High temperature bonding furnace

Abstract

An automated high temperature bonding furnace is prepared for diffusion bonding of bonding materials, e.g. metals and metal workpieces, and provides a heating chamber with a heating device, a workpiece holder disposed within the heating chamber and receiving a workpiece to be processed in the bonding furnace, a pressure device disposed and arranged to apply a pressing force to the workpiece, a sensor device for generating at least one sensor signal, and a control device arranged for controlling at least the pressure device in response to the at least one sensor signal.

Description

[Technical field]

[0001] The present invention relates to an automatic high-temperature bonding furnace and a diffusion bonding method. [Background technology]

[0002] It is generally known that metallic workpieces can be joined by diffusion bonding. For example, metal workpieces can be joined by applying pressure to them in a press at high temperatures, resulting in diffusion welding. The diffusion bonding process is a complex procedure that depends on many different influences, and the same process conditions do not always give equivalent, or at least satisfactory, results.

[0003] For example, the joining process must take into account deformations of the workpieces. For example, cooling channels or other bores or openings inside the workpieces to be joined can locally deflect the pressing forces on the workpieces, resulting in a different overall deformation compared to solids of the same dimensions. The previous history of the materials to be joined also plays a role with regard to the joining result. In this case, the grain size of the metal composite and the manufacturing process of the individual metal layers, for example by rolling, are particularly relevant.

[0004] Thus, the present inventors have recognized that reproducible success in a joining process cannot be readily achieved by simply following standard literature values ​​for, for example, the surface pressure that may be applied to the workpieces.

[0005] Even if the materials in each workpiece are essentially the same, i.e., produced using the same manufacturing process, pre-treated to the same temperatures, and similar grain sizes are expected within the materials, there are still variations between materials that must be considered. This is true even if the workpieces are cut from the same piece of raw material, but for certain materials and / or material combinations this can be even more challenging.

[0006] Therefore, even if specially trained personnel are monitoring the joining process, one employee can only monitor one furnace at a time, limiting the number of joining processes that can be performed in parallel. The entire process may take more than 24 hours to complete. Intensive training on the part of the user, as well as a high degree of experience and understanding of the underlying processes, are required, without which a satisfactory result, i.e. a strong joint result, can not be obtained. This is another reason why diffusion bonding of metals has been relatively rare in industry so far.

[0007] In view of the above, the present invention is directed to the task of automating the process sequence, further improving the joining results and providing consistent results in a way that is not or rarely achieved with this quality even by trained personnel.

[0008] The present invention pays particular attention to ensuring that a consistently high quality end result is achieved during the joining process, even when starting materials differ, e.g. in terms of microstructural properties, as is the case in typical applications.

[0009] This problem is solved by the invention as defined in the independent claims. The dependent claims provide further and preferred embodiments of the invention.

[0010] In the diffusion bonding process, the workpiece or batch is deformed in a controlled way. Pores present in the joining material, recesses inside the workpiece, the number and size of the joining surfaces, the previous history of the joining materials, etc. are uncertainties that can affect the process sequence. When a force is applied to the workpiece or batch in a press, the material contact at the joining surface is improved, for example by reducing the surface roughness. In this way, an inherent interdiffusion can be generated or induced. Thus, the pressure is used to increase the contact surface in the joining surface area. These processes are different for each workpiece, and the differences can be very significant, so that the first component can be joined with sufficient strength, while the next component, although joined with the same parameters, will only have insufficient strength or quality. On the other hand, the shape of one component is preserved, while the next identical component with the same parameters can be deformed, for example in the area of ​​the cooling channels, due to the pressure process.

[0011] According to the invention, an automated high-temperature joining furnace is provided, for example, arranged for diffusion bonding of joining materials. The joining materials may be metals. The metals may be any material or substance that contains a metal. Examples include metals such as iron, copper, aluminum, titanium, and alloys such as high grade steels, stainless steels, tool steels, superalloys, bronze, tin, and the like. The joining materials may be non-metallic or composite materials.

[0012] The automatic high temperature bonding furnace can also be configured for force assisted soldering or sintering of components. For example, the automatic high temperature bonding furnace can be configured to refine materials with or without filler materials using force.

[0013] The automatic high temperature bonding furnace comprises a heating chamber equipped with a heating device, which is designed to heat the interior of the furnace and the workpieces to a processing temperature.

[0014] A workpiece holder is arranged in the heating chamber, which holds the workpieces to be treated in the joining furnace. Typically, the workpiece holder is arranged in the lower part of the heating chamber. For example, the workpiece holder can comprise a plate, but it can also comprise a holder into which the workpieces to be joined are inserted. The workpiece holder can be part of the pressure counter element or arranged on it.

[0015] The joining furnace also comprises a pressing device. The pressing device is arranged and designed to apply a pressing force to the workpiece. For example, the pressing device is arranged such that an upper part, such as a pressing punch, presses the workpiece from above, whereby the workpiece is pressed against a workpiece holder or a pressing resistance element. That is, the workpiece is fixed between the upper part or pressing punch and a pressing resistance element or a workpiece holder. For this purpose, the upper part can comprise, for example, a pressing plate, whereby the pressing force is distributed evenly over the entire surface and the workpiece is pressed evenly. Depending on the application, the surface of the pressing plate can be flattened and the pressing force can be applied evenly to the workpiece by the surface of the pressing plate. In order to shape the pressing plate to the desired surface shape of the workpiece, the pressing plate can also have recesses, protrusions or steps. The pressing plate can therefore be described in general terms as a "pressing element". In the following, the term "pressing plate" is used, since this term is considered to be more understandable to a person skilled in the art in the light of the present description.

[0016] The pressure plate is movable, for example, the pressure plate is moved by one or more pressure punches, and the pressure punches are actuated by one or more pressure cylinders. When a pressing force is applied, the workpieces are continuously deformed or joined.

[0017] The pressure device may also be arranged to apply pressure to the workpiece from below, for example by providing a movable workpiece holder and, for example, by moving the workpiece on the workpiece holder upwards. In further embodiments of the invention, first and second pressure plates may be provided to apply forces on both sides, for example upper and lower pressure plates, or left and right pressure plates. The indicated directions "up" and "down" are preferably simply aligned with the direction of gravity. A "left" or "right" arrangement is also conceivable, but should not be placed outside the protected area, and a "up" or "down" arrangement has design advantages.

[0018] To press the workpiece, one or at least one part that can receive an external force and acts as a pressing punch and a pressing counter element that opposes the pressing force are usually used. The workpiece is clamped between the pressing punch and the pressing counter element and is joined or deformed there.

[0019] A sensor device in the bonding furnace provides at least one sensor signal. For example, the sensor device can detect a position or extension length of a pressing punch or a position of a pressing plate. A control device configured to control at least the pressing device in response to the at least one sensor signal is also included.

[0020] The sensor device of the bonding furnace is capable of detecting a process parameter. The process parameter may be the thickness of the workpiece or the position of the pressure ram or pressure ram of the pressing device. The process parameter may be the applied pressing force, the hydraulic pressure or the travel distance of the pressing device. A sensor signal may then be generated based on the values ​​recorded by the sensor device, i.e. from one of said process parameters. To simultaneously record different process parameters, several sensor devices may be provided. The further sensor device may detect one or more process parameters simultaneously with the first sensor device and thus generate at least one or more further sensor signals. The one or more sensor signals may be processed to control the bonding process or the bonding furnace, so that the different process parameters can be taken into account in the control.

[0021] The pressure device may include a hydraulic device, where increasing the hydraulic pressure increases the pressure. The pressure device may also include, for example, a motorized spindle that rotates to generate the feed and apply the pressure to the workpiece.

[0022] The joining furnace may include an input device for inputting process parameter settings. The input device may be, for example, a terminal operated by a user. Specifications of the process parameters that may be stored before the start of the joining process include, for example, the desired process temperature, the process time, the material of the workpieces, parameters and other data related to the underlying material as well as the number and / or amount of joining surfaces of the workpieces. That is, some of the process parameters may be stored by the operator and some may be generated or calculated by the joining furnace without operator intervention. If desired, the joining furnace may determine all process parameters itself without operator input. In an exemplary embodiment, the operator only inputs component information, i.e. various details related to the components used. The component information includes the net joining area to be welded, the material of the components, their thickness and / or the total allowable plastic deformation. It is preferred that no operator inputs welding process dependent specifications are required, i.e. the welding process dependent process parameters are determined independently by the joining furnace.

[0023] For example, a workpiece may be composed of multiple layers of different materials, e.g., at least two different materials stacked on top of each other, and each surface bonded between the two different materials is described as a bonding surface. For example, for a plate-like workpiece consisting of 25 layers, there will be 24 bonding surfaces located on the workpiece. Information regarding the cavities of the workpiece can also be taken into account in the specification of the process parameters.

[0024] The bonding furnace may also include an output device that may display or select process parameters and / or control programs. For example, information about the current operation of the bonding furnace may be displayed on the output device.

[0025] The pressure device may comprise a pressure plunger to which the pressure force is transmitted and / or may comprise a pressure plate to which the pressure force is applied to the workpiece.

[0026] The pressing device may comprise a pressing cylinder, to which the pressing punch is connected so that the pressing cylinder exerts a pressing force on the pressing punch and the pressing punch can be adjusted in the direction of the workpiece. The pressing device may comprise a plurality of pressing cylinders, for example, two, three or four pressing cylinders.

[0027] It is preferable to use several pressure punches which act together on the workpieces, for example via a pressure plate. The workpieces are subjected to the pressure force by two or more pressure punches as uniformly as possible or as evenly distributed as possible over their surface. Several pressure punches can be arranged next to each other so that a series of pressure punches act on the pressure plate. The aim of the invention is to distribute the pressure force as uniformly as possible on the workpieces to be joined, since otherwise the pressure force required for joining could cause the pressure plate or the pressure element to deform, which would result in the pressure force being non-uniformly applied to the workpieces to be joined.

[0028] The high temperature bonding furnace may include a housing. For example, the heating device, the heating chamber, the workpiece holder, and / or the pressure device may be housed within the housing. The pressure device may be disposed on the housing and / or supported by the housing using a press mount. For example, the press mount may be attached to or rest on the housing such that a pressure cylinder connected to the press mount is supported by the housing of the high temperature bonding furnace.

[0029] For purposes of supporting the pressure device on the housing, the housing can have a support or retaining structure, such as a support frame or cage. The support or retaining structure can be a separate component from the housing or can be an integral component with the housing.

[0030] The support or holding structure and / or the press mount can be designed to be movable and / or deformable. For example, when pressure is applied to the workpiece, the pressure device is supported by the press mount. The press mount then moves and / or deforms, for example due to deformation of the support or holding structure. Here, between the press mount and the pressure device, for example a pressure cylinder with a pressure punch, accumulated forces can be absorbed in a similar manner to the pretension of a spring, so that for example the pressing effect on the workpiece can be increased uniformly or more gently when the pressing force is increased. A movable and / or deformable design of the press mount or the support or holding structure can be used to prepare the pressure device, which is prepared in an initial position where a pre-pressure force is already applied to the workpiece. If the press mount is movable and / or deformable, this pre-pressure force can be applied more finely and therefore more accurately adjusted.

[0031] The joining furnace can be configured such that a compressive force is applied to the workpiece by the pressing device, causing a lateral movement and / or deformation of the press mount, i.e., the application of a compressive force to the press mount, which acts as the abutment of the press, causes a lateral movement and / or deformation of the press mount. By absorbing the compressive force in or in the area of ​​the press mount, a spring effect is created between the press mount and the pressing device, or between the press mount, the pressing cylinder and the pressing punch.

[0032] The pressure device can be set such that a pre-tension can be increased between the pressure punch and the housing during the pressure process or when the pressing force is increased. The presence of pre-tension in the pressure device allows finer pressing and therefore more accurate detection and / or tracking of the punch position during the pressure process. Furthermore, the accumulation of pre-tension allows more accurate setting or measurement of pressure compensation or pressing force compensation.

[0033] For example, the press mount may move or deform by more than 1 mm, such as more than 3 mm, or more than 5 mm, or even more than 10 mm, when a compressive force is applied. This creates a kind of "spring mechanism" or preload force. The press mount may also move or deform by less than 3 mm, preferably less than 6 mm, and more preferably less than 12 mm, when a compressive force is applied. The minimum and maximum deflection values ​​may be combined into an interval, such as greater than 3 mm and less than 6 mm combined into a "range between 3 mm and 6 mm."

[0034] The sensor device can be configured to detect the position of the pressure stamp. The sensor device can also be designed to detect the pressure force applied to the workpiece.

[0035] The sensor device may be adapted to detect the position of the plunger with an accuracy of at least ±10 μm or less, i.e. 10 μm or better. Optionally, the sensor device may detect the position of the pressure stamp with an accuracy of ±1 μm or less, more preferably ±0.1 μm or less. Meanwhile, the measurement resolution of the sensor device for the position of the pressure stamp is at least ±1 μm, preferably at least ±0.1 μm, more preferably at least ±0.05 μm.

[0036] The control device can be set to determine a necessary pressing force on the inserted workpiece for the joining process by recording and evaluating the sensor signals. Furthermore, the control device can automatically control the pressing device based on the determined necessary pressing force, i.e. the control device controls the pressing device taking into account the recorded or evaluated sensor signals.

[0037] If desired, the control device can also adjust or control the heating device so that different temperatures can be maintained within the heating chamber at different times during the bonding process.

[0038] The bonding furnace may have a fill and unload port, Illustratively, the fill and unload ports are connected to a safety circuit that detects the condition of the openings.

[0039] The workpiece holder can advantageously function as a pressure counter element for the pressure device, which can thus press the workpiece against the workpiece holder and clamp the workpiece between the pressure device and the workpiece holder.

[0040] The control device may provide at least one selectable control program. The selectable control program may preselect basic parameters such as a basic pressing force that is frequently applied to a particular material combination and a minimum pressing force that can initiate the joining process. The selectable control program may include a pre-treatment program and / or a pressing execution program.

[0041] The control device is preferably designed to adapt the selected control program in response to at least one sensor signal, for example during execution of the control program. The control program can be adapted such that process parameters, such as for example the pressing force, the temperature and / or the path of the pressing device, are changed or influenced during the bonding process.

[0042] That is, the control device can be designed to detect and process at least one sensor signal during execution of the control program, i.e., during the welding process, and use it to modify a control parameter of the welding process.

[0043] At least one control program may be stored in a program memory of the high temperature bonding furnace. The control device may comprise or be formed by a programmable logic controller.

[0044] The invention further describes a method for diffusion bonding in an automatic high temperature bonding furnace, such as the automatic high temperature bonding furnace described above. The diffusion bonding method includes the steps of: loading workpieces into the bonding furnace, heating the workpieces to a bonding temperature, pressing the workpieces with a pressing device to perform a diffusion bonding process, detecting or determining, during pressing, e.g. by an automatic control device, a pressing force required for the bonding process, and controlling the pressing device in response to the detected or determined pressing force required for the bonding process. For example, the required pressing force can be determined by measuring a distance through the pressing path.

[0045] The method can also be further improved by repeatedly detecting or determining the pressing force required for the joining process, for example at regular time intervals, and adaptively controlling the pressing device depending on the repeatedly detected or determined pressing force.

[0046] The method may also be further improved by a step of continuously monitoring the bonding process by means of at least one sensor device and a step of continuously adapting the bonding process if a deviation of the monitored value from the target value is detected.

[0047] The method may be further improved by the step of inputting process parameter specifications, for example by a user, prior to pressing the workpiece.

[0048] Additionally, taking into account process parameter specifications when providing set points for the automatic process control can be an example of a further improvement of the method.

[0049] The present invention will now be described in more detail with reference to the embodiments and drawings, in which the same and similar elements may be given the same reference numerals, and the features of the various embodiments may be combined with each other. [Brief description of the drawings]

[0050] It is as follows. [Figure 1] FIG. 2 is a side cross-sectional view of the high temperature bonding furnace of the first embodiment with a workpiece inserted therein; [Diagram 2] FIG. 13 is a side cross-sectional view of another embodiment of a high temperature bonding furnace with a pressure device exerting a pressing force on the workpieces. [Diagram 3] FIG. 13 is a side cross-sectional view of another embodiment of a high temperature bonding furnace with a different pressing device. [Figure 4] FIG. 2 is a perspective view of a high-temperature bonding furnace. [Diagram 5] FIG. 2 is another perspective view of the high temperature bonding furnace. [Figure 6] FIG. 1 is a perspective view of a high temperature bonding furnace with peripheral attachments. [Figure 7] FIG. 2 is a top view of the high-temperature bonding furnace. [Figure 8] FIG. 2 is a perspective view of a high-temperature bonding furnace. [Figure 9] 1 is a flow chart of a bonding process. Detailed Description of the Invention

[0051] FIG. 1 shows a first embodiment of a high-temperature bonding furnace 1. Inside the housing 12, a heating chamber 15 is arranged, in which a workpiece 50 is placed for a subsequent pressing process. The bonding furnace 1 has a loading and unloading opening 11, through which a workpiece 50, or a number of workpieces 50 or a batch, can be inserted into or removed from the heating chamber 15. The workpiece 50 is placed on a workpiece holder 34 arranged on the underside of the heating chamber 15. The workpiece holder can be or can be arranged on the pressing counter element 38. In the example shown in FIG. 1, the workpiece 50 is placed directly on the pressing counter element 38.

[0052] In this embodiment, the pressing device 20 is arranged on the upper side of the housing 12 of the joining furnace 1 in order to be able to generate a pressing force from above on the workpiece 50 and on the workpiece holder 34 or the pressing counter element 38. A number of pressing punches 32, four pressing punches 32 in the example shown in FIG. 1, are connected to a pressing cylinder 24. The pressing cylinder 24 is, for example, a hydraulic cylinder. The pressing punches 32 are directed towards the workpiece 50 by the pressing cylinder 24 via a transmission part 26. A pressure distribution element 22 is arranged in the receiving part 6 of the housing 12 in order to distribute the pressing force of the pressing device 20 to the number of pressing punches 32.

[0053] If necessary, a single pressure punch 32 can be used instead of multiple pressure punches 32 (see FIG. 3). On the other hand, multiple pressure punches 32, for example 4, 8 or 12 pressure punches 32, can distribute the pressure force evenly (more evenly) across the pressure element 36. For example, utilizing multiple pressure punches 32 can also improve the thermal sealing of the heating chamber 15. Since each pressure punch 32 requires a relatively small opening in the insulation 16 of the heating chamber 15, the energy loss from the heating chamber 15 can be lower. Furthermore, by using multiple pressure punches 32, the heat energy loss through the outer surface of the heating chamber 15 is also more uniform, resulting in a more uniform temperature distribution in the heating chamber 15 overall. This is equally true for the pressure counter plunger 29 below the heating chamber 15. Reasons of a more uniform pressure distribution across the pressure counter element 38 as well as lower and / or more uniform heat loss are also taken into account.

[0054] A pressing force generating device 28, in the embodiment of the present specification, a hydraulic unit 28, applies pressurized hydraulic fluid to the pressurizing cylinder 24, which is released or released by the pressing force generating device 28 and applied to the workpiece 50. For example, the motor unit 3 can generate hydraulic pressure in the pressing force generating device 28.

[0055] The first sensor device 4 is arranged on the upper side and is used to measure the path of the pressure cylinder 24. The first sensor 4 thus detects the distance of the pressure cylinder 24, the distance of the pressure punch 32 or the extension (stroke) of the pressure cylinder 24 and provides therefrom a first sensor signal 170. Further sensors 5, for example for measuring oil pressure, can be arranged in the pressing force generating device 28 and / or in the pressure cylinder 24 in order to derive information about the applied pressing force and provide it as sensor signal 170.

[0056] The workpiece holder 34 is arranged in the heating device 14 for receiving the workpiece 50 in the heating chamber 15. In order to minimize damage to the insulation 16 which contains the heating chamber 15, the workpiece holder 34 is provided with a number of pressure counter punches 29 which distribute the force distribution from the pressure counter element 38 as evenly as possible, so that deformation of the pressure counter element 38 can be minimized. The pressure counter punches 29 penetrate the insulation 16, which must be damaged as little as possible, so that a relatively small penetration area can be generated overall, or the pressure counter punches 29 can be better thermally sealed.

[0057] A second sensor device 42 is also arranged on the lower side, which can detect, for example, the pressing force applied to the workpiece 50. For example, the second sensor device 42 is a pressure sensor. It is also possible to use several pressure sensors as the second sensor device 42, for example two or more pressure sensors, one in the area of ​​each pressure counter punch 29. This allows the pressure distribution acting on the pressure counter element 38 to be detected and output as a sensor signal. In this way, it is possible to detect whether the pressure distribution on the workpiece or charge 50 occurs in the desired way, for example uniformly across the workpiece or charge 50.

[0058] In another embodiment, the pressing force can be applied from both sides to the workpiece or charge 50. For example, the embodiment of Fig. 1 can be modified in such a way that, for example, instead of the (passive) subassembly consisting of the pressing counter punch 29 and the pressing counter element 38, a further pressing device 20' is arranged below the high-temperature joining furnace.

[0059] In this example, an automatic process control device 44 is arranged in the area of ​​the substructure 8 of the joining furnace 1. Input devices 48 and output devices 46, such as a keyboard 48 and a screen 46, allow inputs and outputs to the control device 44 and thus manual influences on the process sequence or input of process parameters.

[0060] 2 shows the pressure device 20 in the operating position, with the pressure plate 36 placed in full contact with the workpiece 50 and applying a pressure force to the workpiece 50. The pressure cylinder 24 or transmission 26 is shown in the released position. In this embodiment, each pressure punch 32 is provided with two pressure distribution elements 37, which are located at the corners made by the pressure plate 36 and the respective pressure punch 32 and serve to transmit the pressure force to the pressure plate 36 more uniformly.

[0061] The pressing force applied by the pressing device 20 to the workpiece 50 is detected by the pressure sensor 42 and transmitted as a sensor signal 170 to the control device 44. Otherwise, the embodiment of FIG. 2 corresponds to the embodiment shown and described in FIG.

[0062] 3 shows another embodiment of the joining furnace 1, in which a pressure punch 32 transmits the force from the pressure generating device 28 to a pressure plate 36. This more compact design can be selected if necessary, if the pressure plate 36 is designed to distribute the pressure over its entire surface, so that a uniform deformation of the workpiece 50 can be achieved.

[0063] 4-5, a further embodiment of the high-temperature bonding furnace 1 is shown, which includes an outer frame 7, 9, 10 to support a pressing device 20. A pressing cylinder 24 is attached to the supporting frame element 10 and can transmit a pressing force from the pressing device 20 to a workpiece 50 (see Figs. 1-3) placed in the high-temperature bonding furnace 1. When a pressing force is applied, the entire force is absorbed by the outer frame 7, 9, 10, which can be bent in one direction away from the bonding furnace 1 during operation. The bending of the outer frame 7, 9, 10 provides a dynamic support for the pressing device 20, so that a press abutment 18 is formed on the frame 7, 9, 10.

[0064] That is, the pressing device 20 is supported by the outer frames 7, 9, 10 at a "support" to support itself to apply a pressing force to the workpiece 50. This "support" is called the press abutment 18 because it forms an abutment to absorb the pressing force. Therefore, in Figures 4 to 5, the press abutment 18 is only the place where the pressing device 20 is supported. The pressing device 20 can be bolted or permanently connected to the support frame or the outer frames 7, 9, 10.

[0065] In Fig. 4, a position sensor 5 is provided that can detect the positional displacement of the press abutment part 18. The positional displacement can also be used to derive a judgment about the pressing force applied by the pressing device 20, and the information can be provided as a sensor signal.

[0066] 6 to 8 show further embodiments of the high temperature bonding furnace 1, which are shown complete with further accessories. A vacuum generator 54, e.g. a turbomolecular pump, provides a vacuum extraction system. This allows the bonding process in the high temperature bonding furnace 1 to be carried out in near vacuum conditions, e.g. near high or ultra-high vacuum conditions. The pressing force generating device 28 is arranged in a separate housing, where larger units can be accommodated if necessary. The input and / or output devices 48, 46 are arranged in a user terminal 45, which includes a PLC 44 and input / output devices 48, 46.

[0067] 9, there is shown a flow diagram of the bonding process 100. The first step 110 is to load the system with a workpiece or a batch of one or more workpieces, which is typically performed by a user, but can also be automated.

[0068] In step 120, the system is parameterized. Here, various specifications, such as the material of the workpiece or batch 50 and the joining surface, can be stored in the control device 44 using the input device 48. For example, the intended compression of the workpiece 50 or batch can also be input in percentage or distance, for example in millimeters. For example, temperature specifications can also be saved. The parameters entered in step 120 are transmitted to the control device 44. In step 125, a set of control parameters can be generated using the control device 44. After closing the filling port 11, the joining furnace 1 is ready for operation. The heating phase 130 starts with temperature parameters provided by the control unit 44.

[0069] In step 150, the press is prepared. This involves applying a preload to the pressure device 20 such that the abutment portion 18 is displaced, deformed or preloaded, thereby assuming an initial position of the pressure device 20.

[0070] The pressing or bonding process is then performed in step 160 and is monitored and adjusted by the automatic process control 44. The sensors 4, 5, 42 provide sensor signals 170 that are processed by the process control 44. In step 165, the prepared control parameters are checked or adjusted in response to the sensor signals 170 provided by the sensors 4, 42. Once the control parameters are adjusted, the bonding process 160 continues in a modified form using the adjusted control parameters from step 165. This may be implemented as a control loop and may be performed iteratively. For example, an improved parameter configuration may be set during the bonding process and an improved bonding result may be achieved.

[0071] That is, in the example of step 120, a weld time dependent distance is specified as a parameter value. The weld time dependent distance can be specified by the system controls, i.e., the system controls can be set to determine, record or calculate the weld time dependent distance. For example, the target weld distance can be determined for the pressurizing cylinder 24 or the pressurizing ram 32. In step 150, an initial pressing force is applied, and in step 160, the actual pressing process begins. During the pressing process 160, a check 165 is made to see if the corresponding distance per unit time has been reached, and the pressing force is changed if necessary. XXX Expert System

[0072] The operator only needs to provide component information such as net bond area, material, thickness and total allowable deformation; there is no need for the user to specify process information.

[0073] No process knowledge is required, such as welding temperature, upset, and set point force specifications. Also, users do not need to arrive at process parameters by trial and error. Development time is reduced, there is no need to "design" the process, and no need for process engineers. Process design can take anywhere from a few days to a week or two, especially with system variations from one system to the next.

[0074] The process parameters are derived from the component information and generated in the control system.

[0075] The system knows the approximate range of applied force, and the target value is the amount of deformation of the component.

[0076] Displacement sensor, punch is activated. (Punch contact?)

[0077] The displacement sensor is placed outside the vacuum chamber, outside the pressurized cylinder in a cryogenic environment.

[0078] The system is preloaded (compressive, elastic), e.g. the cylinder extends 5 mm and the component drops 0.3 mm (reversible deformation).

[0079] The goal is to obtain the plastic deformation of the component.

[0080] However, the plastic deformation is not measured on the component itself, but is an indirect measurement.

[0081] Small deformations (creep; deformation rate) need to be detected in order to be adjusted.

[0082] The expert specification generates a purely reversible (elastic) actuation force (the response of the system).

[0083] Then wait 1 minute -> the punch stays in place. Increase in force e.g. 2200t->1.5mm->Punch stop? Increase in force e.g. 2400t->1.5mm->Punch stop? →Increase in force e.g. 2600 tons -> 1.5mm -> punch moves very slowly and continuously (creep velocity) →Welding time is obtained from the expert system, this is the system default. Example: 30 minutes → Next, calculate as follows. Example: 1 mm per 30 minutes →Determine the creep speed of the pressure punch. →The new step responds after, say, 1 minute. The creep rate is then measured (in micrometers). →New step response. Creep speed may be too high and does not increase force. →(=feedback) →What happens if the customer doesn't know the ingredients or specifies the wrong ingredients? The system automatically recognizes the material through the press response. → Different starting materials -> Systems can be equalized. XXX

[0084] In the present embodiment, for example, the increasing pressing force is already stored in the set of control parameters generated in step 125 and is adaptively tracked during the bonding process 160. The desired deflection of the pressure cylinder 24 up to a maximum or desired final value may also be pre-stored in the initial set of control parameters. During the control parameter check or adjustment 165, it may also be determined whether the desired final value of the deflection of the pressure cylinder 24 and / or the deformation of the workpiece can be achieved without exceeding the pressing force at which the workpiece or batch 50 is damaged or subjected to excessive deformation.

[0085] In step 180, the workpiece or batch 50 may be subjected to post-processing, which may include further tempering, further heating or cooling at a defined temperature constant. Following post-processing 180, the workpiece or batch 50 may be sufficiently cooled and removed from the system 1 in step 190.

[0086] The above-mentioned embodiments should be understood as examples, and it is obvious to those skilled in the art that the present invention is not limited thereto, and can be modified in many ways without departing from the scope of protection of the claims. Moreover, it is clear that the features of the present invention are defined separately, regardless of whether they are disclosed in the specification, even if they are described together with other features in the claims, drawings, etc. In all figures, the same reference signs represent the same objects, and the description of an object that is only mentioned in one figure, or at least not in all figures, may also be transferred to those figures in which the object is not explicitly described in the description. [Explanation of symbols]

[0087] 1 High temperature bonding furnace 3 Motor unit 4. First Sensor Device 5. Additional Sensor Devices 6 Press machine mounting portion of housing 12 7 Supporting frame elements (horizontal, bottom) 8 Undercarriage 9 Supporting frame elements (vertical) 10 Supporting frame element (horizontal, top) 11 Filling and / or unloading port 12. Housing 14 Heating Devices 15 Heating chamber 16 Insulation 18 Press abutments or support areas of the press on the outer frame or support frame elements 20 Pressurizing Equipment 22 Pressure distribution element 24 Pressurized Cylinder 26 Transmission section 28 Pressure generating device 29 Pressure Counter Punch 32 Pressure punch 34 Workpiece holder 36 Pressure Plate 37 Pressure distributor 38 Pressure Counteracting Element 42 Second Sensor Device 44 Programmable Logic Controller 45 User terminals with PLC, input / output devices 46 Dispensing Device 48 Input Devices 50 work pieces 54 Vacuum generator (vacuum pump) 100 Bonding Process 110 Filling 120 Parameterization 125 Control Parameter Generation 130 Heating Stage 140 Pretreatment as required 150 Preparation 160 Pressurizing or joining process 165 Check or adjust control parameters 170 Providing sensor signals 180 Post-processing if applicable 190 Removal from system

Claims

1. An automatic high-temperature bonding furnace (1) for diffusion bonding of bonding materials such as metal and a metal workpiece (50), for example, a heating chamber (15) provided with a heating device (14), a workpiece holder (34) disposed in the heating chamber for holding a workpiece (50) to be processed in the bonding furnace, a pressure device (20) arranged and adapted to apply a pressing force to the workpiece, a sensor device (4, 5, 42) for generating at least one sensor signal (170), and characterized by including a control device (44, 46, 48) adapted to control at least the pressure device in response to at least one of the sensor signals (170).

2. The automatic high-temperature bonding furnace (1) according to Claim 1, wherein the sensor device (4, 5, 42) detects at least one of the process parameters of the thickness of the workpiece (50), the position of the pressure punch (32) of the pressure device (20), the position of the press contact portion (18), or the pressing force, hydraulic pressure, or path of the pressure device (20) or the pressure cylinder (24) or the transmission part (26), and generates at least one of the sensor signals (170) therefrom.

3. The automatic high-temperature bonding furnace according to Claim 1, further including at least one additional sensor device (4, 5, 42) that simultaneously detects one or more process parameters and generates at least one additional sensor signal (170).

4. The pressure device (20) includes a hydraulic device as a pressing force generating device (28) and increases the pressing force by increasing the hydraulic pressure, and / or the pressure device (20) includes an electric spindle. The automatic high-temperature bonding furnace according to Claim 1.

5. further includes an input device (48) such as a user-operable terminal (45) for inputting process parameter specifications, and / or further includes an output device (46) for displaying or selecting, for example, process parameters and / or control programs. The automatic high-temperature bonding furnace according to Claim 1.

6. The pressure device (20) includes a pressure plate (36) for applying the pressing force to the workpiece (50), and / or The pressure device (20) comprises a pressure cylinder (24), and / or The pressure device (20) comprises a plurality of pressure punches (24), for example two, three, four or more. The automatic high-temperature bonding furnace according to claim 1.

7. The automatic high-temperature bonding furnace comprises an outer frame (7, 8, 10). The pressure device (20) is arranged on and / or supported by the outer frame. The automatic high-temperature bonding furnace according to claim 1.

8. The automatic high-temperature bonding furnace according to claim 7, wherein the outer frame (7, 8, 10) is designed to be movable and / or deformable.

9. Furthermore, it has a press contact part (18), By applying a compressive force to the workpiece (50) by the pressure device (20) to the press contact part (18), It is provided so as to cause lateral displacement and / or deformation. The automatic high-temperature bonding furnace according to claim 7.

10. The pressure device (20) Is set so that the pre-tension can be increased in the support frame element (10) during the pressing operation. The automatic high-temperature bonding furnace according to claim 6.

11. The sensor device (4, 42) detects the position of the pressure punch (32), and / or The sensor device (4, 42) detects the pressing force applied to the workpiece (50). The automatic high-temperature bonding furnace according to claim 1.

12. The sensor means (4, 42) With an accuracy of at least ±10 μm or less, Preferably ±1 μm or less, More preferably ±0.1 μm or less, And / or With an accuracy of ±1 μm or more, preferably ±0.1 μm or more, More preferably ±0.05 μm or more, and is adapted to detect the position of the pressure punch (32). The automatic high-temperature bonding furnace according to claim 11.

13. The control device (44, 46, 48) Determines the required pressing force for the workpiece (50) inserted for the bonding operation by detecting and evaluating the sensor signal (170), and Is designed to automatically control the pressure device (20) based on the determined required pressing force. The automatic high-temperature bonding furnace according to claim 1.

14. The control device (44, 46, 48) is adapted to further control the heating device (14). The automatic high-temperature bonding furnace according to claim 1.

15. The workpiece holder (34) functions as a pressure resistance element, and / or the pressure device (20) presses the workpiece (50) against the workpiece holder (34), The automatic high-temperature bonding furnace according to claim 1.

16. The control devices (44, 46, 48) provide at least one selectable control program, for example, a pre-treatment program and / or a pressure program, The automatic high-temperature bonding furnace according to claim 1.

17. The control devices (44, 46, 48) further are provided to adapt the control program to change process parameters such as the pressing force, temperature, and / or path of the pressure device (20), for example, in response to at least one of the sensor signals (170) during the execution of the selected control program, The automatic high-temperature bonding furnace according to claim 16.

18. At least one of the control programs is stored in the program memory of the high-temperature bonding furnace, and / or the control devices (44, 46, 48) comprise a programmable logic controller (PLC), The automatic high-temperature bonding furnace according to claim 17.

19. For example, a diffusion bonding method in the automatic high-temperature bonding furnace (1) according to claim 1, comprising the steps of loading a workpiece (50) into the bonding furnace, heating the workpiece to the bonding temperature, pressing the workpiece with a pressure device (20) to perform a diffusion bonding process, detecting or determining the pressing force required for the bonding process during pressurization, for example, by sensors (4, 42) and / or an automatic control device (44, 46, 48), and controlling the pressure device according to the detected or determined pressing force required for the bonding process, A diffusion bonding method in an automatic high-temperature bonding furnace.

20. The method according to claim 19, comprising, for example, repeatedly detecting or determining the pressing force required for the bonding operation at regular time intervals, and further comprising adaptively controlling the pressure device (20) according to the repeatedly detected or determined pressing force.

21. The method according to claim 19, comprising continuously monitoring the bonding process by at least one sensor device (4, 42), and continuously adapting the bonding process when a deviation of the monitored value from the set value is detected. Claim 22 The method according to claim 19, comprising: before pressing the workpiece (50), a step of inputting process parameter specifications, and when specifying set values for automatic process control, a step of considering the specifications of the process parameters.

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