EP3095533B1 - Method for straightening metallic parts - Google Patents

Description

The invention relates to a method for straightening metallic parts.

After primary molding, typically after casting, the shape of metallic parts often deviates somewhat from the desired final shape. "Straightening" is a process step in which a preformed part is plastically deformed as a function of determined dimensional differences from the nominal dimensions until, ideally, all dimensions correspond to the nominal dimensions.

The application of the invention is particularly advantageous when the geometry of the metallic parts mainly consists of flat sections that are complexly curved and / or are composed of differently oriented sections, so that the precise prediction of plastic deformation due to bending due to the action of force by means of hydraulic stamps or the like, is not possible or only with many difficulties and restrictions. Such parts are, for example, rather larger, flat aluminum die-cast parts of complex shape, which have a statically load-bearing function as part of the chassis of an automobile.

The DE 196 11 897 C2 deals with the straightening of elongated metallic parts. A part is first measured and then straightened by bending. The plastic bending deformation due to the deformation path temporarily forced by the bending tool is calculated taking into account the material properties. The movement of the bending tool during the bending process is composed of a large, rectified movement and a rapid sequence of forward and backward movements with a relatively small stroke superimposed on this movement. For the calculation of the bending result, numerical values are stored in the calculation program, which represent material parameters. In adaptation to These stored numerical values can be changed as a result of straightening processes that have actually taken place, so that with increasing empirical values, the calculation is increasingly better brought into line with reality. The method is very well suited for simple, elongated parts in which only a few different shape deviations need to be corrected in practice. The method cannot be used for straightening parts with more complex geometry due to the drastically increasing computational complexity.

In the DE 102004043401 A1 It is proposed to straighten cast aluminum parts using an embossing tool. The embossing tool has a plurality of pairs, each of which consists of a lower part and an upper part, all of the pairs jointly enclosing a mold cavity, and wherein pairs can be individually offset from the other pairs in the closing direction of the embossing tool. The workpiece is plastically formed by subsequent stamping of the cast workpiece in this tool. By cleverly adjusting the offset of the individual pairs of bottom and top parts against each other, systematic geometry errors of the cast parts can be corrected well. Due to the high effort for the production and optimization of the form, the method can only be used economically if large series are manufactured and the dimensional deviations from part to part are always the same after casting.

The DE 102008003882 B4 deals with an advantageous method for straightening flat metal castings, such as aircraft window frames in particular. After solution annealing, the geometry of the cast part is automatically measured and the extent of the deformation required at the individual surface areas is calculated automatically, the degree of displacement of the surface areas normal to their plane being important. The straightening deformation is then carried out by placing a blasting material, such as typically steel balls, normal to its surface on selected surface areas is radiated. Straightening can be carried out iteratively in several cycles from measuring and blasting to the desired end result. Above all, the advantage of the process is its flexibility. It can be automated to such an extent that in series production, the shape deviations, which differ from part to part, are fully automated. For production in larger series, it is disadvantageous that the cycle time is relatively long. Due to the shaping by an abrasive, the maintenance and operating resources for the system are also relatively high.

The DE 10 2007 002320 A1 describes a method and a device for straightening a sheet metal part, wherein shape deviations are measured at several measuring points on the sheet metal part and a number of points of retraction are deformed. The information about the straightening processes that are carried out is recorded in a database and is intended to be further processed according to the intended purpose by an artificial neural network to find optimal parameters for future straightening processes, so that a straightening system that is continuously learned is formed.

• a) Anwendbarkeit auch bei sehr komplexer Geometrie des Richtobjekts.
• b) Automatische Auswahl der jeweils passenden Richtverformung auch bei von Richtobjekt zu Richtobjekt stark unterschiedlichen Maßabweichungen.
• c) Kurze Taktzeit
• d Wenig Aufwand für Wartung und Betriebsmittel der Anlage.

The object of the invention is to provide a method for straightening a straightening object, wherein the straightening object can be a shaped metal part, in particular a cast metal part. In contrast to the methods known from the discussed prior art, the method to be created should be advantageous with regard to all of the following criteria:

• a) Applicability even with very complex geometry of the target.
• b) Automatic selection of the appropriate straightening deformation, even in the case of very different dimensional deviations from straightening object to straightening object.
• c) Short cycle time
• d Little effort for maintenance and equipment of the system.

• Auswahl einer Verformung die durch ein oder mehrere Richtstempel auf das Richtobjekt aufzubringen ist.
• Ausführen der ausgewählten Verformung.
• Aufheben der Krafteinwirkung der Richtstempel auf das Richtobjekt.
• Direktes oder indirektes messtechnisches Erfassen der Geometrie die das Richtobjekt in entspanntem Zustand hat.
• Berechnen in welcher Richtung und um welchen Betrag geometrische Maße des Richtobjekts von hinterlegten Sollmaßen abweichen.

A method is used to solve the task, which proceeds as follows:
The straightening object is kept defined and the geometry of the straightening object when it is in a relaxed state is measured. Then it is calculated in which direction and by what amount geometric dimensions of the directional object deviate from stored target dimensions. Then the straightening object is subjected to a repetitive sequence of work steps that includes the following work steps:

• Selection of a deformation to be applied to the leveling object by one or more leveling dies.
• Execution of the selected deformation.
• Cancellation of the force of the straightening stamp on the straightening object.
• Direct or indirect metrological recording of the geometry that the target has in a relaxed state.
• Calculate in which direction and by what amount the geometric dimensions of the directional object deviate from the specified dimensions.

The process ends when either in the last-mentioned step no longer discrepancies from the nominal dimensions or when another termination condition is reached.

• Die im ersten genannten Arbeitsschritt ("Auswahl einer Verformung die durch ein oder mehrere Richtstempel auf das Richtobjekt aufzubringen ist") zu treffende Auswahl wird unter Inanspruchnahme eines Datenbestandes einer Datenbank getroffen, welche Daten bezüglich Ausgangssituation, Maßnahmen und Ergebnissen von schon geschehenen Verformungsvorgängen an Richtobjekten enthält.
• Daten bezüglich der am aktuell gerichteten Richtobjekt durchgeführten Verformungsvorgänge (jeweilige Ausgangsgeometrie, Maßnahmen, Ergebnisgeometrie) werden in die Datenbank eingespeist und der besagte Datenbestand über vergangene Verformungsvorgänge wird damit erweitert.

The following two measures are provided as an improvement according to the invention to this known procedure:

• The selection to be made in the first work step mentioned ("Selection of a deformation to be applied to the leveling object by one or more straightening stamps") is made using a database of data which contains data relating to the initial situation, measures and results of deformation processes already performed on leveling objects ,
• Data relating to the deformation processes carried out on the currently directed straightening object (respective initial geometry, measures, result geometry) are fed into the database, and the aforementioned database of past deformation processes is thus expanded.

Fig. 1:

zeigt extrem stilisiert wesentliche mechanische Komponenten einer erfindungsgemäß verwendbaren Richtvorrichtung

Fig. 2:

zeigt das grundlegende Ablaufschema entsprechend welchem gemäß dem erfindungsgemäßen Verfahren ein Richtobjekt gerichtet wird.

Through the measures according to the invention, which are actually surprisingly easy to implement even in existing systems, a self-learning system is created which continuously utilizes the experience gained in concrete straightening processes and perfects straightening from straightening object to grading object and gradually also for rarely Combinations of dimensional deviations that occur reliably provide successful recipes.

Fig. 1:

shows extremely stylized essential mechanical components of a straightening device that can be used according to the invention

Fig. 2:

shows the basic flow diagram according to which a target object is directed according to the inventive method.

According to Fig. 1 the object 1 is arranged in a device 2. The straightening device 2 has a rigid frame 3.

Brackets 4 protrude from the frame 3 onto defined points of the straightening object 1 and fix these points of the straightening object 1 with respect to the frame 3. Typically, three brackets 4 are used. A holder 4 can be formed, for example, by two hydraulic or pneumatic cylinders, which are directed from the frame 3 from opposite sides to the object 1 and whose position can optionally be mechanically locked.

According to the sketched example, a number of sensors 5 are arranged on the frame 3, which protrude from the object 1 and measure the distance of the surface of the object 1 from the frame 3 at a plurality of points. The sketched measuring sensors 5 can be, for example, rods that can be telescopically extended, on the free tip of which there is a touch or pressure sensor that generates a signal when it comes into contact with the target. The necessary distance measurement between points of the frame 3 and points of the target 1 but could also be done, for example, without contact by means of optical methods.

A plurality of straightening stamps 6 also protrude from the frame 3 onto the straightening object 1. The straightening stamps are typically hydraulic cylinders, the stroke of which can be controlled and measured and from which the force can ideally also be controlled or at least measured. Of course, a drive principle other than hydraulics is also conceivable for driving the straightening stamps, for example electrically (e.g. with a motor-driven screw spindle) or pneumatically.

• Arbeitsschritt a (Fig. 2): Das Richtobjekt 1 wird in definierter Position und Ausrichtung in die Richtvorrichtung 2 eingelegt. Die Halterungen 4 werden geschlossen und das Richtobjekt gegenüber dem Rahmen 3 in definierter Position starr und de facto spannungsfrei gehalten.
  Im Detail kann Arbeitsschritt a folgendermaßen ablaufen: Das Richtobjekt 1 wir erst auf Ablagepunkte gelegt, die aus dem Rahmen 3 nach oben ragen. Dann fahren von unten her drei Halterungen 4 soweit an jeweils einen von drei Referenzpunkten am Richtobjekt 1, dass dieses mit den drei Referenzpunkten auf den drei Halterungen 4 in einer Dreipunktauflage aufliegt. Dann fahren genau von der gegenüberliegenden Seite (also von oben) her drei weitere Halterungen 4 an das Richtobjekt heran und halten dieses auch nach oben hin spielfrei, allerdings dabei so gut wie möglich ohne Krafteinwirkung und damit so gut wie möglich spannungsfrei.
• Arbeitsschritt b: Mit Hilfe der Messfühler 5, welche Abstände messen, wird für eine Reihe von Punkten an der Oberfläche des Richtobjektes 1 deren Lage relativ zum Rahmens 3 gemessen.
• Arbeitsschritt c: Eine - nicht dargestellte - Datenverarbeitungsanlage errechnet die Unterschiede zwischen gemessenen Positionsdaten von Oberflächenpunkten des Richtobjektes 1 zu idealen Positionsdaten dieser Oberflächenpunkte und damit wie sehr die Oberfläche des Richtobjektes 1 an diesen Oberflächenbereichen gegenüber der idealen Position verschoben ist.
  Gemäß einer vorteilhaften - weil einfachen und dennoch zielführenden - Vorgangsweise wird von der Verschiebung der einzelnen Oberflächenpunkte gegenüber der idealen Position immer nur jener skalare Wert gemessen und aufgezeichnet, welcher aussagt, wie sehr der betrachtete Oberflächenpunkt in Normalrichtung zu der betrachteten Oberfläche gegenüber der idealen Position verschoben ist.
  Der Datensatz, welcher beschreibt wie sehr die einzelnen vermessenen Oberflächenpunkte des Richtobjektes 1 gegenüber ihrer idealen Position verschoben sind, wird als "Verschiebungsdatensatz" bezeichnet. Mathematisch kann er in vielem gleich wie ein Vektor angesehen und behandelt werden. Dieser Datensatz wird in eine Datenbank 7 eingelesen.
• Arbeitsschritt d: Die Datenverarbeitungsanlage prüft, ob die gemessenen Werte von Verschiebungen innerhalb der jeweiligen Zulässigkeitsgrenzen liegen oder nicht. Wenn jeder Wert des Verschiebungsdatensatzes innerhalb der zulässigen Grenzen liegt, ist am Richtobjekt 1 kein weiteres Richten erforderlich. Wenn Werte außerhalb besagter Grenzen liegen, wird an Hand hinterlegter Kriterien entschieden, ob ein Richtvorgang durchgeführt wird, oder ob das Richtobjekt als Ausschuss definiert und von weiterer Verarbeitung ausgeschieden wird. Ausscheiden kann beispielsweise gefordert sein, wenn Maßabweichungen so groß sind, dass die notwendige Verformbarkeit des Materials nicht ausreicht um das durch Richten korrigieren zu können, oder wenn das Richtobjekt schon eine zugelassene Höchstzahl von Richtzyklen erreicht hat. Wenn festgestellt wird, dass Richten erforderlich ist, geht es weiter zu Arbeitsschritte.
• Arbeitsschritt e: Durch Vergleich des in Schritt c festgestellten Verschiebungsdatensatzes mit in der Datenbank 7 hinterlegten Verschiebungsdatensätzen, zu denen auch Daten über erfolgte Richtvorgänge hinterlegt sind, wird ein Datensatz festgelegt, welcher aussagt, wie die einzelnen Richtstempel 6 zu bewegen sind. Dieser Datensatz wird des Weiteren als "Bewegungsdatensatz" bezeichnet.
  Beispielhafte vorteilhafte Algorithmen, die in die vorteilhafte Festlegung des Bewegungsdatensatzes münden, sind weiter unten detailliert beschrieben.
  In der Datenbank 7 wird vermerkt, welcher Bewegungsdatensatz gewählt wurde.
• Arbeitsschritt f: Die, gemäß in Arbeitsschritt e festgelegtem Bewegungsdatensatz betroffenen Richtstempel 6, werden in die Ausgangsposition am Richtobjekt 1 gefahren und die Bewegungen gemäß Bewegungsdätensatz werden durchgeführt.
  Im Allgemeinen reicht es aus, die gemäß Bewegungsdatensatz durchzuführenden Bewegungen der einzelnen Richtstempel 6 alle gleichzeitig zu starten und bis zu ihrem jeweiligen Ende ablaufen zu lassen. Bei sehr komplexen Geometrien und Verformungen kann es aber auch sinnvoll sein, eine detaillierte zeitliche Abfolge von Bewegungen der Richtstempel 6 festzulegen.
• Arbeitsschritt g: Die Richtstempel 6 werden entspannt und eventuell etwas vom Richtobjekt 1 zurückgefahren, sodass das Richtobjekt seine entspannte Form einnehmen kann. Eventuell werden dazu auch eine oder zwei Halterungen 4 gelockert.
• Arbeitsschritt b (zweiter Durchgang): siehe obigen Text zu "Arbeitsschritt b".
• Arbeitsschritt c (zweiter Durchgang): siehe obigen Text zu "Arbeitsschritt c".
  Ergänzung: Zusätzlich zu jener Berechnung, welche einen neuen Verschiebungsdatensatz als Ergebnis liefert, wird nun auch berechnet, wie sich die Form des Richtobjektes gegenüber dem Zustand vor dem Richtzyklus verändert hat. Der Datensatz welcher diese Veränderung beschreibt wird des Weiteren als "Veränderungsdatensatz" bezeichnet. Er wird in der Datenbank 7 gespeichert und ist dort dem zuletzt angewendeten Bewegungsdatensatz zugeordnet, der ja zu den betreffenden Veränderungen am Richtobjekt 1 geführt hat.
  Der Veränderungsdatensatz kann einfach durch jene Zahlenwerte gebildet sein, welche beschreiben, um wieviel sich die von den einzelnen Messfühlern 5 am gleichen Richtobjekt 1 gemessenen Werte vor und nach dem Richtvorgang (Arbeitsschritt f) unterscheiden. Mathematisch kann auch der Veränderungsdatensatz in vielem gleich wie ein Vektor angesehen und behandelt werden.

The process sequence is briefly illustrated using the drawings:

• Step a ( Fig. 2 ): The leveling object 1 is inserted into the leveling device 2 in a defined position and orientation. The brackets 4 are closed and the target object is held rigidly and de facto free of tension in relation to the frame 3 in a defined position.
  In detail, step a can proceed as follows: The leveling object 1 is first placed on storage points which protrude from the frame 3. Then move three brackets 4 from below to one of three reference points on the leveling object 1 so that it rests with the three reference points on the three brackets 4 in a three-point support. Then move from the opposite side (i.e. from above) three further brackets 4 to the straightening object and also hold it upwards without play, but as good as possible without force and thus as good as possible free of tension.
• Step b: With the help of the sensors 5, which measure distances, the position relative to the frame 3 is measured for a number of points on the surface of the object 1.
• Step c: A data processing system (not shown) calculates the differences between measured position data from surface points of the object 1 to ideal position data of these surface points and thus how much the surface of the object 1 is shifted from the ideal position at these surface areas.
  According to an advantageous - because simple and yet purposeful - procedure, only the scalar value is measured and recorded from the displacement of the individual surface points in relation to the ideal position, which indicates how much the surface point in question is shifted from the ideal position in the normal direction to the surface in question is.
  The data record, which describes how much the individual measured surface points of the directional object 1 are shifted from their ideal position, is referred to as a "shift data record". Mathematically, it can be viewed and treated like a vector in many ways. This data record is read into a database 7.
• Step d: The data processing system checks whether the measured values of shifts are within the respective permissibility limits or not. If each value of the displacement data set lies within the permissible limits, no further straightening is required on straightening object 1. If values lie outside said limits, it is decided on the basis of stored criteria whether a straightening process is carried out or whether the straightening object is defined as a scrap and is excluded from further processing. Elimination may be required, for example, if dimensional deviations are so large that the material is not sufficiently deformable to correct it by straightening, or if the straightening object is already an approved one Has reached the maximum number of straightening cycles. If it is determined that straightening is required, the work continues.
• Working step e: By comparing the displacement data record ascertained in step c with displacement data records stored in the database 7, for which data on straightening processes that have been carried out are also stored, a data record is established which states how the individual straightening dies 6 are to be moved. This data record is also referred to as a "movement data record".
  Exemplary advantageous algorithms which result in the advantageous definition of the movement data record are described in detail below.
  It is noted in the database 7 which movement data set was selected.
• Step f: The straightening stamps 6, which are affected in accordance with the movement data set defined in step e, are moved into the starting position on the straightening object 1 and the movements according to the movement data set are carried out.
  In general, it is sufficient to start the movements of the individual straightening stamps 6 which are to be carried out in accordance with the movement data record, and to allow them to run to their end. In the case of very complex geometries and deformations, however, it can also make sense to define a detailed chronological sequence of movements of the straightening stamps 6.
• Step g: The straightening stamps 6 are relaxed and possibly moved back somewhat from the straightening object 1, so that the straightening object can assume its relaxed shape. One or two brackets 4 may also be loosened for this purpose.
• Step b (second pass): see text above for "Step b".
• Step c (second pass): see text above for "Step c".
  Complemental description: In addition to the calculation that delivers a new displacement data record as a result, it is now also calculated how the shape of the target object has changed compared to the state before the target cycle. The data record which describes this change is also referred to as "change data record". It is stored in the database 7 and is assigned there to the movement data record last used, which has led to the relevant changes to the object 1.
  The change data record can simply be formed by those numerical values which describe how much the values measured by the individual sensors 5 on the same straightening object 1 differ before and after the straightening process (work step f). The change data record can also be viewed and treated mathematically in much the same way as a vector.

The cycle described is repeated until step d either determines that the geometry of the target object corresponds to the target geometry or until another termination criterion is met.

In the database 7, the mentioned data records displacement data record, movement data record and change data record are best stored in the form of a combination of a vector and an amount. The vector is an ordered group of several numerical values and the amount is a simple scalar number.

Using the example of the displacement data set, the deviations from the ideal position of the respective surface areas of the directional object 1 determined at the individual sensors 5 are recorded in the vector, but not in a numerical value of theirs corresponds to an absolute size, but in a normalized size, so that the vector is a kind of unit vector. Only by multiplying the numerical values of the individual components of the vector by the amount does one arrive at those numerical values which state the distance by which the surface area of the target object 1 there is shifted from the ideal position on the respective individual measuring sensor 5.

Analogously to the method customary in vector calculation, the amount can be calculated as a root from the sum of the squares of the individual values of the displacements measured at the individual sensors 5. The individual components of said (unit) vector are then the individual displacement values divided by the amount.

The individual components of the (unit) vector are each assigned to a specific straightening stamp 6 on the movement data record. Analogously to the displacement data record, the amount by which a straightening stamp 6 has to be moved during a straightening process is obtained by multiplying the component of the vector assigned to the straightening stamp by the amount.

The change data record is the same as the. Displacement data record assigned the individual components of the vector to the individual sensors 5 and thus to the surface areas of the straightening object 1, the position of which is determined by sensors 5. The components of the vector belonging to the change data record multiplied by the amount belonging to the change data record result in the respective distance by which a surface area has been shifted according to the movement of the stamp according to the movement data record assigned to the change data record.

There are probably an infinite number of algorithms according to which the database 7 can be operated by a data processing system and movement data records can be defined.

Assuming that displacement data sets, movement data sets and change data sets are stored as described as a combination of unit vector and scalar, a simple and effective algorithm for the selection of a movement data set (work step e according to Fig. 2 ) work as follows:
For the displacement data record of the straightening object currently present, the most suitable change data record must be selected from the change data records stored in the database 7. The vector contained in the displacement data record has approximately the meaning of a direction, as do the vectors contained in the change data records. It is simply a search for the change data record whose vector is directed as precisely as possible against the vector of the displacement data record. According to the known rules of vector calculation, this is the vector in which the inner product with the vector of the displacement data set has the largest negative numerical value. Consequently, the data processing system forms the inner product of the vector of the displacement data set and the vectors of all change data sets and selects the change data set in which the result - that is, the inner product - has the greatest negative numerical value.

(The inner product of two vectors is the sum of the products of the numerical values of the similar components; e.g.: $$\left(\mathrm{a}/\mathrm{b}\right),\left(\mathrm{c}/\mathrm{d}\right)=\mathrm{a},\mathrm{c}+\mathrm{b},\mathrm{d})$$

In the next step, the amount of the current displacement data record is multiplied by the absolute value of the previously found inner product (which has the largest negative numerical value), and divided by the amount of the change data record found. The amount of the movement data record assigned to the change data record in the database 7 is multiplied by the result.

The result is a newly formed movement data record. If you use this as a movement rule for the straightening stamp 6 (step f in accordance with Fig. 2 ) applies, theoretically, a change data record results which is oriented in the same direction as the previously selected change data record and is so large in amount that it corrects the existing shift in the change direction given by the change data record as best as possible. You can use the calculated movement data set immediately and thus in the cycle Fig. 2 progress further.

If you already see in the pre-calculation in step e that using the calculated movement data record will theoretically result in an improved displacement data record, it will still not be in the target range (- because the forecast change does not go in exactly the right direction -) , it is recommended to refine the definition of the movement data record to be used in advance. Only for the calculation can it be assumed that the first motion data record found was used, that the further displacement data record theoretically predicted therewith has been obtained and, for this further displacement data record, as described, in turn, a further change data record, together with an associated, appropriately scaled, further motion data record, is calculated , The movement data set to be actually used is then the vectorial addition of the movement data set calculated first with the movement data set subsequently calculated.

Theoretically, one could also pre-determine and overlay more than two movement data sets.

It is important that the information about the movement data records actually actually used, including the associated information, that is to say the original displacement data record and the change data record reached, is stored in the database 7 so that the database is improved and the system learns with it.

It is sensible to define limiting conditions for deformations and to monitor them automatically, the relevant limits arising from the properties of the material of the straightening object 1. For example, there should be an upper limit for the entire deformation path and also an upper limit for the number of deformation processes.

When moving, by means of which straightening stamps 6 deform the straightening object 1, it is useful to distinguish whether the movement causes elastic or plastic deformation of the straightening object. As is known, at least approximately, the transition from elastic deformation to plastic deformation can be recognized by the flattening of the function graph, which describes the deformation force as a function of the deformation path. It is therefore sensible to constantly measure both the path and the force at the straightening stamps 6 and to evaluate them in the data processing system with regard to the deformation effect. For the data stored in the movement data records, the movements of the straightening punches 6 which they perform while plastically deforming them on the straightening object 1 are of crucial importance.

In an advantageous embodiment of a device according to the invention, the straightening punches 6 are also equipped with a sensor system, by means of which they can detect contact with the straightening object 1, so that they can therefore also perform the function of sensors 5.

In an advantageous embodiment, the straightening punches 6 can also assume the function of holders 4, that is to say hold points of the straightening object 1 against which they rest in a position that is rigid with respect to the frame 3.

In an advantageous embodiment, the straightening stamps 6 are mounted on a different frame than the measuring sensors 5 and the frame which carries the measuring sensors 5 is held independently of the frame which carries the straightening stamps 6. In this way, those measurement errors that otherwise arise from the fact that the frame which carries the straightening stamps are also necessarily somewhat deformed when the force is applied to the straightening object by the straightening stamps.

It is of course very useful if there is a user interface to the data processing system that controls the straightening device 2 and includes the database 7. Ideally, this user interface can be used to view data on current work processes, edit stored data and influence the selection of movements of straightening stamps 6 (work step e). In particular, during the learning phase of a system according to the invention, it makes sense if, in work step e, movement data records can be easily specified and entered by people.

With regard to data records stored in the database 7, it is advantageous to carry out statistical evaluations and to assign evaluative classifications derived therefrom to the individual data records. For example, it can be seen that some movement data sets lead to predeterminable change data sets in a more reproducible manner than others, and that some movement data sets frequently result in damage to a target object. Statistical evaluation - which can also be carried out automatically by the data processing system - can thus automatically generate prohibition rules for problematic movement data records and bring them to automatic use. Likewise, a group of movement data records that work particularly well can be identified and preferably selected from them.

Claims (2)

1. Method for the straightening of a metallic straightening object (1) wherein the straightening object (1) is held in a defined position relative to the frame (3) of a straightening device (2), the geometry of the straightening object (1) is detected metrologically, it is calculated in which direction and by what amount the position of individual surface areas of the straightening object deviates from a stored ideal position, and the straightening object, in a repetitive sequence of working steps, if necessary, is subjected to

   - calculation, in which direction and by what amount geometrical dimensions of the straightening object deviate from the stored nominal dimensions,

   - selection of a forming which is to be applied by one or more straightening punches (6) on the straightening object (1).

   - performance of the selected forming,

   - cancellation of exerted force of the straightening punches (6) on the straightening object (1),

   - metrological detection of the straightening object (1) and calculation, in which direction and by what amount the position of individual surface areas of the straightening object deviates from a stored ideal position,
   wherein the selection of a forming is made using the data set of a database (7), which includes data relating to the initial situation, measures and results of already occurred forming processes on straightening objects, and that data which is automatically fed into the database (7) during operational straightening operations and expands the database for further selections of forming on straightening objects (1),characterised in that the data contains a shift data set, a movement data set and a change data set, wherein the shift data set contains statements about the deviation of the shape of the straightening object (1) from the ideal form, the movement data set contains statements about movements of the straightening punches(6) with which these form the straightening object (1) and the change data set contains statements as to how the form of the straightening object (1) was changed as a result of movement of the straightening punches (6) according to the movement data set, wherein as intermediate steps for the determination for the respective next movement of the straightening punches (6), a search is performed in the respective available shift data set for the straightening object (1) in the database, for that change data set, which is designed as a vector aligned, preferably inversely, to the shift data set designed as a vector, and then the movement data set associated with this shift data set in the database is used as part of the instruction for the movement of the straightening punches.
2. Method according to claim 1, characterised in that inner products of each present shift data set designed as a vector are formed with shift data sets designed as a vector and stored in the database, and that the shift data set is selected, with which the resulting inner product has the largest negative value.

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