DE102018127991A1 - Process for the mechanical processing of a sandwich structure, tool device and sandwich structure - Google Patents

Abstract

A method is provided for the mechanical processing of a sandwich structure (12), which has a first layer element (18), a second electrically conductive layer element (20) and a core element arranged between the first layer element (18) and the second electrically conductive layer element (20) (16), the sandwich structure (12) being machined by means of a tool (14) at least along a first machining direction (22) from the first layer element (18), at least one of an immersion depth (30) of the tool (14) into the sandwich structure (12) along the first processing direction (22) dependent physical property (28) between the second electrically conductive layer element (20) of the sandwich structure (12) and the tool (14) is monitored.

Description

The present invention relates to a method for mechanical processing of a sandwich structure, which comprises a first layer element, a second layer element and a core element arranged between the first layer element and the second layer element.

The invention further relates to a tool device for use in a method according to the invention.

The invention further relates to a monitoring device.

The invention further relates to a sandwich structure for use in a method according to the invention.

In particular in joining processes of sandwich structures, for example for punctiform joining, it is often necessary to mechanically process the first layer element and the core element of a sandwich structure, while the second layer element remains unchanged. A joining element to be joined is preferably fixed on the second layer element.

Fluctuations in a material thickness of the first layer element, in a material thickness of the second layer element and in a material thickness of the core element can lead to undesirable damage to the second layer element.

Such damage leads in particular to a reduced quality of the joining.

The object of the invention is to provide a method in which damage to the second layer element can be detected and which can also be easily integrated into existing machining methods.

This object is achieved according to the invention by a method in which a sandwich structure, which comprises a first layer element, a second electrically conductive layer element and a core element arranged between the first layer element and the second electrically conductive layer element, by means of a tool at least along a first machining direction from the first Layer element is machined mechanically, at least one physical property dependent on an immersion depth of the tool in the sandwich structure along the first machining direction being monitored between the second electrically conductive layer element of the sandwich structure and the tool.

This can offer the advantage that sandwich structures with damaged and / or weakened second electrically conductive layer elements are weakened in their material thickness.

In particular, the at least one physical property is monitored automatically.

The at least one physical property is preferably monitored by means of a monitoring device. The monitoring device is preferably part of a tool device or forms the tool device. However, it can also be provided that the monitoring device is part of the sandwich structure.

The monitoring device can preferably be integrated into conventional machining structures. A complex exchange of tools is particularly unnecessary.

The at least one physical property is preferably monitored during the entire mechanical processing of the sandwich structure. However, it can also be provided that a monitoring measurement is carried out at fixed intervals, for example every second or more frequently.

Methods according to the invention are preferably suitable for machining a sandwich structure, the tool being, for example, a milling tool. The immersion depth is a milling depth.

The method according to the invention is preferably part of a joining method in which a joining element is fixed on an inside of the second electrically conductive layer element, for example electrically conductive. The inside of the second electrically conductive layer element faces in particular the core element.

In particular, monitoring the immersion depth of the tool in the sandwich structure monitors a distance between the one free end of the tool, which faces the second electrically conductive layer element of the sandwich structure, and a surface (inside) of the second electrically conductive layer element facing the tool. The free end is formed, for example, by one or more cutting elements of the tool. In particular, contact of the tool with the inside of the second electrically conductive layer element is detected by means of the monitoring device.

In addition to machining along the first machining direction, in particular machining along a second machining direction and / or along a third machining direction can be provided. The second machining direction is in particular arranged transversely, preferably perpendicularly, to the first machining direction. The third machining direction is in particular arranged transversely, preferably perpendicularly, to the first machining direction and / or to the second machining direction.

In the sense of the invention, “monitoring” preferably means measuring, in particular recording a measurement curve, and / or detecting changes in an initial state.

The second electrically conductive layer element of the sandwich structure is preferably arranged facing away from the tool during processing of the sandwich structure and / or forms a surface of the sandwich structure facing away from the tool.

For the purposes of the invention, the electrical conductivity is characterized by the specific resistance. The specific resistance is the reciprocal of the electrical conductivity of a material.

The second electrically conductive layer element or other electrically conductive components preferably has a specific resistance of approximately 100 Ω · mm ² / m or less, preferably approximately 50 Ω · mm ² / m or less, particularly preferably approximately 20 Ω · mm ² / m or less, on. The specific resistances each refer to a material temperature of 20 ° C to 25 ° C.

The first layer element and / or the second electrically conductive layer element preferably each comprise one or more layers.

The tool device preferably comprises a control and / or regulating device for controlling and / or regulating the immersion depth of the tool in the sandwich structure.

The immersion depth is in particular automatically controlled and / or regulated.

The monitoring device preferably comprises a first contact element and in particular a second contact element. By means of the monitoring device, a value of the at least one physical property is measured on the first contact element or between the first contact element and the second contact element of the monitoring device. In particular, as soon as a critical value of the at least one physical property is measured, the monitoring device transmits a signal that a critical value has been measured to the control and / or regulating device of the tool device.

This can have the advantage that the control and / or regulation of the immersion depth is directly coupled to the monitoring device and the detection of a critical value of the at least one physical property.

The signal is in particular an electrical signal.

The first contact element is preferably electrically conductive and / or formed from a metallic material. It can be expedient if the first contact element is of a flat design and the second contact element in particular makes a planar contact with the second electrically conductive layer element. However, it can also be provided that the first contact element makes an essentially punctiform and / or ring-shaped contact with the second electrically conductive layer element.

In particular, the second contact element is electrically conductive and / or is formed from a metallic material. It can be expedient if the second contact element is of flat design and, in particular, the tool is contacted via the second contact element. However, it can also be provided that the second contact element makes essentially point-like and / or ring-shaped contacting of the tool.

It can be provided that the first contact element and / or the second contact element are sliding contacts.

The tool and the second electrically conductive layer element are preferably electrically contactable and / or contacted via the first contact element and the second contact element.

It can be advantageous if the critical value is a change in an output value of the at least one physical property. In particular, the critical value is a measured value of the at least one physical property, which is detected as soon as the tool at least approximately touches the second electrically conductive layer element and / or establishes material and / or electrical contact with the second electrically conductive layer element.

The critical value preferably deviates by a factor of 3 or more, in particular by a factor of 4 or more, for example 5 or more, from the initial value of the at least one physical property.

It can be provided that the critical value deviates from the initial value of the at least one physical property by a factor of 100 or more, in particular by a factor of 500 or more, for example 1000 or more.

It can be advantageous if a feed of the tool along the first machining direction into the sandwich structure is braked and / or stopped by means of the control and / or regulating device as soon as the control and / or regulating device receives the signal that a critical value has been measured, received and / or processed.

In particular, by means of the control and / or regulating device, the advance of the tool is slowed down when a critical value is detected by means of the monitoring device. In particular, a collision of the tool with an inside of the second electrically conductive layer element facing the core element is avoided.

This can offer the advantage that the second electrically conductive layer element of the sandwich structure remains undamaged by braking and / or stopping the advance of the tool. In particular, a control and / or regulation of the immersion depth of the tool that is dependent on the at least one physical property is realized in this way.

The monitoring device and the control and / or regulating device are, in particular, integrated into a measuring device. However, it can also be provided that the monitoring device and the control and / or regulating device are designed separately.

The immersion depth of the tool in the sandwich structure is preferably regulated dynamically by means of the control and / or regulating device as a function of the at least one physical property and / or the immersion depth is regulated in such a way that a material thickness of the second electrically conductive layer element during the mechanical, in particular machining, Editing remains essentially unchanged.

It can be provided that the first contact element is fixed to the second electrically conductive layer element or is formed by the second electrically conductive layer element and that the second contact element is fixed to the tool device or is formed by the tool device. It can be expedient if the first contact element and the second contact element are connected to one another, in particular in an electrically conductive manner.

The second contact element is preferably fixed to the tool of the tool device or formed by the tool. In particular, additional components are unnecessary and the monitoring device can be easily integrated into existing tooling devices.

Alternatively, it can be provided that the second contact element is fixed to a tool holder of the tool device or is formed by the tool holder. This can offer the advantage that conventional tools can be used.

It can be advantageous if a physical property of the at least one physical property is an electrical resistance, which is measured between the tool and the second electrically conductive layer element.

An ohmic resistance between the tool and the second electrically conductive layer element is preferably monitored. This can offer the advantage that existing devices for resistance measurement can usually be used in workshops or laboratories, as a result of which this variant of the method can be implemented with comparatively little economic outlay.

The tool is preferably electrically conductive and / or made of a metallic material, so that when the tool and the second electrically conductive layer element are at least approximately touched, the value of the electrical resistance is significantly reduced, in particular essentially zero. For example, the electrical resistance fluctuates R in the range f0.5 Ω, while before an at least approximate contact it lies in the megohm MΩ range.

For the purposes of the invention, at least approximately touching also includes approximation to approximately 0.5 cm or less, in particular approximately 0.1 cm or less. It also includes direct material contact and / or slight deformation of the second electrically conductive layer element by the tool.

The monitoring of the electrical resistance has the particular advantage that the at least approximately contact of the tool with the second electrically conductive layer element of the sandwich structure can be detected by means of a quantity that can be measured simply and by default.

The first contact element of the monitoring device is preferably a strain sensor element, for example a strain gauge, which is located on one facing away from the tool Surface of the second electrically conductive layer element is fixed and by which an at least approximately contact of the tool and the second electrically conductive layer element is detected.

A strain sensor element is used in particular to translate a stretch or extension of the second electrically conductive layer element, which arises when the tool comes into contact with it, into a change in resistance. This change in resistance is preferably detected by means of the monitoring device.

The use of the strain sensor element offers in particular the advantage that a second contact element of the monitoring device is unnecessary. The immersion depth is monitored in particular exclusively via the first contact element.

In variants of the method in which control and / or regulation of the immersion depth is provided via a control and / or regulating device, a second contact element is preferably also provided when using a strain sensor element.

In particular, the immersion depth is controlled and / or regulated via electrical signals which are transmitted to the tool device via the second contact element.

Additionally or alternatively, it can be provided that an impedance measurement is carried out between the tool and the second electrically conductive layer element by means of the monitoring device. Thus, at least approximately contact of the tool with the second electrically conductive layer element of the sandwich structure can be detected, in particular by means of a dynamic measurement.

An alternating resistance measured by means of the impedance measurement is preferably a physical property of the at least one physical property.

According to a further variant, in addition or as an alternative to measuring the electrical resistance, it can be provided that a physical property of the at least one physical property is an electrical capacitance which is measured between the tool and the second electrically conductive layer element.

When the tool comes into contact with the second electrically conductive layer element at least approximately, a critical value of the electrical capacitance is measured in particular. At least before the at least approximate contact, the tool, the second electrically conductive layer element and a part of the sandwich structure arranged between them with respect to the first machining direction form in particular an electrical capacitor.

When monitoring the electrical capacity, the electrical capacity is in particular a physical property that can be measured with devices that are usually present in workshops and / or laboratories. The at least approximately contact of the tool with the second electrically conductive layer element of the sandwich structure can thus be detected with comparatively little effort.

Provision can be made for a vibration-based measurement, in particular a sound measurement, to be carried out on the second electrically conductive layer element by means of the monitoring device. In particular, the second electrically conductive layer element lies on a side facing away from the tool on a first support element of the monitoring device and on a second support element of the monitoring device. In particular, a sound measurement is carried out between the first support element and the second support element, by means of which a change in sound intensity, in particular a change in source strength, is detected as soon as the tool at least approximately touches the second electrically conductive layer element.

In particular, a sound is measured which progresses as a wave in the second electrically conductive layer element between the first support element and the second support element. A sound emission is preferably measured, which changes its value as soon as the tool touches the second electrically conductive layer element at least approximately.

It can also be provided that the sound measurement is carried out without support elements.

The vibration-based measurement, in particular the sound measurement, is preferably independent of the material. In particular, a critical value of the physical property can be detected during sound measurement, regardless of the material from which the individual components of the sandwich structure and / or the tool are made. In particular, in the case of a tool made of a non-electrically conductive material, the at least approximately contact of the second electrically conductive layer element and the tool can be detected, and in particular an advancement of the tool by means of the control and / or Control device can be braked and / or stopped when there is at least approximate contact.

It can be provided that the immersion depth of the tool is subsequently reduced by means of the control and / or regulating device.

In particular for suitability for punctiform joining, the second electrically conductive layer element of the sandwich structure preferably comprises or is formed from a metallic material, for example aluminum.

It can be favorable if the first layer element comprises or is formed from a metallic material, for example aluminum.

The core element preferably comprises or is formed from a polymer material.

It can be advantageous if the sandwich structure comprises an electrically conductive layer which is arranged between the core element and the second electrically conductive layer element and comprises, for example, copper or is formed therefrom.

It can be provided that the electrically conductive layer is a metallic fabric, for example a copper fabric.

The use of an electrically conductive layer preferably offers the advantage that it can provide additional protection for the second electrically conductive layer element against weakening and / or damage by the tool. Even if the tool at least approximately touches the electrically conductive layer, this does not result in a weakening of the second electrically conductive layer element.

It can be provided that the processing of the sandwich structure by means of the tool device creates an essentially blind hole-shaped cavity within the sandwich structure, in particular removes it. The essentially blind-hole-shaped cavity is in particular partially enclosed by the core element and the second electrically conductive layer element and is open to a side facing the tool. Preferably, a connecting element, in particular by means of an adhesive layer, is firmly bonded, preferably exclusively, to the second electrically conductive layer element.

An essentially direct attachment of the connecting element to the second electrically conductive layer element without the use of an electrically conductive fabric leads in particular to an improved connection strength between the connecting element and the second electrically conductive layer element.

In particular, a cohesive connection of the connecting element and the core element and / or the first layer element is unnecessary.

The connecting element is in particular an insert which, for example, comprises a thread into which a joining element can be screwed.

As mentioned at the beginning, the invention further relates to a tool device for use in a method according to the invention.

The features and / or advantages explained in connection with the method according to the invention apply equally to the tool device according to the invention.

As also mentioned at the beginning, the invention further relates to a sandwich structure for use in a method according to the invention.

The features and / or advantages explained in connection with the method according to the invention apply equally to the sandwich structure according to the invention.

The invention further relates to a monitoring device, in particular for use in a method according to the invention.

The monitoring device comprises a first contact element and in particular a second contact element. At least one physical property dependent on a depth of immersion of a tool of a tool device in a sandwich structure can be monitored and / or monitored via the first contact element or between the first contact element and the second contact element.

The features and / or advantages described in connection with the method according to the invention apply equally to the monitoring device according to the invention.

The following description of preferred variants and embodiments serves in conjunction with the drawings to explain the invention in more detail.

• 1 eine schematische Darstellung einer ersten Ausführungsform einer erfindungsgemäßen Werkzeugeinrichtung und einer ersten Ausführungsform einer erfindungsgemäßen Sandwichstruktur vor einer mechanischen Bearbeitung der Sandwichstruktur mittels eines Werkzeugs der Werkzeugeinrichtung mit einem erfindungsgemäßen Verfahren;
• 2 die Werkzeugeinrichtung aus 1, wobei das Werkzeug entlang einer ersten Bearbeitungsrichtung in die Sandwichstruktur bis in ein Kernelement derselben eingedrungen ist;
• 3 die Werkzeugeinrichtung aus den 1 und 2, wobei das Werkzeug der Werkzeugeinrichtung ein bezüglich der ersten Bearbeitungsrichtung gesehen hinten angeordnetes zweites elektrisch leitendes Lagenelement der Sandwichstruktur erreicht hat und dessen Berührung durch das Werkzeug mittels einer Überwachungseinrichtung detektiert wird;
• 4 ein beispielhaftes Messdiagramm einer Überwachung gemäß einem erfindungsgemäßen Verfahren;
• 5 eine schematische Darstellung einer zweiten Ausführungsform einer erfindungsgemäßen Werkzeugeinrichtung und einer erfindungsgemäßen Sandwichstruktur wie in den 1 bis 3, wobei das zweite elektrisch leitende Lagenelement der Sandwichstruktur und das Werkzeug der Werkzeugeinrichtung mittels eines ringförmigen zweiten Kontaktelements und eines flächigen ersten Kontaktelements in elektrisch leitendem Kontakt sind;
• 6 eine schematische Darstellung einer Werkzeugeinrichtung wie in den 1 bis 3 und einer zweiten Ausführungsform einer Sandwichstruktur, wobei die Sandwichstruktur eine elektrisch leitende Schicht umfasst;
• 7 eine schematische Darstellung einer dritten Ausführungsform einer erfindungsgemäßen Werkzeugeinrichtung und der Sandwichstruktur wie in den 1 bis 3, wobei die Überwachungseinrichtung ein Dehnungssensorelement umfasst;
• 8 eine vierte Ausführungsform einer erfindungsgemäßen Werkzeugeinrichtung, mit welcher eine Schallmessung durchgeführt wird; und
• 9 eine dritte Ausführungsform einer erfindungsgemäßen Sandwichstruktur, welche durch die mechanische Bearbeitung einen im Wesentlichen sacklochförmigen Hohlraum aufweist, in den mittels einer Klebeschicht ein Verbindungselement stoffschlüssig an dem zweiten elektrisch leitenden Lagenelement der Sandwichstruktur festgelegt wurde.

Show it:

• 1 is a schematic representation of a first embodiment of a tool device according to the invention and a first embodiment of an inventive Sandwich structure before mechanical processing of the sandwich structure using a tool of the tool device with a method according to the invention;
• 2nd the tool setup 1 , wherein the tool has penetrated into the sandwich structure into a core element thereof along a first machining direction;
• 3rd the tooling from the 1 and 2nd , wherein the tool of the tool device has reached a second electrically conductive layer element of the sandwich structure, as seen with respect to the first machining direction, and whose contact is detected by the tool by means of a monitoring device;
• 4th an exemplary measurement diagram of a monitoring according to a method according to the invention;
• 5 a schematic representation of a second embodiment of a tool device according to the invention and a sandwich structure according to the invention as in the 1 to 3rd , wherein the second electrically conductive layer element of the sandwich structure and the tool of the tool device are in electrically conductive contact by means of an annular second contact element and a flat first contact element;
• 6 is a schematic representation of a tool device as in the 1 to 3rd and a second embodiment of a sandwich structure, the sandwich structure comprising an electrically conductive layer;
• 7 is a schematic representation of a third embodiment of a tool device according to the invention and the sandwich structure as in the 1 to 3rd , wherein the monitoring device comprises a strain sensor element;
• 8th a fourth embodiment of a tool device according to the invention, with which a sound measurement is carried out; and
• 9 a third embodiment of a sandwich structure according to the invention, which, as a result of the mechanical processing, has an essentially blind hole-shaped cavity, in which a connecting element has been firmly bonded to the second electrically conductive layer element of the sandwich structure by means of an adhesive layer.

In the 1 to 3rd is a first embodiment of a tool device according to the invention 10th shown, by means of which a first embodiment of a sandwich structure according to the invention 12th is mechanically processed in a method according to the invention.

The sandwich structure 12th in the present case comprises a core element 16 which is on a the tool 14 facing side of a first layer element 18th and on one the tool 14 facing away from a second electrically conductive layer element 20th is limited. In particular, the core element 16 between the first layer element 18th and the second electrically conductive layer element 20th embedded.

For example, the first layer element 18th and the second electrically conductive sheet member 20th made of aluminum. The core element 16 is made of a polymer foam material.

The tool setup 10th in the present case comprises a tool 14 and a tool holder (not shown) for holding and / or stabilizing the tool 14 during the processing. The tool 14 is, for example, a milling tool, by means of which parts of the first layer element are used for punctiform joining 18th and the core element 16 be milled out.

1 shows a state at the beginning of the method before removal of material of the sandwich structure 12th through (not shown) cutting elements of the tool 14 .

2nd shows a state during machining, the tool 14 the first layer element 18th has penetrated and already in the core element 16 has penetrated.

3rd shows a state of maximum immersion depth 30th of the tool 14 into the sandwich structure 12th .

Main extension planes of the first layer element 18th , the core element 16 and of the second electrically conductive layer element 20th are in particular essentially perpendicular to a first machining direction during the method according to the invention 22 aligned. The second electrically conductive layer element 20th forms one of the tool 14 facing surface 24th the sandwich structure 12th .

For a punctiform joining of the sandwich structure 12th is a lifting and / or removing material of the first layer element 18th and the core element 16 the sandwich structure 12th required, the second electrically conductive layer element 20th should, however, especially in the case of fluctuations in the material thickness of the first layer element 18th and / or the core element 16 and / or the second electrically conductive layer element 20th , not be weakened.

The tool setup 10th preferably comprises a monitoring device 26 , by means of which at least one physical property 28 , which depends on the immersion depth 30th of the tool 14 into the sandwich structure 12th along the first machining direction 22 , is monitored.

For this purpose, the second electrically conductive layer element is used 20th via a first contact element 34 the monitoring device 26 and a second contact element 36 the monitoring device 26 with the tool 14 electrically contacted.

In the present case, electrical contacting takes place directly on the second electrically conductive layer element 20th instead, so in particular the first contact element 34 from the second electrically conductive layer element 20th is formed and / or integrated into this.

On the part of the tool setup 10th electrical contact is made directly on the tool 14 instead, so the second contact element 36 from the tool 14 is formed and / or integrated into this.

As a physical property 28 of the at least one physical property 28 becomes an electrical resistance in the present case R between the tool 14 and the second electrically conductive layer element 20th monitored and during machining by means of the monitoring device 26 continuously recorded using a resistance measuring device.

An exemplary measurement diagram is in 4th shown on the basis of which the monitoring by means of the monitoring device 26 during processing at least along the first processing direction 22 can be understood and / or the processing is qualitative with the immersion depth 30th correlates.

In 4th is the resistance on the y-axis R plotted in megohms MΩ. The measuring time / processing time t in seconds s is plotted on the x-axis. The start of machining is penetration of the tool 14 in the first layer element 18th .

The tool is used for machining 14 at least along the first machining direction 22 on the sandwich structure 12th fed and penetrates the first layer element first 18th the sandwich structure 12th and removes material there. During the immersion of the tool 14 into the sandwich structure 12th (see. 2nd ) by means of the monitoring device 26 an electrical resistance R measured, which is different from zero and represents an initial value.

The tool penetrates during machining 14 in the machining direction 22 ever deeper into the sandwich structure 12th one while steadily an electrical resistance R , which is different from zero and fluctuates around the initial value, is measured. The electrical resistance R fluctuates in the measurement diagram in 4th in a range between approximately 0.6 MΩ and approximately 0.75 MΩ while the tool 14 into the sandwich structure 12th penetrates.

Once the tool 14 the second electrically conductive layer element 20th on a second electrically conductive layer element 20th facing free end 38 of the tool 14 is at least approximately touched by the monitoring device 26 an electrical resistance R measured from essentially zero (cf. 4th ). There is a change in the initial value, in the present case a decrease in the initial value. The at least approximate touch of the tool 14 with the second electrically conductive layer element 20th measured value of electrical resistance R is a critical value.

The at least approximately touch of the tool 14 with the second electrically conductive layer element 20th is in 3rd indicated by the solid line, which by the tool device 10th and the second electrically conductive sheet member 20th runs. There is, in particular direct, electrical contact between the tool 14 and the second electrically conductive layer element 20th . The electrical resistance R is essentially zero (cf. 4th ). For example, the electrical resistance fluctuates R in the range f0.5 Ω.

In the present case, the tool device comprises 10th a control and / or regulating device 40 to control and / or regulate the immersion depth 30th of the tool 14 into the sandwich structure 12th . The control and / or regulating device 40 is to the monitoring device 26 coupled.

By means of the control and / or regulating device 40 there is a forward movement (feed 42 ) of the tool 14 along the first machining direction 22 stopped immediately as soon as by means of the monitoring device 26 the critical value of the physical property 28 - present in 4th a resistance R of essentially zero MΩ - is detected.

The monitoring device transmits immediately after the detection of the critical value 26 in particular an electrical signal to the control and / or regulating device 40 , whereupon the control and / or regulating device 40 the feed 42 of the tool 14 stops.

It can be provided that as a further physical property 28 of the at least one physical property 28 by means of the monitoring device 26 in addition or as an alternative to electrical resistance R an electrical capacitance C between the second electrically conductive layer element 20th and the tool 14 is measured. When the capacity C is monitored and / or measured, the tool is formed 14 and the sandwich structure 12th at least during the feed 42 of the tool 14 along the first machining direction 22 especially an electrical capacitor.

Additionally or alternatively, an impedance measurement between the second electrically conductive layer element 20th and the tool 14 carried out, in which a complex function of the frequency is recorded by applying alternating current.

The control and / or regulating device 40 preferably reacts when a critical value of the electrical capacitance C is detected and / or a critical value is reached during the impedance measurement by stopping and / or braking the feed 42 .

One in 5 shown second embodiment of a tool device according to the invention 50 differs essentially from that in the 1 to 3rd shown first embodiment of a tool device according to the invention 10th that a first contact element 52 and a second contact element 54 a monitoring device 56 the tool setup 50 are separate components.

The first contact element is preferably 52 on one tool 58 the tool setup 50 facing surface 60 a second electrically conductive layer element 62 fixed. In particular, the first contact element 52 in direct material contact with the second electrically conductive layer element 62 and / or is welded to it. For example, the first contact element forms 52 a flat contact.

The second contact element 54 is part of a tool holder in the present case 64 the tool setup 50 . For example, the second contact element 54 an at least approximately ring-shaped sliding contact. Alternatively, it can be provided that the second contact element 54 formed separately and on the tool holder 64 is set.

Incidentally, the in 5 shown second embodiment of a tool device according to the invention 50 with that in the 1 to 3rd illustrated first embodiment of a tool device according to the invention 10th agree, so that reference is made to their description in this respect. The second embodiment of the tool device 50 is suitable for use in connection with the 1 to 4th described inventive method, so that reference is also made to the description thereof.

One in 6 illustrated second embodiment of a sandwich structure according to the invention 70 differs essentially from that 1 to 3rd illustrated first embodiment of a sandwich structure 12th that the sandwich structure 70 an electrically conductive layer 72 includes. The electrically conductive layer 72 is preferably between a core element 74 and a second electrically conductive layer element 76 the sandwich structure 70 arranged.

The electrically conductive layer 72 is an electrically conductive fabric 54 , which in particular comprises or is formed from a metallic material. For example, the electrically conductive layer 72 a copper mesh. Through the electrically conductive layer 72 is the second electrically conductive layer element 76 additionally against weakening and / or damage by the tool 78 protected.

Incidentally, the in 6 illustrated second embodiment of a sandwich structure according to the invention 70 with that in the 1 to 3rd illustrated first embodiment of a sandwich structure according to the invention 12th agree, so that reference is made to their description in this respect. The second embodiment of the sandwich structure 70 is suitable for use in connection with the 1 to 4th described method according to the invention, so that reference is also made to its description in this respect.

One in 7 illustrated third embodiment of a tool device according to the invention 80 differs essentially from that in the 1 to 3rd illustrated first embodiment of a tool device according to the invention 10th that a first contact element 82 a strain sensor element 84 is.

The strain sensor element is present 84 a strain gauge. The strain sensor element 84 translates stretching and compressing deformations into a change in electrical resistance R of the strain sensor element 84 . In particular, minimal deformations of the Strain sensor element 84 which due to at least approximate contact with a tool 86 the tool setup 80 with a second electrically conductive layer element 88 a sandwich structure 90 are caused by means of a monitoring device 92 the tool setup 80 detected.

The strain sensor element 84 is preferably directly or via an intermediate layer with the second electrically conductive layer element 88 connected.

Incidentally, that is correct in the 7 illustrated third embodiment of a tool device according to the invention 80 with that in the 1 to 3rd illustrated first embodiment of a tool device according to the invention 10th agree, so that reference is made to their description in this respect. The third embodiment of a tool device according to the invention 80 is suitable for use in connection with the 1 to 4th described method according to the invention, so that reference is also made to its description in this respect.

One in 8th Fourth embodiment of a tool device according to the invention 100 differs essentially from that in the 1 to 3rd illustrated first embodiment of a tool device according to the invention 10th that a monitoring device 102 the tool setup 100 a first support element 104 and a second support element 106 includes.

Along a first processing direction 105 seen comes on the first support element 104 and the second support element 106 in particular a second electrically conductive layer element 108 a sandwich structure 110 for support and / or is fixed to it. The first support element 104 and the second support element 106 are, for example, tool banks.

According to a variant of the method according to the invention, the monitoring device is used 102 carried out a vibration-based measurement. In the present case, this is a sound measurement. In particular, a change in a sound measurement value, for example a change in frequency and / or a change in source strength, is detected.

This is how the sound propagates in the second electrically conductive layer element 108 depending on an immersion depth 109 of a tool 112 the tool setup 100 into the sandwich structure 110 supervised.

The sound exposure is shown schematically in the 8th indicated. In the present case it takes place on a tool 112 applied side of the sandwich structure 110 , for example by means of a conventional sound generator.

A change in the sound measurement value preferably occurs as soon as the tool 112 the second electrically conductive layer element 108 at least approximately touched. Due to the at least approximate contact, an applied sound signal with a changed amplitude and / or frequency moves in the second electrically conductive layer element 108 away.

The tool setup 100 preferably has a control and / or regulating device 114 on, by means of which - as in connection with the 1 to 3rd described - a feed 116 of the tool 112 into the sandwich structure 110 along the first machining direction 105 is braked and / or stopped as soon as the monitoring device 102 a critical (sound measurement) value is detected. In the present case, the sound measurement value is a physical property 28 .

It can be provided that in addition to the vibration-based measurement, in particular the sound measurement, the electrical resistance R or others related to the 1 to 3rd described physical properties 28 by means of the monitoring device 102 be monitored.

Incidentally, that is correct in the 8th Fourth embodiment of a tool device according to the invention 100 and the variant of the method according to the invention described in this connection with that in connection with the 1 to 3rd described first embodiment and variant of the method, so that reference is made to the description thereof.

As in 9 is shown, it can be provided that by machining a sandwich structure 120 through a tool device (not shown) a cavity 122 arises, which is in particular essentially blind hole-shaped and on one side of a second electrically conductive layer element 124 the sandwich structure 120 closed is. Preferably a connecting element 126 , for example an insert, cohesively with the second layer element 124 connected, being in 9 a state after the introduction and material connection of the connecting element 126 with the sandwich structure 120 is shown. The sandwich structure 120 in 9 is a third embodiment of a sandwich structure according to the invention 120 .

For the integral connection of the connecting element 126 and the sandwich structure 120 was an adhesive layer in the present case 128 made of glue on one the cavity 122 limiting surface 130 of the second electrically conductive layer element 124 and / or on a surface of the connecting element 126 applied and pressed together.

Due to the essentially direct integral connection, in particular gluing, of the connecting element 126 and the second electrically conductive layer element 124 is a connection strength of the fixing compared to embodiments in which between the connecting element 126 and the second electrically conductive layer element 124 an electrically conductive layer is arranged, preferably raised.

The connecting element 126 preferably comprises a thread into which a joining element can be screwed for joining.

Reference symbol list

10th

Tool setup

12

Sandwich structure

14

Tool

16

Core element

18th

first layer element

20th

second layer element

22

first machining direction

24th

surface

26

Monitoring device

28

physical property

30th

Immersion depth

34

first contact element

36

second contact element

38

free end

40

Control and / or regulating device

42

Feed

50

Tool setup

52

first contact element

54

second contact element

56

Monitoring device

58

Tool

60

surface

62

second layer element

64

Tool holder

70

Sandwich structure

72

electrically conductive layer

74

Core element

76

second layer element

78

Tool

80

Tool setup

82

first contact element

84

Strain sensor element

86

Tool

88

second layer element

90

Sandwich structure

92

Monitoring device

100

Tool setup

102

Monitoring device

104

first support element

105

first machining direction

106

second support element

108

second layer element

109

Immersion depth

110

Sandwich structure

112

Tool

114

Control and / or regulating device

116

Feed

120

Sandwich structure

122

cavity

124

second layer element

126

Fastener

128

Adhesive layer

130

surface

Claims (18)

Method for mechanical processing of a sandwich structure (12; 70; 90; 110; 120), which has a first layer element (18), a second electrically conductive layer element (20; 62; 76; 88; 108; 124) and one between the first layer element (18) and the second electrically conductive layer element (20; 62; 76; 88; 108; 124) arranged core element (16; 74), wherein the sandwich structure (12; 70; 90; 110; 120) by means of a tool (14 ; 58; 78; 86; 112) is machined at least along a first machining direction (22; 105) from the first layer element (18), at least one physical property (28) dependent on an immersion depth (30; 109) of the tool (14; 58; 78; 86; 112) in the sandwich structure (12; 70; 90; 110; 120) along the first machining direction (22; 105) between the second electrically conductive layer element (20; 62; 76; 88; 108; 124) of the sandwich structure (12; 70; 90; 110; 120) and the tool (14; 58; 78; 86; 112) is monitored. Procedure according to Claim 1 , characterized in that the tool (14; 58; 78; 86; 112) is part of a tool device (10; 50; 80; 100), that the tool device (10; 50; 80; 100) is a monitoring device (26; 56 ; 92; 102) for monitoring the at least one physical property (28) comprises that the tool device (10; 50; 80; 100) has a control and / or regulating device (40; 114) for controlling and / or regulating the immersion depth ( 30; 109) of the tool (14; 58; 78; 86; 112) in the sandwich structure (12; 70; 90; 110; 120) comprises that the monitoring device (26; 56; 92; 102) has a first contact element (34 ; 52; 82) and in particular a second contact element (36; 54) comprises that by means of the monitoring device (26; 56; 92; 102) on the first contact element (34; 52; 82) or between the first contact element (34; 52 ; 82) and the second contact element (36; 54) of the monitoring device (26; 56; 92; 102) a value of the at least one physical property ft (28) is measured and that as soon as a critical value of the at least one physical property (28) is measured, the monitoring device (26; 56; 92; 102) a signal that a critical value has been measured is transmitted to the control and / or regulating device (40; 114) of the tool device (10; 50; 80; 100). Procedure according to Claim 2 , characterized in that a feed (42; 116) of the tool (14; 58; 78; 86; 112) along the first machining direction (22; 105) into the sandwich structure (12; 70; 90; 110; 120) by means of the Control and / or regulating device (40; 114) is braked and / or stopped as soon as the control and / or regulating device (40; 114) has received and / or processed the signal that a critical value was measured. Procedure according to Claim 2 or 3rd , characterized in that by means of the control and / or regulating device (40; 114) depending on the at least one physical property (28) the immersion depth (30; 109) of the tool (14; 58; 78; 86; 112) in the Sandwich structure (12; 70; 90; 110; 120) is dynamically regulated and / or the immersion depth (30; 109) is regulated in such a way that a material thickness of the second electrically conductive layer element (20; 62; 76; 88; 108; 124 ) remains essentially unchanged during mechanical processing. Procedure according to one of the Claims 2 to 4th , characterized in that the first contact element (34; 52; 82) is fixed to the second electrically conductive layer element (20; 62; 76; 88; 108; 124) or by the second electrically conductive layer element (20; 62; 76; 88 ; 108; 124) and / or that the second contact element (36; 54) is fixed to the tool device (10; 50; 80; 100) or is formed by the tool device (10; 50; 80; 100). Procedure according to one of the Claims 2 to 5 , characterized in that the second contact element (36; 54) on the tool (14; 58; 78; 86; 112) of the tool device (10; 50; 80; 100) fixed or by the tool (14; 58; 78; 86; 112) is formed. Procedure according to one of the Claims 2 to 6 , characterized in that the second contact element (36; 54) is fixed to a tool holder (64) of the tool device (10; 50; 80; 100) or is formed by the tool holder (64). Procedure according to one of the Claims 1 to 7 , characterized in that a physical property (28) of the at least one physical property (28) is an electrical resistance (R) which is between the tool (14; 58; 78; 86; 112) and the second electrically conductive layer element (20 ; 62; 76; 88; 108; 124) is measured. Procedure according to one of the Claims 2 to 8th , characterized in that the first contact element (36; 54) is a strain sensor element (84), for example a strain gauge, which on a surface of the second electrically conductive layer element (20) facing away from the tool (14; 58; 78; 86; 112) ; 62; 76; 88; 108; 124) is defined and by which the tool (14; 58; 78; 86; 112) is at least approximately in contact with the second electrically conductive layer element (20; 62; 76; 88; 108; 124) is detected. Procedure according to one of the Claims 2 to 9 , characterized in that the monitoring device (26; 56; 92; 102) measures an impedance between the tool (14; 58; 78; 86; 112) and the second electrically conductive layer element (20; 62; 76; 88; 108; 124) is carried out. Procedure according to one of the Claims 1 to 10th , characterized in that a physical property (28) of the at least one physical property (28) is an electrical capacitance (C) which lies between the tool (14; 58; 78; 86; 112) and the second electrically conductive layer element (20 ; 62; 76; 88; 108; 124) is measured. Procedure according to one of the Claims 1 to 11 , characterized in that, in particular by means of the monitoring device (26; 56; 92; 102), a vibration-based measurement, in particular a sound measurement, is carried out on the second electrically conductive layer element (20; 62; 76; 88; 108; 124), wherein the second electrically conductive layer element (20; 62; 76; 88; 108; 124) on a side facing away from the tool (14; 58; 78; 86; 112) on a first support element (104) and on a second support element (106 ) of the monitoring device (26; 56; 92; 102) and a change in sound intensity, in particular a change in source strength, is measured as soon as the tool (14; 58; 78; 86; 112) the second electrically conductive layer element (20; 62; 76 ; 88; 108; 124) at least approximately touched. Procedure according to one of the Claims 1 to 12th , characterized in that the second electrically conductive layer element (20; 62; 76; 88; 108; 124) of the sandwich structure (12; 70; 90; 110; 120) comprises or is formed from a metallic material, for example aluminum. Procedure according to one of the Claims 1 to 13 , characterized in that the sandwich structure (12; 70; 90; 110; 120) is an electrically conductive layer arranged between the core element (16; 74) and the second electrically conductive layer element (20; 62; 76; 88; 108; 124) (72), which includes, for example, copper or is formed therefrom. Procedure according to one of the Claims 1 to 14 , characterized in that the machining creates a substantially blind hole-shaped cavity (122) within the sandwich structure (120), the substantially blind hole-shaped cavity (122) being closed on one side by the second electrically conductive layer element (124) and wherein a Connecting element (126), in particular by means of an adhesive layer (128), firmly bonded, in particular exclusively, to the second electrically conductive layer element (124). Tool device (10; 50; 80; 100) for use in a method according to one of the Claims 1 to 15 . Sandwich structure (12; 70; 90; 110; 120) for use in a method according to one of the Claims 1 to 15 . Monitoring device (26; 56; 92; 102), in particular for use in a method according to one of the Claims 1 to 15 , wherein the monitoring device (26; 56; 92; 102) comprises a first contact element (34; 52; 82) and in particular a second contact element (36; 54), wherein via the first contact element (34; 52; 82) or between the first contact element (34; 52; 82) and second contact element (36; 54) at least one of an immersion depth (30; 109) of a tool (14; 58; 78; 86; 112) of a tool device (10; 50; 80; 100) into a sandwich structure (12; 70; 90; 110; 120) dependent physical property (28) can be monitored.

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