structure (4, 5, 4, 5, 11) formed with the machine bed (5) for the lower tool parts for generating the forces acting transversely to the punching force direction for buckling the machine bed in the direction of the press ram.

22. Punching press according to claim 21, wherein the means (8, 9a, 9c, 10a-10f, 10a-101, 11) for warping the machine bed (5) are designed to heat the machine bed (5) in the region of the press ram (2 ) facing side.

23. Punching press according to claim 22, wherein the means (8, 9a, 9c, 10a-10f; 10a-101, 11) for buckling the machine bed (5) are formed around the machine bed (5) in the region of the press ram (2). towards the edges of the aperture (6b) more than near its longitudinal sides.

24. Punching press according to one of claims 21 to 23, wherein the means for buckling of the machine bed are formed for cooling the machine bed in the region of its side facing away from the press ram.

25. Punching press according to claim 24, wherein the means for arching the machine bed are designed to cool the machine bed in the region of its side facing away from the press ram in the vicinity of the boundaries of the opening stronger than in the vicinity of its longitudinal sides.

26. Punching press according to one of claims 21 to 25, wherein the means (8, 9a, 9c, 10a-10f) for arching the machine bed (5) within the machine bed (5) arranged flow channels (10a-10f), which during normal operation of the press with a heated or cooled gaseous or liquid medium (8) are flowed through, for generating the temperature turgradienten.

27. Punching press according to claim 26, wherein the press comprises a lubricating oil circuit and the means for arching the machine bed comprise means with which in the intended operation of the press heated lubricating oil of the lubricating oil circuit through the flow channels (10a-10f) can be performed.

28. The punch press as claimed in claim 21, wherein the means for arching the machine bed comprise electrical heating elements arranged inside the machine bed, which can be supplied with electric current during normal operation of the press, for generating the temperature gradient.

29. Punching press according to one of claims 26 to 28, wherein on both sides of the opening of the machine bed each one or more flow channels and / or electrical heating elements are arranged within the machine ^{bed ¬} , such that each side of the sum of the distances of the flow channels and / or heating elements each breakthrough is smaller than the sum of the distances of the flow channels and / or heating elements to the respective longitudinal side of the machine bed.

30. Punching press according to claim 29, wherein the flow channels and / or heating elements are arranged symmetrically to both sides of the opening.

31. Punching press according to one of claims 21 to 30, wherein a arranged on the machine bed platen is present, which is heated with the means for buckling of the machine bed during normal operation of the press, for generating the temperature gradient by heating the machine bed on his the plunger facing side by means of the clamping plate.

32. Punching press according to one of claims 21 to 31, wherein on the machine bed (5) arranged platen (4) is present, which with the means (8, 9a, 9c, 10a-10f 10a-101, 11) for buckling the Machine bed (5) during normal operation of the press is heated and which is so connected to the machine bed (5) that it can transmit shear forces on the machine bed (5), for buckling of the machine bed (5) in the direction of the press ram (2 ) due to an initiation of thermal expansion the clamping plate (4) generated thrust forces in the tappet (2) facing side of the machine bed (5).

33. Punching press according to claim 32, wherein there is a thermal insulation layer between the clamping plate and the machine bed for reducing heat transfer from the clamping plate to the machine bed.

34. The punch press of claim 33, wherein the thermal insulation layer in the areas adjacent to the longitudinal sides of the platen and the machine bed, respectively, between the platen and the machine bed are present and in the areas adjacent to the breakthrough, a layer between the On ^¬ clamping plate and the machine bed is present, which has a much better thermal conductivity, to promote a heat transfer from the on ^¬ clamping plate on the machine bed in these areas.

35. Punching press according to one of claims 31 to 34, wherein the clamping plate with the means for arching the machine bed during the intended operation of the press is heated such that it is warmer in the areas adjacent to the opening, as in the Areas adjacent to their long sides.

36. Punching press according to one of claims 21 to 35, wherein a on the machine bed (5) arranged platen (4) is present and wherein the means (10a-101, 11) for buckling of the machine bed (5) between the machine bed (5 ) and the platen (4) arranged heating means (11) which is operable during the intended operation of the press, for warping of the machine bed (5) due to heating thereof on its side facing the plunger (2) side.

37. Punching press according to one of claims 21 to 36, wherein on the machine bed (5) arranged platen (4) is present, which in such a way with the Machine bed (5) is connected, that it can transmit shear forces on the machine bed (5), and wherein the means (10a-101, 11) for buckling of the machine bed (5) between the machine bed (5) and the Aufspannplat- te ( 4) arranged heating means (11) operable during the intended operation of the press, for buckling of the machine bed (5) in the direction of the press ram (2) due to an initiation of by a thermal expansion of the platen (4) generated thrust forces in the tappet (2) facing side of the machine bed (5).

38. Punching press according to one of claims 36 to 37, wherein the heating device (11) arranged between the machine bed (5) and the clamping plate (4) is designed such that with it the areas of the machine bed (5) or the clamping plate (4), which adjoin the opening (6b), can be heated more strongly than the areas of the machine bed (5) or the clamping plate (4), which adjoin the longitudinal sides thereof.

39. Punching press according to one of claims 16 to 38, wherein the means for buckling of the machine bed are designed to be adjustable, in particular during the intended operation of the press, to enable a specific adjustment of the warping of the machine bed.

40. Punching press according to one of claims 16 to 39, wherein the punch press comprises a press control, with which the warping of the machine bed, in particular automatically, depending on parameters of the punching process is adjustable, in particular depending on a calculated or measured maximum punching force, and in particular during the intended operation of the press is adjustable.