Machine tool and process for machining bar stock

Abstract

A machine tool comprises a frame and a tool spindle mounted thereon, which is linearly movable in three translational axes relative to the frame, comprising a first horizontal axis, a second horizontal axis, and a vertical axis. The tool spindle is mounted vertically movable via a Z-slide on an X-slide along the vertical axis. The X-slide is mounted horizontally movable on a Y-slide along the first horizontal axis, and the Y-slide is mounted horizontally on the frame along the second horizontal axis. A primary workpiece holding unit, designed as a rotary spindle, and a secondary workpiece holding unit are mounted on the frame. The primary and secondary workpiece holding units are oriented towards each other and coaxially in at least one horizontal orientation.The primary workpiece holding unit is pivotable relative to the frame about a primary pivot axis oriented parallel to the second horizontal axis. The secondary workpiece holding unit is pivotable relative to the frame about a secondary pivot axis oriented parallel to the second horizontal axis. A production system utilizes such a machine tool. A process for machining bar stock utilizes such a production system.

Description

The present disclosure relates to a machine tool, a manufacturing facility, and a method for machining bar material. The machine tool has a frame, a tool spindle mounted on the frame, a primary workpiece holding unit mounted on the frame and configured as a rotary spindle, and a secondary workpiece holding unit mounted on the frame, wherein the primary workpiece holding unit and the secondary workpiece holding unit face each other in at least one horizontal orientation and are oriented coaxially with respect to each other. The machine tool and the manufacturing facility provided with such a machine tool are suitable in particular for machining rod material. In particular, the machine tool is suitable for turning milling and, if appropriate, even for complete machining.DE 10 2010 019 762 A1 discloses a machine tool for turning and milling, which has a tool spindle, a first workpiece spindle and a second workpiece spindle. The tool spindle is pivotable about a horizontal axis (B axis). The second workpiece spindle is part of a headstock which is likewise pivotable about a horizontal axis (B axis) parallel thereto. The first workpiece spindle is not pivotable about a horizontal axis (B axis) parallel thereto. The second workpiece spindle can be used for a workpiece change. Milling processing in five axes can be realized by the pivoting movement of the tool spindle.EP 1 818 136 A1 discloses a machine tool having a tool spindle, a first workpiece spindle and a second workpiece spindle. The two workpiece spindles are each pivotable about a pivot axis, and the second workpiece spindle is translationally movable. Workpieces can thus be transferred between the two workpiece spindles. Furthermore, so-called six-side machining is possible.Keywords such as sustainability and resource efficiency are becoming increasingly important. Against this background, there is a need for compactly designed machine tools with which workpieces of specific dimensions can be processed efficiently. In other words, the aim is to adapt machine tools to specific workpieces with regard to the working space, the required travel paths and / or the electrical connection power. It is thus possible to prevent compact workpieces from being machined using excessively large machine tools. This applies, for example, to typical workpieces in the field of precision mechanics, medical technology, the decorative industry and / or the watch industry. Other applications are conceivable. If a favorable relationship is given between the dimensions of the workpieces to be machined and the working space of the machine tool, the area consumption, the energy consumption and the other resource consumption by the machine tool can be optimized.Against this background, the present disclosure is based on the object of specifying a machine tool and a production installation having a machine tool which, with a compact configuration, permit efficient machining. In particular, the machine tool should be suitable for the complete machining of workpieces based on rod material. In exemplary embodiments, the semi-finished products used are rods with cross sections with a diameter and / or edge dimension of less than 50 mm, less than 30 mm or even 26 mm or less. Workpieces which are produced on the basis of such semi-finished products are intended to be able to be produced particularly efficiently with the machine tool. Preferably, the concept of the machine tool takes into account the desired compact design. In particular, the machine tool should have a favorable ratio of the working space provided and the area consumption / space consumption. Furthermore, a production plant with such a machine tool and a workpiece magazine adapted to the design of the machine tool is to be specified. Finally, a method for processing rod material is to be specified which uses such a production plant.In a first aspect, the present disclosure relates to a machine tool including:a frame,a tool spindle mounted on the frame, which is linearly movable in three translatory axes relative to the frame, comprising a first horizontal axis, a second horizontal axis and a vertical axis, wherein the tool spindle is mounted on an X slide via a Z slide in a vertically movable manner along the vertical axis, wherein the X slide is mounted on a Y slide in a horizontally movable manner along the first horizontal axis, and wherein the Y slide is mounted on the frame in a horizontally movable manner along the second horizontal axis,a primary workpiece holding unit mounted on the frame and designed as a rotary spindle, anda secondary workpiece holding unit mounted on the frame,wherein the primary workpiece holding unit and the secondary workpiece holding unit face each other in at least one horizontal orientation and are oriented coaxially with respect to each other,wherein the primary workpiece holding unit is pivotable relative to the frame about a primary pivot axis which is oriented parallel to the second horizontal axis, andwherein the secondary workpiece holding unit is pivotable relative to the frame about a secondary pivot axis which is oriented parallel to the second horizontal axis.The object of the disclosure is achieved in this way. According to the disclosure, namely, the pivotability of the primary workpiece holding unit and of the secondary workpiece holding unit allows a machine kinematics in which the tool spindle is moved exclusively in translation. In other words, the tool spindle according to this embodiment is not provided with a pivot drive. It is understood that the tool spindle is designed for rotating a tool about a spindle axis.The tool spindle can accordingly be made compact. If a pivot drive is dispensed with at the tool spindle, the tool spindle can be designed to be displaceable easily in three translatory axes. Nevertheless, inertia masses can be limited because no expensive pivot drive has to be integrated into such a design. This can have a favourable effect on the dynamics and the acceleration behavior. Furthermore, the rigidity is increased in this way because the compact configuration leads to a significantly reduced tendency to deform during the machining.The travel paths in the X direction, the Y direction and the Z direction can be adapted to workpiece dimensions to be expected. With a single tool spindle, multi-side machining, in particular complete machining and / or six-side machining, can be carried out. This can be done with high resource efficiency, for example with regard to installation space, energy consumption and / or consumption of cooling lubricant (CSS).In particular, the machine tool is designed for turning milling. Preferably, a complete machining can be realized with the machine tool if the workpiece is transferred directly between the primary workpiece holding unit and the secondary workpiece holding unit without any further handling effort.The primary workpiece holding unit and the secondary workpiece holding unit face each other in at least one operating position and are oriented coaxially with respect to each other and are offset axially from each other. At least the primary workpiece holding unit is designed as a rotary spindle. In this way, turning with a stationary tool is possible. The coaxial orientation can also be referred to as the common rotational orientation. In the coaxial orientation, a workpiece may be attached to both the primary workpiece holding unit and the secondary workpiece holding unit. At least in exemplary embodiments, the primary workpiece holding unit and the secondary workpiece holding unit can each hold the workpiece alone at least temporarily, so that corresponding end regions can be machined which are not accessible when the respective other workpiece holding unit engages the workpiece.The pivotability of the primary workpiece holding unit and of the secondary workpiece holding unit can furthermore be used for a workpiece transfer through the machine tool. For example, the working space of the machine tool can be loaded through the primary workpiece holding unit. According to this embodiment, the primary workpiece holding unit is designed as a hollow spindle.For example, the primary workpiece holding unit has, in addition to the primary pivot axis, a further pivot axis (so-called A axis), which is provided by the rotary spindle. In this way, five-axis machining of workpieces which are clamped into the rotary spindle is made possible.The tool spindle is exclusively linearly movable and does not provide an additional pivot axis. The primary work holding unit provided with a rotating spindle provides a rotational axis. The secondary workpiece holding unit may also provide a rotational axis (in the form of a counter spindle), at least in exemplary embodiments.The machine tool according to the disclosure is suitable for turning and milling. When a workpiece is held by both the primary and secondary workpiece holding units simultaneously, the workpiece can be machined in four axes. If the workpiece is clamped on only one side, the workpiece can be machined in five axes. When the workpiece is transferred between the primary and secondary workpiece holding units, six-axis machining is permitted.In the rotational orientation, the longitudinal axis (rotational axis) of the workpiece is oriented parallel to the X axis. The X-axis is oriented horizontally. The Y axis is orthogonal to the X axis and also horizontally oriented. The X-axis and the Y-axis form a horizontal plane. The Z axis is oriented orthogonally to the X axis and orthogonally to the Y axis. The Z axis is a vertical axis. A longitudinal axis (axis of rotation) of the tool spindle is permanently oriented vertically and consequently parallel to the Z axis.In an exemplary embodiment, the Y carriage has an inclined bed on which the X carriage is guided. An X guide serves to guide the X slide. An inclination of the X-guide relative to the horizontal lies approximately in the range between 30° and 60°, in particular in the range between 40° and 50°, in particular at approximately 45°. This results in a compact and highly rigid design. This leads to a low deformation tendency of the machine kinematics during operation of the machine tool.According to a further exemplary embodiment, the frame has a flat bed on which the Y carriage is guided. A Y-guide serves for guiding the Y-slide. The Y-guide is formed, for example, on an upper side of the machine frame.According to a further exemplary embodiment, the X carriage has a vertical end wall on which the Z carriage is guided. The vertical end wall carries a Z-guide on which the Z-slide is guided. The vertical end wall faces the working space. The Z-slide carries the vertically oriented tool spindle.In an exemplary embodiment, the travel path of the tool spindle in the X direction is greater than the travel path of the tool spindle in the Z direction. Furthermore, the travel path of the tool spindle in the Z direction is greater than the travel path of the tool spindle in the Y direction.According to a further exemplary embodiment, the secondary workpiece holding unit is translationally movable along a linear axis which is oriented parallel to the first horizontal axis. In other words, the secondary workpiece holding unit is thus translationally movable in the X direction.In this way, a distance between the primary workpiece holding unit and the secondary workpiece holding unit in the X direction can be changed. This simplifies, by way of example, the transfer of the workpiece between the primary workpiece holding unit and the secondary workpiece holding unit. This can also include, by way of example, rear-side machining / end machining of the workpiece on its sixth side, which has been previously covered by the primary workpiece holding unit.Furthermore, the secondary workpiece holding unit can be used during loading and / or unloading. Approximately when semi-finished products in the form of rod material are supplied to the working space by the (hollow) rotating spindle of the primary workpiece holding unit, the secondary workpiece holding unit can grip a front end of the semi-finished product and pull it along the first horizontal axis. This is not to be understood as restrictive. The degrees of freedom of the primary workpiece holding unit and of the secondary workpiece holding unit allow at least partially automated workpiece handling. In this way, a rod magazine (rod loader) coupled to the machine tool can be of simple design, for example, because the machine tool itself can assume transfer tasks with the given kinematics.Further, in this manner, the secondary workpiece holding unit can move the workpiece in the horizontal orientation relative to the primary workpiece holding unit in the direction of the first horizontal axis (X direction). Thus, the workpiece can be pulled out from the primary workpiece holding unit. Further, in this manner, a separated portion of the workpiece clamped in the secondary workpiece holding unit can be moved away from the primary workpiece holding unit.In an exemplary embodiment, the primary workpiece holding unit is mounted on the frame such that it cannot move in translation in the first horizontal direction X, the second horizontal direction Y and the vertical direction Z. In an exemplary embodiment, the secondary workpiece holding unit is mounted on the frame such that it cannot move in the second horizontal direction Y and the vertical direction Z and the vertical direction Z. In an exemplary embodiment, the primary workpiece holding unit provides only the primary pivot axis and the pivot axis.In an exemplary embodiment, the frame has a primary frame section on which the tool spindle and the primary workpiece holding unit are accommodated, and a secondary frame section on which the secondary workpiece holding unit is accommodated. In this way, the tool spindle, the primary workpiece holding unit and the secondary workpiece holding unit can be positioned favorably relative to one another. In an exemplary embodiment, the primary workpiece holding unit is mounted in a cantilevered manner on the primary frame section; this applies in particular to the mounting of the primary pivot carrier. In an exemplary embodiment, the secondary workpiece holding unit is mounted in a cantilevered manner on the secondary frame section; this applies in particular to the mounting of the secondary pivot carrier.According to a further exemplary embodiment, an X-guide for the secondary workpiece holding unit is arranged on the frame at the secondary frame section. Alternatively or additionally, a Y-guide for the tool spindle is arranged in the primary frame section. Thus, the regions in which linear guides are arranged on the frame are provided in different regions and are spaced apart from one another.According to another exemplary embodiment, the secondary rack portion provides a flat bed supporting the X-guide. In other words, for example, the primary frame section has an upper side which carries the Y guide for the tool spindle. Further, the secondary frame portion has an upper surface that supports the X guide for the secondary workpiece holding unit. This results in a compact construction of the frame, namely also with regard to the height extension (in the Z direction).According to a further exemplary embodiment, the frame has a recess between the primary frame section and the secondary frame section, which recess provides a free space for a pivoting movement of the primary workpiece holding unit and / or of the secondary workpiece holding unit. In an exemplary embodiment, the frame thus has a common base, as well as structures which extend vertically upwards from the base and form the primary frame section and the secondary frame section. In an exemplary embodiment, the frame is approximately U-shaped when viewed from a cross-sectional plane that is parallel to the Y-Z plane, wherein one leg of the (upright) U is assigned to the primary frame section and the other leg of the U is assigned to the secondary frame section. The base of the U then faces the ground.In an exemplary embodiment, the recess extends through the frame in the X direction. In this way, both for the primary workpiece holding unit and for the secondary workpiece holding unit there is sufficient free space for the respective pivoting movement during pivoting about the primary pivot axis and the secondary pivot axis.In an exemplary embodiment, the primary workpiece holding unit and the secondary workpiece holding unit can be pivoted in opposite directions starting from a common coaxial orientation, for example during the transition between a horizontal orientation and a vertical orientation. In other words, an observer who looks at the working space on a side opposite the tool spindle sees a clockwise pivoting movement in the one workpiece holding unit and a counter-clockwise pivoting movement in the other workpiece holding unit during the transition between the horizontal orientation and the vertical orientation.The pivotal range of the primary workpiece holding unit and the secondary workpiece holding unit is, for example, at least 90° (angular degree). In an exemplary embodiment, the primary workpiece holding unit and the secondary workpiece holding unit are pivotable by at least 90° between a horizontal orientation and a vertical orientation. The pivot range comprises, for example, between -10° and +100° or between +10° and -100°, if 0° corresponds to a horizontal orientation and 90° or -90° corresponds to a vertical orientation, depending on the direction of rotation.In the vertical orientation, the primary workpiece holding unit and the secondary workpiece holding unit usually assume a stationary orientation, in contrast to the suspended tool spindle. In the upright orientation, a clamped workpiece would protrude vertically upward in the direction of the tool spindle starting from the workpiece holding unit.The recess in the frame thus provides sufficient free space for the pivoting movement of the primary workpiece holding unit and the secondary workpiece holding unit. This allows a particularly compact design of the machine tool because the installation space there (below the horizontally oriented rod material) is present anyway. The primary frame section and the secondary frame section carry linear guides for the tool spindle and the secondary workpiece holding unit. The space between the primary frame portion and the secondary frame portion is suitable for the recess. An advantage is that the primary workpiece holding unit and the secondary workpiece holding unit can be pivoted downward starting from the horizontal orientation in order to assume a vertical orientation. By such a pivoting movement "downward", the respective workpiece can be pivoted "upward" and presented to the tool spindle in a favorable manner.According to a further exemplary embodiment, the primary workpiece holding unit and the secondary workpiece holding unit protrude from the frame in the same direction, in particular in the direction of a side of the working space facing an operator. In other words, according to this configuration, the primary workpiece holding unit and the secondary workpiece holding unit are arranged with their pivot supports not on opposite frame sections, but on one and the same frame section. In this way, both workpiece holding units can be positioned with their pivot axes in a manner that is advantageously visible to an operator. Furthermore, the base area of the frame and of the machine tool can be further reduced overall.According to a further exemplary embodiment, the linear axis of the secondary workpiece holding unit is arranged on the frame below the Y guide for the second horizontal axis and in particular below the X guide for the first horizontal axis. The frame can thus have guide sections spaced apart from one another in the Z direction along its vertical extension (Z extension), wherein the X guide for the linear axis of the secondary workpiece holding unit is arranged first and the Y guide for the second horizontal axis is arranged spaced apart therefrom. The Y-guide for the second horizontal axis in turn carries the Y-carriage on which the X-guide for the first horizontal axis is formed.According to a further exemplary embodiment, the frame is designed as a stand which has an end wall over which pivot carriers of the primary and the secondary workpiece holding unit project, in particular in the direction of an operator side. This also ensures a good overview in the working space.According to a further exemplary embodiment, the frame has a frame opening below the Y carriage, in which the secondary workpiece holding unit is mounted and can be moved translationally along the linear axis. By way of example, a flat bed is formed at the base of the frame opening, which flat bed carries the X-guide for the linear axis of the secondary workpiece holding unit.According to a further exemplary embodiment, an X-guide for the secondary workpiece holding unit is arranged in the frame opening, and / or wherein a Y-guide for the Y-slide is arranged above the frame opening in the frame. If the X-guide is formed on a flat bed of the frame and also the Y-guide for the second horizontal axis is formed on a flat bed of the frame, the frame has two flat beds which are offset vertically with respect to one another, one of which is arranged, for example, on an upper side of the frame and another is arranged in the frame opening.According to a further exemplary embodiment, the frame has a first cheek and a second cheek, between which the frame opening is formed, and wherein the frame in particular comprises an upper cross member, which extends from the first cheek to the second cheek. In this way, a high rigidity is obtained even with a compact design. The frame opening provides sufficient space for the movable secondary workpiece holding unit.According to a further exemplary embodiment, the frame opening comprises a Y-recess which extends parallel to the second horizontal axis and an X-recess which extends parallel to the first horizontal axis, wherein the X-recess opens into the Y-recess. By way of example, the X-recess extends in the first horizontal direction (X-direction) through only one of the two cheeks of the frame. By way of example, the Y-recess extends completely through the frame in the second horizontal direction (Y-direction).According to a further exemplary embodiment, the X-recess penetrates the frame outwards starting from the Y-recess. This allows good accessibility. In this way, the Y-recess is accessible from three sides.According to a further exemplary embodiment, the X-recess accommodates a drive for the translatory movement of the secondary workpiece holding unit. The drive can thus be integrated in a favorable manner with little additional installation space requirement.According to a further exemplary embodiment, the tool spindle is a permanently vertically oriented tool spindle, wherein the tool spindle is in particular the only tool spindle of the machine tool. By way of example, the tool spindle is a suspended spindle, in which the tool protrudes downward from a tool holder of the tool spindle. According to an exemplary embodiment, the vertically oriented tool spindle is designed free of pivot drive.According to a further exemplary embodiment, the secondary workpiece holding unit is designed as a pivotable counter spindle, pivotable round table and / or as a pivotable gripper. For example, the secondary workpiece holding unit is designed at least as a gripper that is pivotable about the secondary pivot axis. For example, the secondary workpiece holding unit is designed as a round table with a holding function (for example as a gripper) for the workpiece, which table can be pivoted about the secondary pivot axis. For example, the secondary workpiece holding unit is designed as a counter spindle (with rotary drive) and workpiece clamping unit that can be pivoted about the secondary pivot axis. When designed as a pivotable round table or as a pivotable counter spindle, the secondary workpiece holding unit can additionally provide a pivot axis (A axis) for pivot movements about the longitudinal axis of the workpiece.For machining operations in which the workpiece is clamped both on the primary workpiece holding unit and in the secondary workpiece holding unit, the secondary workpiece holding unit can also be designed as a revolving workpiece holding unit if the drive is effected (at least temporarily) exclusively via the primary workpiece holding unit.When the secondary workpiece holding unit is configured as a counter spindle or a pivotable rotary table, a workpiece clamped in the secondary workpiece holding unit can be machined in five axes. This can be used for the rear side processing. Together with the primary workpiece holding unit, a complete machining in six axes is made possible when the workpiece is transferred between the primary workpiece holding unit and the secondary workpiece holding unit.If the secondary workpiece unit is configured as a pivotable gripper, a workpiece which is clamped in the secondary workpiece holding unit can be machined in at least four axes. This can be used for rear side processing.According to a further exemplary embodiment, the primary workpiece holding unit and the secondary workpiece holding unit have pivot carriers configured as identical parts. This simplifies the construction of the machine tool, and the outlay for maintenance and repair can also be reduced as a result. Furthermore, in this way, similar positioning tolerances about the primary pivot axis and the secondary pivot axis result in the primary workpiece holding unit and the secondary workpiece holding unit.According to a further exemplary embodiment, the pivot carrier of the secondary workpiece holding unit is pivotably mounted on an X slide which is translationally movable relative to the frame in a secondary horizontal linear axis parallel to the first horizontal axis. The X carriage of the secondary workpiece holding unit can also be referred to as a secondary X carriage.According to a further exemplary embodiment, the pivot carrier of the primary workpiece holding unit is pivotably mounted on the frame. In particular, the pivot carrier of the primary workpiece holding unit is pivotably mounted on the primary frame section.According to a further exemplary embodiment, the pivot carrier of the primary workpiece holding unit is pivotably mounted in a pivot housing which is arranged in a frame opening in the frame and is fixedly connected to the frame. The primary workpiece holding unit is not movable relative to the frame, but is, for example, screwed and / or bolted to the frame.By way of example, the frame opening is an opening in the primary frame section, which extends through the primary frame section parallel to the second horizontal axis (Y direction). In other words, the frame opening extends through the primary frame section between a side of the primary frame section facing the working space and a side of the primary frame section facing away from the working space.The installation space on the frame, which is produced by the extent of the X slide in the first horizontal direction (X direction) and the Y guide adapted thereto, is thus used favorably. This may include a configuration in which the primary stage portion has two spaced-apart cheeks forming the Y guide, and the stage opening in which the primary workpiece holding unit is disposed is formed between the two cheeks. This does not exclude that the frame opening is large enough to additionally provide access for workpiece handling, tool handling or the like.According to a further exemplary embodiment, the primary rotary spindle is designed as a pivotable hollow spindle which has a clamping unit for holding an inserted semi-finished product.In this way, semi-finished products can be inserted into the hollow spindle on a rear side. This simplifies the loading of the machine tool. At the front, at least one section of the semi-finished product can protrude from the hollow spindle and protrude beyond the latter. This section then serves as a workpiece.In other words, the primary workpiece holding unit is suitable for receiving and handling bar material. It can be round material, but also material with a non-round cross section. The primary workpiece holding unit is configured to fully receive bar stock of a certain length. On the basis of this semi-finished product, a plurality of sections can then be defined in which a workpiece is produced in each case one after the other. In other words, the portion serving as the raw material for the workpiece does not have to be separated from the rod beforehand. The rod may be fully received by the primary workpiece holding unit. A separation of the workpiece from the rod material can take place when the primary workpiece holding unit and the secondary workpiece holding unit simultaneously hold the rod material. This can also be used for a rod feed which is made possible by the translatory movement of the secondary workpiece holding unit.After machining the workpiece in this state, the secondary workpiece holding unit can grip the workpiece. At least temporarily, the workpiece may be held stationary by both the primary and secondary workpiece holding units. The workpiece can then be separated from the semi-finished product and thus also from the primary workpiece holding unit. The resultant back surface may be processed as needed when the workpiece is held by the secondary workpiece holding unit.According to a further exemplary embodiment, the rotary spindle of the primary workpiece holding unit has an externally actuatable clamping unit for clamping the semi-finished product. In an exemplary embodiment, the clamping unit can be actuated externally in a horizontal orientation of the primary workpiece holding unit.In this way, the rotary spindle can be designed to be particularly compact. This has an advantageous effect during the pivoting movement. The clamping unit can be activated by external elements which can act on the clamping unit, for example, in the horizontal orientation. In this way, a clamping device is created which is installed partly inside the rotary spindle and partly outside the rotary spindle. For example, the clamping unit can basically be operated in the orientation of the primary workpiece holding unit, in which loading with bar material would also take place.It is also advantageous if there is sufficient free space on the frame of the machine tool so that the rotary spindle with a semi-finished product clamped there can be pivoted at least in certain angular ranges. The maximum length of the usable semi-finished product is usually adapted to the possible installation space and the desired pivot angles.According to a further exemplary embodiment, the frame of the machine tool is seated on a substructure, the height (Z-extension) of which has at least half the height (Z-extension) of the frame of the machine tool. This unders emphasises the compact design, and for a favorable position of the working space, the frame of the machine tool can be arranged in an elevated manner. In an exemplary embodiment, the static stiffness of the machine tool is obtained independently of the substructure. In this way, the substructure has only a slight influence on the operating state of the machine tool. In other words, the frame of the machine tool can also be used without the substructure from a rigidity point of view. In other words, the frame is rigid and self-supporting in itself according to this embodiment. The substructure serves only for increased arrangement, at least in exemplary embodiments.According to a further aspect, the present disclosure relates to a production plant having a machine tool according to at least one of the configurations described herein, a rod magazine for receiving and providing rod-shaped semi-finished products, and having a loading mechanism which is designed to introduce semi-finished products into the rotary spindle at least in a horizontal position of the primary workpiece holding unit.The rod magazine can be designed as a short rod magazine. The rod magazine and the loading mechanism can together form a rod loader with which rod material can be provided and loaded.According to an exemplary embodiment, the length of the semi-finished products provided is adapted to an installation space provided for the pivoting movement of the primary workpiece holding unit. In other words, the rod magazine is therefore designed to receive and provide rods of a specific length which can be taken over completely by the primary workpiece holding unit designed as a rotary spindle during loading. The design of the machine tool allows the pivoting movement of the primary workpiece holding unit about the primary pivot axis when using such rods.By way of example, the rods have a length of at most 800 mm. By way of example, the rods have a length of not more than 600 mm. By way of example, the rods have a length of at most 500 mm. The required installation space is obtained by the desired pivot range.In an exemplary embodiment, the travel paths of the tool spindle in the X direction are approximately 320 mm, in the Y direction approximately 75 mm and in the Z direction approximately 120 m. In this way, the kinematics of the machine tool are well suited for machining short rods. Applications are found, for example, in medical technology, fine mechanics, and the watch and decorative industry. Other fields of application are conceivable.By way of example, a diameter (or maximum of the cross-sectional profile) of the rod material is 30 mm or less. By way of example, a diameter (or maximum of the cross-sectional profile) of the rod material is 26 mm or less. The rods may be round profiles or other profiles. Usually, they are rods made of steel materials. Other materials are also conceivable, for example light metals and the like.This can result overall in an extremely compact design. Workpieces which can be produced on the basis of the given dimensions (for example bars with a length of 500 mm and a diameter of 26 mm) can be produced particularly efficiently and with low resource consumption.In an exemplary embodiment, the loading mechanism has a slide which displaces strand-shaped semi-finished products linearly in the first direction in order to insert them into the rotary spindle of the primary workpiece holding unit.According to a further exemplary embodiment, the production plant further comprises an actuation unit mounted indirectly or directly on the frame for a clamping unit of the rotary spindle of the primary workpiece holding unit. Thus, the clamping unit of the rotary spindle can be operated externally. In this way, the rotary spindle can be made compact. By way of example, a clamping unit of the rotary spindle has a spring assembly or the like, wherein a relief of the spring assembly is made possible by using the external actuating unit.According to a further exemplary embodiment, the actuating unit is designed to act on the clamping unit of the rotary spindle in a horizontal orientation of the primary workpiece holding unit in order to activate or deactivate the latter. In the horizontal orientation, a rod feed can take place. In the horizontal orientation, loading with a new rod can also take place.According to a further exemplary embodiment of the manufacturing plant, a common control is provided for the loading mechanism, the primary workpiece holding unit, the secondary workpiece holding unit and the actuating unit for the clamping unit, such that a semi-finished product introduced into the rotary spindle can be displaced step by step in order to produce a plurality of workpieces one after the other. In other words, the rod material can be processed in sections in order to produce a plurality of workpieces one after the other. The partial displacement can comprise a pulling by the secondary workpiece holding unit and / or a pushing by a slider of the loading mechanism.According to a further aspect, the present disclosure relates to a method for processing bar material with a production plant according to at least one of the configurations described herein, having the following steps:providing at least one semi-finished product by the rod magazine,positioning the primary workpiece holding unit in the horizontal orientation for receiving the semi-finished product,loading the rotating spindle of the primary workpiece holding unit with the loading mechanism,machining of the semi-finished product for producing at least one workpiece, comprising a rotational movement of the rotary spindle and a rotational movement of the primary workpiece holding unit for producing the desired contour, wherein the machining takes place with the tool spindle, which can be moved linearly in three translatory axes relative to the workpiece,holding the workpiece with the secondary workpiece holding unit,separating the workpiece from the semi-finished product in a state in which the primary workpiece holding unit and the secondary workpiece holding unit hold the workpiece together, andmachining a previously inaccessible rear side of the workpiece held by the secondary workpiece holding unit.The object of the disclosure is also achieved in this way.It is understood that the workpiece can also be held at least temporarily simultaneously by the primary workpiece holding unit and the secondary workpiece holding unit. This allows, for example, turning machining with a workpiece supported on both sides.According to a further exemplary embodiment, the loading of the rotary spindle of the primary workpiece holding unit with the loading mechanism comprises an actuation of a clamping unit of the rotary spindle by an external actuation unit, in the horizontal orientation of the primary workpiece holding unit. In this way, a clamping unit integrated into the rotary spindle can be operated externally.According to a further exemplary embodiment, after the separation of the workpiece from the semi-finished product, the secondary workpiece unit with the workpiece clamped there is moved translationally along a linear axis parallel to the first horizontal axis in order to make the workpiece accessible for the further processing of the rear side and subsequent handling. In this way, a sixth side of the workpiece can be machined.According to a further exemplary embodiment, the machining of the previously inaccessible rear side of the workpiece to produce the desired contour comprises a pivoting movement of the secondary workpiece holding unit.According to a further exemplary embodiment, unloading follows the machining of the previously inaccessible rear side of the workpiece, wherein the unloading comprises a discharge of the machined workpiece by the secondary workpiece holding unit.Unloading can be effected, for example, assisted by gravity (defined dropping). For this purpose, loading aids can be provided below the secondary workpiece holding unit, for example. Unloading can, however, also comprise the provision of the workpiece for a gripper, for example a gripper of a handling robot.It is understood that the features mentioned above and those still to be explained below can be used not only in the respectively specified combination, but also in other combinations or alone, without departing from the scope of the present disclosure.Further features and advantages of the invention will become apparent from the following description and explanation of a plurality of exemplary embodiments with reference to the drawings. The following are shown: FIG. 1 : a perspective view of a production plant with a machine tool with housing; FIG. 2 : a partial view of the machine tool based on FIG. 1, with the housing omitted; FIG. 3 : shows a further perspective view of the machine tool illustrated with reference to FIGS. 1 and 2, with the view orientation changed; FIG. 4 : a longitudinal view of the machine tool according to FIGS. 1-3 in a partial representation; FIG. 5 is a transverse view of the machine tool according to FIGS. 1-4 in a partial illustration; FIG. 6 is another perspective view of the machine tool according to FIGS. 1-5 to illustrate a pivot function; FIG. 7 : shows a simplified schematic view through a rotary spindle of a machine tool designed as a hollow spindle, to illustrate the actuation of a clamping unit of the rotary spindle; FIG. 8 is a schematic longitudinal view of a machine tool illustrating a portion of a machining process; FIG. 9 is a view based on FIG. 8 for illustrating another subsection of the machining process; FIG. 10 is a view based on FIGS. 8 and 9 for illustrating another partial portion of the machining process; FIG. 11 : shows a perspective view of a further embodiment of a machine tool; FIG. 12 : a transverse view of the machine tool according to FIG. 11 in a partial illustration; FIG. 13 : a perspective view of a further embodiment of a machine tool in a partial illustration; FIG. 14 is a front view of the machine tool of FIG. 13 ; and FIG. 15 is a greatly simplified schematic block diagram illustrating an exemplary embodiment of a method for processing bar material.FIG. 1 illustrates, on the basis of a perspective illustration, an exemplary configuration of a production plant, denoted overall by 10, which has a machine tool 12. The machine tool 12 is basically designed as a machine suitable for milling and turning. In this way, the machine tool 12 is suitable for complete machining. In the exemplary embodiment, the manufacturing system 10 comprises the machine tool 10 and furthermore a rod magazine 14 and a tool magazine 16. In this way, the manufacturing system 10 can be operated autonomously at least temporarily. The loading (usually with semi-finished products in the form of rods) and the tool change can be automated or semi-automated. Unloading can also be automated or partially automated.In at least some of the figures shown herein, a Cartesian coordinate system with axes X, Y, Z is indicated. The X axis generally denotes a longitudinal direction or longitudinal extent. The Y axis generally denotes a transverse direction or transverse extension. The Z axis generally denotes a height direction or height extension (vertical extension). The axes X and Y are horizontal axes. The axes X and Y together form a horizontal plane. The axis Z is a vertical axis. The axis Z is oriented orthogonally to the axes X and Y. Rotations about the X axis are generally associated with a rotational A axis. Rotations about the Y axis are generally associated with a rotational B axis. Rotations about the Z axis are generally associated with a rotational C axis. The coordinate system X, Y, Z and the further axes of rotation / pivot axes A, B, C are used below in particular to illustrate exemplary embodiments and features and are not to be understood as restrictive. The skilled person can readily carry out transformations which may be required. This applies in particular with regard to nomenclature regarding the designation of the axes of conventional lathes and conventional milling machines.The machine tool 12 comprises a frame 20 which, in the exemplary embodiment according to FIG. 1, is surrounded by a housing 22 having at least one access opening. FIG. 2 shows an enlarged illustration of the production installation 10 in the same perspective orientation, wherein the housing 22 of the machine tool 12 is omitted for the sake of illustration. The frame 20 of the machine tool 12 carries kinematics, the degrees of freedom and travel paths of which define a working space 26 in which workpieces can be machined.In the exemplary embodiment, the frame 20 of the machine tool 12 rests on a substructure 28. Therefore, further components and functional groups of the machine tool 12 can be arranged in the substructure 28. Nevertheless, a good overview and accessibility is obtained for a stationary operator on account of the elevated arrangement of the frame 20 and of the working space 26.FIGS. 1 and 2 each show a perspective view. Overall, FIGS. 1 and 2 and in addition to FIG. 3 show the machine tool 12 on its operator side. The operator is offset in front of the working space 26 in the Y direction, for example, in order to have a good overview. In the exemplary embodiment according to FIG. 1, the rod magazine 14 is laterally coupled to the machine tool 12 in order to be able to provide rod material and to be replaced. In FIG. 1, a control of the machine tool 12 or of the production plant 10 is also indicated by 30. The controller 30 is usually configured as an NC controller and a CNC controller, respectively. The controller 30 is used to control components of the machine tool 12 and also further components and assemblies of the manufacturing installation 20 in the periphery of the machine tool 12. the controller 30 controls the axes and degrees of freedom of the machine tool 12. The controller 30 may be integrated with the machine tool 12. However, it is also conceivable to offload tasks of the controller 30 at least partially to external units that are coupled to the machine tool 12 or the manufacturing facility 10 via data connections. CNC controllers are usually designed as a programmable logic controller (PLC).With reference to FIG. 2 and with additional reference to FIG. 3, the structure of the machine tool 12 is illustrated in more detail. A tool spindle 34 is mounted on the frame 20 of the machine tool 12. The tool spindle 34 has a tool holder 36 in order to be able to drive a tool 38 accommodated in the tool holder rotationally about a vertical longitudinal axis. In this way, the tool spindle 34 can be equipped with driven tools 38. This enables milling operations, drilling operations and the like. However, it is also conceivable to equip the tool holder 36 of the tool spindle 34 with stationary tools 38, for example rotary tools. The machine tool 12 is preferably equally suitable for both applications.In the exemplary embodiment, the tool spindle 34 is designed as a vertically oriented, suspended spindle. The tool spindle 34 with the tool 38 is translationally movable relative to the frame 20 in three linear axes. In particular, the tool spindle 34 is not pivotable about a pivot axis (B axis) parallel to the Y axis.The tool spindle 34 is translationally movable along an X axis. For this purpose, an X-carriage 42 is provided, which is mounted on an X-guide 44. Furthermore, a suitable drive is installed. The tool spindle 34 is furthermore translationally movable along a Y axis 50. For this purpose, a Y-slide 52 is provided, which is mounted on a Y-guide 54. Furthermore, a suitable drive is installed. The X-axis 40 and the Y-axis 50 are oriented horizontally and orthogonally to each other. The tool spindle 34 is furthermore translationally movable along a Z axis 60. For this purpose, a Z-slide 62 is provided, which is mounted on a Z-guide 64. Furthermore, a suitable drive is installed.In the exemplary embodiment, the Y-guide 54 is formed on a flat bed 56 of the frame 20 of the machine tool 12. The Y-carriage 52 is mounted on the frame 20 via the Y-guide 54. The Y-carriage 52 has an inclined bed 58 which is inclined with respect to the Y-axis and with respect to the Z-axis. The X guide 44 for the X slide 42 is arranged on the inclined bed 58. The X carriage 42 is mounted on the Y carriage 52. The X-carriage 42 has an end wall 66, which in the exemplary embodiment has a substantially vertical extension (parallel to the X-Z plane). The Z-guide 64 for the Z-slide 62 is arranged on the end wall 66. In other words, from the point of view of the frame 20 in the direction of the tool spindle 34, a specific sequence of the axes results. From the standpoint of the frame 20, the kinematically closest axis is the Y axis 50, followed by the X axis 40, followed by the Z axis 60. in other words, the Z carriage 62 is mounted on the X carriage 42, the X carriage 42 is mounted on the Y carriage 52, and the Y carriage 52 is in turn mounted on the frame 20.The machine tool 12 further comprises a rotary spindle 68 which is a component of a primary workpiece holding unit 70. The primary workpiece holding unit 70 is mounted on the frame 20. The primary workpiece holding unit 70 includes a primary workpiece holder 72 that serves to hold and fix a workpiece, which is typically a bar material. The primary workpiece holding unit 70 thus has the functionality of a rotating spindle 68. The primary workpiece holding unit 70 is pivotably mounted on the frame 20 of the machine tool 12 via a pivot carrier 74. For this purpose, a pivot bearing 76 is provided, which enables the pivoting movement of the pivot carrier 74. In FIG. 3, the resulting pivot axis is denoted by a curved double arrow denoted 78. The pivot axis 78 may also be referred to as a B1 axis (parallel to the Y axis).The machine tool 12 further includes a secondary workpiece holding unit 80 supported on the frame 20. The secondary workpiece holding unit 80 is designed, for example, as a gripper, rotary table and / or as a counter spindle. The primary workpiece holding unit 70 and the secondary workpiece holding unit 80 are arranged coaxially with each other, opposite to each other, and facing each other in FIGS. 2 and 3. In this way, the workpiece holding units 70, 80 can grip workpieces simultaneously at least temporarily.The secondary workpiece holding unit 80 includes a secondary workpiece holder 82. The secondary workpiece holding unit 80 is pivotably mounted on the frame 20 of the machine tool 12 via a pivot carrier 84. For this purpose, a pivot bearing 86 is provided, which enables the pivoting movement of the pivot carrier 84. In FIG. 3, the resulting pivot axis is denoted by a curved double arrow denoted 88. The pivot axis 88 may also be referred to as a B2 axis (parallel to the Y axis).The secondary workpiece holding unit 80 is pivotable relative to the frame 20 about the pivot axis 88. The pivot bearing 86 is formed between the pivot support 84 and a pivot housing 90. The secondary workpiece holding unit 80 is furthermore movable in translation along the frame 20 along an X 2 axis 92 in the X direction. The swivel housing 90 is seated on an X slide 94 which is movable in translation along an X guide 96. In this way, an X-distance between the two pivot axes 78, 88 can be varied by linearly displacing the secondary workpiece holding unit 80 relative to the primary workpiece holding unit 70. This movement can be used for machining purposes. However, the movement can also be used to move workpieces and / or semi-finished products in translation within the scope of workpiece handling. The two pivot carriers 74, 84 are mounted in a cantilevered manner on the frame 20. The pivot carriers 74, 84 are therefore not supported on both sides.In the embodiment of FIG. 2, the X-guide 96 is mounted on a flat bed 98 formed on the frame 20. The X guide 26 for the secondary workpiece holding unit 80 is seated on an upper side of the frame 20, and the Y guide 54 for the tool spindle 34 is seated on an upper side of the frame 20. The secondary workpiece holding unit 80 is pivotable relative to the frame 20 about the pivot axis 88 (B2 axis) and is movable in translation along the linear X2 axis 92. The X2 axis 92 is horizontally oriented and coupled to a corresponding drive.Furthermore, the rod magazine 14 is indicated in FIGS. 2 and 3. The rod magazine 14 serves for the provision of semi-finished products 100. For example, the semi-finished products 100 are short rods. For example, the semi-finished product 100 has a length of at most 600 mm or at most 500 mm. Furthermore, a loading mechanism 102 which is represented merely by symbols in FIG. 2 is assigned to the rod magazine 14. The loading mechanism 102 serves to introduce semi-finished products 100 into the working space 26 of the machine tool 12. This can be done by inserting a prepared semi-finished product 100 into the rotary spindle 68 on the side facing away from the primary workpiece holder 72. If the rotary spindle 68 is designed as a hollow spindle, the semi-finished product 100 can be pushed through the rotary spindle 68 in order to emerge at the opposite end at the primary workpiece holder 72 in the working space 26. This is made possible in the horizontal orientation of the primary workpiece holding unit 70 shown in FIGS. 2 and 3.Between the rod magazine 14 and the working space 26 in the embodiment according to FIGS. 2 and 3 a passage 104 is arranged which is formed on / in a wall 106. In the exemplary embodiment, the wall 106 extends vertically upward starting from the substructure 28. The passage 104 allows passage of semi-finished products 100 from the rod magazine 14 to the rotary spindle 68 for loading the machine tool 12.The primary workpiece holding unit 70 includes a clamping unit 110 for holding and fixing workpieces. The rotary spindle 68 then allows the workpieces to be driven and / or positioned by means of rotary movements about a longitudinal axis of the rotary spindle 68. The bushing 104 comprises, in the exemplary embodiment, an actuating unit 112 which is designed to actuate the clamping unit 110 of the primary workpiece holding unit 70 externally. This is made possible, for example, only in the horizontal orientation of the workpiece holding unit 70 shown in FIGS. 2 and 3. In other words, the clamping unit 110 cannot necessarily be operated in a different pivot orientation of the workpiece holding unit 70. The external actuation of the clamping unit 110 by the actuation unit 112 has the advantage that the workpiece holding unit 70 with the primary workpiece holder 72 can be configured compactly.Loading of the workspace 26 requires, for example, a joint actuation of the loading mechanism 102 and the actuation unit 104 by the controller 30 (FIG. 1 ) when the primary workpiece holding unit 70 is in the horizontal orientation. If the secondary workpiece holding unit 80 is also involved, for example in order to extract a rod-like semi-finished product piece by piece from the primary workpiece holding unit 70 in the X direction, this assembly is controlled accordingly by the controller 30. This also requires a horizontal orientation of the secondary workpiece holding unit 80 as the case may be.In FIG. 3, the secondary workpiece holder 82 of the secondary workpiece holding unit 80 is visible, which in the exemplary embodiment is provided with a clamping unit 118. In this way, workpieces 120 can be gripped and held. In the horizontal, coaxial orientation of the primary workpiece holding unit 70 and the secondary workpiece holding unit 80 shown in FIG. 3, a common longitudinal axis 124 results. The rotating spindle 68 allows the workpiece 120 to rotate about the longitudinal axis 124, compare a curved double arrow designated 126 (also designated as the A axis). In the configuration shown in FIG. 3, turning machining of the tool-standing workpiece 120 in the tool spindle 34 is enabled. A milling machining with a driven tool in the tool spindle 34 is also conceivable.FIGS. 4-6 illustrate the pivotability of the primary workpiece holding unit 80 (about the pivot axis 78) and the secondary workpiece holding unit 80 (about the pivot axis 88). In FIG. 4, pivoted positions of the primary workpiece holding unit 70 and the secondary workpiece holding unit 80 are indicated by broken lines. Pivot angles 130, 132 illustrate the extent of the pivot movement starting from the horizontal orientation, compare the horizontal pivot axis 124 (parallel to the X axis). In the viewing orientation according to FIG. 4, wherein the operator looks at the working space 26 from the side opposite the tool spindle 34, the secondary workpiece holding unit 80 is pivoted clockwise starting from its horizontal orientation. On the other hand, the primary workpiece holding unit 70 is pivoted counterclockwise from its horizontal orientation. This has the advantage that both workpiece holding units 70, 80 can be pivoted freely between a horizontal and a vertical orientation without imminent collisions. A time-parallel pivoting movement of both workpiece holding units 70, 80 is therefore also possible.The respective maximum pivot range (compare the pivot angles 130, 132) comprises, for example, at least the horizontal and the vertical orientation, which leads to a pivot angle of 90° (angle degree). For example, the maximum pivot range then allows in each case pivot movements of 10° beyond the horizontal orientation and the vertical orientation, resulting overall in a maximum pivot angle of 110° (10°+90°+10°). This is not to be understood as restrictive. A workpiece accommodated in the primary workpiece holding unit 70 is allowed to be machined in five axes. If the secondary workpiece holding unit 80 also provides an axis of rotation in addition to the pivot axis 88, processing in five axes is also possible there.FIG. 5 shows a transverse view of the machine tool 12, the plane of view being perpendicular to the X direction. The configuration of the Y-carriage 52 with the inclined bed 58 results in an inclination 138 with respect to the horizontal (Y-direction). The inclined bed 58 permits a favorable and highly rigid mounting of the X slide 42 and the Z slide 62, on which the tool spindle 34 is fixed.The frame 20 of the machine tool 12 includes a primary frame portion 140 and a secondary frame portion 142. The Y-guide 54 is arranged on an upper side (facing away from the substructure 28 (compare also FIG. 6 ) of the primary frame section 140. At an upper side of the secondary frame portion 142, the X guide 96 for the pivot housing 90 of the secondary workpiece holding unit 80 is disposed. For example, the Y-guide 96 is seated on the flat bed 98.With regard to the height extension (Z-axis extension), it holds true that the secondary frame section 142 is designed to be lower than the primary frame section 140. However, when the pivot housing 90 of the secondary workpiece holding unit 80 is mounted on the X-guide 96 of the secondary frame section 142, a total height extension results which approximately corresponds to the height extension of the primary frame section 140. The installation space available is thus used favorably. It can be seen from FIGS. 5 and 6 that the primary workpiece holding unit 70 is mounted on the primary frame section 140 and the secondary workpiece holding unit 80 is mounted on the secondary frame section 142.Between the primary frame portion 140 and the secondary frame portion 142, a recess 144 is provided in the frame 20. A frame base extends between the primary frame portion 140 and the secondary frame portion 142. The recess 144 allows the primary workpiece holding unit 70 and the secondary workpiece holding unit 80 to be inserted during pivoting, cf. also the perspective illustration in FIG. 6 ; in the exemplary embodiment, the recess is open on three sides (two lateral sides and upwards). The installation space occupied by the machine tool 12 is used favorably. Within the scope of a complete machining, workpieces can be machined completely on six sides by turning and milling. The two pivot carriers 74, 84 are arranged at least partially within the recess 114. The pivot support 74 is cantilevered from the primary frame portion 140. The pivot support 84 is cantilevered from the secondary frame portion 142.In exemplary embodiments, the pivot beams 74, 84 of the primary workpiece holding unit 70 and the secondary workpiece holding unit 80 are configured as identical parts. In an exemplary embodiment, the pivot bearings 76, 86 of the primary workpiece holding unit 70 and of the secondary workpiece holding unit 80 are also designed as identical parts. This leads to a smaller diversity of parts and simplifies assembly, maintenance and repair. FIG. 6 also shows the external actuation unit 112 not covered by the primary workpiece holding unit 70 in the given pivot orientation.With reference to FIGS. 7-10, an exemplary loading process with a subsequent machining for producing a workpiece is illustrated by means of schematic views. The view orientation in FIGS. 7-10 corresponds approximately to that of FIG. 4.In FIG. 7, a state is shown in which the primary and secondary workpiece holding units 70, 80 are each in the horizontal orientation. If at least the primary workpiece holding unit 70 is oriented horizontally, a rod-shaped semi-finished product 100 with the loading mechanism 102 can be introduced through the bushing 104 into the rotary spindle 68 designed as a hollow spindle 150. The semi-finished product 100 is, for example, a short rod with a length of 500 mm. The semi-finished product 100 can be introduced into the rotary spindle 68 on the rear side of the rotary spindle 68, on which no machining takes place, and can be guided through the latter.For clamping the semi-finished product 100, the clamping unit 110 is provided, which can be actuated by the external actuating unit 112 in the exemplary embodiment. The clamping unit 110 is, for example, a clamping unit 110 which is actuated by means of spring force and can automatically hold and fix the semi-finished product 100. When the primary workpiece holding unit 70 is in the horizontal orientation, the actuating unit 112 can act on the clamping unit 110, for example in order to relieve (open) it. In this way, the semi-finished product 100 can be introduced or advanced by a certain amount if a plurality of workpieces are to be produced on the basis of a semi-finished product 100.FIG. 8 illustrates multi-axis machining in which the primary workpiece holding unit 70 is pivoted in order to make a front side 152 of the semi-finished product 100 accessible to the tool 38 of the tool spindle 34 at its primary workpiece holder 72. The machining may include turning and / or milling. In the machining shown in FIG. 8, the secondary workpiece holding unit 80 is not yet engaged with the semi-finished product 100, this is not to be understood as restrictive.FIG. 9 illustrates a state in which the primary workpiece holding unit 70 (for example, after the machining illustrated in FIG. 8 ) has been returned to the horizontal orientation. A workpiece 120 was produced on the basis of the semi-finished product 100. However, the workpiece 120 is not yet separated from the semi-finished product 100. The secondary workpiece holding unit 80 can now also be brought up in the horizontal orientation by movement along the X2 axis in order to access the workpiece 120 with the secondary workpiece holder 82. In the orientation shown in FIG. 9, for example, turning or milling is conceivable with semi-finished product 100 clamped on both sides. However, the state shown in FIG. 9 can also be used to separate the workpiece 120 from the semi-finished product 100. This can also be done with a suitable tool 38 of the tool spindle 34.FIG. 10 illustrates a state in which the workpiece 120 has been separated from the remaining semi-finished product 100. The semi-finished product 100 remains in the primary workpiece holding unit 70, a new workpiece can be produced there. Furthermore, the workpiece 120 now held by the secondary workpiece holder 82 can be machined on its previously inaccessible side. This allows complete machining. In this way, the semi-finished product 100 can be machined piece by piece to produce a plurality of workpieces 120. After machining, the workpiece 120 may be properly discharged from the secondary workpiece holding unit 80. This can take place with the assistance of gravity or comprise a defined transfer to handling technology.The translational degree of freedom (compare the X 2 axis 92) of the secondary workpiece holding unit 80 may also be used for rod advancement. This includes, by way of example, an actuation of the internal clamping unit 110 of the primary workpiece holding unit 70 by the external actuation unit 112. In this way, a new section of the semi-finished product 100 can be made accessible for later processing. This is conceivable in principle in the orientation shown in FIG. 9. Thus, when a workpiece 120 has been discharged from the secondary workpiece holding unit 80, the secondary workpiece holding unit 80 can grip the now free end of the semi-finished product 100 at the primary workpiece holder 72 and pull it out of the primary workpiece holding unit 80 when the clamping unit 110 has been operated accordingly. Alternatively, in the state shown in FIG. 9, the secondary workpiece holding unit 80 can already draw out the workpiece 120 and the semi-finished product 100 from the primary workpiece holding unit 70 by movement along the X2 axis before the separation of the workpiece 120 along the X2 axis in order to make sufficient material accessible for a new workpiece.Referring to FIGS. 11 and 12, an example embodiment of a manufacturing facility, generally designated 210, is illustrated. The production installation 210 is basically of similar design to the production installation 10 already illustrated with reference to FIGS. 1-10. Differences will therefore be discussed primarily below. With regard to the remaining detailed configuration, reference is made to the explanations given above.The manufacturing system 210 comprises a machine tool 212 with which a rod magazine 214 is associated. The machine tool 212 comprises a frame 220 which rests on a substructure 228. The machine tool 212 comprises a kinematic system which corresponds in principle to that of the machine tool 12. In this manner, a tool spindle 234 can be moved in three translatory axes (X, Y, Z) relative to the frame 220 in order to machine workpieces. The tool spindle 234 is not pivotable, in particular no B-axis (pivoting movements about the Y-axis) is provided for the tool spindle 234.An X slide 242, a Y slide 252 and a Z slide 262 are provided for the translatory movement of the tool spindle 234. The Y-carriage 252 is mounted on the frame 220 and is movable relative to the latter in the Y-direction. The X carriage 242 is mounted on the Y carriage 252 and is movable relative thereto in the X direction. The Z carriage is mounted on the X carriage 242 and is movable relative to the latter in the Z direction. The tool spindle 234 is mounted on the Z slide 262 and is movable together with the latter.The machine tool further includes a primary workpiece holding unit 270 and a secondary workpiece holding unit 280, each of which is pivotable about a pivot axis parallel to the Y axis. In addition, the secondary workpiece holding unit 280 is mounted in a pivot housing 290, which is mounted on the frame 220 via an X slide 294 and is movable relative to the latter in the X direction. In the exemplary embodiment according to FIGS. 11 and 12, the primary workpiece holding unit 270 is also pivotably mounted in a pivot housing 298. In an exemplary embodiment, the pivot housing 290 for the secondary workpiece holding unit 280 and the pivot housing 298 for the primary workpiece holding unit 270 are configured as identical parts.In particular, the rear view according to FIG. 12 illustrates that the pivot housing 298 for the primary workpiece holding unit 270 is arranged in a frame opening 300 in the exemplary embodiment. In this way, the pivot housings 290, 298 can be designed as identical parts. Between the rod magazine 214 and the primary workpiece holding unit 270 there is arranged a passage 304 through which the machine tool 212 can be loaded with the rod material.Similar to the frame 20 of the machine tool 12, the frame 220 of the machine tool 212 also has a recess 344 formed between a primary frame portion 340 and a secondary frame portion 342 and penetrating the frame 220 in the X direction. The recess 344 provides installation space for the previously described pivoting movement of the primary workpiece holding unit 270 and the secondary workpiece holding unit 280. The X-carriage 294 of the secondary workpiece holding unit 280 is supported on the secondary frame portion 342 so as to be movable in the X-direction. The Y slide 252 of the tool spindle 234 is mounted on the primary frame section 340 such that it can be displaced in the Y direction.In the exemplary embodiment, the frame opening 300 extends in the Y direction through the primary frame section 340. In this way, two cheeks 360, 362 are formed on the frame 220, between which cheeks the frame opening 300 is arranged. The two cheeks 360, 362 are offset relative to one another in the X direction. The two cheeks define a guide distance for guiding the Y carriage 252 in the Y direction. The rear view according to FIG. 12 shows that the frame opening 300 can be used on the one hand to receive the pivot housing 298, but that on the other hand use for other purposes is also conceivable. These can be transfer purposes, for example for transfer purposes for unloading machined workpieces and / or for tool change. This is not to be understood as restrictive.Referring to FIGS. 13 and 14, an example configuration of a manufacturing facility 410 including a machine tool 412 is illustrated. The production installation 410 is basically of similar design to the production installations 10, 210 already illustrated with reference to FIGS. 1-12. Differences will therefore be discussed primarily below. With regard to the remaining detailed configuration, reference is made to the explanations given above.The manufacturing system 410 (see FIG. 14 ) comprises a machine tool 412 and a rod magazine 414 for providing workpieces, see also the passage 504 between the rod magazine 414 and the machine tool 412. Loading with workpieces is therefore made possible analogously to the already described configurations.The machine tool 412 rests on a frame 420. In FIG. 14, it is indicated that the frame 420 rests on a substructure 428. In the exemplary embodiment, the frame 420 is designed as a stand 422. The machine tool 412 comprises a tool spindle 434, the kinematics of which correspond to those of the tool spindles 34, 234 in the exemplary embodiment.The tool spindle 434 is movable in three translatory axes (X, Y, Z). For the X movement, an X slide 442 is provided, which is movable along an X guide 444. For the Y movement, a Y carriage 452 is provided, which is movable along a Y guide 454. For the Z-bin movement, a Z-slide 462 is provided, which is movable along a Z-guide 464. The Y-guide 454 is formed on a flat bed 456 of the frame 420. The X-guide 444 is formed on the Y-slide 452, for example on an inclined bed of the Y-slide 452, and the Z-guide 464 is formed on the Y-slide 442, for example on an end wall of the Y-slide 442.The machine tool 412 includes a primary workpiece holding unit 470 and a secondary workpiece holding unit 480 each pivotable about a pivot axis parallel to the Y direction. The primary workpiece holding unit 470 includes a primary workpiece holder 472. The primary workpiece holding unit 470 is pivotably received on the frame 420 via a primary pivot carrier 474 and a primary pivot bearing 476. The secondary workpiece holding unit 480 includes a secondary workpiece holder 482. The secondary workpiece holding unit 480 is pivotably received on the frame 420 via a secondary pivot carrier 484 and a secondary pivot bearing 486. Also shown in FIGS. 13 and 14 is a pivot housing 490 for the secondary workpiece holding unit 480. The pivot housing 490 houses the secondary pivot bearing 486 and a corresponding pivot drive.The secondary workpiece holding unit 480 is translationally movable along a linear axis 492. The linear axis 492 may also be referred to as an X2 axis. For this purpose, the secondary workpiece holding unit 480 is mounted on an X carriage 494, which is movable in translation along an X guide 496. The X-guide 496 is formed on a flat bed 498 of the frame 420.In the exemplary embodiment according to FIGS. 13 and 14, the frame 420 consequently has at its upper end a flat bed 456 for the Y-guide 454 and, offset vertically (downward) therefrom, a flat bed 498 for the X-guide 496. In a plan view, both flat beds 456, 498 use the same installation space in the X direction and the Y direction. This overall ensures a small space requirement and a small floor plan of the frame 420.The secondary workpiece holding unit 480 is mounted in a frame opening 500 in the frame 420. The frame 420 has an end wall 502 facing the working space. The end wall 502 has a vertical extension at least in sections or predominantly. The primary workpiece holder 472 and the secondary workpiece holder 482 are disposed forward of the end wall 502. The primary pivot support 474 and the secondary pivot support 484 extend through the end wall 502 from the post 422 of the chassis 420.In the exemplary embodiment according to FIGS. 13 and 14, the frame opening 500 comprises a Y-recess 506 and an X-recess 508. The Y-recess 506 may also be referred to as a central recess. The X-recess 508 may also be referred to as a lateral recess. The Y-recess 506 penetrates the stage 420 completely in the Y-direction. The X-recess 508 partially penetrates the stage 420 in the X-direction to make the Y-recess 506 accessible in the X-direction.In the exemplary embodiment, the X-guide 496 is arranged on an underside of the frame opening 500, in particular of the Y-recess 506. The pivot housing 490 can thus be moved within the frame opening 500 along the linear axis 492.In the exemplary embodiment, the Y-recess 506 is arranged between a first cheek 560 and a second cheek 562 of the frame 420. In the exemplary embodiment, a cross member 510 furthermore extends between the first cheek 560 and the second cheek 562 on the upper side of the frame 420 facing the Y carriage 452. In this way, the Y-recess 506 is enclosed on four sides in the view orientation according to FIG. 14.In conjunction, it can be seen from FIGS. 13 and 14 that the X-recess 508 extends through the cheek 562 in the direction of the Y-recess 506. This results in lateral access to the Y-recess 506. The X-recess 508 can accommodate, for example, a drive 516 for the translatory movement of the secondary workpiece holding unit 480 along the linear axis 492. In this way, the translatory degree of freedom of the secondary workpiece holding unit 480 can be integrated favorably into the stand 420 designed in a stand-by design. The frame 420 is compact and at the same time rigid.With reference to FIG. 15, an exemplary embodiment of a method for processing bar material is illustrated with reference to a schematic, greatly simplified block diagram. In the exemplary embodiment, the method starts at a step S 10 and ends at a step S 28. The method can be carried out with a machine tool or production installation according to at least one of the configurations described herein.In a step S 12, at least one semi-finished product is provided, wherein it is in particular rod material. By way of example, these are so-called short rods, wherein different cross sections (round, non-round, polygonal configuration, hollow profiles) are conceivable. For example, the short rods have a length of at most 600 mm or at most 500 mm.This is followed by a step S 14, in which the primary workpiece holding unit is moved into an orientation suitable for receiving the semi-finished product if the suitable orientation is not already present. This can comprise a pivoting movement in the direction of a horizontal orientation.In a subsequent step S 16, the machine tool is loaded by the semi-finished product being introduced into the primary workpiece holding unit. This can comprise the insertion of the semi-finished product into a primary workpiece holding unit designed as a hollow spindle. Step S 16 may further include actuation of a clamping unit integrated with the primary workpiece holding unit by an external actuation unit.In a step S 18, processing of the semi-finished product to form a workpiece can follow. The machining can take place as turning machining and / or milling machining. For example, the semi-finished product can be machined on five sides.In a step S 20, the workpiece is held with the secondary workpiece holding unit. This can comprise at least temporarily holding the semi-finished product together with the workpiece by the primary workpiece holding unit and the secondary workpiece holding unit. In such a state, machining of the workpiece is also conceivable. The gripping and holding of the workpiece with the secondary workpiece holding unit allows the workpiece to be released from the primary workpiece holding unit (separating from the bar material).In a step S 22, the workpiece is separated from the semi-finished product in a state in which the primary workpiece holding unit and the secondary workpiece holding unit hold the workpiece together. In a subsequent step S 24, the workpiece on the previously inaccessible side can then be machined while it is held by the secondary workpiece holding unit. Finally, in a step S 26, discharging can follow. This can comprise a defined delivery of the workpiece from the second workpiece holding unit. By way of example, this can comprise a transfer to handling technology. Gravity assisted dispensing is also conceivable, where the workpiece is dropped from the secondary workpiece holding unit.The primary workpiece holding unit and the secondary workpiece holding unit can furthermore cooperate to provide a controlled feeding of the semi-finished product. Such a feed allows the production of a plurality of workpieces one after the other on the basis of a single semi-finished product in the form of rod material. The secondary workpiece holding unit is translationally movable relative to the frame of the machine tool. In this way, the secondary workpiece holding unit can pull out the semi-finished product from the primary workpiece holding unit when the clamping unit of the primary workpiece holding unit is released, for example as a result of actuation with the external actuation unit.The primary workpiece holding unit and the secondary workpiece holding unit each have a pivot axis in the form of a B-axis. In at least one common horizontal coaxial orientation, the primary workpiece holding unit and the secondary workpiece holding unit can grip the semi-finished product / workpiece together. In this configuration, since at least the primary workpiece holding unit is configured as a rotating spindle, turning processing is possible. Furthermore, the common coaxial orientation can also be used for transfer purposes. The tool spindle does not have to be provided with a pivot axis. Nevertheless, machining in five axes is possible. By using the pivot axes of the primary workpiece holding unit and the secondary workpiece holding unit, six-side machining is possible, workpieces can be completely machined.References included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedDE 10 2010 019 762 A1

[0002] EP 1 818 136 A1

[0003]

Claims

Machine tool (12, 212, 412), which has: - a frame (20, 220, 420), - a tool spindle (34, 234, 434) which is mounted on the frame (20, 220, 420) and is linearly displaceable in three translatory axes (X, Y, Z) relative to the frame (20, 220, 420), comprising a first horizontal axis (40), a second horizontal axis (50) and a vertical axis (60), wherein the tool spindle (34, 234, 434) is mounted on an X slide (42, 442) via a Z slide (62, 462) such that it can be displaced vertically along the vertical axis (60), wherein the X slide (42, 442) is mounted on a Y slide (52, 452) such that it can be displaced horizontally along the first horizontal axis (40), and wherein the Y slide (52, 452) is mounted on the frame (20, 220, 452), 420) supported so as to be horizontally movable along the second horizontal axis (50), - a primary workpiece holding unit (70, 270, 470) supported on the frame (20, 220, 420) and configured as a rotating spindle (68), and - a secondary workpiece holding unit (80, 280, 480) supported on the frame (20, 220, 420), wherein the primary workpiece holding unit (70, 270, 470) and the secondary workpiece holding unit (80, 280, 480) face each other in at least one horizontal orientation and are oriented coaxially to each other, wherein the primary workpiece holding unit (70, 270, 470) is pivotable relative to the frame (20, 220, 420) about a primary pivot axis (78) oriented parallel to the second horizontal axis (50), and wherein the secondary workpiece holding unit (80, 280, 480) is pivotable relative to the frame (20, 220, 420) about a secondary pivot axis (88), which is oriented parallel to the second horizontal axis (50).Machine tool (12, 212, 412) according to Claim 1, wherein the Y carriage (52, 452) has a tilted bed (58) on which the X carriage (42, 442) is guided.Machine tool (12, 212, 412) according to Claim 1 or 2, wherein the frame (20, 220, 420) has a flat bed (56) on which the Y carriage (52, 452) is guided.Machine tool (12, 212, 412) according to one of Claims 1 - 3, wherein the X carriage (42, 442) has a vertical end wall (66) on which the Z carriage (62, 462) is guided.Machine tool (12, 212, 412) according to one of Claims 1-4, wherein the secondary workpiece holding unit (80, 280, 480) is translationally movable along a linear axis (92, 492) which is oriented parallel to the first horizontal axis (40).The machine tool (12, 212) according to any one of claims 1-5, wherein the rack (20, 220) includes a primary rack portion (140) on which the tool spindle (34, 234) and the primary workpiece holding unit (70, 270) are accommodated, and a secondary rack portion (142) on which the secondary workpiece holding unit (80, 280) is accommodated.Machine tool (12, 212) according to Claim 6, wherein an X-guide (96) for the secondary workpiece holding unit (80, 280) is arranged on the frame (20, 220) at the secondary frame section (142), and / or wherein a Y-guide (54) for the tool spindle (34, 234) is arranged at the primary frame section (140).The machine tool (12, 212) of claim 7, wherein the secondary frame portion (142) provides a flat bed (98) that supports the X-guide (96).The machine tool (12, 212) according to any one of claims 6 - 8, wherein the frame comprises a recess (144) between the primary frame portion (140) and the secondary frame portion (142), which recess provides a free space for a pivoting movement of the primary workpiece holding unit (70, 270) and / or the secondary workpiece holding unit (80, 280).Machine tool (412) according to one of claims 1 - 5, wherein the primary workpiece holding unit (470) and the secondary workpiece holding unit (480) protrude in the same direction from the frame (420), in particular in the direction of a side of the working space (26) facing an operator.Machine tool (412) according to claim 10, wherein the linear axis (492) of the secondary workpiece holding unit (480) is arranged on the frame (420) below the Y-guide (454) for the second horizontal axis (50) and in particular below the X-guide (444) for the first horizontal axis (40).The machine tool (412) according to claim 10 or 11, wherein the frame (420) is configured as a stand (422) having an end wall (502) over which pivot beams (474, 484) of the primary and secondary workpiece holding units (470, 480) protrude.Machine tool (412) according to one of claims 10 - 12, wherein the frame (420) has a frame opening (500) below the Y-slide (452), in which opening the secondary workpiece holding unit (480) is mounted and can be moved in translation along the linear axis (492).Machine tool (412) according to claim 13, wherein an X-guide (496) for the secondary workpiece holding unit (480) is arranged in the frame opening (500), and / or wherein a Y-guide (452) for the Y-slide (552) is arranged above the frame opening (500) in the frame (420).Machine tool (412) according to claim 13 or 14, wherein the frame (420) comprises a first cheek (560) and a second cheek (562), between which the frame opening (500) is formed, and wherein the frame in particular comprises an upper cross-member (510) extending from the first cheek (560) to the second cheek (562).The machine tool (412) according to any one of claims 13-15, wherein the frame opening (500) comprises a Y-recess (506) extending parallel to the second horizontal axis (50) and an X-recess (508) extending parallel to the first horizontal axis (40), and wherein the X-recess (508) opens into the Y-recess (506).The machine tool (412) of claim 16, wherein the X-recess (508) penetrates the frame (420) outwardly from the Y-recess (506).Machine tool (412) according to claim 16 or 17, wherein the X-recess (508) houses a drive (514) for the translatory movement of the secondary workpiece holding unit (84).Machine tool (12, 212, 412) according to one of Claims 1 - 18, wherein the tool spindle (34, 234, 434) is a permanently vertically oriented tool spindle (34, 234, 434), and wherein the tool spindle (34, 234, 434) is in particular the only tool spindle (34, 234, 434) of the machine tool (12, 212, 412).Machine tool (12, 212, 412) according to one of Claims 1 - 19, wherein the secondary workpiece holding unit (80, 280, 480) is designed as a pivotable counter spindle, pivotable rotary table or as a pivotable gripper.Machine tool (12, 212, 412) according to one of Claims 1 - 20, wherein the primary workpiece holding unit (70, 270, 470) and the secondary workpiece holding unit (80, 280, 480) have pivot carriers (74, 84; 474, 484) which are designed as identical parts.The machine tool (12, 212, 412) according to claim 21, wherein the pivot carrier (84, 484) of the secondary workpiece holding unit (80, 280, 480) is pivotably mounted on an X slide (94, 494) which is translationally movable relative to the frame (20, 220, 420) in a secondary horizontal linear axis (92, 492) parallel to the first horizontal axis (40).The machine tool (12, 212, 412) according to claim 21 or 22, wherein the pivot carrier (74, 474) of the primary workpiece holding unit (70, 270, 470) is pivotably mounted on the frame (20, 220, 420).The machine tool (12, 212, 412) according to any one of claims 21-23, wherein the pivot carrier (74) of the primary workpiece holding unit (70, 270, 470) is pivotably mounted in a pivot housing (298) which is arranged in a frame opening (300) in the frame (20, 220, 420) and is fixedly connected to the frame (20, 220, 420).Machine tool (12, 212, 412) according to one of Claims 1 - 24, wherein the primary rotary spindle (68) is designed as a pivotable hollow spindle (150) and has a clamping unit (110) for holding an inserted semi-finished product (100).Machine tool (12, 212, 412) according to one of Claims 1 - 25, wherein the rotary spindle (68) of the primary workpiece holding unit (70, 270, 470) has an externally actuatable clamping unit (110) for clamping the semifinished product (100).Manufacturing plant (10, 210) comprising a machine tool (12, 212, 412) according to one of claims 1 - 26, a rod magazine (14, 214) for receiving and providing rod-shaped semi-finished products (100), and comprising a loading mechanism (102) which is designed to insert semi-finished products (100) into the rotary spindle (68) at least in a horizontal position of the primary workpiece holding unit (70, 270, 470).Production plant (10, 210) according to claim 27, wherein the length of the semi-finished products (100) provided is adapted to an installation space provided for the pivoting movement of the primary workpiece holding unit (70, 270, 470).Manufacturing plant (10, 210) according to claim 27 or 28, further comprising an actuating unit (112) mounted indirectly or directly on the frame (20, 220, 420) for a clamping unit (110) of the rotary spindle (68) of the primary workpiece holding unit (70, 270, 470).Manufacturing plant (10, 210) according to claim 29, wherein the actuating unit (112) is configured to act on the clamping unit (110) of the rotary spindle (68) in a horizontal orientation of the primary workpiece holding unit (70, 270, 470) in order to activate or deactivate the latter.Manufacturing plant (10, 210) according to claim 29 or 30, wherein a common controller (30) is provided for the loading mechanism (102), the primary workpiece holding unit (70, 270, 470), the secondary workpiece holding unit (80, 280, 480) and the actuating unit (112) for the clamping unit (110), such that a semi-finished product (100) introduced into the rotary spindle (68) is gradually displaceable in order to produce a plurality of workpieces (120) one after the other.Method for machining bar material with a manufacturing plant (10, 210) according to one of claims 27 - 31, with the following steps: - provision of at least one semi-finished product (100) by the bar magazine (14), - positioning of the primary workpiece holding unit (70, 270, 470) in the horizontal orientation for receiving the semi-finished product (100), - loading of the rotary spindle (68) of the primary workpiece holding unit (70, 270, 470) with the loading mechanism (102), - machining of the semi-finished product (100) for producing at least one workpiece (120), comprising a rotational movement of the rotary spindle (68) and a rotational movement of the primary workpiece holding unit (70, 270, 470) for producing the desired contour, wherein the machining takes place with the tool spindle (34, 234, 434) which takes place linearly in three translatory axes (X, Y, z) is movable relative to the workpiece (120), - holding the workpiece (120) with the secondary workpiece holding unit (80, 280, 480), - separating the workpiece (120) from the semi-finished product (100) in a state in which the primary workpiece holding unit (70, 270, 470) and the secondary workpiece holding unit (80, 280, 480) hold the workpiece (120) together, and - machining a previously inaccessible rear side of the workpiece (120) held by the secondary workpiece holding unit (80, 280, 480).The method of claim 32, wherein loading the rotary spindle (68) of the primary workpiece holding unit (70, 270, 470) with the loading mechanism (102) comprises actuation of a clamping unit (110) of the rotary spindle (68) by an external actuation unit (112) in the horizontal orientation of the primary workpiece holding unit (70, 270, 470).Method according to claim 32 or 33, wherein after the separation of the workpiece (120) from the semi-finished product (100), the secondary workpiece unit with the workpiece (120) clamped there is moved translationally along a linear axis (92, 492) parallel to the first horizontal axis (40) in order to make the workpiece (120) accessible for the further processing of a rear side and subsequent handling.The method of any of claims 32-34, wherein machining a previously inaccessible back side of the workpiece (120) to produce the desired contour comprises pivoting the secondary workpiece holding unit (80, 280, 480).The method of any of claims 32-35, wherein the machining of the previously inaccessible back side of the workpiece (120) is followed by unloading, wherein the unloading comprises unloading the machined workpiece (120) by the secondary workpiece holding unit (80, 280, 480).

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