Method for dynamically determining an open time of a material

Abstract

The invention discloses a method for determining a maximum open time (31) of a reactive material (21) during a joining process (22), which maximum open time is valid for current conditions. The method comprises providing first machine-readable data (28) which characterize batch-accurate material properties provided by the manufacturer (27). Furthermore, second digital data characterizing current parameters of the joining process (22), such as the ambient temperature, are received. The maximum open time (31) valid for the current conditions is determined by means of a mathematical-physical model, into which the first and second data are input. This enables more flexible and more robust process control compared to static worst case parameters.

Description

[0001] R. 413215

[0002] - 1 -

[0003] Description

[0004] title

[0005] Method for the dynamic determination of the open time of a material

[0006] Technical field

[0007] The invention relates generally to a dynamic determination of the maximum open time of a reactive material during a joining process between the material and a component. The invention further relates to a corresponding device and a computer program.

[0008] State of the art

[0009] Currently, in industrial settings, process parameters for material processing, such as with adhesives, are determined by combining static boundary conditions (so-called "worst-case" parameters). For example, when processing an adhesive that cures at room temperature, it must be considered that the curing process begins immediately after application. This also means that subsequent processes must take this behavior into account. In particular, the joining of the second component in the joining or bonding process must occur before the adhesive has partially cured, is partially cured, or fully cured. The time between applying the adhesive to the first component and the subsequent joining process with the second component is generally referred to as the open time, because during this time the adhesive is exposed to the environment.Based on the static boundary position parameters, a so-called static maximum open time is obtained, which takes into account all possible states in manufacturing and thus enables safe process control only under the assumption of the worst possible conditions.

[0010] If this static maximum open time is observed, it is guaranteed that the adhesion strength is sufficiently good and the joining forces are within the permissible range R. 413215.

[0011] - 2 - remain and a desired tightness is achieved. However, this static maximum open time is often very short and can therefore a) make complex intermediate steps in manufacturing impossible or b) lead to increased error costs in the event of process disruptions.

[0012] Otherwise, the adhesion strength (bonding ability) can be reduced, meaning that the probability of failure or delamination of the connection increases; the joining forces can increase so much that sensitive components such as populated circuit boards are damaged during the joining process; and air inclusions or local channels remain in the adhesive after the joining process, which can lead to leakage or a loss of sealing effect.

[0013] Disclosure of the invention

[0014] The invention is therefore based on the objective of providing a method and a device which enable increased flexibility and robustness of joining processes that use a reactive material with a limited open time.

[0015] This problem is solved by a method according to claim 1, a device according to claim 10 and a computer program product according to claim 11.

[0016] Further details are specified in the dependent claims.

[0017] A key idea of ​​the invention is to replace the previous static definition of the maximum open time, which results in low process flexibility and can cause high error costs, with a dynamic parameterization that takes into account the currently prevailing conditions. This allows the maximum open time to be calculated in such a way that it precisely meets the current requirements. Compared to the usual static maximum open time, the calculated maximum open time is significantly longer. A longer open time means greater flexibility in manufacturing. Processes that take place between the application of the reactive material, such as an adhesive, and the joining of a second component can last longer, or more processes can occur. Furthermore, the manufacturing process is more fault-tolerant, as more time is available for [R. 413215].

[0018] - 3 -

[0019] This is available to correct workpiece defects or process errors in these intermediate processes. This can significantly reduce the costs associated with defects.

[0020] According to a first aspect, a method is provided for the dynamic determination of a maximum open time of a reactive material valid for current conditions during a joining process between the reactive material and a joining part, comprising:

[0021] • Providing initial machine-readable data characterizing batch-specific material properties of the reactive material, with the initial data being provided by the manufacturer or supplier of the reactive material,

[0022] • Receiving second digital data that characterize current parameters of the joining process, such as ambient temperature and humidity,

[0023] • Determination of the maximum open time of the reactive material valid for current conditions using a mathematical-physical model into which the provided first and the received second data are entered.

[0024] For the purposes of this invention, machine-readable data is any form of information that can be processed automatically by a computer-aided control system, such as a production control system, without manual input. This includes, in particular, but not exclusively, digital data in a structured format. Further examples of machine-readable data are information encoded in optical codes, such as barcodes or QR codes, or in radio-based storage devices, such as RFID (Radio-Frequency Identification) chips. Such codes or chips can, for example, be affixed to the container of the reactive material.

[0025] The step of providing the initial data includes any method of making this machine-readable data accessible to the mathematical-physical model.

[0026] In a particularly preferred embodiment, which ensures high data quality and automation, the first machine-readable data are contained in R. 413215.

[0027] - 4 - in digital form. In this case, the provisioning step includes receiving this initial digital data via a data connection, for example a network or internet connection, in particular directly from the manufacturer's or supplier's IT system.

[0028] In an alternative embodiment, the data can also be provided by reading a machine-readable code or reading a data carrier at the production line using a suitable reading device (e.g., a scanner or an RFID reader). The essential point is that the batch-specific data provided by the manufacturer is automatically fed into the system.

[0029] Furthermore, the method can provide for the input of a specific dynamic maximum open time into the manufacturing control system of the joining process, whereby the manufacturing control system then manages the joining process according to this specific dynamic maximum open time. This allows for real-time responses to changes in the properties of the reactive material and / or the conditions of the joining process. For example, the control system can ensure that the joining process is only enabled or executed if the time elapsed since the material was applied is less than the specified dynamic maximum open time.

[0030] According to one embodiment, a predetermined static maximum open time of the reactive material can be adjusted or replaced by a specific dynamic maximum open time. This allows, for example, the creation of a control loop for the controlled improvement of the joining process. Furthermore, the static maximum open time can be used as a fallback value if the first and / or second data points are unavailable.

[0031] It may be intended that the first machine-readable data from a manufacturer or supplier of the reactive material is preferably received via a data connection. A data connection, such as a data pipeline, makes it possible to obtain and use data from third-party products, i.e., from a supplier, to optimize manufacturing. R. 413215

[0032] - 5 -

[0033] Furthermore, the process can provide for the initial machine-readable data to characterize the material properties of the reactive material with batch-level accuracy. This allows the manufacturing process to be directly adapted to changing properties of the reactive material.

[0034] According to one embodiment, the first machine-readable data can include at least one value from the group consisting of material reactivity, skin formation time, open time, or curing rate of the reactive material, and / or the second digital data can include at least one value from the group consisting of ambient temperature, humidity of the joining process, or degree of compression of the applied reactive material. These values ​​allow for a comprehensive characterization of the material and manufacturing process, enabling precise control. Material reactivity can be characterized, for example, by the skin formation time or curing rate under standard conditions (e.g., 23°C and 50% relative humidity). The reactive material can be an adhesive, sealant, gel, potting compound, printed circuit board varnish, thermal interface material, paint, lacquer, glue, or plaster. The method is suitable for all materials with an open time.

[0035] Furthermore, the method can provide that the mathematical-physical model includes a digital twin of the joining process, wherein input variables of the model include a static maximum open time and a reactivity of the reactive material characterized by the first machine-readable data, an ambient temperature, an ambient humidity, and optionally a degree of compression of the applied reactive material, and wherein output variables of the model include the strength of the joint and optionally the tightness of the joint. The determined dynamic maximum open time can be another key output variable of the model. This digital twin can be used directly as a controller for the manufacturing or joining process. Alternatively, the digital twin can be used to create a controller or a controller instruction.For example, a correlation such as a characteristic curve diagram can be generated, which includes input variables and at least one output variable, such as a dynamic or updated maximum open time of the reactive material. R. 413215.

[0036] - 6 -

[0037] The mathematical-physical model can include a correlation between the input variables ambient temperature and humidity on the one hand, and the output variable dynamic maximum open time of the reactive material on the other. This parameter set allows for real-time control of the joining process. (Brief description of the drawings)

[0038] Preferred embodiments of the present invention are explained in more detail below with reference to the accompanying drawings. These show:

[0039] Figure 1 shows a flowchart of an embodiment of the inventive method for dynamically determining a maximum open time of a reactive material during a joining process;

[0040] Figure 2 shows a schematic representation of an embodiment of the device according to the invention for dynamically determining a maximum open time of a reactive material during a joining process;

[0041] Figure 3 shows a schematic representation of the modeling of a joining process; and

[0042] Figure 4 shows a diagram for determining the maximum open time.

[0043] Description of embodiments

[0044] Figure 1 shows a flowchart of an embodiment of method 10 for the dynamic determination of a maximum open time of a reactive material during a joining process between the reactive material and a joining part.

[0045] A first step (11) involves providing or receiving initial machine-readable data that characterizes the material properties of the reactive material. The reactive material may, for example, be adhesive, sealant, gel, potting compound, printed circuit board varnish, thermal interface material, paint, lacquer, glue, or plaster. R. 413215

[0046] - 7 -

[0047] Providing this data can encompass the design and operation of data infrastructures, such as data pipelines, to calculate the precise maximum open time required. This includes both data from direct manufacturing and data from suppliers of the reactive substances.

[0048] Such data infrastructures from suppliers to customers have often served only for documentation purposes. In this case, the data from such infrastructures includes physical material properties of the supplied products, which are then used for machine control and / or production control.

[0049] A second step (12) involves receiving secondary digital data that characterize current parameters of the joining process. This data includes current manufacturing conditions and can originate from sensors in production and / or machine or plant controls. A third step (13) involves determining the dynamically determined maximum open time of the reactive material using a mathematical-physical model into which the provided first and received second data are input. Such a mathematical-physical model is explained with reference to Figures 3 and 4. A digital twin or simpler models such as controllers, look-up tables, or similar can be used for the model.

[0050] In this step, the internal manufacturing data (second data) and the supplier's data (first data) are combined to determine a constantly updated dynamic maximum open time for the reactive material. This dynamically determined maximum open time is significantly more accurate than the usual static maximum open time, which is calculated from the worst possible values ​​of the internal manufacturing data and the supplier's data.

[0051] An optional fourth step 14 involves inputting the specified dynamic maximum open time into a manufacturing control system for the joining process, and the manufacturing control system then controlling the joining process with the specified dynamic maximum open time. R. 413215

[0052] - 8 -

[0053] Figure 2 shows a device 20 for dynamically determining a maximum open time of a reactive material 21 during a joining process 22 between the reactive material 21 and a joining part 23. The device 20 can be implemented in hardware and / or software and is configured to carry out the previously described method 10.

[0054] The reactive material 21 and at least one joining component 23 are joined to form a product 24 in the joining process 22. A computing unit, such as a manufacturing controller 25, controls or regulates the joining process 22. The manufacturing controller 25 can be implemented in hardware and / or software and is configured to carry out the previously described procedure 10. Second digital data, which characterize current parameters of the joining process 22, are supplied to the manufacturing controller 25 via one or more sensors 26.

[0055] The reactive material 21 originates from a supplier 27. In addition to the material 21, the supplier 27 provides initial machine-readable data 28, which characterize the material properties of the reactive material 21. The initial machine-readable data 28 is transmitted to the production control system 25, for example, via an interface, a data line, or a data pipeline 29. The data 28 is transmitted in a machine-readable format and processed in the production control system 25. Data transmission can occur in push or pull mode. Accordingly, the supplier 27 can send the initial data 28 upon delivery of the reactive material 21, or the manufacturer can retrieve the initial data 28 when processing the reactive material 21.

[0056] The characterization or transmission of the properties of the reactive material 21 by means of the first machine-readable data 28 can, for example, be carried out for each batch of the reactive material 21 produced. If the material 21 is delivered continuously, for example via a pipeline, the transmission of the first data 28 can also be carried out continuously.

[0057] Based on the first and second data points, the production control system 25 calculates the dynamic and therefore current R, as explained in procedure 10 above. 413215

[0058] - 9 - maximum open time of the reactive material 21 . Based on the determined dynamic maximum open time, it then controls the joining process 22.

[0059] Figure 3 shows a model 30 of a joining process which may correspond to the joining process 22 from Fig. 2.

[0060] In the example of a room-temperature curing adhesive, here a one-component alkoxy silicone that cures with moisture, the maximum open time can be determined by the following parameters: a) The current temperature 33 and humidity 34 in the production area. These are determined by sensors 26 on the machine or in the production hall and transmitted via a data pipeline to the production control system 25 or, in this case, the modeling system 30. b) The material reactivity 32, which, for example, in the form of the so-called "skinning time," "tack-free time," or "curing rate," is supplied electronically via the data pipeline 29. c) Optionally, the static maximum open time 31, which is supplied electronically via the data pipeline 29. The static maximum open time from the conventional calculation using "worst-case" parameters can, for example, be used as a fallback solution if the data pipeline 29 experiences a malfunction.d) Optionally, the degree of compression of the applied adhesive bead. This parameter can be set statically, as it usually remains constant throughout the production process. Sensors for component measurement can be incorporated, in which case this parameter could also be taken into account dynamically.

[0061] Together with the currently available time between adhesive application and the joining process, i.e., the current open time, all parameters for modeling are available.

Claims

R. 413215 - 10 - Claims 1. Method for determining a maximum open time (31) of a reactive material (21) valid for current conditions during a joining process (22) between the reactive material (21) and a joining part (23), comprising: o Providing first machine-readable data (28) characterizing batch-specific material properties of the reactive material (21), wherein the first data are provided by the manufacturer or supplier (27) of the reactive material (21), o Receiving second digital data characterizing current parameters of the joining process (22), o Determining the maximum open time (31) of the reactive material (21) valid for current conditions using a mathematical-physical model into which the provided first and received second data are input.

2. Method according to claim 1, wherein the first machine-readable data (28) are in digital form and the provision comprises receiving the first digital data (28) via a data connection (29).

3. Method according to claim 1 or 2, wherein the first machine-readable data (28) comprise at least one value from the group material reactivity, skin formation time, adhesive time or curing rate of the reactive material (21), and wherein the second digital data comprise at least one value from the group ambient temperature or humidity of the joining process (22).

4. Method according to any one of claims 1 to 3, further comprising: R. 413215 - 11 - o Input of the determined maximum open time (31) into a manufacturing control (25) of the joining process (22) and control of the joining process (22) with the determined maximum open time (31) by the manufacturing control (25).

5. Method according to any one of claims 1 to 4, wherein the reactive material (21) comprises or consists of adhesive, sealant, gel, potting compound, circuit board lacquer, thermal conductivity medium, paint, varnish, glue or plaster.

6. Method according to any one of claims 1 to 5, wherein the mathematical-physical model comprises a digital twin of the joining process (22).

7. Method according to any one of claims 1 to 6, wherein a static maximum open time is used as a fallback value if the first and / or second data are not available.

8. Device (20) for determining a maximum open time (31) of a reactive material (21) valid for current conditions during a joining process (22) between the reactive material (21) and a joining part (23), wherein the device comprises a processing unit configured to carry out a method according to any one of claims 1 to 7.

9. Computer program product comprising instructions which, when the program is executed by a computer, cause the computer to execute the method according to any one of claims 1 to 7.

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