WO2011089185A1

WO2011089185A1 - Complete machining of tools

Info

Publication number: WO2011089185A1
Application number: PCT/EP2011/050758
Authority: WO
Inventors: Hubert Müller
Original assignee: Erwin Junker Maschinenfabrik Gmbh
Priority date: 2010-01-25
Filing date: 2011-01-20
Publication date: 2011-07-28
Also published as: DE102010005630A1; DE102010005630B4

Abstract

The invention relates to a grinding center, wherein a workpiece headstock (2) and a tailstock (3) are disposed on a machine stand (1). The tension and rotation axle (4) for the workpiece, not shown, is provided between said stocks. A compound slide rest (8) is displaceable parallel and perpendicular to the tension and rotation axle (4). Said rest perpendicularly displaceably supports a grinding headstock (11), on which a grinding spindle (16) having a grinding disc (17) is fastened, a further potential adjustment being provided by the pivot axis (15). A dressing spindle (7) and a device (30) for changing out the grinding discs (17) are further provided. A changeover robot (25) having a gripper (29) selectively picks a particular cooling nozzle set (21) from a storage magazine (22) as needed, and guides said set into the operating position thereof at the workpiece. A flexible hose connection (23) connected to a supply line (24) supplies the selected cooling nozzle set (21) with coolant. Selecting and transporting of the cooling nozzle sets are CNC controlled by the machine controller in the enclosure (31). Actuation can be controlled from an operator console (6).

Description

COMPLETE MACHINING OF TOOLS

The invention relates to a grinding center, in which workpieces are ground, which have a certain geometric longitudinal axis, with a control device, which controls the sequence of the grinding process automatically by acting on the various components of the grinding center, according to the preamble of claim 1.

Such grinding centers are state of the art. The material of the workpieces that are ground in these grinding centers are in particular steel, iron, hard metals and ceramic materials. A typical field of application is the complete machining of differently designed tools such as milling cutters, drills, reamers, taps and the like. However, in the abovementioned grinding centers, various individual operations on workpieces can also be carried out in separate fixtures and machine parts such as shafts or flanges are ground. The grinding wheels can assume very different positions with respect to the workpiece, and there are also a variety of trajectories possible on which grinding wheel and workpiece must be moved relative to each other during grinding. The known grinding centers are provided with means by which the grinding point is supplied in the correct manner with cooling lubricant. The grinding point is that point of the workpiece at which the grinding wheel acts on the workpiece surface in the current grinding operation. It is also possible to speak of a grinding zone of the workpiece which is in the vicinity of the grinding wheel engagement and which is not allowed to heat excessively. As a cooling lubricant emulsions and grinding oil are common. The cooling lubricant is supplied to the grinding point via one or more cooling nozzles by means of a cooling liquid. Depending on the material of the workpiece and the type of grinding process, the optimum number and arrangement of the cooling nozzles can be very different. It wants to meet conflicting demands, so bring an optimal grinding result with a short processing time and not too strong heating in the grinding zone with each other.

In this context, it is already known to provide magazine locations in a grinding center of the type mentioned in which grinding wheel packages together with the individual coolant supply are stored (Saacke CNC grinding center model UVV ID, company publication of the Gebr. Saacke GmbH & Co KG in 75181 Pforzheim). If a change in the grinding process requires it, in this known grinding center of the grinding wheel set is automatically changed by accessing a specific magazine location, and together with the grinding wheel set and a plurality of cooling nozzles are brought into solid, matched to this set of grinding wheels arrangement in the operative position. Grinding wheel set and cooling nozzles are parked as assembled units in the magazine locations of a rotary storage and are brought in an immutable arrangement to each other in the operative position, if necessary. In the preamble of claim 1 of this application, this prior art is taken into account.

With the known grinding center already sufficient for many practical cases adaptation of the cooling and lubricating effect is achieved at each running grinding process. However, there is a need for further individual adaptation in order to meet the ever-advancing demands for an optimum grinding result in every specific grinding operation. The individual adaptation relates to the design, arrangement and number of cooling nozzles that come into effect at the grinding point, but also on the course of the respective spraying. The object of the invention is to improve the cooling operation in a grinding center of the type mentioned so that these requirements are met.

This object is achieved with the entirety of the features of claim 1. In a grinding center according to the preamble of claim 1 is thus provided that a storage magazine with a plurality of sets of cooling nozzles and a storage magazine associated Umsetz- tion robot are provided, which is designed as a transport device to and from the grinding point, wherein a signal of the control device the conversion robot is activated, a selected set of cooling nozzles transported to the grinding point and there to take effect.

With the embodiment of the grinding process according to the invention, it is thus advantageously achieved that the spraying process for one or more in the operative position

Grinding wheels can be individually adjusted in a variety of ways. While in the prior art grinding center preselected combinations of grinding wheels and cooling nozzles are selectively brought to the operating position, any number of cooling nozzle sets can be selected and added to each grinding wheel or set of grinding wheels in the grinding center according to the invention. Since a cooling nozzle set, which may comprise a single or a plurality of cooling nozzles, is a relatively compact structural unit, a large number of cooling nozzle sets can be set in a "parking position" in a grinding center. for example, ten to twenty or more, depending on the workpieces to be machined in the grinding center. The number of possible combinations of grinding wheel ^) and cooling nozzle (s) is thus significantly increased. By transporting a selected set of cooling nozzles from the supply magazine ("parking position") into the operative or operative position by means of a conversion robot, a proven component is used, for which there are powerful specialist manufacturers, including the control of these conversion robots that for the incorporation of the robot control in the control device of the grinding center good conditions exist and a reliable operation can be expected.

In the simplest case, the conversion robot transports the selected set of cooling nozzles to the grinding point or zone, ie the area of the workpiece in which the grinding wheel acts on the workpiece, and holds the cooling nozzle set there until the special grinding task is completed. In many cases, this will only be a subtask. Thereafter, the conversion robot transports the cooling nozzle set back into the supply magazine and possibly brings another set of cooling nozzles into its stationary operative or operating position. According to an advantageous first development, however, the grinding center is designed such that the conversion robot tracks the selected cooling nozzle set at the grinding point of the grinding wheel individually. The conversion robot in this case can follow the Schleiffortschritt and leads the cooling nozzle set of the grinding wheel in dependent controlled movements. This does not mean that the grinding wheel and the cooling nozzle set move synchronously, but the cooling nozzle set executes its own movements advantageous for the grinding process, which, however, are adapted to the movements of the grinding wheel. Also, for example, reciprocating movement of the cooling nozzle set with a stationary grinding wheel is conceivable. The individual tracking can be associated with a regulation of the amount of cooling liquid leaving the cooling nozzles. All these possibilities exist regardless of whether they relate to a grinding process with one or more grinding wheels.

In the grinding center according to the invention, it is necessary that the respectively selected cooling nozzle set detected by the conversion robot must be connected to the supply of the cooling liquid and that this connection is disconnected again when the cooling nozzle set is returned to the supply magazine. For this purpose, it is provided according to a first embodiment that the conversion robot is provided with a movable coolant supply line is constantly connected to the supply of cooling liquid and ends in a docking station in the area of the robot head. In this case, the docking station is designed as a coupling piece for docking one of the cooling nozzle sets, and by docking a cooling nozzle set the connection between the coolant supply line and the or the cooling nozzle (s) is produced. The coolant supply line is in this case connected to the moving parts of the conversion robot, for example, made flexible or formed by individual sections, which are interconnected by pivot pieces. In this case, only a single coolant supply line is required, wherein at the docking station electrical switch contacts may be present, which allow the release or the blocking of the cooling liquid flow.

Another possibility for supplying the cooling liquid is that each cooling nozzle set is connected in its storage position to the supply of the cooling liquid with a flexible hose connection, wherein the activated conversion robot entrains the hose connection. In this embodiment, however, a plurality of hose connections is required, which must be connected to a common supply line for the cooling liquid. In the case of the return transport of a cooling nozzle set to the storage magazine, a device is also required which also returns the connecting tube to its "parked position." Further advantageous embodiments of the invention relate to the fact that the conversion robot for the cooling nozzles at the same time as a loading robot for loading the grinding cell with the workpieces may be formed, and also to the fact that the replaceable cooling nozzle sets can be well combined with an automatic grinding wheel changing device and that the change of the cooling nozzle sets and the subsequent operations are CNC-controlled.

The invention will be explained in more detail with reference to embodiments shown in the drawings. In the drawings: Fig. 1 is a top view of a grinding center according to a first embodiment of the invention.

FIG. 2 is the enlarged detail A of FIG. 1. FIG. FIG. 3 shows the grinding center according to FIG. 1 in another working phase of the conversion robot. 4 is a top view of a grinding center according to a second embodiment of the invention.

Fig. 5 shows a third embodiment of the invention at a grinding center equipped with a loading robot.

Fig. 6 contains a representation of a detail on a conversion robot.

FIGS. 1 to 3 schematically show a first embodiment of the grinding center according to the invention in a top view with the protective hood removed. On a machine frame 1 different machine structures are arranged. These include a workpiece headstock 2 and a tailstock 3, which face each other with identical clamping and rotation axis 4 (C-axis). The illustration shows the workpiece headstock 2 and the tailstock 3 in a stationary arrangement; but they can also be displaced in the direction of the clamping and rotation axis 4 on the machine frame 1, if that is useful for grinding and clamping the workpieces not shown. The stationary arrangement of the workpiece headstock 2 on the machine frame 1 has the advantage that the workpiece is clamped very stiff, which benefits the grinding accuracy. The workpieces are clamped in the usual clamping devices of workpiece headstock 1 and tailstock 2 and rotate during grinding around the clamping and rotation axis 4. Depending on the shape and nature of the workpiece and the grinding point on the workpiece but also a flying clamping in the Workpiece headstock 2 suffice; the tailstock 3 remains in this case without function or can be completely eliminated. The grinding center shown in Figures 1 to 3 is intended for manual loading operation; the workpieces are introduced from the operating side 5 ago in the grinding center and removed. Thus, the pivoting control panel 6 is located on this page. Workpiece headstock 2 and tailstock 3 are thus located in the front region of the grinding center. Behind the workpiece headstock 2, a dressing spindle 7 is attached.

In the rear region of the grinding center, a cross slide 8 is arranged. Its horizontally extending lower and upper guideways can be seen on their covers 9 and 10, which are formed as usual as elastic bellows. In the process, the covers 9 cover the upper guideways and the covers 10 cover the lower guideways. The lower guideways are parallel to the tension and rotation axis 4 and the upper guideways perpendicular thereto. As a result, a grinder bar 1 1 arranged on the cross slide 8 becomes parallel in a first movement axis 12 (Z-axis) moved the clamping and rotation axis 4 and in a second movement axis 13 (X-axis) perpendicular thereto. The wheelhead 1 1 is also arranged vertically movable on the cross slide 8. For this purpose, 8 perpendicularly extending guideways 8a are formed on the cross slide, in which the wheel head 1 1 is slidably guided. The wheelhead 1 1 thereby has a third axis of movement 14 (Y-axis) which is perpendicular to the axes of movement 12 and 13. Finally, a horizontal pivot axis 5 (A-axis) is formed on the wheelhead 1 1, which runs perpendicular to the clamping and rotation axis 4. At this pivot axis 15, a grinding spindle 16 is pivotally mounted with a grinding wheel 17 whose axis of rotation 18 is perpendicular to the pivot axis 15. The grinding spindle 16 can be pivoted about the pivot axis 15 by an angle of 120 ° to the left and right. For moving and adjusting the grinding wheel 17 there are thus three linear axes 12, 13 and 14 and a pivot axis 15.

The versatile adjustment possibilities for the grinding wheel 17, which are only shown here by way of example, make it clear in which different positions the grinding wheel 17 on the grinding wheel 17

Workpiece can come into effect and how different may be the trajectories that performs the grinding wheel 17 along the workpiece. The grinding center according to the invention can therefore be used for very different grinding operations. This allows the complete machining of differently designed tools such as milling cutters, drills, reamers, taps and the like. However, it is also possible to carry out various individual operations in separate fixtures and to grind other workpieces such as shafts or flange parts in the grinding center. In order for these various grinding operations to be quickly achieved a good result, it is also necessary to carefully tune the cooling of the grinding point with cooling liquid to the respective grinding process.

The system of exchangeable cooling nozzle sets 19, 20, 21, which are located in a supply magazine 22, is used for this purpose. Each cooling nozzle set 19, 20, 21 may consist of a single cooling nozzle or a plurality of cooling nozzles; the decisive factor is always the special design of the individual cooling nozzle set 19, 20, 21 for a specific spraying process for supplying the grinding zone with cooling lubricant. The cooling nozzle sets 19, 20, 21 are in releasable holders, which are formed in the supply magazine 22. Each cooling nozzle set 19, 20, 21 is connected via a flexible hose connection 23 to a supply line 24 for the cooling liquid. The coolant used are emulsions or grinding oil. However, the supply of cooling fluid to the cooling nozzle sets 19, 20, 21 is blocked, as long as they are in their holders in the supply magazine 22, ie in their "parking position". A conversion robot 25 serves to bring a selected cooling nozzle set 19, 20 or 21 from its parking position in the supply magazine 22 into its operative position on the workpiece. The conversion robot 25 is shown only schematically in the figures, because it is known in principle. As shown in Figures 1 and 2, it is in the front region of the

Abrasive center mounted and consists of a base 26 on which a first pivot arm 27 is mounted. The first pivot arm 27 carries a second pivot arm 28, on which a gripper 29 is located. The top view reveals only the pivoting of the pivot arms 27, 28 about vertical axes. However, the conversion robot 25 also has at least two horizontal pivot axes, which may result in the view from above an apparent extension or shortening of a pivoting arm.

Figures 1 and 2 show that moment in the workflow in which the gripper 29 is coupled to the cooling nozzle set 21 and releases it from its holder in the supply magazine 22. In the state according to FIG. 3, the conversion robot 25 has released the cooling nozzle set 21 from its parking position, taken it over and brought it into the operating position on the clamping and rotation axis 4, where the workpiece is also located during the grinding operation. The flexible

Hose connection 23 pulls the cooling nozzle set 21 behind. At the latest when reaching the operating position, which is also the grinding position, the connection to the supply line 24 is opened, so that cooling liquid is sprayed onto the grinding point.

Depending on the grinding process, which is being supplied with coolant, the conversion robot 25 can hold the cooling nozzle set 21 at the position shown in FIG. 3 or track the cooling nozzle set 21 of a grinding point traveling on the workpiece. For example, in an operation of longitudinal grinding, the gripper 29 of the conversion robot 25 will execute a movement parallel to the clamping and rotation axis 4. Likewise, however, a radial tracking or a combination of both directions of movement is possible. Finally, the gripper 29 can be articulated on the second pivot arm 28 in the manner of a ball joint, whereby almost any position of the cooling nozzles relative to the workpiece can be set. If another grinding operation required on the same workpiece requires a different set of cooling nozzles, the conversion robot 25 returns the cooling nozzle set 21 to the supply hopper 22 and another set of cooling nozzles into the operative position on the tension and rotation axis 4. The flexible hose connections 23 must be provided with means for returning or rolling up, similar to that provided for the electric cable in household vacuum cleaners The reference numeral 30 denotes a device for changing the grinding wheel 17. The grinding wheels 17 are changed according to the changing grinding tasks - even when processing a single workpiece. To change the grinding wheel 17, the grinding spindle 16 is moved in front of the device 30 and the replacement is carried out fully automatically against another grinding wheel 17 contained in the grinding wheel magazine and selected. Such means for changing the grinding wheel 17 belong with their details to the prior art and therefore need not be described in detail here. During the time in which the grinding wheel 17 is changed during the transition to a new processing section, the replacement of the cooling nozzle set 19, 20, 21 can also take place. The cooling nozzle set 19, 20, 21 located on the conversion robot 25 can be tracked during grinding of the moving grinding wheel 17. The movement of the conversion robot 25 will take place in accordance with the control for the grinding wheel 17. These processes, like all other movements of the grinding process, are CNC-controlled; the machine control is housed in the cabinet 31.

The embodiment according to FIGS. 1 to 3 has the disadvantage that the conversion robot 15 impedes access to the interior of the grinding center. An improvement brings about the variant according to FIG. 4. In this the reference numerals of parts of the invention which have remained unchanged are

Maintain grinding center. By contrast, the conversion robot 32 is now arranged on the base 33 in the middle right area of the grinding center. The gripper 34 located on it now has to travel a longer distance up to the supply magazine 22. In its drawn with full lines position of the gripper 34 just grips the cooling nozzle set 21st The dashed representation shows the conversion robot 32 in an operative position in which the gripper 34 is in the vicinity of the tailstock 3. During loading and unloading, the conversion robot 32 can assume a retracted position behind the workpiece headstock 2 and / or the tailstock 3. According to the third embodiment shown in Figure 5 is based on a grinding center, which has a loading center with a loading robot 35 and two pallet trays 36, 37. The loading robot 35 grips the individual workpieces and transports them into the area between the workpiece headstock 2 and the tailstock 3. In the same way, the finished ground workpiece is transported back to the pallet trays 36, 37. The conversion robot 25 is therefore the same again as in Figures 1 to 3, because no other space is available. FIG. 5 shows a splashguard 50 which displays an undesired spray effect of the cooling liquid within the grinding cell and to the outside. prevents. It comes in this or a modified form for the other embodiments into consideration.

However, if free access to the interior of the grinding center is particularly important, in the case of the embodiment according to FIG. 5 it is possible to combine the functions of the conversion robot 32 according to FIG. 4 and that of the loading robot 35 according to FIG. The conversion robot is formed in this case at the same time as a loading robot, which serves to load the grinding center with the workpieces. In the schematic representation of FIG. 5, the loading robot 25 in the area of the operating side 5 is then omitted, and the area of action of the loading robot 35 is to be expanded. A disadvantage of this embodiment can be seen in the fact that the set-up time is prolonged, if at a change of the workpiece and the cooling nozzle set 19, 20, 21 must be changed. The two change processes can then only take place one after the other. Finally, Fig. 6 shows another way to supply the individual cooling nozzle sets 19, 20, 21 with the cooling liquid. Here, a robot head 38 is shown, which is located at the end of a swivel arm and carries a gripper unit 39 with a gripper 40. On the gripper unit 39, a docking station 42 is permanently attached, which is connected to a coolant supply line 41. The docking station 42 is used for exchangeable docking of a cooling nozzle set 49, which carries a cooling nozzle 43 at its lower end. The cooling nozzle set 49 here has the shape of a mouthpiece from which a branch line 44 leads to a lower cooling nozzle 45. 46 denotes the clamped and rotating workpiece, and 47 denotes the contour of a grinding wheel which contacts the workpiece 46 at the grinding point 48. It can be seen that the grinding point 48 is uniformly cooled by an upper cooling nozzle 43 and at the same time by a lower cooling nozzle 45.

In the embodiment according to FIG. 6, the docking station 42 and the coolant supply line 41 carry along all the movements of the conversion robot. The coolant supply line 41 must therefore be designed to be flexible or made up of individual parts interconnected by pivot pieces. The embodiment of FIG. 6 has the advantage that only a single coolant supply line 41 is required. Compared to the embodiment according to FIGS. 1 to 5, the problem of how the flexible hose connections 23 are to be returned when the cooling nozzle sets 9, 20, 21 are returned to the storage magazine 22 is also eliminated. According to FIG. 6, only the cooling nozzle set 49 has to be coupled to the docking station 42 and the supply of the cooling liquid to the cooling nozzle set 49 has to be opened. LIST OF REFERENCE NUMBERS

1 machine stand

2 workpiece headstock

3 tailstock

4 clamping and rotation axis

5 operating page

6 control panel

7 dressing spindle

8 cross slides

8a vertical guideways

9 Cover of upper guideways

10 Cover of the lower guideways

1 1 wheelhead

12 first movement axis

13 second movement axis

14 third movement axis

15 pivot axis

16 grinding spindle

17 grinding wheel

18 axis of rotation of the grinding wheel

19 Cooling nozzle set

20 cooling nozzle set

21 cooling nozzle set

22 supply magazine

23 flexible hose connection

24 supply line

25 conversion robots

26 sockets

27 first pivot arm

28 second swivel arm

29 grippers

30 Device for changing the grinding wheel

31 Cabinet for receiving the machine control

32 conversion robots

33 sockets grab

loading robot

pallet storage

robot head

gripper unit

grab

Coolant supply line docking station

Cooling nozzle (upper cooling nozzle) branch line

lower cooling nozzle

workpiece

grinding wheel

grinding site

Cooling nozzle set

Protection sheet

Claims

claims

1 . Grinding center, in which workpieces are ground, which have a determining geometric longitudinal axis, with a control device, which controls the course of the grinding process automatically by acting on the various components of the grinding center, wherein the grinding center includes the following components:

a) a workpiece headstock, which receives the workpiece and sets in rotation about its determining geometric longitudinal axis,

b) at least one rotation-driven grinding wheel, which is moved and delivered by its drive and adjusting device with respect to the workpiece in different positions relative to its determining geometric longitudinal axis, and c) replaceable cooling nozzles, through which the grinding point is supplied in the grinding operation, a cooling liquid,

characterized,

in that a supply magazine (22) is provided with a plurality of sets (19, 20, 21) of cooling nozzles and a conversion robot (25, 32) associated with the supply magazine (22), which is designed as a transport device to and from the grinding point, wherein a signal the control device of the conversion robot (25, 32) is activated, a selected cooling nozzle set (19, 20, 21) transported to the grinding point and there to take effect.

2. grinding center according to claim 1, characterized in that the conversion robot (25, 32) individually tracks the selected cooling nozzle set (19, 20, 21) at the grinding point of the grinding wheel (17).

3. grinding center according to claim 1 or 2, characterized in that the conversion robot (25, 32) is provided with a movable coolant supply line (41) which is constantly connected to the supply of the cooling liquid and in a docking station (42) in the area of the robot head (38) ends, and that the docking station (42) is designed as a coupling piece for docking one of the cooling nozzle sets (19, 20, 21), wherein by docking of the cooling nozzle set (19, 20, 21) the connection between the coolant supply line (41) and the one or more cooling nozzle (s) (43, 45) is produced.

4. grinding center according to claim 3, characterized in that the docking station (42) is provided with electrical switching contacts, which allow depending on the presence of a cooling nozzle set (19, 20, 21), the release or the blocking of a cooling liquid flow.

5. grinding center according to claim 1 or 2, characterized in that each cooling nozzle set (19, 20, 21) is connected in its storage position to the supply of the cooling liquid with a flexible hose connection (23), wherein the activated Umsetzungsroboter (25, 32) the Hose connection (23) entrains.

6. grinding center according to at least one of claims 1 to 5, characterized in that the conversion robot (32) at the same time as a loading robot (35) is formed, which serves to load the grinding cell with the workpieces.

7. grinding center according to at least one of claims 1 to 6, characterized in that an automatic grinding wheel changing device (30) is provided, each grinding wheel (17) by the conversion robot (25, 32) different selected cooling nozzle sets (19, 20, 21 ) can be supplied.

8. grinding center according to at least one of claims 1 to 7, characterized in that the change of the cooling nozzle sets (19, 20, 21) and the subsequent operations are CNC-controlled.