Abstract
A method for reducing an energy demand of a machine tool (2, 3, 4) of a machine tool system (1), wherein the machine tool system (1) comprises at least a first machine tool (3), with a first machine cycle time, and a second machine tool (4), with a second machine cycle time. Identical workpieces (9) are transported sequentially in time for processing (101, 107), first to the first machine tool (3) and then to the second machine tool (4). The second machine cycle time is shorter than the first machine cycle time. The method according to the invention is characterized in that the workpieces (9), after being processed by the first machine tool (3), are collected (105, 106) before they are conveyed (107) to the second machine tool (4) for processing. The invention also concerns a related device (10) and a machine tool system (1).
Claims
1-16. (canceled)
17. A method of reducing an energy demand of a machine tool (2, 3, 4) of a machine tool system (1) having at least a first machine tool (3), with a first machine cycle time, and a second machine tool (4), with a second cycle time, the method comprising: processing (101, 107) identical workpieces (9) sequentially in time first with the first machine tool (3) and then with the second machine tool (4), with the second machine cycle time being shorter than the first machine cycle time, and collecting (105, 106) the workpieces (9) after processing by the first machine tool (3) and before being transported (107) to the second machine tool (4).
18. The method according to claim 17, further comprising, when the second machine tool does not have any workpieces (9) for processing, changing the second machine tool (4) to an idle mode (113).
19. The method according to claim 18, further comprising dividing the idle mode into a plurality of idling mode stages, and when changing to the idle mode, one of the plurality of idling mode stages is selected in accordance with an expected duration of the idle mode.
20. The method according to claim 17, further comprising collecting a specified number of the workpieces (9) processed by the first machine tool (3).
21. The method according to claim 20, further comprising changing the second machine tool (4), from the idle mode to a working mode (109), once the specified number of the workpieces (9) are collected.
22. The method according to claim 17, further comprising continually transporting the workpieces (9) to the first machine tool (3) such that the first machine tool is in a continuous working mode.
23. A device (10) for reducing an energy demand of a machine tool (2, 3, 4) of a machine tool system (1) having at least a first machine tool (3), with a first machine cycle time, and a second machine tool (4), with a second machine cycle time, the machine tool system (1) having a conveyor (8) designed to transport identical workpieces (9) sequentially in time for processing, first to the first machine tool (3) and then to the second machine tool (4), and the second machine cycle time being shorter than the first machine cycle time, the device comprising: a counter (11) for counting a specified number of workpieces (9) processed by the first machine tool (3); and a collector (12) for collecting the specified number of workpieces (9) processed by the first machine tool (3) before the workpieces are conveyed to the second machine tool (4).
24. The device (10) according to claim 23, wherein the device (10) comprises a controller (13) for reading the counter (11), the controller controlling the collector (12) and, when the specified number is reached, the controller producing an electrical signal designed to change the second machine tool (4) from an idle mode to a working mode.
25. The device (10) according to claim 24, wherein the device (10) also comprises a signal transmission means (14), and the signal transmission means (14) is designed to send the electrical signal to a data transmission medium (15).
26. The device (10) according to claim 24, wherein the collector (12) comprise either a workpiece gate (12) or an individually controllable part-section of the conveyor (8).
27. The device (10) according to claim 24, wherein the counter (11) comprise a light-screen (11).
28. The device (10) according to claim 24, wherein the device (10) is designed to carry out a method for reducing an energy demand of the machine tool (2, 3, 4) of the machine tool system (1), the method including: processing (101, 107) the identical workpieces (9) sequentially in time first with the first machine tool (3) and then with the second machine tool (4); and collecting (105, 106) the workpieces (9) after being processed by the first machine tool (3) but before being transported (107) to the second machine tool (4).
29. A machine tool system (1) comprising: at least a first machine tool (3) with a first machine cycle time; a second machine tool (4) with a second machine cycle time; a conveyor (8) for transporting identical workpieces (9) sequentially in time for processing, first to the first machine tool (3) and then to the second machine tool (4), and the second machine cycle time being shorter than the first machine cycle time; a device (10) for reducing an energy demand of at least one of the first and the second machine tools (2, 3, 4), the device having a counter (11) for counting a specified number of workpieces (9) processed by the first machine tool (3), and a collector (12) for collecting the specified number of workpieces (9) processed by the first machine tool (3) before the workpieces are conveyed, via the conveyor, to the second machine tool (4).
30. The machine tool system (1) according to claim 29, wherein the machine tool system (1) is designed to process the workpieces (9) by at least one of grinding, milling and turning.
31. The machine tool system (1) according to claim 30, wherein the machine tool system (1) is designed to at least one of grind and mill gearwheel teeth.
32. The machine tool system (1) according to claim 29, wherein the conveyor (8) is a conveyor belt.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0039] Below, examples of the invention are explained with reference to embodiments illustrated in the drawings, which show:
[0040] FIG. 1: As an example and schematically, a possible embodiment of a device according to the invention,
[0041] FIG. 2: As an example and schematically, a possible embodiment of a machine tool system according to the invention, and
[0042] FIG. 3: An example embodiment of a method according to the invention, shown in the form of a flow chart.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0043] The same objects, functional units and comparable components are denoted by the same indexes in all the figures. In relation to their technical features these objects, functional units and comparable components are designed identically unless indicated explicitly or implicitly in the description.
[0044] FIG. 1 shows, schematically and as an example, a device 10 according to the invention which comprises counting means 11, collecting means 12, control means 13 and signal transmission means 14. The counting means 11 in this example are in the form of a quartz oscillator based clock-pulse generator 11 whose pulse signals are a fixed time interval apart and are counted and summed by the control means 13. The control means 13, in turn, are in the form of a microcontroller 13. In this example the collecting means 12 are in the form of a workpiece gate 12 designed to interrupt the delivery of workpieces 9 to a downstream machine tool 2, 3 or 4 and to collect the workpieces 9 until a specified number of workpieces 9 has been reached. The reaching of the specified number of workpieces 9 is recognized in this example by the lapse of a time interval required for the specified number of workpieces 9 to be processed by an upstream machine tool 2, 3 or 4. In other words, the counting means 11 determine the time continuously and after the lapse of a specified time interval the control means 13 recognize that the specified number of workpieces 9 have been collected. As soon as the control means 13 recognize that the specified number of workpieces 9 have been collected, an electrical signal is emitted to the workpiece gate 12, which then releases the collected workpieces 9 to that they can be passed on by conveyor means 8 which do not belong to the device 10 and are not shown in FIG. 1. At the same time the control means 13 emit an electrical signal to the signal transmission means 14, which in this example is in the form of a socket for a plug of a data transmission medium 15. In this example the signal transmission means 14 consist of an RJ45-socket 14 and the plug of the data transmission medium 15 is an RJ45 plug, so that the data transmission medium is in the form of a network cable. The electrical signal sent by the control means 13 to the signal transmission means 14 is designed to change a machine tool 2, 3 or 4 from an idling mode to a working mode.
[0045] FIG. 2 schematically shows, as an example, a possible embodiment of a machine tool system 1 according to the invention. The machine tool system 1 shown as an example comprises three machine tools 2, 3 and 4. Each of the machine tools 2, 3 and 4 comprises a control unit, 5, 6 and 7 respectively, which in each case comprise in turn a plurality of subordinate, secondary control units (not shown) for the control and regulation of various tool modules (also not shown) of the machine tools 2, 3 or 4. The machine tool system 1 shown as an example also comprises conveyor means 8 in the form of a conveyor belt 8, on which workpieces 9 are arranged. In this example the workpieces 9 are all the same, i.e. identical workpieces 9 in the form of metallic cylinders. Sequentially in time, the workpieces 9 are conveyed first to the machine tool 2, then to the machine tool 3 and finally to the machine tool 4 for processing. The machine tool 2 has a machine cycle time of, for example, 20 s. This means that to process a workpiece 9 the machine tool 2 needs 20 s. The machine tool 2 is a furnace that heat treats the workpieces 9. When the machine tool 2 has finished processing a workpiece 9, the workpiece 9 is taken by the conveyor belt 8 to the machine tool 3. In this example the machine tool 3 carries out a milling operation on the workpiece 9 and for this has a machine cycle time of 25 s, meaning that it needs 25 s to process a workpiece 9. When the machine tool 3 has finished processing a workpiece 9, the workpiece 9 can be passed on by the conveyor belt 8 to the machine tool 4. In this example the machine tool 4 has a machine cycle time of 16 s, which means that the time taken by machine tool 4 to process a workpiece 9 is 16 s. In this example the machine tool 4 is a grinding machine which carries out a rough-machining and a finish-machining operation on the workpiece 9. Since the total processing time for a workpiece 9 by the machine tool system 1 in this example is characterized by the longest machine cycle time or corresponds to it, the total processing time amounts to 25 s. In this example the machine tool 3 now represents the first machine tool in the sense of the invention, whereas in the example the machine tool 4 represents the second machine tool in the sense of the invention. Since as described the machine cycle time of the machine tool 4 is 16 s and the machine cycle time of the machine tool 3 is 25 s, the second machine cycle time is shorter than the first machine cycle time. After the processing of a workpiece 9 by the machine tool 3, the workpiece 9 is conveyed by the conveyor belt 8 to a device 10 designed according to this example. The device 10 comprises a light-screen 11, a workpiece gate 12 and an electronic computer unit 13 that controls the light-screen 11 and detects its condition at the time. For this, with reference to the number of interruptions of the light beam 16 the electronic computer unit 13 counts the number of workpieces 9 that have been transported onward from the machine tool 3. The light-screen 11 represents the counting means 11, the workpiece gate 12 represents the collecting means 12 and the electronic computer unit 13 represents the control means 13. In this example the condition of the light-screen 11 can be light beam 16 interrupted and light beam 16 not interrupted. Each interruption of the light beam 16 indicates that a workpiece 9 has moved past the light-screen 11. The electronic computer unit 13 also controls the condition of the workpiece gate 12, which in this example has an arm that can be raised or lowered as a mechanical barrier. Thus, the condition of the workpiece gate 12 can be open or closed. Depending on the number of workpieces 9 collected and counted by the light-screen 11 and the electronic computer unit 13, the electronic computer unit 13 opens or closes the workpiece gate 12. In the open condition the workpieces 9 can move past the workpiece gate 12 whereas in contrast in the closed condition thereof the workpieces 9 cannot pass the workpiece gate 12 and are collected. During the collection of the workpieces 9 after they have been processed by the machine tool 3, the conveyor belt 8 is not stopped but continues moving regardless of the condition of the workpiece gate 12. Thus, the workpiece gate 12 is made correspondingly strong and load-bearing, in order to stand up to the conveying pressure produced by the conveyor belt 8 and the collecting of the workpieces, i.e. their retention. Thus the workpieces 9 remain on the conveyor belt 8 while the belt 8 continues moving and slides away under the retained workpieces 9. As soon as the light-screen 11 or the electronic computer unit 13 has counted a specified number of workpieces 9, in this example 17, the electronic computer unit 13 opens the workpiece gate 12 by transmitting a corresponding electrical signal so that the collected workpieces 9 can be conveyed together to the machine tool 4. At the same time the collecting means 12 emit by way of a signal transmission means 14 an electrical signal to a data transmission means 15, which passes the electrical signal on to the control unit 7 of the machine tool 4. The electrical signal switches the machine tool 4 out of its idling mode back to its working mode. Depending on the selected idling mode stage to which the machine tool 4 was previously changed, this takes up a certain time, for example 20 s. In that as described in this example the workpieces 9 are collected by the device 10, the related time duration of the idle mode of the machine tool 4, during which no workpieces 9 are present for processing in the machine tool 4, can be extended. In this example the time duration now amounts to 153 s. That duration is known, and is stored in the control device 7 of the machine tool 4. The control device 7 is designed to change the machine tool, depending on the situation, into the idle mode or into a special idling mode stage and back again into the working mode. Since the idle mode of the machine tool 4 is divided into a plurality of different idling mode stages, which can be selected in accordance with an expected duration of the idle mode, it is now possible starting from the known expected idle mode duration of 153 s to change the machine tool 4 to its standby mode stage. Here, the standby mode stage is that idle mode stage in which the power demand is comparatively the smallest, since in this example all the tool modules and most of the secondary control units are deactivated. But if the expected duration in the idle mode were shorter, then it would not be worth changing the machine tool 4 to the standby mode stage since due to the time taken to reactivate all the tool modules and secondary control units that were deactivated in the standby mode stage, the processing of the workpieces 9 would be delayed, which would extend the total processing time of the workpieces 9 to 28 s. That would affect efficiency and costs adversely.
[0046] FIG. 3 shows an example embodiment of the method according to the invention, in the form of a flow chart. In process step 101 a workpiece 9 is processed by a first machine tool 3 with a first machine cycle time. At the same time as process step 101 a second machine tool 4 with a second machine cycle time is in an idle mode in step 102. The second machine cycle time is shorter than the first machine cycle time, which means that the first machine tool 3 takes longer to process a workpiece 9 than does the second machine tool 4. In process step 103 the processing of the workpiece 9 by the first machine tool 3 is completed and the workpiece 9 is taken away from the first machine tool 3 by the conveyor means 8. In the next process step 104 the workpiece 9 is counted by counting means 11 and in step 105 it is collected by collecting means 12 before, as the process continues, it is transported to the second machine tool 4. In step 106 the counting and collecting means 11 and 12 count and collect further workpieces 9 until a specified number of workpieces 9 have been counted and collected. When the specified number of workpieces 9 have been counted and collected, then in step 107 the collecting means 12 are first instructed by an electrical signal not to collect any more workpieces 9 and to allow the conveyor means 8 to transport the collected workpieces 9 to the second machine tool 4. At the same time, in step 108 an electrical signal is sent to the second machine tool 4 which, in step 109, changes the machine tool from its idle mode to the working mode. Also at the same time as the steps 107 and 108, in step 110 the counting means 11 are reset so that they can again count the workpieces 9 processed by the first machine tool 3, starting from zero. But if in step 111 the specified number of workpieces 9 have not yet been counted or not yet been collected, then the process described in this example is repeated from step 106 onward. In process step 112 the collected workpieces 9 are now processed by the second machine tool 4. Once the processing of the collected workpieces 9 by the second machine tool 4 has been completed, in step 113 the second machine tool 4 is returned to its idle mode and the process described as an example begins again at step 101 or 102.
INDEXES
[0047] 1 Machine tool system [0048] 2 Machine tool [0049] 3 Machine tool [0050] 4 Machine tool [0051] 5 Control unit of machine tool 2 [0052] 6 Control unit of machine tool 3 [0053] 7 Control unit of machine tool 4 [0054] 8 Conveyor means, conveyor belt [0055] 9 Workpiece [0056] 10 Device [0057] 11 Counting means, light-screen, pulse emitter [0058] 12 Collecting means, workpiece gate [0059] 13 Control means, microcontroller [0060] 14 Signal transmission means, RJ45 socket [0061] 15 Data transmission means [0062] 16 Light beam [0063] 101 Processing of a workpiece by the first machine tool [0064] 102 Second machine tool is in its idle mode [0065] 103 Completion of the processing of the workpiece by the first machine tool [0066] 104 Counting of the workpiece [0067] 105 Collection of the workpiece [0068] 106 Counting and collection of further workpieces [0069] 107 Transport of the collected workpieces to the second machine tool [0070] 108 Emission of an electrical signal to the second machine tool [0071] 109 Change of the second machine tool to its working mode [0072] 110 Resetting of the counting means [0073] 111 Counting and collection of further workpieces [0074] 112 Processing of the collected workpieces by the second machine tool [0075] 113 Changing the second machine tool to its idle mode
