DE102018111643A1 - Electric resistance heating element and method for material-bonded joining of fiber-plastic composite components - Google Patents

Abstract

An electrical resistance heating element (200) for plasticizing fiber-plastic composite components at a common mating contact surface to integrally bond the fiber-plastic composite components, the resistance heating element (200) forming electrically conductive heating sections (202) and between heating resistors electrically insulating insulating portions (204) acting on the heating sections (202), and method for materially joining fiber-plastic composite components to a common joint contact surface, wherein such a resistance heating element (200) between fiber-plastic composite components to be joined together is arranged and the heating sections (202) are electrically applied to plasticize plastic material of the fiber-plastic composite components and / or the insulating sections.

Description

The invention relates to an electrical resistance heating element for plasticizing fiber-plastic composite components at a common joint contact surface, in order to connect the fiber-plastic composite components together materially. In addition, the invention relates to a method for cohesive bonding of fiber-plastic composite components to a common joint contact surface.

From the document DE 10 2011 114 306 A1 a method is known for joining at least two FVK components lying on top of one another in a joining region by means of a metal joining element, wherein for fixing the superposed FRP components in the joining region a setting bolt as a joining element first by the FRP components and then by a metal sheet fitting in the joint area is driven, and then by means of resistance or friction welding a cohesive connection between the setting bolt and metal sheet is produced.

From the document DE 10 2012 216 255 A1 a device is known for materially joining two plastic components with a pressing device with which the plastic components to be joined are pressed against each other, and a heater with which the surface of at least one plastic component is at least partially heated to a predetermined temperature, wherein the two plastic components and the device to each other are relatively movable and are movable in a direction of movement relative to the device, wherein the plastic components are heated at the joint first and then pressed against each other.

From the on 12.03.2018 registered German patent application with the file number 10 2018 105 690.7 For example, an electrical resistance heating layer is known for plasticizing fiber-plastic composite components at common joining contact surfaces in order to materially connect the fiber-plastic composite components, wherein the resistance heating layer has a heating power distribution individually adapted to the joint contact surfaces. In addition, from the registered on 12.03.2018 German patent application with the file number 10 2018 105 690.7 a method is known for producing such an electrical resistance heating layer, wherein initially, taking into account geometric data of the joint contact surfaces and / or material data of the fiber-plastic composite components, an individually required heating power distribution is determined. In addition, from the registered on 12.03.2018 German patent application with the file number 10 2018 105 690.7 a method is known for joining thermoplastic fiber-plastic composite components, wherein the fiber-plastic composite components are plasticized by means of an electrical Widerstandsheizschicht for mutual cohesive connection to joint contact surfaces, wherein for plasticizing the fiber-plastic composite components at the joint contact surfaces such an electrical resistance heating layer is used.

The invention has for its object, structurally and / or functionally to improve a resistance heating element mentioned above. In addition, the invention has for its object to improve a method mentioned above.

The object is achieved with a resistance heating element with the features of claim 1. In addition, the object is achieved by a method having the features of claim 8. Advantageous embodiments and further developments are the subject of the dependent claims.

The fiber-plastic composite components may be vehicle components. The vehicle may be a land vehicle, motor vehicle, aircraft, watercraft or spacecraft. The fiber-plastic composite components may be fuselage parts of an aircraft. The fiber-plastic composite components may be wing portions of an aircraft.

The fiber-plastic composite components may include organic fibers such as aramid fibers, carbon fibers, polyester fibers, nylon fibers, polyethylene fibers, plexiglass fibers, and / or inorganic fibers such as basalt fibers, boron fibers, glass fibers, ceramic fibers, silica fibers, respectively. The fibers may be in the form of woven, knitted, knitted, braided or stitchbonded threads. The fibers can be present as textile. The fibers may be single-layered or multi-layered. The fiber-plastic composite components may comprise a thermoplastic matrix material. The matrix material may include polyetheretherketone (PEEK), polyphenylene sulfide (PPS), polysulfone (PSU), polyetherimide (PEI) and / or polytetrafluoroethene (PTFE). The fibers may be embedded in the matrix material.

The fiber-plastic composite components may each have at least one joint contact surface. The at least one joint contact surface may be flat. The at least one joint contact surface may be curved once or several times. The common joint contact surface may have a joint contact surface length and a joint surface width.

The resistance heating element can be connected to one another for arrangement between common joining contact surfaces connected fiber-plastic composite components serve. The resistance heating element can serve for plasticizing matrix material of the fiber-plastic composite components.

The heating sections may each comprise, individually or in groups, at least one electrical contact section. The at least one contact section may be arranged outside the joint contact surfaces. The heating sections can be separately acted upon electrically separately. The heating sections may be acted upon in groups separately electrically. A group of heating sections may comprise a plurality of successively arranged heating sections. A group of heating sections may comprise a plurality of non-consecutively arranged heating sections.

The heating sections may each have a thread or web-like shape. The heating sections may each extend along a path. The trajectory can be straight. The course can be curvy. The heating sections can be unidirectionally oriented. The heating sections may be arranged parallel to each other at least in sections. The heating sections may be spaced from each other. The heating sections may have mutually at least approximately equal distances. Density and / or orientation of the heating sections may be customized. The heating sections may have different distances from each other. The heating sections may extend in joining contact surface longitudinal direction. The heating sections may extend in the mating contact surface width direction.

The resistance heating element may be permeable at least in sections for plasticized plastic material of the fiber-plastic composite components. The insulating sections may be plasticizable. The heating sections may serve to plasticize the insulating sections. The heating sections may be made of a metal. The insulating sections may be made of a plastic. The insulating sections may be made of a thermoplastic material. The insulating sections may be made of a plastic compatible with a matrix material of the fiber-plastic composite components. In this context, "compatible" means, in particular, that the plastics can be connected to one another in a materially bonded manner. The insulating sections may be made of polyetheretherketone (PEEK), polyphenylene sulfide (PPS), polysulfone (PSU), polyetherimide (PEI) and / or polytetrafluoroethene (PTFE).

The resistance heating element can be designed as a hybrid fabric with thread-like heating sections and thread-like insulating sections. The hybrid fabric may have a first thread system with threads that are at least approximately parallel to one another and a second thread system with threads that are at least approximately parallel to each other. The first thread system and the second thread system may be crossed with each other. The first thread system may have heating sections. The first thread system may have heating sections and insulating sections. The first thread system may alternately have one or more heating sections and insulating sections. The second thread system can only have insulating sections.

The insulating sections may be formed by means of a carrier foil. The heating sections may be applied to the carrier film in a generative manufacturing process. The heating sections may be applied to the carrier foil by selective laser melting. The heating sections may be printed on the carrier film.

For cohesive joining of fiber-plastic composite components, first the fiber-plastic composite components can be arranged with the joint contact surfaces together. Between the joint contact surfaces, the resistance heating element can be arranged. Subsequently, an electrical power can be applied to the resistance heating element in order to heat the resistance heating element in such a way that the fiber-plastic composite components are plasticized on the joining contact surfaces and / or the insulating sections. The resistance heating element can be heated until the matrix material heats up above a crystallite melting temperature and / or until the matrix material and / or the insulating sections have at least a sufficiently reduced viscosity. In this case, the matrix material and / or the insulating sections can be liquefied. The liquefied matrix material of the fiber-plastic composite components to be joined can diffuse through the heated resistance heating layer, so that the matrix materials of the fiber-plastic composite components and / or Isolierabschnittmaterial at least partially mix. In order to assist in joining the fiber-plastic composite components together, the fiber-plastic composite components can be moved relative to each other and / or the joint contact surfaces can be pressed against each other. Subsequently, an application of electrical power to the resistance heating element may be terminated so that the resistance heating layer cools and the matrix material and / or the insulating section material re-solidifies.

The heating sections can be acted upon individually and / or in groups with different electrical power. The heating sections can individually and / or in groups with different electrical power are applied to cause a different heat input. The heating sections can be acted upon individually and / or in groups with different electrical power in order to achieve a homogeneously distributed heat input within the joining surface during the joining process, to compensate for increasing heat dissipation towards edge sections of the joining surface, to avoid temperature gradients across the joining zone and / or Avoid excessive and / or reduced temperature.

The heating sections can be charged with electrical power at the same time. The heating sections can be acted upon individually and / or in groups successively with electrical power. Several heating sections can be applied simultaneously with electrical power.

In summary, and in other words, the invention thus provides inter alia a use of unidirectionally conductive welding elements in electrical resistance welding for the joining of thermoplastic fiber composite components.

In static and continuous resistance welding, advantages can be achieved through the use of welding elements consisting of conductive and insulating components. Functionalized welding elements can be used in static and continuous electrical resistance welding processes. The welding elements can be functionalized by unidirectionally conductive components. The welding elements may comprise hybrid fabrics or conductors fixed to carrier film or even SLM printed carrier films. A conductivity can exist in one direction only. One degree of freedom in design is high, conductor density and orientation can be varied.

In the static welding process, an energy input can be targeted and thus a homogeneous temperature distribution can be achieved. Cooling in peripheral areas can be counteracted by higher power to be applied there. The targeted introduction of energy can produce high strengths over the entire surface and thus improved component performance. Welding time can be shortened. Contacting can be done in several phases in order to deliver different power levels to the functionalized welding element.

An area of elevated temperature along the weld seam can be increased. As a result, on the one hand, a process time can be significantly shortened, because an energy input at a plurality of successive electrical conductors can enable a significant increase in a feed rate of a welding tool. Depending on the number of contact points, speed increases can be achieved by a factor of 10. This can increase the profitability of a continuous electric resistance welding process for a wide range of applications. In addition, a targeted energy input can allow a shallower temperature gradient over the weld. This can lead to slower heating and especially cooling behavior and thereby avoid mechanical and morphological weakening due to residual stresses, vacuoles, porosity or cracks.

By "may" in particular optional features of the invention are referred to. Accordingly, there is an embodiment of the invention each having the respective feature or features.

With the invention, an energy input can be targeted. An energy input can be adjusted. A temperature distribution can be homogenized. An area of elevated temperature can be increased. Process times can be shortened. A feed rate can be increased.

A connection between thermoplastic fiber-plastic composite components can be improved. A cohesive solid connection over the entire joint contact surface can be ensured. A cohesive firm connection can also be ensured at edge sections. A load capacity of a connection between thermoplastic fiber-plastic composite components can be increased. These advantages can be realized for any geometry of joint contact surfaces. These advantages can be realized for non-rectangular geometries of joint contact surfaces. Restrictions on joint geometries can be overcome.

Hereinafter, embodiments of the invention will be described with reference to figures. From this description, further features and advantages. Concrete features of these embodiments may represent general features of the invention. Features associated with other features of these embodiments may also constitute individual features of the invention.

• 1 ein Fügen thermoplastischer Faser-Kunststoff-Verbund-Bauteile mithilfe eines elektrischen Widerstandsheizelements mit Heizabschnitten und Isolierabschnitten,
• 2 ein als Hybridgewebe mit fadenartigen Heizabschnitten und fadenartigen Isolierabschnitten ausgeführtes Widerstandsheizelement,
• 3 ein Widerstandsheizelement, bei dem Isolierabschnitte mithilfe einer Trägerfolie gebildet und Heizabschnitte an der Trägerfolie angeordnet sind und
• 4 einen Temperaturverlauf bei einem kontinuierlichen Widerstandsschweißen mithilfe eines Widerstandsheizelements mit Heizabschnitten und Isolierabschnitten.

They show schematically and by way of example:

• 1 a joining of thermoplastic fiber-plastic composite components by means of an electrical resistance heating element with heating sections and insulating sections,
• 2 a resistance heating element designed as a hybrid fabric with thread-like heating sections and thread-like insulating sections,
• 3 a resistance heating element in which insulating portions are formed by means of a carrier foil and heating portions are arranged on the carrier foil, and
• 4 a temperature profile in a continuous resistance welding using a resistance heating element with heating sections and Isolierabschnitten.

1 shows a joining of thermoplastic fiber-plastic composite components 100 . 102 using an electrical resistance heating element 104 with heating sections and insulating sections.

The fiber-plastic composite components 100 . 102 include organic fibers, such as aramid fibers, carbon fibers, polyester fibers, nylon fibers, polyethylene fibers, plexiglass fibers, and / or inorganic fibers, such as basalt fibers, boron fibers, glass fibers, ceramic fibers, silica fibers, which are contained in a thermoplastic matrix material, such as polyetheretherketone (PEEK), polyphenylene sulfide (PPS), polysulfone (PSU), polyetherimide (PEI) and / or polytetrafluoroethene (PTFE).

The fiber-plastic composite components 100 . 102 each have a joint contact surface. First, the fiber-plastic composite components 100 . 102 arranged with their joint contact surfaces to each other, wherein between the joint contact surfaces, the resistance heating element 104 is arranged. The following is the resistance heating element 104 applied with an electrical power to the resistance heating element 104 to heat such that the matrix material of the fiber-plastic composite components 100 . 102 liquefied at the joint contact surfaces. If necessary with movement of the plastic composite components 100 . 102 relative to each other and / or under mutual contact pressure of the joint contact surfaces penetrates the liquid matrix material, the Widerstandsheizschicht 104 and the liquid matrix material of the plastic composite components 100 . 102 mixes up. Subsequently, an application of electrical power to the resistance heating element is terminated so that the resistance heating element cools and the matrix material solidifies again. The plastic composite components 100 . 102 are then connected cohesively to each other at the joint contact surfaces.

The insulating portions may be made of a thermoplastic material such as polyetheretherketone (PEEK), polyphenylene sulfide (PPS), polysulfone (PSU), polyetherimide (PEI) and / or polytetrafluoroethene (PTFE). In addition, when the resistance heating element is heated, the insulating sections can then be liquefied, so that the liquid matrix material of the plastic composite components 100 . 102 and mix the liquid insulating section material.

2 shows a resistance heating element 200 as resistance heating element 104 according to 1 used as a hybrid fabric with thread-like heating sections, such as 202 , and thread-like insulating sections, such as 204 , is executed. The hybrid fabric has a first thread system 206 with parallel threads and a second thread system 208 with parallel threads on. The thread systems 206 . 208 are crossed with each other. The first thread system 206 alternately has heating sections 202 and insulating sections 204 on. The second thread system 208 has only insulating sections 204 on. The heating sections 202 each have a thread-like shape and extend parallel to each other and spaced apart in the illustration according to 1 unidirectional vertical. The resistance heating element 200 is permeable to plasticized plastic material of fiber-plastic composite components.

3 shows a resistance heating element 300 as resistance heating element 104 according to 1 in which insulating sections, such as 302 , using a carrier foil 304 formed and heating sections, like 306 , on the carrier film 304 are arranged. The heating sections 306 are by selective laser melting on the carrier film 304 printed. The heating sections 306 each have a web-like shape and extend parallel to each other and spaced apart in the illustration according to 1 unidirectional vertical. The carrier foil 304 is made of a plastic compatible with a matrix material of fiber-plastic composite components and using the heating sections 306 plastifiable r.

The resistance heating element 200 . 300 is used for plasticizing fiber-plastic composite components, such as fiber-plastic composite components 100 . 102 according to 1 at a common joint contact surface, to connect the fiber-plastic composite components together materially. The heating sections 202 . 306 each individually or in groups separately electrically acted upon. For example, the heating sections 202 . 306 sequentially applied sequentially electrically, each with a plurality of heating sections 202 . 306 be applied simultaneously overlapping electrically.

4 shows a temperature profile 400 in a continuous resistance welding using a resistance heating element, such as resistance heating element 104 according to 1 , Resistance heating element 200 according to 2 or resistance heating element 300 according to 3 , with heating sections and insulating sections. The temperature profile 400 is in a diagram 402 shown in the on a x -Axis a time or a way of a welding tool and on a y -Axis a temperature are plotted.

By sequentially successive and overlapping simultaneous electrical loading of several heating sections results in a broad energy input range 404 ,

LIST OF REFERENCE NUMBERS

100

Fiber-reinforced plastic component

102

Fiber-reinforced plastic component

104

resistance

200

resistance

202

heating section

204

insulating

206

thread system

208

thread system

300

resistance

302

insulating

304

support film

306

heating section

400

temperature curve

402

diagram

404

Energy input range

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 102011114306 A1 [0002]
• DE 102012216255 A1 [0003]
• DE 102018105690 [0004]

Claims (10)

An electrical resistance heating element (104, 200, 300) for plasticizing fiber-plastic composite components (100, 102) at a common joint contact surface in order to materially connect the fiber-plastic composite components (100, 102), characterized in that the resistance heating element (104, 200, 300) has electrically conductive heating sections (202, 306) forming heating resistors and electrically insulating insulating sections (204, 302) acting between the heating sections (202, 306). Resistance heating element (104, 200, 300) after Claim 1 , characterized in that the heating sections (202, 306) individually and / or in groups separately electrically acted upon. Resistance heating element (104, 200, 300) according to at least one of the preceding claims, characterized in that the heating sections (202, 306) are oriented unidirectionally. Resistance heating element (104, 200) according to at least one of the preceding claims, characterized in that the resistance heating element is at least partially permeable to plasticized plastic material of the fiber-plastic composite components (100, 102). Resistance heating element (104, 200, 300) according to at least one of the preceding claims, characterized in that the insulating sections (204, 302) are plastifiable. Resistance heating element (104, 200) according to at least one of Claims 1 to 5 , characterized in that the resistance heating element (104, 200) is designed as a hybrid fabric with thread-like heating sections (202) and thread-like insulating sections (204). Resistance heating element (104, 300) according to at least one of Claims 1 to 5 , characterized in that the insulating sections (302) are formed by means of a carrier foil (304) and the heating sections (306) are arranged on the carrier foil (304). A method for integrally joining fiber-plastic composite components (100, 102) on a common joint contact surface, characterized in that a resistance heating element (104, 200, 300) according to at least one of the preceding claims between to be joined together fiber-plastic composite Components (100, 102) are arranged and the heating sections (202, 306) are electrically applied to plasticize plastic material of the fiber-plastic composite components (100, 102) and / or the insulating sections. Method according to Claim 8 , characterized in that the heating sections (202, 306) individually and / or in groups are subjected to different electrical power. Method according to at least one of Claims 8 to 9 , characterized in that the heating sections (202, 306) individually and / or in groups successively applied with electrical power.

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