WO2012084680A2

WO2012084680A2 - Composite workpiece, method for producing same, and use

Info

Publication number: WO2012084680A2
Application number: PCT/EP2011/072894
Authority: WO
Inventors: Eberhard Ritzhaupt-Kleissl
Original assignee: Siemens Aktiengesellschaft
Priority date: 2010-12-21
Filing date: 2011-12-15
Publication date: 2012-06-28
Also published as: WO2012084680A3; DE102010063809A1

Abstract

The invention relates to a composite workpiece, to a method for producing same, and to a use, in particular having high electrical strength and low thermal resistance and mechanical strength. A metal foil coated with an adhesive is adhered to the joining partners.

Description

description

Composite piece, manufacturing method and application

The invention relates to a composite workpiece, a manufacturing method thereof and an application, in particular one in which high current-carrying capacity, low thermal resistance and mechanical stability to vibrations are required.

In the production of generators, motors, dynamos and other current-carrying metal components, especially in machines that produce or process high currents and high voltages, the coils required for electrical or magnetic induction ^¬ tion composed of sections.

The requirements for the connection between the metallic individual parts of the coil are very high, both in mechanical terms and in electrical terms, for example in the production of generator coils. Flow over the place very high currents at high voltages and at the same time come in the operation of the machine mechanical Be ^¬ loads in the form of vibrations to the point added.

In this case, the individual metallic coil parts are connected by means of a solder material, usually a brazing alloy.

For soldering temperatures of up to 900 ° C are used to melt the brazing alloy. After soldering, a post-processing step is usually needed to remove excess solder from the bonded metal pieces. Overall, soldering can take up to 20 minutes.

Although this method produces the required mechanically and electrically high-quality connection, it is time-consuming and energy-intensive. On the other hand, soldering is also used to solder directly to metal substrates in high power electronic chips where high currents of a few amperes flow across the chip (eg, high power LEDs) to achieve as little electrical resistance as conventional electrically conductive adhesives have too high a specific resistance and thereby heat the junction strongly by ohmic losses and finally the component would be destroyed by overheating. The soldering also brings here some disadvantages, in ^¬ example, that the chips are placed in a solder deposit, which was applied to the Sub ^¬ strate, and are not well fixed to eigentli ^¬ chen soldering process and virtually float in this solder deposit. The soldering process is further associated with a leakage of flux, which is then to remove for subsequent processes of the assembly and connection technology. Disadvantage of this is particularly the enormous expenditure of sorg ^¬ fältigem transporting the components to be soldered and cleaning after the soldering process.

The object of the present invention is therefore to provide a mechanically and / or electrically loadable connection between metal pieces, the production of which requires no soldering process.

General knowledge of the invention is that instead of soldering, the connection can be made by gluing, when a surface-structured and / or perforated metal foil, in which an adhesive, for example, on both sides, incorporated, is used as a connector and bonded to the workpieces to be joined. The metal foil produces electrical and thermal conductivities which were hitherto unthinkable for adhesive bonds, and the finely distributed quantities of adhesive in the structures of the metal foil create a mechanically stable, load-bearing composite of the metal pieces. Depending on the adhesive system no misalignment of the parts to be joined, for example, after placing of the chip and a subsequent sequent ^¬ light activation more occur. This process is then completed within a few seconds; the complete curing between the joining partners happens then in the further course completely by itself. The subject matter of the present invention is therefore a composite workpiece comprising joined components in the form of workpieces to be joined, wherein the joining partners are connected via a structured and / or perforated metal foil which is coated on at least one side with an adhesive mass. Outside the object of the invention is a process for bonding parts to be joined, wherein a structured metal foil with adhesive is coated in a first process step, is brought into a second process step the coated Metallfo ^¬ lie between the joining partners, and is fixed there until by the adhesive a self-supporting stability of Kle ^¬ order is reached and cured in a third step of the adhesive. Finally, the use of a composite piece produced by the method in generator production is the subject of the invention.

A combination of workpieces, for example, where at least one workpiece thereof is metallic, with very little electrical and / or thermal resistance, which can be produced with the speed of a gluing operation, is achieved by the combination of a surface-structured, e.g. embossed metal foil, achieved with an example light-curing / light-activated adhesive system. Here, a structured metal foil is preferably provided on both sides and / or preferably punctually with a suitable adhesive and placed between the materials to be joined.

One of the two workpieces to be joined in applied pressure causes the metal foil, that the structuring ^¬ tion so deformed that is exploiting Dende in the wells or structures adhesive flows and the metal piece ^¬ surfaces wetted. A small amount of adhesive emerges at the edges, which is applied by means of a suitable light source in the outer regions, the adhesive seam around the composite workpiece. is hardened. The curing reaction then further self ^¬ constantly runs through the entire adhesive layer between the me ^¬-metallic join partners through, although there can be no light-curing. For example, a UV-activated catalyst species is sufficient for this process. Ge ^¬ is any adhesive which ak ^¬ tivieren can be by means of light source and the curing subsequently continues to progress independently; eg cationic curing UV epoxies. Furthermore, in the case of light-activatable adhesives, the adhesive on the metal foil can be briefly irradiated with a suitable light source even before the joining of the metallic joining partners.

According to a further embodiment, the film can also be perforated. In this case, the adhesive may be applied to one or both sides of the workpieces to be joined. Subsequently, the perforated film is placed on one of the two mating surfaces to be joined of the joining partners and the two workpieces are joined together. By applying pressure from the outside, the adhesive is pressed into the perforation of the film and thus bonds the two joining partners, while the metal foil ensures a very good passage of heat and electricity. According to an advantageous embodiment, the ends of the two contact surfaces of the joining partners are designed according to the key-lock principle, so that from the parts ends, for example the coil ends of generator coils or substrate / conductor track and electronic component, matching partners are matched to one another a joining partner the

Castle form and a joint partner represents the key shape, which result in one another, the composite workpiece in the form of a zu ^¬ sammengefügten multipart workpiece. This embodiment is also called click connection.

According to an advantageous embodiment of the invention, the electrical or thermal resistance of the joint is adjustable via the choice of the material of the metal foil. If For example, the joining partners are both made of copper, then preferably a metal foil made of copper or a metal having a comparable electrical and / or thermal conductivity is used, so that the resistance of the joining parts to the resistance of the bulk materials is minimized.

In this case, the structured and / or perforated and coated with adhesive composition metal foil between the joining ^¬ partner is introduced and because of the engagement of one joining partner in the corresponding opening of the other joining part ^¬ ner, a fixation of the metal parts to be bonded at the beginning of bonding superfluous.

This type of joining in the key-lock principle is also called a Klickverbindeverfahren. The figures show examples of the design of the joining partners.

The structuring of the metal foil can be designed as desired, both on the dimensions of the structuring and on the shape of the structure. For example, the metal foil may also be simply embossed, for example indentations may be produced in the surface of the metal in an imprint process, into which the adhesive is then doctored. The structuring and / or perforation may be in the range of several millimeters down to the submicron range. The metal foils used have a thickness between 0.5μπι - 1000 μπι, preferably between Ιμπι and 200μπι and more preferably between 2μπι and ΙΟΟμπι. According to the invention, the metal foil may be constructed in a single-layered or laminated manner from a plurality of layers.

The coating of the metal film with adhesive may be großflä ^¬ chig in areas over the entire surface, the entire surface with islands, in regions in strip form, in a pattern selectively designed etc.. The adhesive system can be filled or unfilled and also a two-component system. In this case, for example, a component may be applied to the joining partner or smooth metal part to be joined and a component to the metal foil. In addition, the adhesive system can be a pre-reacted so-called B-stage resin fully cross-linked with a short annealing and / or eg cures ^¬, a pre-reacted epoxy resin system. In the following the invention will be explained in more detail with reference to figures:

FIG. 1 shows an example of a click connection,

Figure 2 shows a further example of a Klickverbin ^¬ dung,

FIGS. 3 to 5 show embodiments of adhesive-coated and structured metal foils. FIG. 6 shows a schematic of the metal foil production and

Bonding in general and

Figure 7 shows an embodiment with a perforating ^¬ th metal foil.

FIG. 1 shows two metal ends to be connected, for example of generator coil pieces. The two shown metal ends 1 and 2 are examples of the joining partners 1 and 2, between which the adhesive-coated metal foil ^¬ when bonding (for clarity not shown here) is placed a ^¬. During bonding, the structured and / or perforated and coated metal foil is then pressed in such a way that the structuring is squeezed and / or even partially pressed flat and exposes the adhesive, which then seals the two joining partners 1 and 2 with the metal foil adhesive bonding, but always a direct connection of metal to metal is achieved, so that the electrical and / or thermal conductivity and Strombe ^¬ loadability of eg metals on the connection point ^¬ way is maintained. During bonding, for example, the structured and / or perforated metal foil is provided on both sides with the adhesive at points and placed between the ends of the workpieces to be joined, ie the joining partners 1 and 2. The illustrated workpiece ends 1 and 2 may be, for example, generator coil ends. After pressing the two ends wetted to the adhesive and / or precoat ^¬ te film and a temporary fixing of the splice is so far pressed together, the weld line, that the structuring of the film is deformed and located in the recesses or between the structures adhesive wets the work piece surface of the joining partners ^¬ 1 and 2. FIG. This results in a bonding of the joining partners 1 and 2 with the metal foil.

Evident is the joint partner end 1, which is arranged on the left and forms the shape of the castle of the key-lock pair. In this lock the Fügepartne ^¬ Rende 2 is introduced einge- in the direction indicated by the arrow, so as to form a continuous workpiece of the at ^¬ the sections 1 and 2 connected by the metal foil (not shown).

The resulting in the Figure 1 link is to a very good electrically and thermally conductive since directly comes to lie on metal metal and comprises on the other a very high bond strength between the three parts to be joined, as a suitable polymer system, such as Anaerobic metal ^¬ adhesives , Epoxy resin systems etc., enable very good metal bonds.

FIG. 2 shows another embodiment as shown in FIG. 1, wherein once again a joining partner can be brought together with the other according to the key-lock principle. Although in the figures, two examples of click connections, where the two joining partners are designed according to the key-lock principle shown, but the application of smooth metal ends and joining partners is just as possible, it is only one step required for fixing and / or adjustment of the joining partners.

The curing of the adhesive takes place either by exposure, at room temperature or by brief heating, but the temperatures rise to a maximum of 400 ° C. so that the adhesive is not decomposed.

FIGS. 3 to 5 show structured metal foils in which adhesive is introduced. Evident are the metal foils 3, which are for example metal foils of copper, aluminum, gold, silver, other good conductive metals and metal alloys. The metal foils have on the surface structures 4, in which adhesive 5 is incorporated. The thickness of the metal foil 6 can vary, preferably it is Zvi ^¬ rule 0,5μπι - 1000 μπι, more preferably between Ιμπι and 200μπι and more preferably between 2μπι and ΙΟΟμπι.

In the example shown here, the thickness of the adhesive coating 7 is below the height of the structures 4, so that the adhesive 5, which is embedded in the structures 4, is released when the structure 4 of the metal foil 3 is pinched.

FIGS. 4 and 5 show further exemplary embodiments, wherein FIG. 4 shows a round structuring and FIG. 5 shows a staggered structuring.

Figure 6 shows the scheme of metal foil production and bonding in general, initially starting from a simple metal foil 3. This is converted by a structuring step 8 into a metal foil 3 with structures 4.

After application of the adhesive 5 from it creates the guren in Fi 3 to 5 already shown, added with adhesive 5 in the structural ^¬ structures 4, metal foil 3. This is, as shown in Figure 5, bottom line on the far left, between the joining partners 1 and 2 placed. As a result of the pressure exerted on the metal foil 3 during the fixing of the joining partners, the structure 4 of the metal foil 3 is deformed so that the adhesive 5 emerges from the structures 4 of the metal foil and wets the contact surfaces of the joining partners 1 and 2.

By the arrow 9 is given by way of example, from where the pressure on the joint and thus on the provided with adhesive 5 in the structures 4 metal foil 3 is applied. By the arrow 10 so that the adhesive 5 containing in at ^¬ play radiation activatable catalyst is released is given, such as radiation can impinge on the adhesive.

After curing of the adhesive, which can also be done by increasing the temperature or continue by radiation or simply by time, the two joining partners 1 and 2 are permanently connected.

Although in the figures described so far preferred metal foils are shown with textures, but the invention can be just as well realized with embossed depressions and with perforations.

Figure 7 shows an embodiment with a perforated metal foil: can be seen above the joining partner 1 and below the joining partner 2, in the upper part of the figure still spatially separated. The contact surfaces of the joining partners are coated with adhesive 5. In the example shown both Berüh ^¬ approximately surfaces of the parts to be joined with adhesive 5 are coated, but may also be only one joining partner with adhesive 5 to be coated. Between the coated with adhesive 5 joining partners 1 and 2, the perforated metal foil 11 is placed. Then, the joining partners are joined and fixed with or without pressure, wherein after first curing of the adhesive 5, the fixation the joint takes place. As already described, a first fixation of the metallic joining partners to be joined can already have taken place after seconds, so that no further working step may possibly be required, in particular if the curing has already been started with a light-curing adhesive.

The invention relates to a composite workpiece, a manufacturing method thereof and an application, in particular one with high current carrying capacity, low thermal resistance and high mechanical stability. In this case, an adhesive-coated metal foil is bonded to the joint partners and / o ^¬ of an uncoated film is ge ^¬ sandwiched between mating parts, which are switched on on both sides with adhesive or the like. The bonding can be done in various ways, in a two-component adhesive, for example, an adhesive component may be applied to the surface of a joining partner or both joining partners and the second component on the metal foil, which comes to lie between the joining partners, be applied. By joining or joining the join partners (depending on the embodiment), the two components are then mixed and give the adhesive mass, which then hardens. Only the film (one or both sides), one each adherend surface or both Fügeteilo- (e of the film according to disclosed embodiment) may at Einkomponen tenklebstoffen ^¬ berflächen either be coated with adhesive.

In addition to a very good electrical conductivity of the metal foil in the adhesive bond also ensures a very low thermal resistance, which means a very good thermal conductivity between the two connection partners. This is of particular interest in all aspects of high power electronics cooling, such as High Brightness LED, or power modules in the industrial sector. Here highly filled adhesives are currently used, which are often unfriendly production in ih ^¬ rer storage, application and handling. A system like the one provided by constricting invention, first introduced makes it carry away heat through an appropriate, quick and easy bonding ef ^¬ fizient.

Claims

claims

1. composite workpiece, wherein the joining partners over a structured, embossed and / or perforated metal foil, which is coated at least on one side with an adhesive mass, are ver ^¬ bound.

2. Composite workpiece according to claim 1, wherein the joining partners are designed on the surfaces to be joined and / or edges so that a first joining partner engages in a corresponding Publ ^¬ tion of a second joining partner.

3. The composite piece according to claim 2, wherein the coated with adhesive composition metal foil between the joining partners is arranged so that their structure when snapping the first joining partner in the opening of the second joining partner so ge ^¬ squeezes that the adhesive contained therein is freige ^¬ sets.

4. A process for bonding parts to be joined, with a structured and / or perfo ^¬ tured metal foil is at least on one side be ^¬ a layer of adhesive in a first process step, is brought into a second process step the be ^¬ coated metal foil between the parts to be joined and fixed there until a self-supporting stability of the splice is achieved by the adhesive and cured in a third step of the adhesive.

5. The method of claim 4, wherein the fixation of the adhesive point is performed by a holder.

6. The method of claim 4, wherein the fixing of the splice occurs by the engagement of a first joining partner in an opening of a second joining partner.

7. Use of a composite piece produced by the method in the manufacture of generators, high brightness LEDs and / or power modules in the industrial sector.