DE102016007698A1 - Method for producing a component composite - Google Patents

Abstract

The invention relates to a method for producing a component composite in which at least one plastic component (1) is connected by means of a joining auxiliary element (3) to a joining partner (5), in particular of metal, which joining auxiliary element (3) in a joining direction by the plastic component on the side (1) is guided and welded to the joining partner downstream in the joining direction (5). According to the invention, the method comprises a flow-hole forming step, in which the joining auxiliary element (3) is driven with a contact pressure (pF) and with an ultrasound frequency application (fF) through the plastic component (1) into contact with the joining partner (5), and in terms of process technology downstream ultrasonic welding step, in which the by the plastic component (1) driven joining auxiliary element (3) with the joining partner (5) is ultrasonically welded.

Description

The invention relates to a method for producing a composite component according to the preamble of claim 1 and such a composite component according to the preamble of claim 8.

The joining of fiber composite plastic components or plastic components with metals presents production engineering with major joining technology challenges. In order to produce such hybrid connections between plastic and metal, adhesives and mechanical joining processes are currently available. The disadvantages of bonding are not only a long process time in the limited temperature resistance of the compound and in the maximum achievable strength, which depends on the type of stress and the available adhesive surface. Conventional mechanical joining methods, such as riveting, clinching or screwing, damage the reinforcing fibers embedded in the plastic by means of joining auxiliary elements and bores, which leads to a disturbed power flow and increased corrosion potential.

From the DE 101 24 920 A1 a generic method is known in which a plastic component by means of a joining auxiliary element with a joining partner made of metal is connectable. The joining auxiliary element is guided in a joining direction by the set-side (that is, the first in the joining direction) plastic component into contact with the joining partner downstream in the joining direction. Subsequently, the joining auxiliary element is welded to the joining partner.

In the DE 10 2010 044 886 A1 Before the joining process in the plastic component at the joint to be produced a pre-hole is incorporated. The pre-hole is dimensioned such that it can be enforced by the joining auxiliary element with a hole play. The provision of such a Vorloches in fiber composite plastic component is associated with process engineering effort. In addition, the Vorlochoperation especially in a fiber-reinforced plastic component lead to component damage. In the subsequent welding step there is generally the risk that due to excessive heat development, the thermally less resilient plastic component is damaged, which can lead to a faulty joining result.

The object of the invention is to provide a composite component and a method for producing such a composite component, in which the plastic component process reliable without affecting the joining result with a joining partner is connectable.

The object is solved by the features of claim 1 or claim 8. Preferred embodiments of the invention are disclosed in the subclaims.

According to the characterizing part of claim 1 or claim 8, the manufacturing process is divided into a flow-forming step and a process-technically subsequent ultrasonic welding step. In the flow-hole forming step, the joining auxiliary element is driven with a contact pressure and with an ultrasound frequency impingement through the plastic component into contact with the joining partner. Subsequently, the ultrasonic welding step takes place in which the joining auxiliary element driven by the plastic component is ultrasonically welded to the joining partner. In this way, it is possible to dispense with a complex pre-hole operation before carrying out the welding process. In addition, ultrasonic welding results in reduced heat generation compared to conventional welding processes, which reduces the risk of thermal damage to the plastic component. In the case of a fiber composite plastic component, moreover, fiber damage due to a pre-hole operation can be prevented.

In an ultrasonic welding system required for carrying out the method, the sonotrode serves as a welding tool. Due to the working surface of the sonotrode which is in contact with the joining auxiliary element during the joining process, mechanical ultrasonic oscillations and the preferably pneumatically controlled contact force are transmitted to the joining partners. The sonotrodes work surface is usually designed with Kreuzrasterung or wave profiles to move the joining auxiliary element without slippage under high-frequency ultrasonic oscillation. The joining partners are located between the anvil and the sonotrode during ultrasonic welding. On the one hand, the anvil should absorb the contact force and the vibrating force of the sonotrode and, on the other hand, should not absorb any vibration energy.

In contrast to conventional welding processes, the entire ultrasonic welding process takes place in the fixed aggregate state. Accordingly, the ultrasonic welding process is also considered as a diffusion welding process. The complete welding process causes by the introduced mechanical vibration energy intensive external and internal friction processes, which contribute to the compound formation. Under this high vibrational energy occur atomic movements, which lead to atomic and / or grain interleaves. The relative movement produces frictional heat at the welding contact point. This frictional heat promotes the atomic movement, but does not melt the metal on. The internal friction is located in the ultrasonically excited workpiece to be joined. The external friction occurs between the sonotrode and the joining auxiliary. During the welding process, the mechanical vibration energy is absorbed by internal friction and converted into heat. This dampens the mechanical vibration. The mechanical vibrations of the sonotrode preferably act transversely to the feed direction of the sonotrode.

In a technical implementation, the joining auxiliary element can be subjected to a first contact pressure and a first ultrasonic frequency in the flow-hole forming step. In the subsequent ultrasonic white step, the joining auxiliary element can be subjected to a second contact pressure and a second ultrasonic frequency. Due to the different material properties between the plastic component and the joining partner (in particular made of metal) can be reduced in the flow-forming step, the contact pressure and the ultrasonic frequency, which act on the joining auxiliary, compared to the subsequent welding step.

As already mentioned above, it is preferred if the plastic component can be prepared pre-hole-free at the joint to be produced before the flow-hole-forming step. In the following flow-hole forming step, the joining auxiliary element is then driven into the plastic component by means of the pressure-loaded and vibration-excited sonotrode, specifically with local plasticization of the plastic material and formation of a flow hole or passage in the plastic component.

The joining auxiliary element may have an element shaft whose outer contour is cylindrical or tapers conically in cross section up to the shaft tip. This ensures that in the flow-hole forming step, the reinforcing fibers in the plastic material can be largely displaced without damage. In addition, the element shaft can be rotationally symmetrical about its longitudinal axis and have a round profile in cross-section. Alternatively, the element shaft may also have any polygonal profile and / or be rotationally symmetrical.

To prepare the manufacturing process, the two joining partners to be joined are first placed on the anvil. In the subsequent Fließlochform- and welding steps, the sonotrode is guided under ultrasonic excitation and with a contact pressure in a feed movement via a Fließlochformhub and a subsequent welding stroke against the anvil. In the case of the ultrasound step, the joining auxiliary element merges with the joining partner, whereby the joining auxiliary element length is shortened, specifically until the element head is in contact with the entire surface and / or in positive and frictional connection with the plastic component.

In order to increase the connection strength between the joining auxiliary element and the plastic component, a form-fitting contour, in particular a serrated contour, may additionally be attached to the underside of the element head facing the plastic component. This engages after completion of the welding process positive and positive in the material of the plastic component.

With the method according to the invention, the two flow-hole forming and ultra-white partial steps can be carried out in a common process step. In addition, pre-hole operations are eliminated. Due to the reduced heat development in ultrasonic welding and the risk of delamination and combustion of the plastic can be reduced. In addition, a component delay is prevented. The penetration / penetration of the joining auxiliary element in the plastic component is thus more gentle compared to common practice. In addition, results in the flow hole a cohesive connection between the joining auxiliary and the plastic component.

The joining method according to the invention is preferably used for joining plastics with metals. A complete connection between the joining partners is only present if a fabric connection is produced between the joining auxiliary element and the metallic joining part.

The joining auxiliary element preferably consists of a cold-upsetting and cold-extruded steel and is also suitable for welding. In addition, the auxiliary joining element can have a defined coating, preferably a zinc coating, which protects against corrosion. Further conceivable coatings are, for example, ZnNi or an Almac coating. Optionally, uncoated joining auxiliary elements are conceivable.

The element tip is preferably designed such that little ultrasound force is required to enable a secure penetration process and a secure ultrasonic welding. In addition, the ultrasonic welding can be performed with the bonding as a hybrid method.

The advantageous embodiments and / or further developments of the invention explained above and / or reproduced in the dependent claims can be used individually or else in any desired combination with one another, for example in the case of clear dependencies or incompatible alternatives.

The invention and its advantageous embodiments and further developments and advantages thereof are explained in more detail below with reference to drawings.

Show it:

1 a finished component composite;

2 the joining auxiliary element in a unique position; and

3 to 5 each views illustrating the method for producing the composite component.

In the 1 a composite component is shown in which a fiber composite plastic component (hereinafter FVK component) 1 with the help of a joining auxiliary element 3 with at a joint F with a metal sheet 5 connected is. Optionally, between the FRP component 1 and the metal sheet 5 In addition, an electrically insulating adhesive layer (not shown) may be provided. The FRP component 1 has a semi-finished fiber 7 made of reinforcing fibers in a plastic matrix 9 are embedded.

In the 1 has the Joining auxiliary element 3 an elementary body 11 and one opposite the elementary shaft 11 radially expanded element head 13 on. The element head 13 is on its underside with a serrated contour 15 trained in the 1 is positively and positively integrated in the FRP component. The elementary system 11 passes through the FRP component 1 forming a flow hole or a passage 17 backlash-free and medium-tight and with its shaft tip with the metal sheet 5 ultrasonically welded.

In the 2 is the Joining auxiliary element 3 shown in its undeformed state. As a result, the elementary is 11 about a longitudinal axis L ( 1 ) rotationally symmetrical and smooth surface formed. The elementary system 11 is also tapered in the direction of its tip frustoconical. By way of example, the joining auxiliary element 3 , viewed in the longitudinal direction L, have a height of 5 mm, wherein the material thickness m ( 1 ) of the FRP component 1 may be in a range of 1 to 3 mm.

The following is based on the 3 to 5 the process for the preparation of in the 1 Thus, according to the 2 first the FRP component 1 and the metal sheet 5 preparing for an anvil 19 filed an ultrasound system. The fixedly positioned anvil 19 acts with an in-flight opposite, stroke-adjustable sonotrode 21 together.

This is followed by a flow-hole forming step in which the sonotrode 21 under ultrasonic excitation frequency f _F, as well as with a contact pressure p _F in an advance movement over a Fließlochformhub .DELTA.h _F against the anvil 19 is moved. In the flow-hole forming step, the matrix material becomes 9 due to the sonotrode 21 on the joining auxiliary element 3 transmitted ultrasonic frequency f _F and the contact pressure p _F locally plasticized. This allows the elementary 11 the reinforcing fibers in the semifinished fiber product 7 displace largely damage-free. The elementary system 11 becomes the flow hole 17 until in contact with the metal sheet 5 through the FRP component 1 driven, as it is in the 3 is indicated.

The ultrasonic whitening step is followed without delay by the flow-hole forming step, and the sonotrode is used to carry it out 21 is driven with a contact pressure p _S and an ultrasonic frequency f _S , which are sized larger than in the flow-hole forming step. In the ultrasonic welding step, the sonotrode becomes 21 in a further feed movement to a welding stroke .DELTA.h _S against the anvil 19 moved until the in the 5 shown system connection between the element head 13 and the FRP component 1 results. At the contact point to the metal sheet 5 merges the shaft tip of the element shaft 11 forming a cohesive connection, preferably a nugget 23 , ( 5 ) with the metal sheet 5 ,

For a safe coupling of the element head 13 at the sonotrode 21 and the metal sheet 5 on the anvil 19 To achieve are both the anvil 19 as well as the sonotrode 21 with corresponding surface contours 22 educated.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 10124920 A1 [0003]
• DE 102010044886 A1 [0004]

Claims (8)

Method for producing a component composite, in which at least one plastic component ( 1 ) by means of a joining auxiliary element ( 3 ) with a joining partner ( 5 ), in particular of metal, which adjuvant ( 3 ) in a joining direction by the plastic side component ( 1 ) and with the joining partner downstream in the joining direction ( 5 ) is welded, characterized in that the method comprises a flow-hole forming step in which the joining auxiliary element ( 3 ) with a contact pressure (p _F ) as well as with an ultrasonic frequency impingement (f _F ) through the plastic component ( 1 ) in contact with the joining partner ( 5 ), and has a process engineering downstream ultrasonic welding step, in which the through the plastic component ( 1 ) driven joining auxiliary element ( 3 ) with the joining partner ( 5 ) is ultrasonically welded. Method according to Claim 1, characterized in that the joining auxiliary element ( 3 ) in the flow-hole forming step with a first contact pressure (p _F ) and a first ultrasonic frequency (f _F ) is acted upon and in the welding step with a second contact pressure (p _S ) and a second ultrasonic frequency (f _S ) is applied, and in particular the contact pressure (p _S ) and the ultrasonic frequency (f _S ) in the welding step are greater than the contact pressure (p _F ) and the ultrasonic frequency (f _F ) in the flow-hole forming step. A method according to claim 1 or 2, characterized in that prior to the execution of the flow-hole forming step, the plastic component ( 1 ) is provided pre-hole-free at the joint (F) to be produced, and / or that the joining auxiliary element ( 3 ) in the flow-hole forming step with local plasticization of the plastic material ( 9 ) of the plastic component ( 1 ) and forming a flow hole or passage ( 17 ) through the plastic component ( 1 ) is driven. A method according to claim 1, 2 or 3, characterized in that the flow-hole forming step and the welding step take place in a common ultrasound system and / or combined into a common process step, and that in the ultrasonic whitening system before the flow-hole forming step, the joining partners to be joined ( 1 . 5 ) on an anvil ( 19 ) and then a sonotrode ( 21 ) for carrying out the Fließlochform- and welding steps under ultrasonic excitation (f _F , f _S ) and with a contact pressure (p _F , p _S ) in a feed movement via a Fließlochformhub (.DELTA.h _F ) and a subsequent welding stroke (.DELTA.h _S ) against the anvil ( 19 ) to be led. Method according to one of the preceding claims, characterized in that the joining auxiliary element ( 3 ) an elementary ( 11 ), whose outer contour is cylindrical or tapers conically in cross-section to the stem tip. Method according to claim 5, characterized in that the element shaft ( 11 ) is rotationally symmetrical about a longitudinal axis (L), and / or that the element shaft ( 11 ) has a round profile or a polygonal profile in cross-section. Method according to one of claims 5 or 6, characterized in that the joining auxiliary element ( 3 ) one against the elementary ( 11 ) radially expanded element head ( 13 ), and that the element head ( 13 ) in abutment with the plastic component ( 1 ), and in particular that the element head ( 13 ) at its the plastic component ( 1 ) facing bottom a form-fitting contour ( 15 ), in particular a serrated contour. Component composite with a plastic component ( 1 ), which by means of a joining auxiliary element ( 3 ) with a joining partner ( 5 ), in particular of metal, which adjuvant ( 3 ) in a joining direction through the plastic component ( 1 ) and with the joining partner downstream in the joining direction ( 5 ) is welded, characterized in that the joining auxiliary element ( 3 ) to form a flow hole ( 17 ) play-free and medium-tight by the plastic component ( 1 ) and with the joining partner ( 5 ) is ultrasonically welded.

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