DE102017202641A1 - Evaluation of the quality of a connection - Google Patents

Abstract

In a method for evaluating a mechanical connection made by means of a tool, evaluation ranges 1, 2, 3 are defined, and it is checked whether a measured value curve 5 runs inside or outside of the weighting ranges 1, 2, 3.

Description

The present invention relates to a method for evaluating a mechanical connection made by means of a tool and to a corresponding tool.

State of the art

At present, tools are known which make connections based on a special tool program. Here are usually measured values recorded, which can be displayed as a curve. After or during the production of the compound, the curve is evaluated. On the basis of the evaluation, the connection process is then improved as required by setting suitable parameters or detection criteria on the tool. As a result, the connection is always more precisely monitored and deviations from the desired curve are easier to recognize. If the tool recognizes a non-desired curve, it terminates the connection manufacturing process prematurely if necessary.

The disadvantage, however, is that in the tool program for the parameters or detection criteria usually only thresholds can be set, which must not be exceeded or fallen below. As a result, in the case of a waveform with waves, jumps or overshoots, the response threshold may need to be set very high in order not to cause unnecessary disconnection or influencing of the tool during a connection. To solve this problem, it would be conceivable to monitor the connection a little finer. However, such a procedure has the disadvantage that the tool program and its parameterization are significantly more complex. In addition, short-term deviations from the parameters in a connection, but do not require a shutdown, nevertheless lead to a shutdown of the tool.

Therefore, it is the object of the present invention to provide a method for evaluating a mechanical connection, so that this connection can be evaluated as precisely as possible with a small amount of parameterization. It is also desirable to be able to assess complex connection processes, in particular connections based on jerky or jerky movements of the tool mechanism. Further, it is the object of the invention to provide a suitable tool.

Disclosure of the invention

The invention proposes a method for evaluating a mechanical connection made by means of a tool and a tool for carrying out the method as claimed. Advantageous embodiments are the subject of the dependent claims and the following description.

Advantages of the invention

The method according to the invention enables the efficient evaluation of a mechanical connection produced by means of a tool in real time. For this purpose, measured values are used which are detected during the connection establishment by means of a detection device encompassed by the tool and are stored as a measured value curve in a tool memory. An evaluation range for the measured value curve is predefined by means of an adjustment unit encompassed by the tool and it can be evaluated during or immediately after the connection has been established by means of a valuation unit likewise included in the tool whether the measured value curve is within or outside the evaluation range. Boundary lines of the evaluation range can be defined using boundary line parameters whose physical unit corresponds to the physical unit of the measured values. In particular, tool-internal processes which influence the connection production can be recorded as a measured value curve and subsequently evaluated. The invention thus enables a precise and non-destructive inspection and documentation of the quality of a manufactured mechanical connection with low Parametrieraufwand.

With the method according to the invention it is also possible, for example, to detect a real force-displacement curve or force-angle course of the tool mechanism during a connection as a measured value curve, safely, quickly and cost-effectively. The connection produced may be a screw connection or a riveted connection.

Preferably, a selection of boundary line parameters based on a plurality of reference measured value curves is determined, which during the production of reference compounds, for example in the Commissioning of the tool, were recorded and stored in a tool memory for comparison purposes with measured value curves to be recorded later. The reference measured value curves form permissible and reliable tolerance ranges in order to identify the position of the measured value curve of an ideal connection and to define suitable evaluation ranges.

More preferably, the position of a measured value curve and an evaluation range relative to each other by means of a, preferably Cartesian, coordinate system defined within the tool and preferably also represented for example on a tool display. It is thereby checked whether at least one coordinate value pair of the measured value curve coincides with at least one coordinate value pair of a boundary line parameter. Thus, it is easy to determine whether there is an intersection between the measured value curve and a boundary line and whether the measured value curve enters and / or exits at a preferred section of the boundary line in the evaluation area. The entry point and / or the exit point of the measured value curve into an evaluation area is thus available as an additional quality criterion.

It is very particularly preferably additionally or alternatively checked whether the measured value curve runs inside or outside the boundary lines of the evaluation range. Depending on the result of this check, it is further preferable to trigger an action.

An operation of the tool can be made dependent, for example, on the course of the measured value curve and / or on the entry and / or exit of the measured value curve with respect to the evaluation range. This results in possibilities of quality control for a connection, immediately after or even during the production of the connection. Particularly preferably, the tool is locked for further operation, if the connection does not meet the quality specifications. For example, the tool mechanism could be damaged or operate outside the allowable tolerances.

It is advantageous if a scoring area comprises at least three borderlines, in particular straight lines, which can be specified by the user, whose end points are interconnected in such a way that a closed geometric shape results. In this case, also any angle between two interconnected lines can be specified by the user and anschießend be adjusted by the setting.

Any shapes for a scoring area can thus be realized, starting from a simple triangularly limited scoring area, to a complex geometric body whose border forms the boundary lines of the scoring area (e.g., a trapezoidal, dragon-shaped, diamond-shaped border, or the like).

Further advantageously, at least two mutually independent evaluation areas can be defined and used, so that an evaluation of the connection can be made based on the at least two evaluation areas. Preferably, the tool user selects from a selection of several possible evaluation areas, combines these to evaluate the measured value curve, and the evaluation unit considers this selection in the evaluation. Several sections of the measured value curve can be evaluated at the same time. Ideally, a user can specify the course of at least one boundary line directly on the tool, for example by means of a touch screen, wherein the setting unit takes into account such a predetermined course when specifying the evaluation area.

In a first preferred embodiment, the measured value curve describes the course of a force which acts on the pulling mechanism of a blind riveting tool during the performance of a blind rivet connection. In a second preferred embodiment, the measured value curve describes the course of a force which acts on the output of a screwing tool during the execution of a screw connection (for example torque). Thus, the method can be used both with riveting tools with regard to riveting curves, as well as with screwing tools with regard to screwing curves.

Preferably, a computer program is provided that causes a tool control or tool to perform a method as described above when executed on the tool control or on the tool. The computer program advantageously implements the processability of screw and rivet curves with the same executable program code. Thus, it is universally applicable to screwdrivers and riveting tools. By means of suitable parameterization of the program, the tool manufacturer can make a selection with regard to the desired program functions. With a riveting tool, only the program passages relevant to the riveting process are then executed; in the case of a screwdriver, the program passages relevant to the screwdriving process.

A riveting tool or a screwing tool with integrated tool control, which is set up and provided for carrying out the method according to the invention, is likewise provided. The main advantages of such a tool are evident from the previous explanations.

It is e.g. It is possible to switch the tool on or off depending on the detected curve. As a result, unwanted and costly processing downtime can be avoided. This is especially advantageous when the tool is used in an automation system and a faulty connection can result in a standstill of a part or even of the entire automation system.

Particularly preferred by means of the invention, the evaluation of a force-displacement / angle curve (rivet or screw) to decide whether a rivet setting process or a screwing meets the requirements (IO / NIO rating). The quality of the IO / NIO rating is thereby improved. IO stands for "OK", NIO for "Not OK". By means of the solution according to the invention, complex tool-internal sequences as trace curves can now be evaluated simply and efficiently. Further advantages and embodiments of the invention will become apparent from the following description and the drawings.

It is understood that the features mentioned above and those yet to be explained below can be used not only in the particular combination indicated, but also in other combinations or in isolation, without departing from the scope of the present invention.

list of figures

• 1 shows simplified and schematic a waveform curve (rivet curve).
• 2 shows essential method steps, carried out by means of a computer program.

Detailed description of the drawing

1 shows a curve as an example 5 which was detected by the detection device when riveting a blind rivet with a blind riveting tool. The curve 5 refers to the available and accessible parameters "Pulling force K" (unit N) and "Pulling distance s" (unit mm) that are relevant in the tool and that become relevant in particular when removing the rivet mandrel. The curve 5 is forwarded by the detection device to a memory device covered by the blind riveting tool and stored there. In addition, the detection device gives the curve 5 to a setting unit on. The adjustment unit in this example provides several evaluation areas 1 . 2 . 3 for the curve 5 one. The setting is based on inputs of the tool user to the tool, which he can specify on a tool user interface (keyboard, display, touch screen, etc.). The curve 5 can also be defined and stored as a reference curve for subsequent connections, if this was first detected, for example, during the commissioning of the tool.

In the 1 shown number of three evaluation areas 1,2,3 is not limiting. The invention enables the tool user to define any number of evaluation areas 1, 2, 3, whereby, depending on the application, variants with one, two, three or a multiplicity of evaluation areas 1, 2, 3 can result.

All representations are to be seen schematically and are not restricted to the physical unit for measured values and / or parameters shown. Also, the geometric shapes of the evaluation regions 1, 2, 3 may differ from the shapes shown in the figures. In the 1 Shown forms for the evaluation areas 1,2,3 are also to be seen as examples only. In the following, some non-exhaustive examples of evaluation areas are presented, which can be realized by means of the invention.

In general, the method according to the invention makes it possible to adjust at least the following types of evaluation areas, which can be delimited by means of evaluation windows predefinable by the user:

Complex valuation areas, such as valuation windows 1 to delineate an evaluation range for a measured value curve course with a large change in the slope, which can occur, for example, in a rivet mandrel break.

Simple rating areas, such as rating windows 2 . 3 to delineate an evaluation range for a measured gradient curve with uniform slope, which can occur, for example, when pulling on the rivet mandrel or after the rivet mandrel break.

For each of these aforementioned evaluation areas 1,2,3, it can additionally be determined whether the curve of the measured value curve 5 is assessed in such a way that it is at least partially within the valuation area 1,2,3 (inclusion principle, see valuation areas 1 and 2 ). For each of these aforementioned evaluation areas 1,2,3, alternatively or additionally, it can also be determined whether the measured value curve course 5 is assessed that it is at least partially outside the valuation range 1,2,3 (exclusion principle, see valuation section 3 ).

Furthermore, the method according to the invention makes it possible to determine and check for all evaluation areas 1, 2, 3, by which boundary line 4 of a rating range 1,2,3 a measured value curve 5 enters a coverage area 1,2,3 and / or exit (edge conditions, see Edge 4 at evaluation window 1 ).

The underlying tool (here, for example, portable Blindnietsetzgerät) is set up to make the evaluation of a connection by means of the evaluation window 1,2,3 immediately after and / or during the preparation of the connection (IO / NIO evaluation), ie in any case before another Connection is made. In this case, it is optionally also provided, the entry or exit behavior of the measured value curve 5 in the evaluation area 1 to evaluate with.

As in 1 A first rating range is shown 3 in the present embodiment along and below the curve 5 , wherein the curve 5 preferably outside this evaluation range 3 lies. Alternatively or additionally, a second evaluation area runs 2 in the present embodiment also along the curve 5 , where the curve 5 preferably within the evaluation range 2 lies. Alternatively or additionally, at least some boundary lines of a third evaluation range run 1 in the present embodiment on both sides along the curve 5 , ie the curve is also here at least partially within the evaluation range 1 , This evaluation area 1 However, it is parameterized in such a way that it also causes a huge change in the slope of the curve 5 (eg rivet mandrel break) with recorded by the curve 5 is preferably evaluated by means of a voltage applied to the slope change and limited envelope section. To realize this, the evaluation area is 1 preferably V-shaped or U-shaped, so that the curve 5 , which includes the abrupt slope change, can run within these shapes.

According to 2 In a preferred method according to the invention, in a first step S1, a plurality of reference connections are made with a tool and reference curves are detected with a detection device and stored in the tool memory. Preferably, this step S 1 takes place only once when the tool is put into operation or during the first use in the specific application.

In the step S2, the evaluation range is set and stored with a setting unit.

In step S3, machining with the tool is started to establish a connection required in manufacturing a product or machining one or more workpieces. Due to this, the detection device begins to detect and store a measured value curve.

In step S4, the determination unit determines how the measured value curve runs relative to the set evaluation range, in particular whether it is within or outside the evaluation range. Depending on the result of this determination, an error case can be derived from this.

It is particularly preferably checked in step S4 whether the slope of the measured value curve at least partially substantially corresponds to the slope and / or the course of a boundary line section and / or whether the measured value curve runs at least in sections substantially parallel to the course of a boundary line section.

It is further preferred to additionally or alternatively check whether and, if appropriate, also how frequently the measured value curve intersects a boundary line and / or individual measured values of the measured value curve lie on a boundary line. It is further preferred to additionally or alternatively check whether and, if appropriate, how often the Measured value curve not directly connected boundary line sections, preferably opposite threshold sections, cuts.

If a desired condition is not satisfied (error case), the flow proceeds to a step S5. Otherwise, the flow returns to the step S3, so that a new processing can be started. In step S5, an action is initiated by the tool, for example, a shutdown of the tool. In addition, a warning message can be output to a user, for example via an operating device of the tool. A tool-integrated WLAN could optionally provide wireless information to a higher-level process controller.

Thereafter, the flow preferably proceeds to a step S6. In step S6, the user is prompted to correct an error that has occurred. This can be realized by a corresponding display on the operating device. Optionally, a procedure for error correction can also be carried out automatically by a control device of the tool. Thereafter, the flow returns to the step S3. The process is finished when the tool is turned off. Alternatively, after step S6, the method may alternatively return to step S1 or alternatively to step S2. If the tool is switched off after an error, the warning message is available again when switching on and is therefore not lost.

Consequently, in a method according to the invention, first reference screw connections and / or reference burrs are executed when it is used in screwdriving devices and / or riveting devices. This serves to record reference measured value curves by means of which the boundary lines of evaluation ranges are determined and specified by the setting unit, by using these to define evaluation sections which are preferably envelope-like.

Boundary lines can preferably be set arbitrarily, so that evaluation areas of any shape can be defined by means of the boundary lines. Accordingly, the adjustment unit is configured such that portions and / or boundary lines of boundary lines (e.g., curved, straight, angular, etc.) and / or angles between and / or between boundary lines are queried and received by a user interface. Additionally or alternatively, self-contained boundary line profiles can be interrogated and accepted by the user interface (for example, circular courses, rectangular courses). The outlines of the queried and received courses are then automatically converted by the setting unit into boundary line parameters. Alternatively, the setting unit can also interrogate and accept boundary line parameters directly, so that concrete individual number values can be input by a user. The limit line specification very particularly preferably takes place by reading in a limit line curve graphically predetermined by a user on a touchscreen and then automatically converting it into boundary line parameters.

The user can define by means of graphical markings of the evaluation area whether an exclusion criterion or an inclusion criterion should be applied. For an exclusion criterion, the measured value curve must be outside the defined limit line. For an inclusion criterion, the measurement curve must run within the defined boundary line. Based on the markers is therefore preferably recognized, which criterion is to be applied for a specific measured value curve. For example, a hatching of an evaluation area may preferably characterize an exclusion criterion.

There is also the possibility that a user interacts with the adjustment unit to adjust or change or redefine individual borderline points of the measurement curve as needed. The boundary lines may preferably be provided in sections with section-specific deviation tolerances, which may preferably also differ from section to section.

LIST OF REFERENCE NUMBERS

Evaluation area for rivet mandrel tear 1 Evaluation range for course after rivet mandrel tear 2 Evaluation range for history before rivet mandrel tear 3 Entry into the evaluation area 1 4 Measurement trace 5 steps S1 to S6

Claims (11)

Method for evaluating a mechanical connection realized by means of a tool, based on measured values which are detected during the connection by means of a detection device included in the tool and stored as a measured value curve (5) in a tool store, wherein at least one adjusting unit comprises a setting unit Rating range (1,2,3) for the measured value curve (5) is predetermined and is evaluated by means of a tool included by the assessment unit, whether the measured value curve (5) within and / or outside of the evaluation range (1,2,3) runs, the Boundary lines of the evaluation range (1,2,3) are defined using boundary line parameters. Method according to Claim 1 , wherein an action is triggered when the measured value curve (5) within and / or outside of the evaluation range (1,2,3) runs. Method according to one of the preceding claims, wherein a boundary line parameter is determined based on a plurality of reference measured value curves from the setting unit. Method according to one of the preceding claims, wherein the position of the measured value curve (5) and the position of the boundary lines of the evaluation range (1, 2, 3) are defined by means of coordinates in a coordinate system, wherein the evaluation unit also checks whether a coordinate value pair of a measured value curve point coincides with at least one coordinate value pair of a borderline point. Method according to one of the preceding claims, wherein an evaluation range (1, 2, 3) having at least three boundary lines is predetermined, the end points of which are connected to one another such that a self-contained geometric shape results, wherein an arbitrarily predeterminable angle between two with one another Connected boundary lines is set by the setting unit. Method according to one of the preceding claims, wherein at least two mutually independent evaluation areas (1, 2, 3) are specified by the setting unit and the evaluation of the connection is carried out based on the at least two independent evaluation areas (1, 2, 3). Method according to one of the preceding claims, wherein the measured value curve (5) describes the course of a force which acts on the pulling mechanism of a blind riveting tool during the manufacture of a blind rivet connection. Method according to one of the preceding Claims 1 to 6 , wherein the measured value curve (5) describes the course of a force which acts on the output of a screwing tool during the manufacture of a screw connection. Tool, in particular portable riveting tool or portable screwing tool, comprising an integrated tool control, which is set up and provided for carrying out a method according to one of the preceding method claims. Computer program for a tool with integrated tool control, which causes the tool control to perform a method according to one of the preceding method claims when executed on the tool control. Machine-readable storage medium with a computer program stored thereon in accordance with Claim 10 ,

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