Methods for setting up and operating a machine tool

Abstract

Method for setting up and operating a machine tool (10) which has at least one working spindle (11), is connected to a tool magazine (15) and has a tool gripper (16) as well as a pallet carrier (17) designed to receive pallets, which is movable between a setup station (II) and a machining station (I), wherein the method: a tool palette (21) is provided which is equipped with at least one angle head (22) and with at least one tool holder (25) which fits into the angle head (22), a workpiece pallet (20) is provided which is equipped with a workpiece (27), the tool pallet (21) is arranged on the setup station (II) of the machine tool (10), the tool palette (21) is transferred from the setup station (II) to the machining station (I), the workpiece pallet (20) is arranged on the setup station (II), if present, a tool holder (25) located in the work spindle (11) is transferred to the tool magazine (15), the angle head (22) is transferred into the working spindle (11), the tool holder (25) mounted on the tool pallet (21) is transferred into the angle head (22), the tool pallet (21) is transferred from the machining station (I) to the setup station (II) and the workpiece pallet (20) is transferred from the setup station (II) to the machining station (I), the machining of the workpiece (27) is carried out using the tool of the tool holder (25) held in the angle head (22), After completion of the work to be carried out with the angle head (22), the workpiece pallet (20) is transferred from the machining station (I) to the setup station (II) and the tool pallet (21) is transferred from the setup station (II) to the machining station (I). the tool holder (25) held in the angle head (22) is placed on the tool pallet (21), the angle head (22) held in the work spindle (11) is placed on the tool pallet (21), the tool palette (21) is transferred from the machining station (I) to the setup station (II).

Description

[0001] The subject of the invention is a method for setting up and operating a machine tool, in particular a machining center.

[0002] Machine tools, especially machining centers, typically have a tool changer that connects the machine tool to a tool magazine. Depending on the machining sequence, the tool changer inserts tools into the work spindle and removes other tools from the work spindle, allowing machining operations to be performed on a workpiece using different tools.

[0003] A machining center connected to a tool magazine is known, for example, from DE 197 08096 A1. The tool magazine used there comprises several circular tool disks arranged one above the other, thus forming a tower-like tool storage system. This tool storage system, also known as a drum storage system, is arranged on a rotary table together with several workpiece holders, so that the drum storage system can be moved into and out of the machine tool's work area as needed. Once the drum storage system has been moved into the work area, the work spindle can pick up or deposit tools or tool holders.

[0004] DE 37 07 318 A1 describes a flexible manufacturing facility with several processing machines arranged side by side with their axes parallel. These are linked together via a pallet transport system. The pallet transport system serves both to transport workpiece pallets and tool pallets, allowing tools to be brought to the processing machines from a remote magazine.

[0005] DE 39 25 568 A1 also discloses a manufacturing system with a pallet transport system and a tool magazine that is arranged next to the machine tool and can be moved on rails. A handling device connects the movable tool magazine to load and unload tools from the work spindle.

[0006] From the textbook Neugebauer, Reimund: Machine Tools: Function and Application of Cutting and Abrasive Machine Tools. Berlin, Heidelberg: Springer, 2012. pp. 132–144. ISBN 9783642300763, it is known that a work spindle can pick up tools arranged in tool holders from tool magazines or transfer them to them.

[0007] Although machining centers of the known type can be used for a wide variety of machining operations because different tools can be transferred to the work spindle and because the respective work spindle can move linearly and, in some cases, also pivotably, there are machining operations that lie outside the spectrum of the possibilities provided.

[0008] For this reason, DE 10 2006 020 895 A1 proposes, for the machining of differential housings, to provide a cutting tool on a workpiece pallet that can be picked up by a mandrel held by a tool holder coupled to the work spindle.

[0009] Although this provides a solution for the special case of internal machining of differential housings, there is a wide range of other machining operations that require additional equipment on the machining center, such as angle heads. When using angle heads, problems can arise due to the alignment of the spindle on the angle head, which differs from the alignment of the work spindle. The angle head spindle is therefore not accessible to tool grippers of the machine's own tool changing system. In addition, the tool holder receptacles of the angle head can have different dimensions than the holder receptacles of the work spindle. The correspondingly smaller tool holders for tools on the angle head cannot usually be gripped by the gripper of the machine's own tool changing system.

[0010] Based on this, the object of the invention is to provide a method for efficiently operating a machining center, even one that incorporates angle heads. In particular, manual interventions for tool changes should be completely unnecessary.

[0011] This object is achieved by the method according to claim 1 and by a pallet system according to claim 10: The method according to the invention uses at least one tool pallet to set up the machine tool, in particular the machining center, which tool pallet can be arranged like a workpiece pallet on the set-up station of the machine tool and transferred into the machining position using the same transport means as the workpiece pallet. At least one angle head and at least one tool intended for the angle head, optionally provided with a tool holder, are arranged on the tool pallet. The angle head has at least one tool holder receptacle and can be inserted into the tool holder receptacle of the work spindle. In principle, a tool or a tool holder provided with a tool can already be located in one or more tool holder receptacles of the angle head. However, the angle head arranged on the tool pallet can also be empty.

[0012] An angle head is understood in particular to be a structural unit which has a housing in which a gear unit, in particular a step-up or step-down gear unit, for example, is arranged, with an input shaft and at least one output shaft, which are preferably at an angle to one another and / or offset from one another and / or run at different speeds. The input shaft is designed to be releasably coupled in a rotationally fixed manner to a tool holder receptacle provided on the work spindle. The output shaft is provided with a tool holder receptacle which is designed for releasable, rotationally fixed coupling to a tool holder. The housing can be releasably coupled in a rotationally fixed manner to a spindle housing.

[0013] During the process, the tool pallet is moved into the machining position, and from there, the angle head is moved into the work spindle. Once the angle head is coupled to the work spindle, the desired tool or the tool holder of the desired tool can be inserted into the angle head, or more precisely, into its tool holder receptacle, through controlled relative movement between the work spindle and the tool pallet. Meanwhile, the pallet with the workpiece can be positioned at the setup station. The machine tool is ready for operation by extending the tool pallet from the work area and retracting the workpiece pallet into the machining station.

[0014] After the workpiece has been machined with the angle head, the workpiece pallet is moved out of the work area and the tool pallet is moved into the work area, after which, for example, the angle head held in the work spindle places the tool on the tool pallet using the pick-up process and picks up another tool. If, however, no further machining is to be carried out with the angle head, first the tool holder in the angle head and then the angle head are transferred to the tool pallet. The machine's own tool changing system can now insert a tool from the machining center's tool magazine into the work spindle, after which or during this time the tool pallet is moved out of the work area and the workpiece pallet, or another workpiece pallet, is moved into the work area in order to machine the respective workpiece using a tool from the tool magazine.

[0015] The angle head can be transferred to the work spindle using a gripper, in particular the machine's own tool gripper, which is otherwise used to handle the tools held in the tool magazine. However, it is also possible for the angle head to be picked up by the work spindle using the pick-up method, in which the work spindle is moved towards the tool pallet in such a way that the coupling half of the tool holder, which is typically a hollow shank taper (HSK), moves into a corresponding tool holder receptacle in the work spindle and is locked there. The angle head is preferably designed so that the tool holders it holds can be clamped and released automatically. This eliminates the need for a gripper to transfer the tools from the tool pallet to the angle head and from the angle head to the tool pallet.This also makes it possible to insert tools or tool holders into the angle head that do not fit into the gripper. For example, the gripper can be designed for tool holders with a given nominal size (e.g., HSK 100), while the tools or tool holders to be inserted into the angle head have a different nominal size (e.g., HSK 63, HSK 50, HSK 40, HSK 32).

[0016] Preferably, only tools, not workpieces, are arranged on the tool pallet. In particular, one or more angle heads and one or more tools or tool holders intended for operation in the angle head can be arranged on the tool pallet. Each angle head can have one or more tool holder receptacles, which can be arranged in different positions and / or orientations on the angle head.

[0017] Preferably, no tools are arranged on the workpiece pallet. However, the additional use of tool pallets with mixed equipment, as known, for example, from DE 10 2006 020 895 A1, is also possible within the scope of the invention.

[0018] The method according to the invention allows so-called angle heads required for certain machining processes to be inserted into the work spindle of the machine tool, in particular of the machining center. Angle heads allow tools to be positioned in a spatial position that is often unattainable when the tool in question is clamped directly into the work spindle. Due to their size and / or shape, angle heads typically cannot be stored directly in the tool magazines of a machine tool, in particular of a machining center. This applies in particular to chain magazines and disc magazines. If the angle heads are nevertheless stored in the tool magazine, for example, in an additional tool magazine specially adapted for this purpose, a specific tool is usually already arranged in each angle head.If different tools are required for the machining to be performed with an angle head, a corresponding number of angle heads must be provided. However, angle heads are relatively complicated, expensive, and heavy components. The invention now overcomes this situation by placing one or more angle heads on a pallet together with a number of identical or different tools that are to be used together with the angle head(s). In particular, the number of tools kept ready on the pallet can be greater than the number of angle heads arranged on the pallet.

[0019] According to one embodiment, the tool pallet can be removed from the pallet changer to set up the next workpiece to be machined at the pallet changer's setup station. Alternatively, it is also possible to always leave the tool pallet on the pallet changer. This is especially true if the pallet changer has three or more pallet locations. In this way, at least two pallet locations can be used for the simultaneous setup and machining of workpieces, while the third pallet location is reserved for the tool pallet, which can transfer the angle heads and tools required in the meantime to and from the work spindle.

[0020] The invention enables the use of angle heads in machining centers where angle heads cannot be stored in the machine's own tool magazine, for example due to their size or weight. The invention expands the spectrum of possible machining operations on a workpiece without requiring modifications to the machine, and it avoids the need to machine the operations performed with the angle head on another machine. This guarantees that the workpiece can be machined in a single setup, which can lead to improvements in accuracy. The invention is particularly suitable for machining with long tool usage times, where the chip-to-chip time, especially between tools from the machine magazine and tools from the tool pallet, is not important.

[0021] The angle head can have a work spindle connection and a tool holder receptacle that have the same nominal dimensions. For example, a hollow shank taper with a given nominal diameter (e.g., HSK 100) can be provided on the work spindle side, while the tool holder receptacle of the angle head is designed to accommodate at least a hollow shank taper of the same nominal dimension (e.g., HSK 100) or a hollow shank taper with a smaller nominal dimension (e.g., HSK 63 or others). It is also possible to provide one or more other tool holder receptacles or tool holder receptacles on the angle head.

[0022] The invention is described below using the example of a machining center with reference to the attached drawing. The drawing shows: Fig. 1 a machining center in a very schematic side view, in an initial situation and Fig. 2 to 5 the machining center after Fig. 1, in different processing situations.

[0023] In Fig. 1 illustrates a machine tool 10, which is designed, for example, as a machining center. The machine tool 10 has a work spindle 11 with a spindle housing in which a shaft provided with a holder receptacle 12 is rotatably mounted, which shaft can be coupled in a rotationally fixed manner to a tool holder of a tool. The shaft of the work spindle 11 is rotatably driven, with corresponding drive means in Fig. 1. The work spindle 11 is movable relative to a workpiece 27, for example in the vertical direction (at 13 in Fig. 1) and / or in the transverse direction thereto and, if necessary, around a tilt axis 14 (in Fig. 1) pivoting.

[0024] The machine tool 10 is assigned a tool magazine 15, which is Fig. 1 is only indicated schematically. The dashed lines indicate the center axes of the tools 28 accommodated in the tool magazine 15. A tool gripper 16 is used to transport the tools 28 into the work spindle 11, i.e. more precisely, into the holding receptacle 12 and from there for return transfer to the tool magazine 15. This is designed to grasp gripping disks of a tool holder 25, 26, to guide the tool holder 25, 26 out of the holding receptacle 12 in a short axial stroke or into it and to transfer tools 28 from the position of the work spindle 11 into the tool magazine 15 and back.

[0025] The machine tool 10 also includes a pallet holder 17, which is designed, for example, as a rotary table. The pallet holder 17 has at least two, preferably three or more pallet receiving locations 18, 19, which are configured to accommodate workpiece pallets 20 and tool pallets 21. Preferably, the interfaces between the pallet receiving location 18 and the tool pallet 21, as well as between the pallet receiving location 19 and the workpiece pallet 20, are identical to one another. However, different configurations are possible.

[0026] In Fig. 1, the workpiece pallet 20 is shown in a machining position, in which it is placed near the work spindle 11 and is located in the work area. On the other hand, the tool pallet 21 is located in Fig. 1 in setup position II, i.e. at a setup station.

[0027] At least one angle head 22 is arranged on the tool pallet 21, which has a connection 23 that can be coupled to the holder receptacle 12. Furthermore, the angle head 22 has a holder receptacle 24, which can be identical to the holder receptacle 12 or can otherwise be designed, in particular, smaller than it. At least one, preferably several, tool holders 25, 26 with identical or different tools are mounted on the tool pallet 21. The tool holders 25, 26 fit into the holder receptacle 24.

[0028] The operation of the machine tool 10 and in particular its setup is as follows: To set up the machine tool 10 for machining a workpiece 27 (dashed in Fig. 1) by means of one of the tool holders 25, 26 and by means of the angle head 22, the tool pallet 21 is first provided in the setup position at the setup station II, which contains the angle head 22 and at least one of the tool holders 25, 26. By appropriate positioning, for example rotation of the pallet holder 17, the tool pallet 21 is removed from the Fig. 1 into the work area to the machining station I in the machining position. Preferably, the angle head 22 is arranged on the tool pallet 21 such that, in the machining position, the axis of rotation of the connection 23 is oriented parallel to the axis of rotation of the work spindle 12. The angle head 22 can now be inserted into the holder receptacle 12 with its connection 23, for example with the aid of the tool gripper 16. Alternatively, the angle head 22 can be picked up by the work spindle 11 using the pick-up method, in which the work spindle 11 moves the angle head 22 so that the holder receptacle 12 couples to the connection 23. Before, after, or during this process, the workpiece 27 can be placed on the workpiece pallet 20 in the setup position at setup station II and clamped to it, if a workpiece 27 is not already arranged on the workpiece pallet 20.

[0029] The further setup of the machine tool 10 is in Fig. 3. The angle head 22 located in the work spindle 11 now picks up one of the tool holders 25, 26 with its holder receptacle 24 using the pick-up method. Once this has been done, the tool pallet 21 is moved out of the machining position and, for example, transferred back to setup station II in the setup position or to another position outside the work area 22, but in any case outside the machining position. This state is shown in Fig. 4. Machining can now be carried out on the workpiece 27 using the tool holder 26 and the angle head 22.

[0030] If further machining is to be carried out using the angle head 22, for example with the tool holder 25, the workpiece pallet 20 is again moved out of the machining position and the tool pallet 21 is moved into the machining position and the tool holder 26 is placed on the tool pallet 21, so that the state after Fig. 3 is reached. The tool holder 25 can now be picked up by the angle head 22 using the pick-up method, and then the tool pallet 21 can be moved out of the machining position and the workpiece 27 with the workpiece plate 20 can be moved into the machining position. Machining can now be continued with the angle head 22 and the tool of the tool holder 25.

[0031] If machining with the angle head 22 is no longer desired, the pallet holder 17 is repositioned accordingly so that the workpiece pallet 20 is moved out of the machining position and the tool pallet 21 into the machining position. Now, first, the tool holder 25 or 26 last held in the angle head 2 can be placed on the tool pallet 21 and then the angle head 22 can be placed on the tool pallet 21. If further machining is required on the workpiece 27, a tool 28 can be transferred from the tool magazine 15 to the work spindle 11 by means of the tool changer (gripper 16), and the workpiece 27 can be machined with the tool 28. This state is shown in Fig. 5 illustrates.

[0032] In the method according to the invention for operating and setting up the machine tool 10, the range of applications of the machine tool 10 is expanded to include the use of tools intended for operation with an angle head 22 without increasing the capacity of the tool magazine 15 and, in particular, without structurally modifying the latter. The angle head 22 and one or more tools assigned to it are arranged on a tool pallet 21, which, like a workpiece pallet 20, is moved into and out of the machining position using the pallet changer. The angle head 22 can be exchanged using the pick-up method or by means of the tool gripper 16. The tool holders 25, 26 are exchanged into the angle head 22 using the pick-up method. Reference symbol 10 Machine tool 11 Work spindle 12 Holder mount 13 Arrow 14 Tilt axis 15 tool magazine 16 tool grippers 17 Pallet holder 18, 19 Pallet receiving station 20 workpiece pallets 21 Tool palette I Processing station II Preparation area 22 Angle head 23 Connection 24 holder mount 25, 26 tool holder 27 Workpiece 28 tools 29 pallet system

Claims

[1] Method for setting up and operating a machine tool (10) which has at least one work spindle (11), is connected to a tool magazine (15) and has a tool gripper (16) and a pallet carrier (17) which is designed to receive pallets and is movable between a set-up station (II) and a machining station (I), wherein in the method: a tool pallet (21) is provided which is provided with at least one angle head (22) and with at least one tool holder (25) which fits into the angle head (22), a workpiece pallet (20) is provided which is provided with a workpiece (27), the tool pallet (21) is arranged on the setup station (II) of the machine tool (10), the tool pallet (21) is transferred from the setup station (II) to the machining station (I), the workpiece pallet (20) is arranged on the setup station (II), if present, a tool holder (25) located in the work spindle (11) is transferred into the tool magazine (15), the angle head (22) is transferred into the work spindle (11), the tool holder (25) mounted on the tool pallet (21) is transferred into the angle head (22), the tool pallet (21) is transferred from the machining station (I) to the setup station (II) and the workpiece pallet (20) is transferred from the setup station (II) to the machining station (I), the machining of the workpiece (27) is carried out by means of the tool of the tool holder (25) held in the angle head (22), after completion of the work to be carried out with the angle head (22), the workpiece pallet (20) is transferred from the machining station (I) to the setup station (II) and the tool pallet (21) is transferred from the setup station (II) to the machining station (I), the tool holder (25) held in the angle head (22) is placed on the tool pallet (21), the angle head (22) held in the work spindle (11) is placed on the tool pallet (21), the tool pallet (21) is transferred from the processing station (I) to the setup station (II). [2] Method according to claim 1, characterized by that the angle head (22) is transferred into the work spindle (11) by means of the tool gripper (16) or into the work spindle (11) in the pick-up process. [3] Method according to one of the preceding claims, characterized by that the tool holder (25) mounted on the tool pallet (21) is transferred into the angle head (22) using the pick-up method. [4] Method according to one of the preceding claims, characterized by that several angle heads (22) are arranged on the tool pallet (21). [5] Method according to one of the preceding claims, characterized bythat several tool holders (25, 26) are arranged on the tool pallet (21). [6] Method according to one of the preceding claims, characterized by that no workpiece (27) is placed on the tool pallet (21). [7] Method according to one of the preceding claims, characterized by that no tool is placed on the workpiece pallet (20). [8] Method according to one of the preceding claims, characterized byin that, in order to change the tool holder (25) held in the angle head (22), the workpiece pallet (20) is transferred from the machining station (I) to the setup station (II) and the tool pallet (21) is transferred from the setup station (II) to the machining station (I), after which the tool holder (25) held in the angle head (22) is transferred from the angle head (22) to the tool pallet (21) and another tool holder (26) is transferred into the angle head (22), after which the tool pallet (21) is transferred from the machining station (I) back to the setup station (II) and the workpiece pallet (20) is transferred from the setup station (II) to the machining station (I). [9] Method according to one of the preceding claims, characterized bythat after transferring the tool pallet (21) from the machining station (I) to the setup station (II), the workpiece pallet (20) is transferred from the setup station (II) to the machining station (I) and a tool (28) is transferred from the tool magazine (15) into the work spindle (11), after which the workpiece (27) is machined with the tool (28) from the tool magazine (15). [10] Pallet system for a machine tool (10), comprising at least one workpiece pallet (20) for receiving a workpiece (27) and at least one tool pallet (21) which is provided with means for storing tool holders (25, 26) and with means for storing at least one angle head (22), wherein the workpiece pallet (20) and the tool pallet (21) are of identical design on the part of a pallet holder (17). [11] Pallet system according to claim 10, characterized by that the tool pallet (21) is free of workpiece holding devices. [12] Pallet system according to claim 10 or 11, characterized by that the tool holders (25, 26) are arranged on the workpiece pallet (20) in positions which are set up for the pick-up tool change of the angle head (22). [13] Pallet system according to claim 10 or 12, characterized by that the number of angle heads (22) arranged on the tool pallet (21) is less than the number of tool holders (25, 26) arranged on the tool pallet (21). [14] Pallet system according to claim 10 or 13, characterized by that the angle head (22) has a work spindle-side connection (23) and a tool holder receptacle (24) which have different dimensions. [15] Pallet system according to claim 10 or 13, characterized by that the angle head (22) has a work spindle-side connection (23) and a tool holder receptacle (24) which have the same nominal dimensions.

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