DE102018118890A1 - Device and method for monitoring objects, in particular tools on machine tools and / or for mechanically scanning objects, in particular tools or workpieces, and a computer program for operating such a device and / or for executing such a method - Google Patents

Abstract

The invention relates to a method for monitoring objects (22), in particular tools on machine tools and / or for mechanically scanning objects (22), with a device (10), the method comprising the following steps: - Defining a tolerance range ( T) by means of the control unit (20), which extends from the test position with the same dimension towards the rest position and away from the rest position around the test position, and - defining a first stopping condition (C1) valid within the tolerance range (T) and one outside the Tolerance range (T) of the second stopping condition (C2) for the stylus (18) by means of the control unit (20), when fulfilled the presence of an object (22) is assumed, the first stopping condition (C1) being easier to meet than the second Stop condition (C2), - in the event that the presence of an object (22) in the tolerance range (T) is assumed, generating a Ge Object detection signal by means of the control unit (20), and - in the event that no presence of an object (22) in the tolerance range (T) is assumed, generation of an error signal by means of the control unit (20). The invention further relates to a device with which the Method can be carried out, as well as a computer program for executing the method and / or for operating this device.

Description

The present invention relates to a method for monitoring objects, in particular tools on machine tools and / or for mechanically scanning objects, in particular workpieces or tools. Furthermore, the present invention relates to a device which is set up to carry out such a method. Furthermore, the invention relates to a computer program for executing such a method and / or for operating such a device.

The use of fully automated production systems with short cycle rates requires continuous quality assurance and thus control of all production steps. In order to be able to identify defective or broken tools, incorrectly inserted or ejected workpieces, or worn tools, and to avoid exclusion and consequential damage to the machine in question, tactile measurements are often carried out using a stylus with which the appropriate tools and / or Workpieces are scanned. Such a stylus can be moved and in particular pivoted, for example by means of a drive device, which usually comprises an electric motor, from a rest position to a predeterminable angular position (test position) and back again. The presence of an object is assumed when a stopping condition is met. When the stylus comes into contact with the object, a resistance acts on the stylus, which brakes the stylus. The stopping condition can be met, for example, when the stylus is stopped for a certain period of time due to contact with the tool, that is, the speed of the stylus is zero. As soon as the stopping condition is fulfilled, the stylus is moved back into the rest position.

A device for monitoring tools or workpieces with an electric drive device and a stylus, which can be rotated about an axis of rotation between a rest position and a test position by means of the electric drive device, is described, for example, in the published patent application DE 102 18 315 A1 described. The stylus can be connected to a counterweight which, when the electrical drive device is deactivated, for example in the event of a power failure, holds the stylus in its current position or pivots away from the test position. In addition, the balance weight ensures that the same moment always acts on the drive device regardless of the angular position of the stylus.

If the key needle feels an object, in particular a tool or a workpiece, in the test position, the drive device generates a corresponding signal (object detection signal), otherwise it is determined that the object in question is not present or is not correctly positioned. The test position thus represents the position in which ideally contact of the stylus with the object is expected. In this case, the tool takes up the ideal position. For example, if the tool is in the ideal position, the stylus in the test position registers a certain resistance due to the contact with the tool, which indicates that the tool is present on the one hand and that the tool is in the ideal position on the other. The object detection signal generated in this case is therefore an “OK message”. Alternatively, no signal can be generated at all. In both cases, the intended processing sequence is continued unchanged.

Nowadays, it is not difficult to determine the position of an object to within a few tenths of a millimeter in the manner described above. However, the position of the tool can change during operation of the tool and when changing tools, so that the tool no longer assumes the ideal position. However, certain deviations from the ideal position can be tolerated without sacrificing the precision of the workpieces machined with the tool. It is therefore from the DE 30 03 431 A1 known to define a tolerance range around the ideal position and to generate an object detection signal or no signal even if the deviation from the ideal position is within the tolerance range.

If no resistance or the resistance is registered in the test position or within the tolerance range before the test position or the tolerance range has been reached, an error signal is generated which, for example, triggers an acoustic and / or visual warning signal and / or deactivates the tool and interrupts the further machining process ,

As mentioned, such devices are mainly used to check the presence of a tool. In many cases, the tools are fragile, for example when the tools are designed as diamond-coated drills. Therefore, only slight forces that do not damage the tool may act on contact between the stylus and the tool. As a result, the stopping condition mentioned above is met relatively easily. As a result, external influences such as dripping coolants or air currents that blow out the Tool holder arise when changing tools, already cause the device to incorrectly assume the presence of an object. If the presence of the object is assumed to be outside the tolerance range, an error message is generated, as mentioned, and the further processing sequence is interrupted. In the event that an error signal is generated, an employee must check whether the error signal was generated as a result of a damaged tool or a tool that is positioned significantly different from the ideal position, or whether it was caused by the external influences described above. To do this, the employee must check the tool and decide whether the tool needs to be replaced or repositioned or whether the machining process can be continued without any further measures. In the latter case, the error signal causes unnecessary delays.

It is therefore an object of an embodiment of the present invention to provide a method for operating objects such as tools on machine tools and / or for mechanically scanning objects such as workpieces or tools, with which it is possible to detect error signals caused by external influences such as Air currents or coolants are caused, and to avoid unnecessary interruptions in the operation. Furthermore, an embodiment of the present invention is based on the object of creating a device which is set up to carry out this method. In addition, one embodiment of the invention is based on the object of providing a computer program for carrying out this method and / or for operating such a device.

This object is achieved with the features specified in claims 1, 7 and 9. Advantageous embodiments are the subject of the dependent claims.

• - eine Antriebseinrichtung,
• - eine mit der Antriebseinrichtung zwischen einer Ruhestellung und einer vorgebbaren Prüfstellung bewegbare Tastnadel, wobei der Gegenstand in der Prüfstellung eine Idealposition einnimmt, und
• - eine Steuereinheit zum Steuern der Vorrichtung aufweist.

One embodiment of the invention relates to a method for monitoring objects, in particular tools on machine tools and / or for mechanically scanning objects, in particular tools or workpieces, with a device, the device

• - a drive device,
• a stylus that can be moved with the drive device between a rest position and a predeterminable test position, the object assuming an ideal position in the test position, and
• - Has a control unit for controlling the device.

• - Definieren eines Toleranzbereichs mittels der Steuereinheit, der sich ausgehend von der Prüfstellung mit demselben Maß zur Ruhestellung hin und von der Ruhestellung weg um die Prüfstellung erstreckt, und
• - Definieren einer im Toleranzbereich geltenden ersten Anhaltebedingung und einer außerhalb des Toleranzbereichs geltenden zweiten Anhaltebedingung für die Tastnadel mittels der Steuereinheit, bei deren Erfüllung die Präsenz eines Gegenstands angenommen wird, wobei
• - die erste Anhaltebedingung leichter erfüllbar ist als die zweite Anhaltebedingung,
• - für den Fall, dass die Präsenz eines Gegenstands im Toleranzbereich angenommen wird, Erzeugen eines Gegenstandsfeststellungssignal mittels der Steuereinheit, und
• - für den Fall, dass keine Präsenz eines Gegenstands im Toleranzbereichs angenommen wird, Erzeugen eines Fehlersignals mittels der Steuereinheit.

The process comprises the following steps:

• - Defining a tolerance range by means of the control unit, which extends from the test position with the same dimension towards the rest position and away from the rest position around the test position, and
• - Defining a first stopping condition that is valid within the tolerance range and a second stopping condition that is valid outside the tolerance range for the stylus by means of the control unit, the fulfillment of which is assumed to be the presence of an object, wherein
• the first stopping condition is easier to meet than the second stopping condition,
• in the event that the presence of an object in the tolerance range is assumed, generating an object detection signal by means of the control unit, and
• - In the event that no presence of an object in the tolerance range is assumed, generating an error signal by means of the control unit.

According to the proposal, a tolerance range can be selected which extends symmetrically around the test position. The probability that the stylus hits an object is highest in the tolerance range. In most cases, the stylus performs a rotary movement, so that the tolerance range can be specified based on a tolerable angular deviation from the ideal position, for example ± 1 °. If the stylus performs a translatory movement, the tolerance range can be specified on the basis of a tolerable distance deviation, for example ± 0.1 mm. So that the tolerance range, starting from the test position in which the object to be monitored is in the ideal position, extends to the rest position and away from the rest position around the test position, the amount of the deviation in one and the other direction is the same , which creates the symmetrical extension. The amount of the deviation can be selected on the one hand on the basis of statistical considerations, so that deviations from the ideal position that usually occur during tool operation and during tool changes can be taken into account. On the other hand, the amount can be selected taking into account the necessary precision of the workpiece machining.

In addition, according to the proposal, a first stopping condition applies within the tolerance range and a second stopping condition outside the tolerance range. The first and second stopping conditions are formulated so that when they are met, the presence of a Object can be accepted with a sufficiently high probability. According to the proposal, the second stopping condition is more difficult to meet than the first stopping condition. This ensures that the above-mentioned external influences, such as coolant or air currents, which act on the stylus outside the tolerance range, lead to an error message in much rarer cases than is the case with corresponding methods from the prior art. This avoids unnecessary and costly interruptions in the operational process.

• - Definieren eines sich dem Toleranzbereich zur Ruhestellung hin anschließenden Annäherungsbereichs mittels der Steuereinheit, in welcher die zweite Anhaltebedingung gilt.

According to another embodiment, the method has the following step:

• - Defining an approach range following the tolerance range towards the rest position by means of the control unit, in which the second stopping condition applies.

As mentioned, the probability that the stylus hits an object is highest in the tolerance range. If the stylus passes through the tolerance range without hitting an object there, it can be assumed with a sufficiently high probability that the object, in particular the tool, has broken. It is therefore not necessary to allow the second stopping condition to apply after the tolerance range from the rest position. It is sufficient to let the second stopping condition apply in the approximation area. This keeps the requirements on the control unit low.

• - die erste Anhaltebedingung dann erfüllt ist, wenn die Geschwindigkeit der Tastnadel über eine erste geschwindigkeitsbezogene Zeitdauer gleich null ist oder über die erste geschwindigkeitsbezogene Zeitdauer eine Grenzgeschwindigkeit unterschreitet, und
• - die zweite Anhaltebedingung dann erfüllt ist, wenn die Geschwindigkeit der Tastnadel über eine zweite geschwindigkeitsbezogene Zeitdauer gleich null ist oder über die zweite geschwindigkeitsbezogene Zeitdauer die Grenzgeschwindigkeit unterschreitet, wobei
• - die zweite geschwindigkeitsbezogene Zeitdauer länger ist als die erste geschwindigkeitsbezogene Zeitdauer.

In a further developed embodiment, the method can be characterized in that

• - The first stopping condition is met when the speed of the stylus is equal to zero over a first speed-related period of time or falls below a limit speed over the first speed-related period of time, and
• - The second stopping condition is met when the speed of the stylus is equal to zero over a second speed-related time period or falls below the limit speed over the second speed-related time period, wherein
• - The second speed-related period is longer than the first speed-related period.

While within the tolerance range the speed of the stylus for the shorter first speed-related period of time must be zero or less than the limit speed in order to consider the presence of an object as given, this condition must be fulfilled outside the tolerance range for the longer second speed-related period of time to the presence of an object as given. As a result, this condition is more difficult to meet outside the tolerance range than within the tolerance range. On the one hand, in the tolerance range in which the probability that the stylus hits a tool is highest, the tool is spared due to the easier-to-meet first stopping condition; of a tool is reduced.

• - die Antriebseinrichtung einen Elektromotor umfasst, der mit einem Motorstrom betrieben wird,
• - die erste Anhaltebedingung dann erfüllt ist, wenn der Motorstrom über eine erste motorstrombezogene Zeitdauer ansteigt, und
• - die zweite Anhaltebedingung dann erfüllt ist, wenn der Motorstrom über eine zweite motorstrombezogene Zeitdauer ansteigt, wobei
• - die zweite motorstrombezogene Zeitdauer länger ist als die erste motorstrombezogene Zeitdauer.

An embodiment can be designed such that

• the drive device comprises an electric motor which is operated with a motor current,
• - The first stopping condition is met when the motor current increases over a first period related to the motor current, and
• - The second stopping condition is met when the motor current increases over a second period related to the motor current, wherein
• - The second motor current-related time period is longer than the first motor current-related time period.

In this embodiment too, the tool is spared due to the easier to meet first stopping condition, while outside the tolerance range due to the more difficult to meet second stopping condition the likelihood of incorrect assumption of the presence of a tool is reduced.

• - Übermitteln der Gegenstandsfeststellungssignale oder der Fehlersignale an eine Kontrolleinrichtung mittels einer Übertragungseinrichtung.

In a further embodiment, the following step is provided:

• - Transmission of the object detection signals or the error signals to a control device by means of a transmission device.

The control device can communicate with several proposed devices. The control device can record each measurement process performed by a device and count how many object detection signals, error signals and foreign object detection signals have been generated within a certain period of time. As a result, workpieces can be assigned to a tool test so that traceability and error analysis can be carried out. Tools and / or machine tools that are particularly reliable or particularly susceptible can also be identified.

• - eine Antriebseinrichtung,
• - eine mit der Antriebseinrichtung zwischen einer Ruhestellung und einer vorgebbaren Prüfstellung bewegbare Tastnadel umfasst, wobei der Gegenstand in der Prüfstellung eine ideale Position einnimmt, und
• - eine Steuereinheit zum Steuern der Vorrichtung aufweist, wobei die Steuereinheit derart eingerichtet ist, dass
• - ein Toleranzbereich, der sich ausgehend von der Prüfstellung mit demselben Maß zur Ruhestellung hin und von der Ruhestellung weg um die Prüfstellung erstreckt, und
• - eine im Toleranzbereich geltende erste Anhaltebedingung und eine außerhalb des Toleranzbereichs geltende zweite Anhaltebedingung für die Tastnadel definierbar sind, bei deren Erfüllung die Präsenz eines Gegenstands angenommen wird, wobei
• - die erste Anhaltebedingung leichter erfüllbar ist als die zweite Anhaltebedingung.

An embodiment of the invention relates to a device for monitoring objects, in particular tools on machine tools and / or for mechanically scanning objects, in particular tools or workpieces, the device

• - a drive device,
• comprises a stylus that can be moved with the drive device between a rest position and a predeterminable test position, the object assuming an ideal position in the test position, and
• - Has a control unit for controlling the device, the control unit being set up in such a way that
• a tolerance range which extends from the test position with the same dimension towards the rest position and away from the rest position around the test position, and
• - A first stopping condition valid in the tolerance range and a second stopping condition valid outside the tolerance range can be defined for the stylus, the fulfillment of which is assumed to be the presence of an object, wherein
• - The first stopping condition is easier to meet than the second stopping condition.

The technical effects and advantages that can be achieved with the proposed device correspond to those that have been discussed for the present method. In summary, it should be pointed out that, on the one hand, the tool is spared in the tolerance range due to the easier to meet first stopping condition, while outside the tolerance range, the probability of the incorrect assumption of the presence of a tool is reduced due to the second stopping condition, which is more difficult to achieve.

• - die Tastnadel aus der Ruhestellung auf eine erste Geschwindigkeit beschleunigt wird, und
• - die Tastnadel von der ersten Geschwindigkeit auf eine geringere zweite Geschwindigkeit derart abgebremst wird, dass die Tastnadel im Toleranzbereich mit der zweiten Geschwindigkeit bewegt wird.

In a further training it is provided that

• - The stylus is accelerated from the rest position to a first speed, and
• - The stylus is braked from the first speed to a lower second speed such that the stylus is moved at the second speed in the tolerance range.

In this embodiment of the device, the time required for monitoring the object, in particular the tool, on a machine tool is kept short, which also applies to the machining time and the machining costs of the workpiece as a whole. Since in most cases the stylus hits the tool within the tolerance range, the tool is also spared due to the lower second speed.

• - Definieren eines Toleranzbereichs mittels der Steuereinheit, der sich ausgehend von der Prüfstellung mit demselben Maß zur Ruhestellung hin und von der Ruhestellung weg um die Prüfstellung erstreckt, und
• - Definieren einer im Toleranzbereich geltenden ersten Anhaltebedingung und einer außerhalb des Toleranzbereichs geltenden zweiten Anhaltebedingung für die Tastnadel mittels der Steuereinheit, bei deren Erfüllung die Präsenz eines Gegenstands angenommen wird, wobei
• - die erste Anhaltebedingung leichter erfüllbar ist als die zweite Anhaltebedingung,
• - für den Fall, dass die Präsenz eines Gegenstands im Toleranzbereich angenommen wird, Erzeugen eines Gegenstandsfeststellungssignal mittels der Steuereinheit, und
• - für den Fall, dass keine Präsenz eines Gegenstands (22) im Toleranzbereichs angenommen wird, Erzeugen eines Fehlersignals mittels der Steuereinheit.

An embodiment of the invention relates to a computer program for executing a method according to one of the above-discussed embodiments for operating a device according to one of the above-described embodiments for monitoring objects, in particular tools on machine tools and / or for mechanically scanning objects, in particular tools or workpieces , wherein the computer program comprises program means for causing a control unit to carry out the following steps when the computer program is executed on the control unit:

• - Defining a tolerance range by means of the control unit, which extends from the test position with the same dimension towards the rest position and away from the rest position around the test position, and
• - Defining a first stopping condition that is valid within the tolerance range and a second stopping condition that is valid outside the tolerance range for the stylus by means of the control unit, the fulfillment of which is assumed to be the presence of an object, wherein
• the first stopping condition is easier to meet than the second stopping condition,
• in the event that the presence of an object in the tolerance range is assumed, generating an object detection signal by means of the control unit, and
• - in the event that there is no presence of an object ( 22 ) is assumed in the tolerance range, generating an error signal by means of the control unit.

The technical effects and advantages that can be achieved with the proposed computer program correspond to those that have been discussed for the present method. In summary, it should be pointed out that, on the one hand, the tool is spared in the tolerance range due to the easier to meet first stopping condition, while outside the tolerance range, the probability of the incorrect assumption of the presence of a tool is reduced due to the second stopping condition, which is more difficult to achieve.

• 1 eine prinzipielle Ansicht einer Vorrichtung, mit welcher ein erfindungsgemäße Verfahren durchgeführt werden kann,
• 2 eine prinzipielle Darstellung zur Verdeutlichung des erfindungsgemäßen Verfahrens,
• 3 eine graphische Darstellung der Anhaltebedingungen und der Geschwindigkeiten über den verschiedenen Bereichen, und
• 4 ein Ablaufdiagramm einer Ausführungsform des erfindungsgemäßen Verfahrens.

Exemplary embodiments of the invention are explained in more detail below with reference to the accompanying drawings. Show it

• 1 2 shows a basic view of a device with which a method according to the invention can be carried out,
• 2 a basic representation to illustrate the method according to the invention,
• 3 a graphical representation of stopping conditions and speeds over the various areas, and
• 4 a flow chart of an embodiment of the method according to the invention.

In 1 is an embodiment of the device according to the invention 10 shown using a basic illustration. The device 10 comprises a drive device 12 an electric motor in the illustrated embodiment 13 comprises and may have a rotary encoder, not shown. The encoder provides route information. The drive device 12 provides a rotational movement that drives it onto an output shaft 14 transmits that about an axis of rotation R is rotatably mounted. The output shaft 14 is with a stylus holder 16 connected to which a stylus 18 perpendicular to the axis of rotation R attached facing outward. The device further comprises 10 a control unit 20 with which different signals from the drive device 12 and in particular generated by the encoder, can be evaluated, which will be discussed in more detail later. This is the drive device 12 by means of electrical lines 21 with the control unit 20 connected. The control unit 20 is with a transmission device 28 equipped with which it can transmit information wirelessly or by cable and in particular bidirectionally with a control device 30 can exchange. The control device can be arranged in a control center of a workshop.

2 shows a basic side view of the stylus holder 16 and the stylus 18 , There are also four items to be monitored 22 , for example tools 24 like drills or workpieces. In the following, the present invention is based on as tools 24 executed items 22 explained, the explanations analogous to other embodiments of the objects 22 are transferable.

The object 22i or the tool 24i is in an ideal position. Things 22x or the tools 24x are not in the ideal position. The positions which the tools 24x ingest, but move within the normal range of tool operation 24 setting deviations, for example due to wear or tool changes. If these deviations are within predefinable limits, they have a negligible influence on the machining of the workpieces not shown here and can therefore be tolerated.

The ideal tool 24i can be used as reference. The stylus becomes in a teach mode 18 from the in 2 with 18a designated rest position to the tool in the ideal position 24i moved up and thus determined the predeterminable test position. The control unit 20 thus receives information on where the tools are 24 should ideally be arranged. As described, it cannot be avoided that the tools are in operation 24 are arranged in a position deviating from the ideal position, a certain deviation being tolerable. Therefore, a user can have a tolerance range T define the size of which he can choose himself. Depending on the length of the stylus 18 and the tolerable deviations from the ideal position, the tolerance range T with a deviation of, for example, ± 1 ° from the ideal position. It should be noted that the tolerance range T is therefore symmetrical in relation to the ideal position, since the accepted deviations are the same on one side and on the other side.

In the tolerance range T a first stopping condition applies C1 , whose definition will be discussed in more detail later. Out of tolerance T , in this case within a tolerance range T to rest the stylus 18a towards the subsequent approximation area A , a second stopping condition applies C2 which is harder to meet than the first stopping condition C1 , The stopping conditions C1 . C2 can be defined in the following ways: The first stopping condition C1 is satisfied when the speed v the stylus 18 over a first speed-related period of time tv1 is zero or over the first speed-related period tv1 a limit speed vG falls below while the second stopping condition C2 then if the speed is satisfied v the stylus 18 over a second speed-related period of time tv2 is zero or over the second speed-related period tv2 the limit speed vG below. The second is the speed-related period tv2 longer than the first speed-related period tv1 ,

The stopping conditions C1 . C2 can also be defined in the following way: The first stopping condition C1 is fulfilled if the motor current with which the electric motor 13 is operated over a first time period related to the motor current tm1 increases. The second stopping condition is corresponding C2 then met if the motor current over a second period related to the motor current tm1 increases. The second time is related to the motor current tm2 longer than the first period related to the motor current tm1 ,

In the illustrated embodiment, the approximation area extends A based on the tolerance range T approximately up to the bisector of the angle that the legs, the rest position and the rest position of the stylus 18a indicative limit of the tolerance range T include, include. But it is equally possible that the area of approach A based on the tolerance range T until the stylus is at rest 18a extends. Outside the proximity area A and out of tolerance T is the probability of getting an item there 22 to hit very low. In addition, external influences such as dripping coolants or air currents outside these areas are usually less, so that stopping conditions can apply that are even more difficult to meet than the second stopping condition C2 , or there are no stopping conditions at all, so the stylus 18 no objects there 22 can monitor.

In 3 is a graphical representation of the stopping conditions C1 . C2 and the speeds v the stylus 18 shown over the different areas. The proximity area extends there A from the rest position of the stylus 18a up to the tolerance range T , Starting from the rest position in which the stylus 18 the speed v is zero, the stylus 18 always along a defined tactile direction D to the object to be monitored 22 moved there (see 2 ) and at a first speed v1 accelerated, which is maintained for a certain time. Then the stylus 18 braked so that when entering the tolerance range T a second speed v2 which is less than the first speed v1 , Within the entire proximity range A the second stopping condition applies C2 , Within the tolerance range T becomes the stylus 18 at the second speed v2 emotional. In the tolerance range T the first stopping condition applies C1 , which is easier to meet than the second stopping condition C2 , This is in 3 represented graphically by the second stopping condition C2 has a higher numerical value with respect to the ordinate than the first stopping condition C1 ,

It is believed that there is an item under test 22x exactly at the limit of the tolerance range pointing away from the rest position T located. The stylus 18 consequently hits the object 22x if they have the tolerance range T has gone through completely. The stylus 18 is now in the test position, which is in 2 With 18c is marked. Because of the contact between the stylus 18 and the object 22x there is resistance on the stylus 18 , causing the first stopping condition C1 is fulfilled. As a result, the presence of an object 22x accepted and a corresponding object detection signal generated. Furthermore, the stylus 18 in one of the tactile directions D Moves in the opposite direction back to the rest position, leaving a reset area F sweeps. The stylus 18 to a reset speed vR accelerated. Since no measurement is carried out when moving back to the rest position, the reset speed can be reduced vR be as high as possible and therefore above the first speed v1 lie to save time. Shortly before reaching the rest position, the stylus 18 from the reset speed vR braked so that it reaches zero speed when it reaches rest position. Since no measurements are carried out when resetting, no stopping conditions apply here either C1 . C2 ,

In the event that the stylus 18 when going through the tolerance range T experiences no resistance and in the area B penetrates (see 2 ), which is within the tolerance range T on the side pointing away from the rest position is the tool 24x or the workpiece 22x either not available, broken or positioned to an extent that is no longer tolerable and deviates from the ideal position. In this case, an error signal is output and the further processing sequence is interrupted. The stylus 18 will stop as soon as it hits the area B has reached, and with the high reset speed vR moved back to the rest position.

In 3 you can see the following connection very clearly: As mentioned, the stylus becomes 18 in the proximity area A from the first speed v1 braked so that when entering the tolerance range T already the second speed v2 having. Because of the reduced second speed v2 the impact of the stylus falls 18 on an object 22x who is more likely to be within the tolerance range T located more gently than in the event that the stylus 18 to an object at a speed above the second speed 22x would hit. Therefore, only for this reason become the object 22x and in particular a tool designed as a diamond-coated drill 24x spared. As also mentioned, the first stopping condition must be met C1 for example the limit speed v the stylus 18 over a shorter first speed-related period of time tv1 to fall below than for the outside of the tolerance range T applicable second stopping condition C2 , This also makes the item 22x spared.

With decreasing speed of the stylus 18 takes the kinetic energy of the stylus 18 from. With approximation to the tolerance range T however, external influences such as dripping coolants or air currents increase. In devices known from the prior art 10 for monitoring objects 22x the same stopping conditions apply everywhere. In order to protect the tools, the stopping conditions that are easy to fulfill apply, that of the first stopping condition C1 can correspond. Due to the lower kinetic energy of the stylus 18 in the tolerance range T adjacent section of the proximity area A there is the likelihood that the device 10 erroneously the presence of an object 22x assumes the greatest. According to the invention, however, the second stopping condition that is more difficult to fulfill applies C2 over the entire approximation section A away, so that the likelihood of incorrectly assumed presences is significantly reduced and unnecessary interruptions to the operational process triggered thereby are avoided.

In 4 The essential steps of the method according to the invention are shown using a flow chart. As a step P1 is by means of the control unit 20 a tolerance range T defined, which is based on the test position of the stylus 18a extends by the same amount towards the rest position and away from the rest position around the test position. Then as a step P2 by means of the control unit 20 a the tolerance range T approach area to the rest position A Are defined. After the tolerance range T and the proximity area A are defined as a step P3 one in the tolerance range T applicable first stopping condition C1 and one out of tolerance T applicable second stopping condition C2 by means of the control unit 20 defines the fulfillment of the presence of an object 22x Is accepted. Here is the first stopping condition C1 easier to meet than the second stopping condition C2 ,

In step P4 becomes the stylus 18 from the rest position along the tactile direction D to the object to be monitored D emotional. As a step P5a in case the first stopping condition C1 in the tolerance range T is fulfilled by the control unit 20 generates an object detection signal which corresponds to an OK signal. The following processing procedures are carried out.

As a step P5b is from the control unit 20 in the event that the first stopping condition C1 in the tolerance range T is not met or the second stopping condition C2 in the proximity area A is met, an error signal is generated with which the further processing sequence is interrupted.

LIST OF REFERENCE NUMBERS

10

contraption

12

driving means

13

electric motor

14

output shaft

16

Tastnadelhalter

18

wand

18a

Stylus in the rest position

18c

Stylus in the test position

20

control unit

21

electrical line

22

object

22i

Object in ideal position

22x

Item in tolerance

24

Tool

24i

Tool in ideal position

24x

Tool in the tolerance range

26

Foreign body, chip

28

transmission equipment

30

control device

A

approach area

B

Area

C1

first stopping condition

C2

second stopping condition

D

tactile sense

F

Reset section

P1 to P5b

Steps of the procedure

R

axis of rotation

T

tolerance

tm1

first period related to motor current

tm2

second period related to motor current

tv1

first speed-related period

tv2

second speed-related period

v

Speed stylus

v1

first speed

v2

second speed

vG

limit speed

vR

Recovery rate

QUOTES INCLUDE IN THE DESCRIPTION

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Patent literature cited

• DE 10218315 A1 [0003]
• DE 3003431 A1 [0005]

Claims (9)

Method for monitoring objects (22), in particular tools on machine tools and / or for mechanically scanning objects (22), in particular tools or workpieces, with a device (10), the device having (10) - a drive device (12), - A stylus (18) movable with the drive device (12) between a rest position and a predeterminable test position, the object (22) assuming an ideal position in the test position, and - A control unit (20) for controlling the device (10), the method comprising the following steps: - Defining a tolerance range (T) by means of the control unit (20), which extends from the test position with the same dimension towards the rest position and away from the rest position around the test position, and - Defining a first stopping condition (C1) which is valid in the tolerance range (T) and a second stopping condition (C2) which is valid outside the tolerance range (T) for the stylus (18) by means of the control unit (20), when fulfilled the presence of an object (22 ) is assumed, whereby the first stopping condition (C1) is easier to meet than the second stopping condition (C2), - In the event that the presence of an object (22) in the tolerance range (T) is assumed, generating an object detection signal by means of the control unit (20), and - In the event that no presence of an object (22) in the tolerance range (T) is assumed, generating an error signal by means of the control unit (20). Procedure according to Claim 1 , comprising the following step: - defining an approach range (A) following the tolerance range (T) towards the rest position by means of the control unit (20), in which the second stopping condition (C2) applies. Procedure according to one of the Claims 1 or 2 , characterized in that - the first stopping condition (C1) is fulfilled when the speed (v) of the stylus (18) is zero over a first speed-related time period (tv1) or a limit speed over the first speed-related time period (tv1) vG), and - the second stopping condition (C2) is fulfilled if the speed (v) of the stylus (18) is zero over a second speed-related time period (tv2) or the limit speed over the second speed-related time period (tv2) vG) falls below, whereby - the second speed-related time period (tv2) is longer than the first speed-related time period (tv1). Procedure according to one of the Claims 1 or 2 , characterized in that - the drive device (12) comprises an electric motor which is operated with a motor current, - the first stopping condition (C1) is fulfilled when the motor current increases over a first time period (tm1) related to the motor current, and - the second Stopping condition (C2) is fulfilled if the motor current increases over a second motor current-related time period (tm2), the second motor current-related time period (tm2) being longer than the first motor current-related time period (tm1). Method according to one of the preceding claims, comprising the following step: - Transmitting the object detection signals or the error signals to a control device (30) by means of a transmission device (28). Method according to one of the preceding claims, comprising the following steps: - Accelerate the stylus (18) from the rest position to a first speed (v1), and - Braking the stylus (18) from the first speed (v1) to a lower second speed (v2) such that the stylus (18) is moved within the tolerance range (T) at the second speed (v2). Device for monitoring objects (22), in particular tools on machine tools and / or for mechanically scanning objects (22), in particular tools or workpieces, the device (22) - a drive device (12), - A stylus (18) movable with the drive device (12) between a rest position and a predeterminable test position, the object (22) occupying an ideal position in the test position, and - A control unit (20) for controlling the device (10), the control unit (20) being set up in such a way that - a tolerance range (T), which extends from the test position with the same dimension towards the rest position and away from the rest position around the test position, and - A first stopping condition (C1) valid in the tolerance range (T) and a second stopping condition (C2) valid outside the tolerance range (T) can be defined for the stylus (18), when fulfilled the presence of an object (22) is assumed, whereby - The first stopping condition (C1) is easier to meet than the second stopping condition (C2). Device after Claim 7 , The control unit (20) being set up in such a way that - the stylus (18) is accelerated from the rest position to a first speed (v1), and - the stylus (18) from the first speed (v1) to a lower second speed (v2) is braked in such a way that the stylus (18) is moved in the tolerance range (T) at the second speed (v2). Computer program for executing a method according to one of the Claims 1 to 6 and / or for operating a device according to one of the Claims 7 or 8th for monitoring objects (22), in particular tools on machine tools and / or for mechanically scanning objects (22), in particular tools or workpieces, the computer program comprising program means for causing a control unit (20) to carry out the following steps if the computer program is executed on the control unit (20): - defining a tolerance range (T) by means of the control unit (20), which extends from the test position with the same dimension towards the rest position and away from the rest position around the test position, and - defining a first stopping condition (C1) which is valid in the tolerance range (T) and a second stopping condition (C2) which is valid outside the tolerance range (T) for the stylus (18) by means of the control unit (20), when fulfilled the presence of an object (22) is assumed , where - the first stopping condition (C1) is easier to meet than the second stopping condition ngung (C2), - in the event that the presence of an object (22) in the tolerance range (T) is assumed, generating an object detection signal by means of the control unit (20), and - in the event that no presence of an object (22) in the tolerance range (T) is assumed, generating an error signal by means of the control unit (20).

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