Apparatus and method for forming and bonding fiber-reinforced composite devices

Abstract

A method (5000) for forming a composite device (1010), comprising: forming (5010) a first part (1000) by depositing (5020) an electrically-conductive tow (110) comprising a thermoplastic material onto a substrate (200, 201, 202), the tow comprising one or more electrically- conductive fibers (100EF); placing (5040) a second part (1005) against the first part; and passing (5060) an electrical current through the electrically-conductive tow.

Description

Apparatus and Method for Forming and Bonding Fiber-Reinforced Composite DevicesField

[0001] This disclosure relates to apparatuses and methods for forming and bonding fiber- reinforced composite devices.Background

[0002] Fiber-reinforced plastics (FRP), also called fiber-reinforced polymers, for example carbon fiber-reinforced plastics (CFRP) are widely used materials for lightweight structures, ranging from sports equipment, to automotive components, to aerospace structures. A method for manufacturing of FRP devices comprises depositing fiber tows, for example preimpregnated tows, onto a substrate. In some embodiments, manufacturing the device comprises forming a stack comprising a plurality of layers comprising FRP.Summary

[0003] This disclosure presents a method for forming a composite device, comprising: forming a first part by depositing an electrically-conductive tow comprising a thermoplastic material onto a substrate, the tow comprising one or more electrically-conductive fibers; placing a second part against the first part; and passing an electrical current through the electrically-conductive tow.

[0004] For example, one or more of the electrically-conductive fibers comprise carbon fibers. For example, one or more of the electrically-conductive fibers comprise continuous fibers. For example, the electrically-conductive tow is forming a path comprising one or more curves. For example, the electrically-conductive tow is adjacent to one or more thermoplastic-rich paths. For example, one or more of the first part and the second part comprise a thermoplastic material. For example, the passing an electrical current through the electrically-conductive tow comprises passing the electrical current from a first end of the tow to a second end of the tow. For example, a third part comprising a thermoplastic material is comprised between the first part and the second part. For example, the electrically-conductive tow has a rectangular crosssection. For example, one or more of the curves comprise one or more U-turns. For example, the electrically-conductive tow has a width in a range from 0.3 mm to 5 mm. For example, the electrically-conductive tow is embedded into layer. For example, the electrically-conductive tow is comprised within a recess at a surface of one or more of the first part and the second part. For example, the electrically-conductive tow forms a lining along one or more portions of a border of one or more of the first part and the second part. For example, the rotating comprises orienting a forward direction of the rotatable shoe along a tangent to the path. For example, the rotating comprises orienting a forward direction of the rotatable shoe into a cant angle with respect to a tangent to the path. For example, the tow is supplied into a channel of the shoe that partially surrounds an axis of rotation of the shoe. For example, the method is executedonboard a vehicle.

[0005] The disclosure further presents a system for depositing a tow comprising: a rotatable shoe comprising a channel that partially surrounds an axis of rotation of the shoe; and a non- transitory computer-readable storage medium, wherein the non-transitory computer-readable storage medium comprises instructions for: depositing an electrically-conductive tow onto a substrate wherein the depositing of the electrically-conductive tow comprising a thermoplastic material comprises forming a path; and passing an electrical current through the electrically- conductive tow. For example, the system further comprises a vehicle to which the system is fastened.

[0006] The disclosure further presents a non-transitory computer-readable storage medium comprising instructions for: depositing an electrically-conductive tow comprising a thermoplastic material onto a substrate wherein the depositing of the electrically-conductive tow comprises forming a path; and passing an electrical current through the electrically-conductive tow.Brief description of drawings

[0007] Fig. 1 is an isometric view of a flat first part comprising an electrically-conductive tow having a plurality of curves.

[0008] Fig. 2 is an isometric view of a first part having a recess and comprising an embedded electrically-conductive tow having a plurality of curves and facing a second part.

[0009] Fig. 3 is an isometric view of a first part having a lined recess and comprising an electrically-conductive tow having a plurality of curves and facing a second part and a third part.

[0010] Fig. 4A is an isometric view of a first part having a chamfered recess and comprising a first electrically-conductive tow having a plurality of curves and facing a matching second part comprising a second electrically-conductive tow.

[0011] Fig. 4B is an isometric view of a composite device formed by bonding a first part with a second part.

[0012] Fig. 5 is a variation of the first part of Fig. 4A wherein the electrically-conductive tow is arranged beneath a surface of the recess.

[0013] Fig. 6 is a variation of Fig. 2 wherein resin-rich paths are deposited adjacent to the electrically-conductive tow in one or more of the first part and the second part.

[0014] Fig. 7A is a top view of an electrically-conductive tow arranged in a sawtooth-shaped snaking pattern and lined on both sides by a thermoplastic-rich path.

[0015] Fig. 7B is a top view of an electrically-conductive tow arranged in a sawtooth-shaped snaking pattern wherein regions between two or more peaks of the snaking pattern are filled by thermoplastic-rich paths.

[0016] Fig. 7C is a top view of an electrically-conductive tow arranged in a square wave-shaped snaking pattern wherein regions between two or more peaks of the snaking pattern are filled by thermoplastic-rich paths.

[0017] Fig. 8 is a perspective view of an aircraft having electrically-conductive tows arranged for assembly, disassembly, and reconfiguration.

[0018] Fig. 9 is a perspective view of a bicycle crank comprising components assembled using electrically-conductive tows.

[0019] Fig. 10A is a top view of a bicycle crank onto which a foldable reinforcement plate is about to be folded.

[0020] Fig. 10B is a cross-section of the bicycle crank and of the foldable reinforcement plate.

[0021] Fig. 11 A is an isometric view of a tow comprising continuous fibers.

[0022] Fig. 11 B is an isometric view of a tow comprising discontinuous fibers.

[0023] Fig. 12A is a side view of a robotic system for depositing the tow.

[0024] Fig. 12B is a bottom view of a shoe for depositing the tow.

[0025] Fig. 13 is a block diagram of a method for bonding a first part to a second part using electric resistance welding.Detailed description

[0026] The present disclosure relates to a method 5000 (Fig. 13) for forming a composite device wherein a first part 1000 is bonded 5050 to a second part 1005 using a method of electric resistance welding wherein a current is passed 5060 into one or more electrically- conductive tows 110. For example, the method comprises depositing 5020 an electrically- conductive tow 110, for example comprising a thermoplastic material, for example using a tow deposition apparatus 2000. The method for forming a composite device comprises, for example, depositing 5020 an electrically-conductive tow or filament 110 comprising one or more electrically-conductive fibers 100EF, for example a plurality of electrically-conductive fibers 100EF, wherein a path 150 of the tow comprises one or more curves 150C and the depositing comprises, for example, rotating 5030 a rotatable shoe 2101 of a tow deposition apparatus 2000 for guiding the tow along the curves of the path. Throughout this disclosure, the words filament or tow are used interchangeably to refer to a same material, namely a bundle comprising a plurality of fibers 110F, 110EF, 110FC, 110FD1, 110FD2. For example, a method of guiding deposition of a tow by rotating the rotatable shoe 2101 improves the flatness of the tow being deposited by reducing one or more of the amount of twisting in the deposited tow and the waviness that may occur, for example in curves of a path having one or more portions comprising curves or turns. For example, the improved flatness of the tow improves the uniformity, for example along a longitudinal path of the tow, of one or more of electrical resistivity and heat radiated by the tow in a method wherein an electrical current passes through the tow 110, for example by passing 5060 an electrical current from a first end 110E1 of the tow 110 to a second end 110E2 of the tow.

[0027] Fig. 1 is an isometric view of a first part 1000 comprising an electrically-conductive tow110 having one or more curves 150C between a first end 110E1 of the tow and a second end 110E2 of the tow. For example, the electrically-conductive tow is configured as a serpentine. For example, one or more of the curves is configured as a U-turn, for example wherein a portion of the tow departs from the U-turn in a range from 150° to 180° with respect to a portion of tow incoming into the U-turn. For example, the electrically-conductive tow comprises one or more waves of a sinewave. For example, 3 or more successive curves of the tow are separated by a spatially constant period. For another example (Fig. 4A), 3 or more successive curves of the tow 110 are separated by a spatially irregular period.

[0028] A filament or tow 100, for example the electrically-conductive tow 110, comprises a plurality of fibers 110F, 110EF (Fig. 11 A). For example, the filament comprises a resin, for example a thermoplastic resin. For example, the resin is comprised in the filament by one or more processes of: pre-impregnation, wherein the filament supplied to the automated filament placement system 2000 comprises the resin; and impregnation, wherein the resin is supplied to the filament within the system 2000. For example, the filament is deposited onto an object surface or substrate 200. For example, the filament is continuously fed onto the substrate, for example fed at a speed corresponding to that of the filament deposition system with respect to the surface of the substrate. For example, the substrate 200 is a plate, for example a build plate of an automated filament placement system 2000 (Fig. 12A).

[0029] For example, the substrate is a device comprising one or more filaments 100, for example arranged as a layup, for example comprising one or more layers 201, 202. For example, a first layer 201 comprises one or more filaments arranged in a first direction, for example a Y-direction. For example, the first layer is formed by depositing one or more of the filaments 100 onto the substrate or build plate 200. For example, a second layer 202, for example deposited onto the first layer 201, comprises one or more filaments arranged in a second direction, for example an X-direction. For example, the second direction is different from the first direction, for example at 45° to the first direction, for another example, as shown in Fig. 1 , at 90° to the first direction. For example, the electrically-conductive tow 110, for example having one or more curves 150C, is deposited onto one or more of the layers 201 , 202. For example, the electrically-conductive tow 110 comprises one or more of a first end 110E1 and a second end 110E2 that extend beyond a perimeter of one or more of the underlying layers. For example, a method to pass an electrical current into the electrically-conductive tow 110 comprises connecting an electrical power supply to one or more or more of the first end 110E1 and the second end 110E2. For example, one or more of the first end 110E1 and the second end 110E2 are cut, for example cut flush with the perimeter of one or more of the underlying layers, for example after the bonding by electric resistance welding is completed.

[0030] For example, a problem when depositing a filament or tow 100, 110 having one or more curves 150C by continuous layup, is that fibers running close to an outer edge of a curve resistelongation and tend to shortcut the curve. For example, a further problem is that fibers running close to an inner edge of the curve tend to buckle and form one or more surface irregularities in the form of waves, bumps, or folds at the surface of the deposited tow. For example, the surface irregularities radiate towards the outer edge of the curve. The tighter the curve, the more pronounced the problems are. The problems further are a function of one or more of: a width, a thickness, and a cross-section of the tow; stresses within the tow, for example related to the configuration of curves of the tow deposited prior to forming a given tow; the type of thermoplastic resin; the bonding temperature; and cross-tow bonding uniformity. For example, one or more of the problems affect the lengthwise electrical resistivity of the electrically- conductive tow 110.

[0031] The method 5000 for depositing 5020 the filament or tow, for example by continuous layup of the filament, for example using the automated filament placement system 2000 comprising a rotatable shoe 2101 (Figs. 12A and 12B), for example rotating 5030 during filament deposition, for example as part of an automated fiber placement (AFP) process, alleviates one or more of the problems and improves uniformity at the surface of the deposited tow. The method 5000 further improves lengthwise uniformity of heat radiated by the tow, for example at the exposed surface of the tow opposite that of the bonded surface of the tow, wherein an electric current is passed through the tow, for example along at least a portion of a length of the tow, for example from a first end 110E1 of the tow to a second end 110E2 of the tow.

[0032] For a further example, forming a curve along the path of the tow 100, 110 comprises forming an acute turn. For example, forming an acute turn comprises guiding a filament around a turn departing with an angle greater than 90° from an initial path direction and wherein the radius of curvature of the path followed by the filament is less than 5 times the width 100W (Fig. 11A) of the filament, for example less than 3 times, for example less than 2 times, for example less than the width of the filament, for example less than 0.7 times. For example, the radius of curvature is measured from the center of the turn to the mid-line of the width of the filament.

[0033] For example, the filament or tow has a width 100W comprised in a range from 0.3 mm to 5 mm. For example, the width 100W of a tow or filament 100 is comprised in a range from 0.2 mm to 10 mm, for example from 0.4 mm to 5 mm, for example from 0.4 mm to 3 mm, for example from 0.4 mm to 2 mm, for example from 0.4 mm to 1 mm, for example from 0.45 mm to 0.6 mm. For example, the filament is a tape comprising fibers. For example, a tape is formed by cutting a sheet or a web comprising a plurality of fibers in a direction parallel to the fibers. For example, a filament, for example a tape, has a width 100W in a range from 0.4 mm to 3 mm, for example from 0.6 mm to 2 mm, for example from 0.8 mm to 1.5 mm, for example from 0.9 mm to 1.2 mm. For example, the filament has a thickness, for example in the Z-direction, in a range from 0.01 mm to 10 mm, for example from 0.05 mm to 2 mm, for example from 0.05 mm to0.5 mm, for example from 0.1 mm to 0.25 mm.

[0034] For example, the filament comprises one or more thermoplastic resins. For example, the filament is preimpregnated with one or more thermoplastic resins. For a further example, the filament is pre-impregnated or impregnated with one or more thermoplastic resins within 10 minutes prior to or upon deposition of the filament onto the substrate. For example, the filament 100, 110 comprises one or more of: a plurality of continuous fibers 110FC, a plurality of discontinuous fibers 110FD, 110FD1, 110FD2, and a plurality of chopped fibers.

[0035] For example, a filament comprising a plurality of discontinuous fibers 110FD comprises one or more sets of discontinuous fibers arranged as a plurality of parallel fibers, for example as shown in Fig. 11B with a first discontinuous fiber 110FD1 and a second discontinuous fiber 110FD2 which, apart from being parallel to each other, are also, for example, colinear. For example, the fibers are arranged unidirectionally, for example parallel to the longitudinal axis of the filament. For example, the fibers in a filament comprising discontinuous fibers have a uniform length. For example, the discontinuous fibers have a length comprised in a range from 2 mm to 20 mm, for example from 2 mm to 10 mm, for example from 3 mm to 8 mm, for example from 3 mm to 6 mm. For example, the length-to-diameter ratio of a discontinuous fiber is in a range from 500 to 1500, for example from 600 to 1200. For example, a fiber having a length that is greater than that of a discontinuous fiber is a continuous fiber. For example, a fiber having a length that is less than that of a discontinuous fiber is a chopped fiber. For example, the discontinuous fibers are arranged parallel to the longitudinal direction of the filament. For example, at least 50%, for example more than 75%, for example more than 90%, for example more than 95% of the fibers are parallel to the longitudinal direction of the filament, for example within 15° of the longitudinal direction of the filament, for example within 10°, for example within 5°. For example, a filament or tow comprises continuous fibers and discontinuous fibers. For example, the continuous fibers comprise a first material, for example one or more of carbon fibers and copper fibers, for a further example at least carbon fibers. For example, the discontinuous fibers comprise a second material, for example one or more of carbon fibers and copper fibers, for a further example at least copper fibers.

[0036] For example, a filament comprises one or more fiber materials, for example selected from one or more of: a carbon fiber, a glass fiber, an aramid fiber, a basalt fiber, a metal fiber, and a natural fiber. For example, a natural fiber comprises fiber extracted from one or more of: a sisal, a flax, a ramie, a cotton, a banana, and a hemp. For example, a set of continuous fibers or a set of discontinuous fibers comprises fibers of one or more of the fiber materials. For example, a filament comprises one or more metal-coated fibers, for example one or more of nickel- and copper-coated fibers, for example metal-coated carbon fibers. For example, an electrically- conductive tow 110 comprises a plurality of continuous carbon fibers which are electrically- conductive fibers 110EF. For example, all the fibers 110EF in an electrically-conductive tow 110are electrically-conductive, for example electrically-conductive carbon fibers. For example, the carbon fibers confer one or more of strength, electrical conductivity, controlled mechanical anisotropy, continuity in the manufacturing process of the part, bonding uniformity by using a resin-impregnated tow, and bonding material compatibility by using, for example, the same adhesive material throughout the manufactured part.

[0037] For example, a filament 100, 110 comprises an adhesive material, for example a thermoplastic adhesive. For example, a thermoplastic adhesive comprises one or more of: a polyaryletherketone (PAEK), a polyether ether ketone (PEEK), a polyetherketoneketone (PEKK), a polyetherimide (PEI), an acrylonitrile butadiene styrene (ABS), a nylon, a polybutylene terephthalate (PBT), a polycarbonate (PC), a polycarbonate-ABS (PC-ABS), a polyether sulfone (PES), a polyethylene (PE), a polyamide (PA), a polyimide (PI), a polyethylene terephthalate (PET), a polyphenylene sulfide (PPS), a polyphenylsulfone (PPSLI), a polyphosphoric acid (PPA), a polypropylene (PP), a polysulfone (PSU), a polyurethane (Pll), and a polyvinyl chloride (PVC). For example, a thermoplastic further comprises a filler, for example a filler comprising a plurality of microspheres. For a further example, the electrically- conductive tow 110 is one or more of pre-impregnated and impregnated by an electrically- conductive thermoplastic resin.

[0038] For example, the filament has a fiber volume fraction in a range from 0.1 to 0.9, for example from 0.3 to 0.9, for example from 0.4 to 0.85, for example from 0.5 to 0.85, for example from 0.55 to 0.82.

[0039] Fig. 2 is an isometric view of a first part 1000, 1020 that, compared to the flat geometry of the first part shown in Fig. 1, has a recess 1020R. The first part 1020 further comprises an electrically-conductive tow 110 that is embedded into a layer, for example the layer 202 at the surface of the recess. The electrically-conductive tow 110 has, for example, a plurality of curves. For example, bonding the first part 1000 to a second part 1005 comprises, for example, placing 5040 a second part 1005, 1025, for example aligning the second part with the first part, for contacting one or more of the first part and the electrically-conductive tow for bonding. For example, the placing the second part is against a surface of the first part that is closest to the electrically-conductive tow. For example, the contacting comprises pressing, for example pressing the second part against the first part. For example, the aligning comprises using one or more of: an actuated support, for example the substrate 200; one or more clamps, for example actuated clamps; and one or more robotic arms comprising an end-effector configured to grasp one or more of the parts.

[0040] For example, the geometry of a portion of the second part that contacts the first part matches a portion of the geometry of the first part. For example, the recess 1020R comprises one or more borders 1020B. For example, one or more of the borders form a staircase arrangement 1020S wherein the edge of the border approximates a ramp wherein one or morelayers 203 deposited successively onto the layer 202 at the surface of the recess are arranged in a staircase. For example, one or more filaments 100 of one or more layers of the staircase arrangement feed into the staircase, for example orthogonally, for example wherein fibers of the filament feed into the staircase, for example orthogonally.

[0041] Fig. 3 is an isometric view of a first part 1000, 1030 that, compared to the first part shown in Fig. 2, comprises one or more liner filaments 100L lining internal contours of the borders 1030B of the recess 1030R. For example, a first liner filament 100L, for example forming a lining contour of a first border layer 203, forms a first step of a staircase 1030S. For example, a second liner filament 100L, for example forming a lining contour of a second border layer 204, forms a second step of the staircase 1030S. For example, a third part 1002 comprising a thermoplastic material is comprised between the first part 1000 and the second part 1005. For example, the third part is a sheet comprising a thermoplastic material. For example, the sheet substantially extends over a surface comprising a convex envelope around a portion of the electrical ly-conductive tow 110 at the surface of the first part. For a further example, the sheet substantially covers the surface of the recess 1030R, for example bounded by one or more of the borders 1030B. For yet a further example, the third part 1002 comprises one or more filaments comprising a thermoplastic material, for example more than 50% of thermoplastic material by volume, for example a thermoplastic material comprising chopped fibers, for another example exclusively a thermoplastic material.

[0042] Fig. 4A is an isometric view of a first part 1000, 1040 having a chamfered recess 1040R and comprising a first electrically-conductive tow 110. For example, the chamfered recess comprises one or more surfaces comprising a chamfer 1040C connecting the recess 1040R to one or more borders 1040B. Although Fig. 4A presents a recess bordered by a plurality of borders 1040B arranged in an open polygon, a skilled person will, for example, extend the border to have a plurality of borders forming a closed polygon, one or more arcs, a circle, or any other contour. The first part 1040 is represented facing a matching second part 1005, 1045 comprising a second electrically-conductive tow 112. For example, the first electrically- conductive tow 110 has a plurality of curves 150C, for example formed as one or more U-turns, for example spaced irregularly apart from each other, for example arranged with respect to one or more axes of symmetry of the geometry of one or more of the recess and the first part.

[0043] For example, the second part comprises one or more contours, for example chamfers, matching one or more of the contours of the first part, for example the contours of the recess 1040R of the first part. For example, one or more portions in a path of the second electrically- conductive tow 112 are facing one or more portions in a path of the first electrically-conductive tow 110. For another example, in a configuration wherein the second part 1045 is placed against the first part 1040, one or more portions in the path of the second electrically-conductive tow 112 are facing a region comprised between a first portion of the path of the first electrically-conductive tow 110 and a second portion of the path of the first electrical ly-conductive tow 110, for example in an interlacing arrangement, for example with the portion 112P1 in the path of the second electrically-conductive tow 112 at equidistance from the first 110P1 and the second 110P2 portions of the path of the first electrically-conductive tow 110.

[0044] Fig. 5 presents a variation of the first part of Fig. 4A wherein the first part 1000, 1050 comprises one or more electrically-conductive tows 110 arranged beneath a surface of the recess 1050R. For example, the surface 1050RS of the recess 1050R is one or more of coated and covered by one or more layers 1050RL comprising a thermoplastic material. For example, the layer 1050RL comprising a thermoplastic material comprises one or more of: a plurality of continuous fibers, a plurality of discontinuous fibers, a plurality of chopped fibers, and exclusively a thermoplastic material. For example, the layer 1050RL is formed by one or more of: an automated fiber placement (AFP) process, a fused deposition modeling (FDM) process, a coating process, and placing a sheet comprising a thermoplastic material. For example, the tow deposition apparatus 2000 is used for depositing the layer 1050RL comprising a thermoplastic material.

[0045] For example, one or more of the first part 1000 and the second part 1005 comprise one or more tows 100L lining one or more portions of one or more of walls, ramps, staircases, recesses, and surfaces. For example, Fig. 5 shows a first part comprising one or more tows 100L lining one or more portions of the contour of the recess 1050R. For example, the lining tow 100L is embedded within a surface of the part 1050, for example within a surface 1050RS of the recess 1050R. For example, a lining tow is configured as a lining electrically-conductive tow 110L, for example along one or more portions of a border 1050B of the recess 1050R.

[0046] Although illustrations depict the electrically-conductive tows 110 against or within a layer at the surface of a part, an alternative or combinable arrangement comprises one or more electrically-conductive tows embedded within one or more layers that are comprised one or more layers beneath a surface of the part, the layers comprising, for example, one or more of: a thermoplastic material; a metal, for example configured as a foil; and a thermal insulator, for example configured as a foil or a sheet. For example, the metal is electrically isolated from the electrically-conductive tows by one or more of an insulating material and a layer comprising a thermoplastic material. For example, assuming a layer has a thickness of an electrically- conductive tow 110, an electrically-conductive tow used for melting a thermoplastic material is arranged to a practical maximum of 20 layers beneath the bonding surface, for example from 0 to 10 layers, for example from 0 to 5 layers, for example from 0 to 3 layers beneath the bonding surface. For example, the layers are electrically isolating, for example comprising one or more thermoplastic-rich paths or materials. For example, assuming a layer has a thickness of an electrically-conductive tow 110 in a range from 0.05 mm to 0.4 mm, a practical maximum of 20 layers beneath the bonding surface is in a range from 1 mm to 8 mm. For example, a bondingprocess is limited by a maximum temperature to avoid degradation of the thermoplastic material and a process duration, for example to limit heat diffusion within a part to a point wherein structural components are deformed beyond a desired scope, for example beyond a bonding region or a region targeted for deformation, due to reaching one or more of a glass transition temperature and a melting temperature.

[0047] Fig. 6 is a variation of Fig. 2, wherein one or more thermoplastic-rich paths 120 are adjacent, for example deposited adjacent, to one or more of the electrically-conductive tows 110, for example in one or more of the first part 1000, 1020 and the second part 1005, 1025. Conversely, for example, the electrically-conductive tows 110 are deposited adjacent to one or more thermoplastic-rich paths 120. For example, a thermoplastic-rich path has a fiber volume fraction that is lower than 0.6, for example lower than 0.5, for example lower than 0.4. For example, a thermoplastic-rich path comprises one or more fibers, for example comprising one or more lengths, for example comprising one or more of continuous fibers, short fibers, and chopped fibers. For example, a thermoplastic-rich path is deposited from one or more of a filament, a molten filament, a tape, a powder, and a bulk molding compound. For example, a thermoplastic-rich path is deposited or arranged along one or more portions of one or more sides of one or more electrically-conductive tows 110. For example, a thermoplastic-rich path is arranged between two portions of electrically-conductive tows.

[0048] For example, as shown in Fig. 6, an electrically-conductive tow 110 is arranged in a snaking pattern, for example having a plurality of U-turns, for example having a plurality of parallel portions or arms connected to one or more of the U-turns. For example, one or more thermoplastic-rich paths are arranged between the arms of the snaking pattern, for example parallel to one or more of the arms of the snaking pattern. For another example, the snaking pattern is arranged in one or more of a sinewave, a square wave, a sawtooth, and other, for example spline-based, periodic or non-periodic waves. For example, a thermoplastic-rich region is formed in contact with the snaking pattern, for example, as shown in Fig. 7A, as one or more of: one or more thermoplastic-rich paths following one or more portions of one or more of the sides of the snaking pattern; and one or more thermoplastic-rich paths, as shown in Fig. 7B and in Fig. 7C, for example arranged as parallel paths, for example filling at least one or more regions comprised between two or more peaks of the snaking pattern.

[0049] For example, a method for one or more of forming and selectively increasing the strength of a bond between a first part and a second part comprises selecting one or more of a heating temperature and a heating duration of one or more of the electrically-conductive tows 110 comprised in one or more of the first part and the second part. For example, the method comprises selecting one or more of a voltage, a current, and a power supply duration feeding into one or more of the electrically-conductive tows. For example, one or more of a first electrical power supply and a first electrical power supply duration induce melting of one ormore first thermoplastic-rich paths or path portions 120-1 closest to the electrically-conductive tows. For example, one or more of a second electrical power supply and a second electrical power supply duration induce melting of one or more second thermoplastic-rich paths or path portions 120-2 at a greater distance from the electrically-conductive tows than those closest to the electrically-conductive tows.

[0050] For example, the method for forming and selectively increasing the strength of a bond is comprised in a method for forming an assembly comprising the first part and the second part wherein, for example, selecting to melt only the closest thermoplastic-rich paths or path portions 120-1 forms a bond configured as a mechanical fuse, for example over a first bonding region, for example by supplying electrical power to a first electrically-conductive tow. For example, selecting one or more of the second electrical power supply and the second electrical power supply duration, for example over a second bonding region, for example distant from the first bonding region, for example by supplying electrical power to a second electrically-conductive tow, confers greater bonding strength to the second region than to the first region. For example, the selective method is comprised in a method for consuming one or more of less energy and time for forming a low strength assembly using one or more of the first electrical power supply and the first electrical power supply duration than forming a high strength assembly using one or more of the second electrical power supply and the second electrical power supply duration.

[0051] For example, in an aircraft wing (Fig. 8), for example of a hand-launched aircraft, assembled from a plurality of wing elements 1060WS arranged in a spanwise direction, one or more outboard wing elements require less bonding strength than wing elements closer to the wing root, for example enabling an outboard wing element to snap off an inboard wing element if an outboard wing element is hit by an object, for example one or more of in flight and upon landing.

[0052] Fig. 6 further illustrates the second part 1005, 1025 comprising one or more electrically- conductive tows 110 being brought to contact the first part 1000, 1020. For example, the electrically-conductive tows 110 of the second part are offset, for example in a direction of a phase of the snaking pattern of the electrically-conductive tows of the first part, by an offset 110O. For example, as shown in Fig. 6, in an assembly wherein the second part mates with the first part, the offset is a quarter of a wavelength of the snaking pattern of one or more of the electrically-conductive tow of the first part and the electrically-conductive tow of the second part. For example, one or more portions of the electrically-conductive tow of the second part respectively face one or more portions of thermoplastic-rich paths of the first part. For example, one or more portions of the electrically-conductive tow of the first part respectively face one or more portions of thermoplastic-rich paths of the second part. For example, one or more of the portions of electrically-conductive tow facing one or more of the portions of thermoplastic-rich paths are comprised between a trough and a peak, for example in succession, for example afirst U-turn and a second U-turn, of the snaking pattern of the electrically-conductive tow.

[0053] Fig. 7B is a top view of an electrically-conductive tow 110 arranged in a sawtoothshaped snaking pattern. For example, the regions between two or more peaks of the snaking pattern are filled by thermoplastic-rich paths 120. For example, the thermoplastic-rich paths 120 are arranged as parallel paths. For example, the paths are arranged parallel to one of the edges 110E of a sawtooth. For example, from sawtooth to sawtooth along the sawtooth-shaped snaking pattern, the thermoplastic-rich paths are arranged parallel to a same edge 110E of the sawtooth. For example, a method for forming an anisotropic bonding comprises one or more of: forming the thermoplastic-rich paths arranged parallel to a same edge 110E of the sawtoothshaped snaking pattern; and supplying electrical power to resistively heat the electrically- conductive tow 110 arranged in a sawtooth-shaped snaking pattern with one or more of a power level and a power supply duration causing melting of one or more of the thermoplastic-rich paths arranged parallel to a same edge 110E. For example, one of the directions of the anisotropic bonding arrangement, for example comprising the sawtooth-shaped snaking pattern and the one or more thermoplastic-rich paths, for example arranged in parallel, has a stronger bonding than the other direction of the sawtooth. For example, an assembly comprising an anisotropic bonding separates under less shear force in one direction than in another direction.

[0054] Fig. 8 is a perspective view of an aircraft 1060 having electrically-conductive tows 110, 110F arranged for assembly, disassembly, and reconfiguration. For example, the aircraft comprises a wing assembled from a plurality of wing sections 1060WS. For example, one or more of the wing sections are one or more of fixed, bonded, and locked using one or more electrically-conductive tows 110. For example, an electrically-conductive tow is supplied with electrical power to one or more of melt a thermoplastic polymer comprised in the electrically- conductive tow and melt one or more thermoplastic-rich paths adjacent to the electrically- conductive tow. For example, supplying electrical current or power to the electrically-conductive tow heats the thermoplastic material to one or more of a glass transition temperature and a melting temperature. For example, supplying electrical power to the electrically-conductive tow is used for one or more of: bonding a first wing section to a second wing section, for example prior to flight; unbonding a first wing section from a second wing section, for example after a flight or during a flight, for example to get rid of a damaged part, for another example to drop a payload; reducing the rigidity of a portion used to lock a component, for example a first wing section, against another component, for example a second wing section, a fuselage, or a mounting point; reducing the rigidity or modifying the configuration of a spring-loaded component, for example a snap-fit mechanism or a spring, for example comprising one or more of electrically-conductive tows 110 and a thermoplastic polymer.

[0055] For example, the aircraft comprises one or more electrically-conductive tows 110 arranged at one or more of the leading edge of the wing section and the trailing edge of thewing section, for example at one or more of an inboard side and an outboard side of the wing section. For example, an electrically-conductive tow 110 arranged at a leading edge of the wing is forming a bonding strength, for example in combination with adjacent thermoplastic-rich paths, that is one or more of different from and greater than that of an electrically-conductive tow 110 arranged at a trailing edge of the wing. Although Fig. 8 illustrates usage examples on the main wing of an aircraft, other usage examples include one or more of connecting and bonding one or more of: one or more of a horizontal stabilizer and a vertical stabilizer; fuselage components; and payloads.

[0056] For example, the aircraft comprises one or more spanwise electrically-conductive tows 110F arranged along at least a portion of the span of one or more of the wing sections 1060WS. For example, Fig. 8 illustrates spanwise electrically-conductive tows 110F arranged one or more of beyond a mid-length of the chord of the wing section and along the trailing edge of one or more of the wing sections. For example, the spanwise electrically-conductive tow 110F comprises one or more lengths, for example in one or more of an outboard direction and an inboard direction, along a span of the wing section. For example, each length of tow is connected in series, for example as a result of a continuous filament deposition, for example using a robotic system 2000 for depositing the tow, for example by forming one or more turns in the path of the tow, for example U-turns. For example, a tow of a first wing section is electrically connected to a tow of a second wing section, for example in parallel or in series.

[0057] For example, a method for adjusting a camber of one or more of the wing sections comprises supplying electrical power to one or more of the spanwise electrically-conductive tows 110F, for example to heat one or more of the spanwise electrically-conductive tows, adjacent tows, thermoplastic-rich paths, and thermoplastic material, for example to a temperature equal to or greater than a glass transition temperature of one or more thermoplastic materials comprised in one or more of the spanwise electrically-conductive tows, the adjacent tows, the thermoplastic-rich paths, and the thermoplastic material. For example, the adjusting the camber comprises deforming one or more of the wing sections, for example during one or more of the heating and one or more portions of the wing sections being at a temperature greater than or equal that of a glass transition temperature of the one or more thermoplastic materials. For example, the deforming comprises deforming one or more of: a lower surface of the wing section, for example a lower surface skin; an upper surface, for example an upper surface skin; and a structural component comprised inside the wing section, for example a wing rib, for example comprising one or more electrically-conductive tows. For example, the deforming comprises adding a load onto the wing section. For example, the deforming further comprises one or more of interrupting the power supply and cooling, for example to return one or more of the thermoplastic materials to a solid state. Although this description focuses on deforming the trailing edge of one or more wing sections, the method and tow arrangement isapplicable to one or more of the leading edge and other aerodynamic surfaces or structural components, including to form deformations in one or more directions. For example, the deforming method is a method to adapt aerodynamic characteristics of an aircraft one or more of prior to flight, during flight, and after flight, for example to tune the aircraft, for example one or more of its wing profile and spanwise twist, to a desired payload, wing loading, flight speed, or mission configuration. Although the described method is applied to a winged aircraft, the method is also applicable to, for example, a rotorcraft, for example to adjust the twist of one or more arms supporting propellers of a multicopter, for example of a quadcopter.

[0058] Fig. 9 is a perspective view of a crank 1070, for example a bicycle crank. For example, a version of the crank, for example having an aspect ratio different from that represented, is usable as an arm comprised on a multicopter. For example, the crank comprises components, for example lids 1070L1 , 1070L2, that are, in a method for bonding, bonded to the crank by supplying electrical power to one or more electrically-conductive tows 110. For example, one or more of the crank 1070 and the lids 1070L1 , 1070L2 comprise one or more electrically- conductive tows. For example, one or more of the crank 1070 and the lids 1070-L1 , 1070L2 comprise a thermoplastic material facing, upon applying the lid against the crank, one or more of the electrically-conductive tows. For example, one or more of the crank and the lids are manufactured by a robotic system 2000 for depositing a filament, a tow, for example in successive layers. For example, one or more of the crank and the lids are, in a first step, each manufactured by a robotic system, for example one or more of the robotic system 2000 and a pick-and-place system, for example to deposit or assemble profiled rods, for example comprising one or more of fibers and thermoplastic materials. For a further example, one or more of the lids comprises an organosheet, for example comprising a thermoplastic material, for example a thermoplastic fiber- reinforced laminate. For example, one or more of the crank, for example as a first part, and the lids, for example as second parts, are, in a second step, each subjected to one or more of pressing, stamping, molding, and compression molding, for example inside one or more molds.

[0059] For example, the thermoplastic material is comprised in one or more of: one or more electrically-conductive tows; one or more thermoplastic-rich paths or blobs; one or more thermoplastic foils; one or more thermoplastic coatings; and one or more thermoplastic powders. For example, the method for bonding comprises pressing one or more of the lids 1070L1, 1070L2, for example one or more portions of the lids, against the crank. For example, the method for bonding comprises heating one or more of the crank and the lids, for example to a temperature lower than a melting temperature of one or more of the crank and the lids.

[0060] Although Fig. 9 presents an electrically-conductive tow 110 comprised in each of the lids 1070L1, 1070L2, in a further example, one or more electrically-conductive tows are comprised at one or more of the surface, embedded in a surface layer, and embedded beneath a surfacelayer of one or more of the crank 1070 and one or more of the lids 1070L1 , 1070L2.

[0061] Fig. 10A is a top view of the bicycle crank 1070 onto which a foldable reinforcement plate 1070L3 is about to be folded. For example, the plate 1070L3 comprises one or more electrically-conductive tows 110. For example, the plate comprises materials as those comprised in the lids 1070L1, 1070L2. For example, a method of forming the plate comprises steps as those described for forming one or more of the lids, the first part 1000, and the second part 1005. For example, the plate comprises, for example as visually segmented in Fig. 10 by dashed folding lines 1070FL, one or more flaps 1070F1 , 1070F2, 1070F3. For example, for forming a wrapping around an axis of the crank, the plate comprises, for example sequentially, a first flap 1070F1 , a first lid surface 1070LS1, a second flap 1070F2, a second lid surface 1070LS2, and a third flap 1070F3. For example, the plate 1070L3 comprises one or more electrically-conductive tows. Fig. 10A illustrates how, for example, a single electrically- conductive tow is arranged to span the entire plate, extending from the first flap, through the lid surfaces, and ending onto the third flap. For example, the electrically-conductive tow extends on one or more of the flaps and the lids along one or more of: one or more contours; one or more inner surfaces; one or more portions facing or contacting surfaces of the crank; and one or more folding lines. For example, a path 110PF of the electrically-conductive tow across a folding line forms an angle that is equal to or less than 90° with respect to an average path direction running along a folding line, for example in a range from 60° to 30° with respect to the folding line. For example, the electrically-conductive tow comprises ends 110E1, 110E2 extending beyond an external contour of the plate, for example for connecting to a power supply source. For example, the ends are cut after bonding the plate to the crank. For example, one or more of the electrically-conductive tows are arranged one or more of against one or more of the faces of the plate and within the thickness of the plate, for example beneath one or more layers of material, for example thermoplastic material, comprised in the plate.

[0062] For example, a method for forming a wrapping around a part, for example the bicycle crank 1070, comprises one or more of: i) supplying electrical power to one or more of the electrically-conductive tows 110, for example raising a temperature along one or more folding lines 1070FL to a temperature greater than a glass transition temperature of a thermoplastic material comprised along the folding line; ii) forming one or more folds by applying a load against one or more of the plate and the crank for deforming the plate, for example against one or more of a face and an angle of the crank, for example against a die, for example against a sheet bending device; iii) closing the wrapping, for example by folding the third flap against the first flap; and iv) supplying further electrical power to one or more of the electrically-conductive tows 110, for example raising a temperature of one or more of the tows and thermoplastic materials along the tows to a melting temperature, for example for bonding the plate to the crank. For example, the method for forming the wrapping further comprises heating one or moreof the plate and the crank, for example in one or more of a press and a mold, for another example, by irradiating one or more of the plate and the crank with infrared energy, for example using a laser. For example, the method for forming the wrapping comprises pressing one or more of the flaps, the folds, and the lid surfaces against the crank.

[0063] Fig. 10B is a cross-section of the bicycle crank 1070 and of the foldable reinforcement plate 1070L3. For example, the plate 1070L3 comprises one or more grooves 1070G, for example formed along one or more of the folding lines 1070FL. For example, forming the grooves comprises depositing fewer layers of material, for example of material comprising a thermoplastic, along the groove compared to the locations comprising one or more of the flaps and the lid surfaces. For another example, forming the grooves comprises one or more of pressing using a die, cutting away, and eroding material of the plate. For example, forming the grooves comprises heating the plate, for example along the folding lines.

[0064] For example, the method for one or more of folding and bonding a foldable reinforcement plate 1070L3 is applicable to one or more of folding and bonding a skin 1060S to a structure, for example to an aircraft structure, for example to one or more of a wing and a fuselage structure. For example, the aircraft 1060 presented in Fig. 8 further comprises one or more electrically-conductive tows HOLE arranged along one or more of a leading edge, the lower surface, and the upper surface of the one or more wing section 1060WS of the aircraft.For example, a method for forming the wing section comprises supplying electrical power to one or more of the electrically-conductive tows 110, HOLE, 110F arranged in one or more of the skin 1060S and the structure of the aircraft, for example raising a temperature of the skin, for example configured as a sheet comprising one or more thermoplastic materials, along one or more folding lines to a temperature greater than or equal to a glass transition temperature of one or more of the thermoplastic materials comprised in the skin and applying a load to deform the skin against one or more of the structure of the wing section and a mold component or die having a geometry matching that of at least a portion of the wing section. For example, the method for forming the wing section further comprises supplying power to raise a temperature of one or more portions of one or more of the wing skin and a structure against which the wing skin is in contact, for example pressed against, to a melting temperature of one or more of the thermoplastic materials comprised in one or more of the wing skin and the structure.

[0065] Fig. 12A is a side view of a robotic system 2000 for depositing a filament or tow 100, 110, for example an elongate fiber tow. For example, the system 2000 is used to deposit an electrically-conductive tow 110. For example, the system 2000 comprises a slide head 2800 comprising one or more axes 2810, 2820. For example, the slide head 2800 comprises a first axis 2810 that is orthogonal to a second axis 2820. For example, the slide head 2800 is connected to a tow deposition head 2100. For example, a method for depositing a tow 100, 110, for example using the tow deposition head 2100, comprises depositing one or more tows 100,110, for example a section of an elongate fiber tow, onto a supporting surface, for example the substrate or build plate 200. For example, the tow deposition head 2100 moves, for example translates, in one or more directions with respect to the substrate or build plate 200. A method for forming one or more parts 1000, 1005 comprising an electrically-conductive tow 110 comprises rotating 5030 the shoe 2101 connected to a rotating support 2102, for example rotating around a rotating axis 1130MPZ, for example parallel to the Z-axis. For example, one or more of the axes 2810, 2820 is intersected by the Z-wise extension of the rotating axis 1130MPZ. For example, the system 2000 further comprises a polymer deposition head 2002, for example comprising an extruder 2002E. For example, one or more of the thermoplastic-rich paths 120 are deposited by the polymer deposition head 2002. For example, one or more of the tows and other materials, for example the thermoplastic-rich paths, are deposited in one or more layers 201 , 202.

[0066] For example, the system 2000 for depositing a filament or tow 100, 110 comprises a computer system 4000, for example to control the tow deposition head 2100. For example, the computer system 4000 generates or receives, for example from one or more of a computer network and a non-transitory computer-readable storage medium (NTCRSM) 4120, instructions to form one or more of the parts 1000, 1005 and depositing one or more of the electrically- conductive tows 110. For example, the NTCRSM comprises instructions for one or more of: orienting the shoe 2101 into one or more directions with respect to the direction at which the tow deposition head 2100 advances with respect to the substrate 200; rotating the shoe 2101 during deposition of the filament or tow 100, 110, for example simultaneously to advancing the shoe with respect to the substrate 200, for example as a function of the radius of curvature of the path of the tow being deposited; dispensing filament or tow 100, 110 at one or more rates, for example as a function of one or more of the speed at which the shoe 2101 is advancing with respect to the substrate 200, the radius of curvature of the path of the tow being deposited, the orientation of the show with respect to the direction at which the tow deposition head 2100 advances, and the rotating speed of the shoe.

[0067] Fig. 12B is a bottom view of the shoe 2101 for depositing the filament or tow 100, 110. For example, the shoe 2101 comprises a first toe surface 1161 and a second toe surface 1162 set at an azimuthal offset comprised in a range from 30° to 90° with respect to the frontal direction of the shoe. For example, the device comprises: a shoe surface 1150, for depositing the filament or tow 100, 110 onto the surface of an object, for example the substrate 200, the shoe surface 1150 comprising a straight shoe segment 1110 for applying the fiber tow 100 onto the surface of the object, the straight shoe segment 1110 comprising a rear end 1112 and a front end 1111 that define a frontal direction Fx from the rear end to the front end. For example, the filament 100, 110 is channeled, for example supplied, into a channel 2101C of the shoe 2101 that partially surrounds the axis of rotation ZR of the shoe and comprises an opening2101CO oriented towards a forward direction Fx of the shoe. For example, the shoe surface 1150 comprises a first toe surface 1161 at a first side of the channel 2101C and a second toe surface 1162 at a second side of the channel. For example, the channel comprises a flared end 1120 for guiding the filament onto the bottom surface of the shoe. For example, the geometry of the bottom of the shoe comprises an azimuthal sector 1150A of a truncated hollow body of revolution the axis of which is comprised within the channel 2101C. For example, the axis is colinear with the axis of rotation of the shoe.

[0068] Fig. 13 is a block diagram of the method 5000 for forming a composite device, the method comprising forming 5010 a first part 1000 and bonding the first part to a second part 1005 using a method of electric resistance welding. For example, the method 5000 comprises rotating 5030 the shoe 2101 of the tow deposition apparatus 2000. For example, the shoe 2101 is connected to a rotating support 2102, for example connected to a motor (not shown). For example, the forward direction Fx of the shoe is oriented along a tangent to the path of the tow during deposition of the tow 110. For a further example, rotating the shoe, for example progressively as the shoe advances with respect to the substrate, into an increasing cant angle of the forward direction Fx of the shoe with respect to a tangent to the path of the tow during the forming of the curve 150C within the path of the tow, improves the flatness of an exposed surface of the tow. For example, the cant angle is into the turn of the path formed by the deposition of the tow. For example, the increase in cant angle is commanded if the radius of curvature of the path of the tow is less than a threshold, for example less than 5 tow widths 100W. For example, the cant angle is one or more of reduced and canceled upon completing the forming of the curve and, for example, continuing depositing into a straight path.

[0069] For example, the method 5000 for forming a composite device 1010, comprises forming 5010 a first part 1000 by depositing 5020 one or more electrically-conductive tows 110 onto a substrate 200, 201 , 202. For example, one or more of the tows comprise one or more electrically-conductive fibers 100EF. For example, the electrically-conductive tow is forming a path 150 comprising one or more curves 150C. For example, the depositing comprises rotating 5030 the rotatable shoe 2101 for guiding the tow along the curves of the path. For example, the method 5000 comprises placing 5040, for example comprising pressing, a second part 1005 against the first part. For example, the method 5000 comprises passing 5060 an electrical current through the electrically-conductive tow.

[0070] For example, the method 5000 for forming a composite device 1010, comprises: forming 5010 a first part 1000 by depositing 5020 an electrically-conductive tow 110 onto a substrate 200, 201 , 202, the tow comprising one or more electrically-conductive fibers 100EF; placing 5040, for example comprising pressing, a second part 1005 against the first part; and passing 5060 an electrical current through the electrically-conductive tow, wherein the electrically-conductive tow is forming a path 150 comprising one or more curves 150C; and the depositing comprises rotating 5030 a rotatable shoe 2101 for guiding the tow along the curves of the path.

[0071] For example, one or more of: the forming 5010 one or more of the parts 1000, 1002, 1005; and the bonding 5050, for example comprising passing 5050 an electrical current through the electrically-conductive tow 110, are carried out within one or more environments and onboard one or more infrastructures. For example, the infrastructure comprises one or more of: one or more enclosures; a shipping container; a clean room; one or more sealed enclosures; a vacuum chamber; and a pressurized vessel. For example, the environment comprises one or more of: a controlled environment premises; a clean room environment; an atmospheric environment; an environment subjected to ionizing radiation; a gaseous environment where the ratio of oxygen is greater than 20%; a condensing atmospheric environment; a fluid, for example water; an outer space vacuum environment; and a planetary atmosphere environment. For example, the system 2000 executing the bonding 5050 is fastened to a vehicle, for example using one or more of bolts, straps, adhesives, welds, and a material comprising fiber hooks. For example, the vehicle comprises one or more of: a land-based vehicle, a ship, an aircraft, and a spacecraft. For a further example, one or more of the forming 5010 one or more of the parts 1000, 1002, 1005 and the bonding 5050 are executed in an environment wherein the acceleration due to gravity is less than about 9.8 m.s-2, for example onboard an aircraft executing one or more reduced gravity flight trajectories, for a further example onboard a spacecraft, for yet a further example on a celestial body other than Earth.

Claims

CLAIMS1. A method (5000) for forming a composite device (1010), comprising: forming (5010) a first part (1000) by depositing (5020) an electrically-conductive tow (110) comprising a thermoplastic material onto a substrate (200, 201, 202), the tow comprising one or more electrically-conductive fibers (100EF); placing (5040) a second part (1005) against the first part; and passing (5060) an electrical current through the electrically-conductive tow.

2. The method according to claim 1 , wherein one or more of the electrically-conductive fibers (100EF) comprise carbon fibers.

3. The method according to any one of the preceding claims, wherein one or more of the electrically-conductive fibers (100EF) comprise continuous fibers.

4. The method according to any one of the preceding claims, wherein the electrically- conductive tow (110) is forming a path (150) comprising one or more curves (150C).

5. The method according to any one of the preceding claims, wherein the electrically- conductive tow (110) is adjacent to one or more thermoplastic-rich paths (120).

6. The method according to any one of the preceding claims, wherein one or more of the first part (1000) and the second part (1005) comprise a thermoplastic material.

7. The method according to any one of the preceding claims, wherein the passing an electrical current through the electrically-conductive tow (110) comprises passing the electrical current from a first end (110E1) of the tow to a second end (110E2) of the tow.

8. The method according to any one of the preceding claims, wherein a third part (1002) comprising a thermoplastic material is comprised between the first part (1000) and the second part (1005).

9. The method according to any one of the preceding claims, wherein the electrically- conductive tow (110) has a rectangular cross-section.

10. The method according to any one of the preceding claims, wherein one or more of the curves (150C) comprise one or more U-turns.

11. The method according to any one of the preceding claims, wherein the electrically- conductive tow (110) has a width (100W) in a range from 0.3 mm to 5 mm.

12. The method according to any one of the preceding claims, wherein the electrically- conductive tow (110) is embedded into layer (201, 202).

13. The method according to any one of the preceding claims, wherein the electrically- conductive tow (110) is comprised within a recess (1020R, 1030R, 1040R, 1050R) at a surface of one or more of the first part (1000) and the second part (1005).

14. The method according to any one of the preceding claims, wherein the electrically- conductive tow (110) forms a lining (110L) along one or more portions of a border (1050B) of one or more of the first part (1000) and the second part (1005).

15. The method according to any one of the preceding claims, wherein the passing (5060) an electrical current comprises heating the thermoplastic material to one or more of a glass transition temperature and a melting temperature.

16. The method according to claim 15, wherein the electrically-conductive tow (110) is along one or more folding lines (1070FL).

17. The method according to claim 16, further comprising forming one or more folds by applying a load against one or more of the first part and the second part.

18. The method according to any one of the preceding claims, further comprising one or more of pressing, stamping, molding, and compression molding one or more of the first part and the second part.

19. The method according to any one of the preceding claims, wherein the depositing (5020) comprises rotating (5030) a rotatable shoe (2101) for guiding the electrically-conductive tow along the curves of the path.

20. The method according to claim 13, wherein the rotating (5030) comprises orienting a forward direction (Fx) of the rotatable shoe (2101) along a tangent to the path (150).

21. The method according to claims 13 or 14, wherein the rotating (5030) comprises orienting a forward direction (Fx) of the rotatable shoe (2101) into a cant angle with respect to a tangent to the path (150).

22. The method according to any one of claims 13 to 19, wherein the tow (110) is supplied into a channel (2101C) of the shoe (2101) that partially surrounds an axis of rotation (ZR) of the shoe.

23. The method according to any one of the preceding claims, wherein the method is executed onboard a vehicle.

24. A system (2000) for depositing a tow (110) comprising: a rotatable shoe (2101) comprising a channel (2101C) that partially surrounds an axis of rotation (ZR) of the shoe; and a non-transitory computer-readable storage medium (4120), wherein the non-transitory computer-readable storage medium comprises instructions for: depositing (5020) an electrically-conductive tow (110) comprising a thermoplastic material onto a substrate (200, 201, 202) wherein the depositing of the electrically- conductive tow comprises forming a path (150); and passing (5060) an electrical current through the electrically-conductive tow.

25. The system according to claim 24, further comprising a vehicle to which the system is fastened.

26. The system according to any one of claims 24 to 25, wherein the path comprises one or more curves (150C) and the depositing comprises rotating (5030) the rotatable shoe (2101)for guiding the electrically-conductive tow along the curves of the path.

27. A non-transitory computer-readable storage medium (4120) comprising instructions for: depositing (5020) an electrically-conductive tow (110) comprising a thermoplastic material onto a substrate (200, 201, 202) wherein the depositing of the electrically- conductive tow comprises forming a path (150); and passing (5060) an electrical current through the electrically-conductive tow.

28. The medium according to claim 27, wherein the path comprises one or more curves (150C) and the depositing comprises rotating (5030) a rotatable shoe (2101) for guiding the electrically-conductive tow along the curves of the path.

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