Transmission welding apparatus and welding method

Abstract

A transmission welding apparatus and a welding method for welding a thermoplastic resin material part in which a pressure plate is segmented into a plurality of plate segments which are movably arranged with respect to each other are disclosed.

Description

Technical Field

[0001] The present invention relates to a transmission welding device for welding parts made of thermoplastic resin materials and a method for transmission welding parts made of thermoplastic resin materials. Background Art

[0002] Transmission welding is a joining process by means of heat and pressure. Plastic material parts are joined by melting the interface between them and pressing them together. The heat is generated by laser radiation or infrared radiation. The pressure is applied via a transparent pressure plate driven by a pneumatic or hydraulic pressure generator. It is well known that this process is suitable for small parts. An exemplary welding method using infrared is described in the applicant's EP patent application EP3 953 153 A1. Summary of the Invention

[0003] The object of the present invention is to provide a transmission welding device suitable for welding large material parts and a suitable transmission welding method.

[0004] The object of the present invention is achieved by a transmission welding device having the features described in claim 1 and a transmission welding method having the features described in claim 9. Advantageous embodiments are disclosed in the dependent claims, the description and the drawings.

[0005] The transmission welding device for welding parts made of thermoplastic resin materials according to the present invention includes at least one heat source emitting thermal radiation and at least one pressure device adapted to apply welding pressure on the material parts. The pressure device includes at least one pressure generator, at least one pressure plate and at least one pressure transmission system, wherein the at least one pressure generator is used to supply pressure, the at least one pressure plate is transmissive to thermal radiation, and the at least one pressure plate is adapted to introduce pressure into the material parts, and the at least one pressure transmission system is used to transmit pressure to the pressure plate. At least one pressure plate is segmented into a plurality of plate segments, and the plurality of plate segments are arranged to be movable relative to each other.

[0006] According to the present invention, a method for transmission welding parts made of thermoplastic resin materials uses the welding device of the present invention.

[0007] The segmentation of the large pressure plate into a plurality of small plate segments enables the transmission welding of large material parts. The pressure segments can individually follow the local contour of the material parts. The plate segments are located on the material parts to be joined and follow their upper surfaces throughout the welding cycle, including compensation for thermal expansion and deformation during the welding process.

[0008] Separating a single pressure plate allows welding of material parts with thickness variations in one operation without changing or adjusting the welding equipment. This is highly beneficial for welding with tolerance compensation between joined parts. Even curved material parts can be joined. Exemplary applications in the aircraft industry are welding longitudinal beams or multipliers with ramps or thickness variations, welding stringers for the fuselage, welding wings and tails, welding longitudinal joints, welding circumferential joints, welding components to larger parts (e.g., for pressure bulkheads), welding movable parts or frames. Exemplary heat sources are infrared lamps and halogen lamps that emit 1 / 3 visible light and 2 / 3 infrared light.

[0009] For example, if machining convex or concave joints, due to workspace reasons, it may be advantageous not to directly pressure-activate each plate segment. For example, the plate segments can be linked to each other, which enables direct pressure activation of every other plate segment, while the segments between two active plate segments move passively via their rotational connection to adjacent active plate segments.

[0010] In a preferred embodiment, the plate segments are operatively connected to the same pressure generator. Thereby, only a single pressure generator is required.

[0011] In an alternative embodiment, the plate segments are operatively connected to separate pressure generators. Thereby, the plate segments can be positioned relative to each other in a very flexible manner, since they all have their own pressure generators.

[0012] Exemplary pressure transfer devices include at least one sliding element of a rod and a pressure generator housing. The rod extends between the at least one sliding element and the plate segment. Preferably, the rod is positioned on the opposite edge portions of the plate segment, thereby avoiding tilting of the plate segment when pressure is applied.

[0013] To support the rod, guiding means for guiding the rod are provided.

[0014] The at least one heat source can be positioned between the rods. Thereby, the heat source is positioned close to the plate segment.

[0015] Preferably, the heat source has a length that extends over all the plate segments. In one embodiment, two parallel heat sources are provided. To support the heat source at its ends, sliding elements can be provided that carry the heat source and slide on the upper material part during welding.

[0016] To avoid heating of the material part areas adjacent to the welding area, at least one heat protection element is provided.

[0017] In a preferred transmission welding method, after forming the joint segments, the welding joint is sequentially formed by moving the welding equipment forward. This enables the production of a joint that is longer than the transmission welding equipment, especially the extension of its plate segments in the joint direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In the following, preferred embodiments of the present invention are explained with reference to the drawings. It should be understood that the various elements and components are only depicted as examples and can be implemented and / or combined in ways different from those depicted. Furthermore, for reasons of brevity, components that are clearly corresponding to each other are not always described or referenced again for each figure. Schematically shown are:

[0019] Figures 1 to 4 different views of a first transmission welding device according to the present invention;

[0020] Figure 5 a longitudinal sectional view of a second transmission welding device according to the present invention;

[0021] Figures 6 to 9 different views of a third transmission welding device according to the present invention; and

[0022] Figures 10 to 12 different views of a fourth transmission welding device according to the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0023] In Figures 1 to 4 a first embodiment of a transmission welding device 1 of the present invention is shown. The device 1 is adapted to form a joint 2 at the interface between two material parts 4, 6 by heat and pressure. Exemplary material parts 4, 6 are thermoplastic resin material parts, in particular fiber-reinforced thermoplastic parts.

[0024] The device 1 has a main extension in its moving direction, which is the longitudinal direction x of the joint 2. The device 1 includes a heat source 8 that emits thermal radiation (in particular infrared light) and a pressure device 10 adapted to apply welding pressure on the material parts 4, 6. An exemplary heat source 8 is an infrared lamp or a halogen lamp.

[0025] The pressure device 10 includes: a pressure generator 12 for providing pressure, a segmented pressure plate 14 adapted to introduce pressure into the material parts 4, 6, and a pressure transmission system 16 for transmitting the pressure to the segmented pressure plate 14.

[0026] The segmented pressure plate 14 is divided into a plurality of plate segments 18. The plate segments 14a, 14b are arranged adjacent to each other in the longitudinal direction x and are operatively connected to the pressure generator 12 via the pressure transmission system 16. They can move relative to each other in the vertical direction z. They are made of a material that is transmissive to thermal radiation, such as transparent glass. They have a greater extension in the direction perpendicular to the joint 2 to be manufactured (horizontal direction y) than in the longitudinal direction x.

[0027] The pressure transmission system 16 includes a plurality of rods 20a, 20b and at least one sliding element 22a, 22b. Here, for each plate segment 14a, 14b, one sliding element 22a, 22b is provided. The rods 20a, 20b extend in the vertical direction z between the sliding elements 22 and the corresponding plate segments 14a, 14b. Each plate segment is operatively connected to two rods 20a, 20b (a pair of rods). A pair of rods 20a, 20b are positioned on the opposite edge portions of the plate segment 14a, 14b. The pairs of rods 20a, 20b are aligned in a row in the longitudinal direction x. Thereby a longitudinal space 24 (channel) is formed between the opposite rows of rods, in which the heat source 8 is positioned.

[0028] The sliding elements 22a, 22b are crossbeams forming the movable bottom of the pressure generator housing 26. They are movable in the vertical direction z by the application of pressure.

[0029] Furthermore, the pressure transmission system includes guiding means 28a, 28b for supporting the rods 20a, 20b, especially when pressure is applied, to avoid tilting of the rods 20. Here, the guiding means 28a, 28b are longitudinal plates extending over the entire length of the device 1. They are laterally fixed at different heights and have a plurality of through holes 30a, 30b through which the rods 20a, 20b are guided. Thus, since they are arranged at a certain vertical distance from each other, each rod 20a, 20b is radially guided at two vertical positions.

[0030] The pressure generator 12 includes a longitudinal pneumatic pressure tube extending over the entire length of the device 1. The pressure tube 12 is positioned in the pressure generator housing 26, which via its movable bottom (sliding elements 22a, 22b) enables a spatial expansion of the pressure tube 12 only in the lower vertical direction z.

[0031] The heat source 8 has a cylindrical shape and extends in the longitudinal direction x over all the plate segments 14a, 14b. The heat source 8 is fixed within the channel 24 (the space between the opposite rods) and is supported at its end located inside the welding device 1 by two holding elements 34. Here, the holding elements 34 are attached to the lower guiding means 28a. In order to concentrate the heat radiation onto the plate segments 14a, 14b, a concave shield 35 extending over the entire length of the plate segments 14a, 14b is positioned above the heat source 8.

[0032] In order to avoid heating the material part regions 36a, 36b adjacent to the welding area 18, heat protection elements 38a, 38b are provided on both sides in the longitudinal direction x. The heat protection elements 38a, 38b are positioned transversely to the heat source 8 and the plate segments 14a, 14b in the region between the lower guiding means 28a and the material parts 4, 6.

[0033] To position the transmission welding device 1 in place, side walls 40a, 40b are provided when the plate segments 14a, 14b are depressurized. The pressure generator housing 26 rests on the side walls 40a, 40b. The guiding devices 28a, 28b also rest on the side walls 40a, 40b, wherein the lower guiding device 28a divides each side wall 40a, 40b into two longitudinal side wall elements.

[0034] To form the joint 2, the transmission welding device 1 moves forward in the longitudinal direction x while applying heat and pressure. During the welding process, the plate segments 14a, 14b are pressed downwards. When forming the joint part (sequence), the pressure is reduced, and the welding device 1 moves forward. Then, the pressure is generated again, and the next joint sequence is completed.

[0035] In Figure 5 is shown a second embodiment of the transmission welding device 1 of the present invention. In contrast to the first welding device 1 according to Figures 1 to 4 , the second embodiment has two heat sources 8, 8a. The heat sources 8, 8a are of the same type and extend parallel within the channel 24 between a row of rods 20a, 20b. A concave shield 35 extends above the two heat sources 8, 8a.

[0036] In the appendix Figures 6 to 9 is shown a third embodiment of the transmission welding device 1 of the present invention. The third embodiment 1 is adapted to produce convex or concave joints such as known from an aircraft frame 42.

[0037] It includes a plurality of pressure devices 10, 10a, each pressure device being operatively connected to one of the plate segments 14a, 14b of a segmented large pressure plate 14. The large pressure plate 14 extends in the longitudinal direction x and has linked plate segments 14a, 14b, 14c, 14d. Thus, only every other plate segment 14a, 14b is directly pressure-activated (active plate segments) via rods 20a, 20b, 20C, 20d. The plate segments 14c, 14d between these active plate segments 14a, 14b are linked to them via rotary joints 44a, 44b and move passively (passive plate segments). Each rotary joint 44a, 44b enables a rotational movement about a horizontal axis. The active and passive plate segments 14a, 14b, 14c, 14d are all made of a transparent material permeable to infrared radiation. In addition, here four rods 20a, 20b, 20C, 20d are provided for each active plate segment 14a, 14b, and only one guiding device 28 and one sliding element 22 as the movable bottom of the pressure generator housing 26 driven by a pressure generator (such as a pressure tube 12).

[0038] Each pressure device 10, 10a is positioned in a single holding frame 45. Each holding frame 45 has two parallel legs 46, 48 extending in the horizontal direction y. The lower leg 46 serves as a counter-bearing adapted to be positioned on the lower side 48 of the flange 50 to be processed. The upper leg 48 is used to guide and carry the pressure devices 10 and 10a in the vertical direction z on the upper side 52 of the flange 50 to be processed.

[0039] A single heat source 8 is positioned in the channel 24 between a row of rods 20a to 20d and extends over the entire length of the welding device 1 and thus over the entire segmented pressure plate 14. The heat source 8 has a cylindrical shape and is positioned in a separate carrier 56. The carrier 56 has a longitudinal beam 58 which is pivotally supported in the front slider 60 and the rear slider 62 in order to balance the convex or concave curvature of the material parts 4, 6. Two pivot joints enable a rotational movement about a horizontal axis. During welding, the sliders 60, 62 are laid via their lower sides on the upper flange side 54. The heat source 8 is also pivotally supported in the sliders 60, 62.

[0040] Furthermore, a heat radiation shield 35 and a heat protection element 38a divided into a plurality of parts 38c, 38d according to the pressure devices 10, 10b are provided. Between the pressure devices 10, 10b, the heat protection part 38d extends in the vertical direction z, thereby minimizing the gap between their adjacent pressure generator housings 26, 26a.

[0041] In order to form the transmission weld joint 2, the transmission welding device 1 is moved forward in the longitudinal direction x while applying heat and pressure. During the welding process, the plate segments 14a to 14d are pressed downwards. When the joint part (sequence) is formed, the pressure is reduced and the welding device 1 is moved forward. Then, the pressure is generated again and the next joint sequence is completed.

[0042] In Figures 10 to 12 shows a unit 63 of a fourth embodiment of the transmission welding device 1 of the present invention. The fourth embodiment 1 includes a plurality of units 63, wherein each unit 36 has a pressure plate segment 14a moved by two pressure generators 12, 12a. Furthermore, a pressure transmission system 16 without rods is provided. In addition, each plate segment 14a is equipped with its own heat source 8.

[0043] Each pressure generator 12, 12a has a pressure generator housing 26, 26a which is divided into a lower half 64a and an upper half 64b. The lower half 64a is supported by a slider 66 carrying the plate section 14 and the heat source 8. Inside each generator housing 26, 26a, a pneumatic pressure tube 12, 12a is provided. When the pressure tubes 12, 12a expand, the lower half 64a moves downward and applies a welding pressure to the slider 66 on the plate section 14a.

[0044] The heat source is oriented perpendicular to the moving direction x of the transmission welding device 1. Thus, the heating source 8 is oriented in the horizontal direction y. The heating source 8 is fixed at its ends above the respective plate sections and inside the slider 66 in the holding elements 34a, 34b.

[0045] To optimize the welding process, two vibration elements 68a, 68b can be arranged transversely to the plate section 14a in the slider 66.

[0046] To form a transmission welding joint, a plurality of units 63 are arranged adjacent to each other in the longitudinal direction x to a welding device 1 and then moved forward while applying heat, pressure, and vibration. During the welding process, the plate section 14a is pressed downward. When the joint part (sequence) is formed, the pressure is reduced and the welding device moves forward. Then, the pressure is generated again and the next joint sequence is completed.

[0047] It should be noted that for all embodiments, the entire joint can also be completed in one step instead of sequentially in multiple steps. This depends on the size of the joint, the size of the transmission welding device, and the profile of the parts to be welded. If the material part has a very complex profile, it may be advantageous to weld the material part in one step because in this way each plate section can be perfectly adapted and its lower pressing surface can be perfectly adapted to the corresponding very complex area.

[0048] The present invention discloses a transmission welding device for welding parts of thermoplastic resin materials, wherein the pressure plate is segmented into a plurality of plate sections which are movably arranged relative to each other, and the present invention also discloses a welding method.

[0049] Reference Signs 1 Transmission welding device / apparatus 2 Joint 4 Material part 6 Material part 8, 8a Heat source 10, 10a Pressure device 12, 12a Pressure generator / pressure tube 14 Segmented pressure plate 16 Pressure transmission system Plate segments 14a, 14b (active) Plate segments 14c, 14d (passive) Welding area 18 Rods 20a, 20b Sliding elements 22, 22a, 22b Channel 24 Pressure generator housings 26, 26a Guiding devices 28, 28a, 28b Through holes 30a, 30b Retention elements 34a, 34b Shield 35 Material part areas 36a, 36b Thermal protection elements 38a, 38b Side walls 40a, 40b Frame 42 Rotary joints 44a, 44b Retention frame 45 Lower leg 46 Upper leg 48 Flange 50 Lower side 52 Upper side 54 Carrier 56 Longitudinal beam 58 Front slider 60 Rear slider 62 Unit 63 Lower half of the generator housing 64a Upper half of the generator housing 64b Slider 66 Vibration elements 68a, 68b Longitudinal direction x Horizontal direction y Vertical direction z

Claims

1. A transmission welding device (1) for welding thermoplastic resin material parts (4, 6), the transmission welding device (1) comprising: at least one heat source (8, 8a), the at least one heat source (8, 8a) emitting thermal radiation; at least one pressure device (10, 10a), said at least one pressure device (10, 10a) being adapted to exert welding pressure on said material part, comprising at least one pressure generator (12, 12a), the at least one pressure generator (12, 12a) being used to supply pressure; at least one pressure plate (14), the at least one pressure plate (14) being transparent to the thermal radiation and the at least one pressure plate (14) being adapted to introduce the pressure into the material part; as well as at least one pressure transfer device (16) system, the at least one pressure transfer device (16) system being used to transfer the pressure to the pressure plate (14); The at least one pressure plate (14) is segmented into a plurality of plate segments (14a, 14b, 14c, 14d), and the plurality of plate segments (14a, 14b, 14c, 14d) are arranged to be movable relative to each other.

2. The transmission welding device (1) according to claim 1, wherein: The plate segments (14a, 14b, 14c, 14d) are rotationally linked to one another.

3. The transmission welding device (1) according to claim 1 or 2, wherein: The plate segments (14a, 14b, 14c, 14d) are operatively connected to the same pressure generator (12) or to separate pressure generators (12, 12a).

4. A transmission welding device (1) according to claim 1, 2 or 3, wherein: The at least one pressure transmission device comprises a rod (20a, 20b, 20c, 20d) and at least one sliding element (22, 22a, 22b) of a pressure generator housing (26), wherein the rod (20a, 20b, 20c, 20d) extends between the at least one sliding element and the plate segment (14a, 14b, 14c, 14d).

5. The transmission welding device (1) according to claim 4, wherein: Guiding means (28, 28a, 28b) are provided, which are suitable for guiding the rods (20a, 20b, 20c, 20d).

6. The transmission welding device (1) according to claim 6, wherein: The at least one heat source (8, 8a) is positioned between the rods (20a, 20b, 20c, 20d).

7. The transmission welding device (1) according to claim 6, wherein: The heat source (8, 8a) extends over all plate segments (14a, 14b, 14c, 14d).

8. Transmission welding apparatus (1) according to any one of the preceding claims, wherein At least one heat protection element (38a, 38b) is arranged in the moving direction of the transmission welding device (1).

9. A method (4, 6) for transmission welding parts of thermoplastic resin material, using a transmission welding device (1) according to any one of the preceding claims.

10. The method according to claim 9, wherein: The welded joints (2) are produced sequentially by moving the transmission welding device (1) forward after producing the joint segments.

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