DE102019113695B4 - Contour plate for applying hot gas along a welding line of a plastic part, method for producing a contour plate and a device for welding plastic parts - Google Patents

Abstract

Contour plate (20) for applying hot gas along a welding line of a plastic part (18), for use in a device (10) for welding plastic parts (18), which has a heating plate (12), on the opposite sides of which a heat exchanger plate ( 14) is arranged, which has a gas control system (16) for the hot gas, wherein the contour plate (20) is arranged on the outside of the heat exchanger plates (14) and has nozzles (22) for delivering the gas to the welding line, characterized in that A plurality of protruding nozzles (22) are provided on the surface (23) of the contour plate (20) which have a nozzle inlet opening (24a) and a nozzle outlet opening (24b), a cross section of the nozzle outlet opening (24b) being larger than a cross section of the Nozzle inlet opening (24a).

Description

The invention relates to a contour plate for applying hot gas along a welding line of a plastic part, for use in a hot gas welding device, which has a heating plate, on the opposite sides of which a heat exchanger plate is arranged, which has a gas control system for the hot gas, the contour plate on the outside of the Heat exchanger plate is arranged and has nozzles for delivering the gas to the welding line.

Devices for welding plastic parts which comprise a plate which contain bores for the application of hot gas along a welding line are known from the prior art.

EP 1 415 789 B1 discloses a method and a device for welding plastic parts, in particular for connecting plastic parts along a welding line. The device according to the invention for welding plastic parts comprises two heated, radiant heat emitting radiation bodies on opposite sides of a heating plate, in which there is a gas control system for the supply and heating of a hot protective gas. The radiation bodies comprise outer cover plates, in each of which there is a row of nozzle bores following the welding line for releasing the hot protective gas from the gas control system onto the welding line.

DE 100 19 300 B4 discloses a method for welding complex and delicate plastic parts. The device comprises a tool consisting of a heating plate with welding blocks attached to the top and bottom. A hot stream of natural gas is passed through the device onto the workpiece area to be welded. The gas is introduced into the inlet bore of the upper welding block and guided through a system of channels to a channel through which the hot gas is applied to the welding line.

The DE 10 2015 122 219 A1 describes a nozzle device for hot gas welding which has a plurality of nozzle tubes arranged next to one another in a transverse axis, from which a respective hot gas stream can be led out. At a distance from an outlet opening of the nozzle tube, a workpiece to be welded can be arranged, to which the hot gas flows can flow. The outlet openings have a cross-sectional shape which differs from a circular shape and which has a greater extent in the direction of the transverse axis and a smaller extent in a direction perpendicular to the transverse axis.

WO 2017/198 483 A1 discloses a method for welding a first shaped body to a second shaped body. For this purpose, a tool is used which has a first outer surface and a second outer surface, the first and the second outer surface each comprising a channel. The end of the first shaped body and the joining surface of the second shaped body are heated by a hot gas. The heated end and the heated joining surface are then brought into contact with one another, cooled and a weld seam is formed between the first molded body and the second molded body. Devices for welding plastic parts, which have a plate, can lead hot gas to the plastic part via a row of holes lead to uneven melt zones. Directly opposite the bores, there is a higher heat input on the surface of the weld metal than next to the hot gas jet. Round melt zones, so-called dimples, are created. Although these grow together with neighboring dimples, so that uniform melt zones arise on the surface, the dimples continue into the depths. Another critical factor when using round nozzle bores is that bores which are not perfectly aligned with the center of the welding rib lead to a preferably one-sided melting of the welding ribs. This leads to an uneven melt depth in the weld zone and thus to an impaired weld seam quality.

The invention is based on the object of creating a contour plate and a device for welding plastic parts, which enables an improved distribution of a hot gas along a welding line. Furthermore, the invention is based on the object of creating a method for producing a contour plate which is inexpensive and can enable the realization of complex shapes of the contour plate.

To solve this problem, a contour plate for applying hot gas, in particular a heated protective gas, to a welding line of a plastic part, of the type mentioned at the outset, is proposed, on the surface of which a plurality of protruding nozzles are provided, which have a nozzle inlet opening and a nozzle outlet opening a cross section of the nozzle outlet opening is larger than a cross section of the nozzle inlet opening. Due to the protruding nozzles, the hot gas can be distributed homogeneously along the welding line and directed to the welding line to be welded. The nozzle inlet opening, which is a continuation of the sub-distribution, is located at the foot of the nozzle. The nozzle outlet opening is located at the end of the nozzle and is aligned in the direction of the welding line to be welded. As a cross section in relation to the nozzle is to understand a surface that is orthogonal to the orientation orientation of the nozzle. Since the nozzles protrude from the contour plate and are aligned towards the welding line, the hot gas can be transferred in a targeted manner and a constant melting depth can be guaranteed. Due to the increasing cross-section towards the outlet opening, it is possible for the nozzle opening to cover the entire width of the welding rib. At the same time, the speed of the outflowing gas is reduced so that the heat transfer from the hot gas into the welding zone of the plastic component is optimized. Since the nozzle tapers at least partially in the direction of its connection point, it is partially flexible. In particular, it is more flexible than a nozzle of constant cross section with the same initial cross section as the nozzle according to the invention. As a result, the nozzle is designed to be adjustable in the transverse direction to the welding line. Component tolerances of the plastic parts can thus be compensated for.

Advantageous refinements of the invention are the subject matter of the subclaims.

The cross section advantageously expands from the nozzle inlet opening to the nozzle outlet opening. The course of the expansion of the nozzle cross-section from a nozzle inlet opening to a nozzle outlet opening can be linear, exponential, step-shaped, undulating or shaped in any desired manner. This enables an improved flow and distribution of the hot gas.

In a further advantageous embodiment, the nozzle has a lower nozzle area that is rectangular. Two thirds of the lower nozzle area extends from the base of the nozzle to the nozzle outlet opening, while the upper nozzle area extends for one third from the nozzle outlet opening to the base of the nozzle. Furthermore, the nozzles can be largely rectangular in cross section.

In a further conceivable advantageous embodiment, the cross section of the nozzles is oval, square, triangular or trapezoidal. These can also be arranged next to one another in combination with a large number of nozzles.

Nozzles which have curved sides, in particular in the upper nozzle area, are also conceivable. This makes it possible to apply the hot gas evenly along different lines on welding lines. It should be noted, however, that the nozzles advantageously have a lower area which can be adjusted in the transverse direction and which is curved as little as possible perpendicular to the bending direction. Furthermore, a double or also multi-row row of nozzles running parallel to one another is conceivable. This makes it possible to form parallel weld seams that run close to one another in the case of particularly large wall thicknesses of the welding zones.

An upper nozzle area of the nozzles advantageously runs along a welding line. This allows a continuous weld line to be formed.

Adjacent nozzles are advantageously spaced apart by a uniformly narrow gap, the gap running in the plane perpendicular to a weld line. In this way it is possible for the hot gas to flow evenly over the entire welding surface and to avoid dimples.

The nozzles are advantageously designed to be adjustable in the transverse direction to the welding line. Component tolerances of the plastic parts can thus be compensated for.

The nozzles advantageously have a smaller wall thickness in the lower nozzle area than in the upper nozzle area. This ensures that when the nozzle is aligned, the lower nozzle area is deformed, whereas the cross section of the upper nozzle area remains unchanged.

The nozzles advantageously have a radius in the region of the transition to the surface of the contour plate. Alternatively, the nozzle can have a wall thickness that decreases from the surface of the contour plate to the remaining lower nozzle area of the nozzle. This ensures a reduced notch effect in the transition area between the nozzle and the surface of the contour plate. A repeated adjustment without fatigue in the area of the transition to the surface of the contour plate is guaranteed.

The nozzles advantageously have opposite guide plates at the nozzle outlet opening. These can be used to guide the hot gas. As a result, an additional, more precise guidance of the hot gas to the weld seam can be guaranteed. In addition, the heat transfer can be optimized in this way, so that shorter process times are possible.

The alignment of the guide plates is advantageously adjustable. This ensures that the hot gas can be matched to the component tolerances and the hot gas is brought to the weld seam.

Advantageously, there are no guide plates at the intersection of the welding line. These can be omitted on individual nozzles and / or on individual sides in such a way that the weld metal can dip into the groove that is being formed.

The nozzle head advantageously has a protruding plateau on which at least one guide plate is arranged. The guide plate can be designed straight or curved. The plateau has the advantage that, despite an uncurved nozzle cross-section, curved guide plates can be implemented.

Furthermore, in order to achieve the object, a method for welding plastic parts is proposed in which the contour plate is produced in a 3-D printing process. Any nozzle contours can be produced by such a production. In particular, a rectangular contour in the cross section of the nozzles can be represented in this way, in contrast to a bore which has a round opening. The manufacturing process enables a large number of different nozzle geometries to be created. Another advantage is that the nozzle geometries that can be created by means of the manufacturing process also prevent the formation of round dimples in the area of the weld seam on the plastic part and further reduce the lateral outflow of the hot gas.

The outer surface of the nozzle advantageously has an inclination of up to 45 ° at the most. This simplifies the manufacturing process due to reduced post-processing costs, since no support structures are required for 3D printing.

The nozzle head advantageously has a plateau which is supported by a support web in the manufacturing process. The plateau is supported by means of the support bar printed for production. After production, the support bar is removed mechanically. The plateau has the advantage that the upper area of the nozzle remains unbent when the guide plates are adjusted.

The contour plate is advantageously made from a metal, in particular steel or aluminum. This allows a shielding gas with high process temperatures for welding plastic parts to be passed through the gas guide plates and nozzles.

Furthermore, to achieve the object, a device for welding plastic parts, in particular for connecting plastic parts along a welding line to a heating plate, is proposed, on the opposite sides of which a heat exchanger plate is arranged, which has a gas control system for the hot gas, with a contour plate on the Outside of the heat exchanger plate is arranged and has nozzles for delivering the gas to the welding line. The contour plate of such a device can advantageously be exchanged and particularly well weld plastic parts.

• 1 einen Längsschnitt durch eine Vorrichtung zum Schweißen von Kunststoffteilen mit einer Konturplatte gemäß einer möglichen Ausführungsform;
• 2 einen vergrößerten Ausschnitt der in 1 gezeigten Konturplatte;
• 3 eine Draufsicht auf die in 2 dargestellte Konturplatte;
• 4 einen vergrößerten Ausschnitt einer zweiten Ausführungsform der in 1 gezeigten Konturplatte;
• 5 einen Schnitt entlang der Linie I-I in 4;
• 6 einen vergrößerten Ausschnitt einer dritten Ausführungsform der in 1 gezeigten Konturplatte;
• 7 einen vergrößerten Ausschnitt einer vierten Ausführungsform der in 1 gezeigten Konturplatte;
• 8 Draufsicht auf die in 7 gezeigte Konturplatte;
• 9 einen vergrößerten Ausschnitt einer fünften Ausführungsform der in 1 gezeigten Konturplatte;
• 10 einen vergrößerten Ausschnitt einer sechsten Ausführungsform der in 1 gezeigten Konturplatte;
• 11 einen vergrößerten Ausschnitt einer siebten Ausführungsform der in 1 gezeigten Konturplatte.

A contour plate and a device are explained in more detail below on the basis of exemplary embodiments which are shown schematically in the accompanying drawings. Here shows:

• 1 a longitudinal section through a device for welding plastic parts with a contour plate according to a possible embodiment;
• 2 an enlarged section of the in 1 contour plate shown;
• 3 a top view of the in 2 contour plate shown;
• 4th an enlarged section of a second embodiment of the in 1 contour plate shown;
• 5 a section along the line II in 4th ;
• 6th an enlarged section of a third embodiment of the in 1 contour plate shown;
• 7th an enlarged section of a fourth embodiment of the in 1 contour plate shown;
• 8th Top view of the in 7th contour plate shown;
• 9 an enlarged section of a fifth embodiment of the in 1 contour plate shown;
• 10 an enlarged section of a sixth embodiment of the in 1 contour plate shown;
• 11 an enlarged section of a seventh embodiment of the in 1 contour plate shown.

In the 1 illustrated device 10 for welding plastic parts 18th has a central heating element 12th with two opposing heat exchanger plates 14th on. In the heat exchanger plate 14th there is a gas control system in each case 16 . Between the heat exchanger plate 14th and the plastic part 18th is a contour plate 20th attached. The contour plate 20th is interchangeable with the heat exchanger plate 14th connected. The plastic parts 18th are exemplary on opposite sides of the device 10 for welding plastic parts 18th arranged.

The central heating element 12th is with the heat exchanger plates 14th connected in such a way that the heat goes to the heat exchanger plates 14th is transmitted.

The gas control system 16 conducts in the heat exchanger plate 14th the protective gas, in particular Nitrogen, and heats this up while sub-distributing it 29 the contour plate 20th to be led.

The contour plate 20th consists of metal, in particular steel or aluminum. The contour plate 20th is with the heat exchanger plate 14th connected in such a way that the heat on the contour plate 20th can be transferred until the required working temperature for heating the protective gas is set.

As in 1 can be seen, closes the sub-distribution 29 the contour plate 20th to the gas control system 16 at. Inside the contour plate 20th is an under-enticement 29 of the gas control system 16 available. All with a sub-distribution 29 connected nozzles 22nd form a heating circuit. Are multiple subdistributions 29 are present and if these are not connected to each other, there can also be several heating circuits to be independently temperature controlled.

From a surface 23 the contour plate 20th protrude nozzles 22nd from. At the foot of the nozzle 22nd is the nozzle inlet opening 24a which is a continuation of the sub-distribution 29 represents. The nozzle outlet opening 24b is at the end of the nozzle 22nd and is aligned in the direction of the weld line to be welded.

The nozzles 22nd the in 1 contour plate shown 20th are arranged in such a way that they cover all areas of the plastic part to be welded 18th can melt at the same time.

Optionally, but not shown here, the contour plate can also be divided into several contour plates, their nozzles 22nd together apply hot gas to the entire welding zone.

An enlarged section of the contour plate 20th is in 2 shown. The contour plate 20th has at least one nozzle 22nd or a row of nozzles 22nd on that from the surface 23 the contour plate 20th protrudes and is aligned towards the weld line. The nozzle 22nd has in the illustrated embodiment one in a horizontal plane 42 extending and to the nozzle outlet opening 24b the nozzle 22nd extending, enlarging sub-distribution 29 on. Thus, despite a slim, flexible design in the area of the connection of the nozzle 22nd to the surface of the contour plate 20th a wide welding zone can be exposed to hot gas at the same time and evenly. In addition, the flow rate of the protective gas is relative to the enlargement of the cross section of the nozzle 22nd reduces the heat transfer from the gas to the welding line of the plastic part 18th can improve.

An upper nozzle area 32 the nozzle 22nd has a wider cross-section than a lower nozzle area 34 the nozzle 22nd . A transition 36 the nozzle 22nd to the surface of the contour plate 23 is provided with a radius. This will help when aligning the nozzle 22nd across the welding line along an adjustment direction 38 the notch effect in this area is reduced. By means of the orientation of the nozzle 22nd the hot gas flow can be aligned within the adjustment range. In particular, component tolerances of the plastic part 18th be compensated. The welding zone is melted more evenly, the welding quality can consequently be increased and, as a result, there can be scrap of plastic parts to be welded 18th can be significantly reduced.

In 3 is a top view of the contour plate 20th with nozzles 22nd the in 2 illustration shown. Here the nozzles point 22nd a rectangular contour, which can also be largely rectangular. Furthermore, the illustrated embodiment has the nozzles arranged in a row 22nd along a weld line. The nozzles 22nd a row form an almost continuous line running in the direction of adjustment 38 can be aligned transversely to the welding line. The hot protective gas flows out of the nozzles 22nd on the plastic part 18th along the welding line to be welded, the rectangular shape of the shielding gas evenly on the welding line of the plastic part 18th is distributed and so the formation of round melt dimples is avoided.

After the welding line by means of the hot protective gas and possibly also by radiant heat, starting from the contour plate 20th , has been heated, the device 10 away. Then the opposite plastic parts 18th pressed together and welded in the process.

The contour plate is manufactured 20th by means of a 3-D printing process. Existing nozzle outer surfaces exceed 25th a maximum opening angle of 45 °. The opening angle of the nozzle outer surface 25th is based on a vertical plane 41 measured and corresponds to 90 ° - α. Due to the 3-D printing process of the contour plate 20th can make complex shapes of the contour plate 20th and especially the sub-distribution 29 in the contour plate 20th which are connected to the gas supply system 16 connected. The sub-distribution 29 in the contour plate 20th have an elongated passage or opening geometry which is configured such that the surface of the subdistribution 29 the contour plate 20th , which is in contact with the protective gas, is enlarged. This can be achieved in particular by a labyrinth-like subdistribution or a subdistribution comprising lamellae 29 be implemented to guide the protective gas. The protective gas can be additionally heated and a more efficient temperature transfer can be created. The local cross-sections of the sub-distribution 29 can with regard to the desired distribution of the hot gas flows to the nozzles 22nd be adjusted. The shape of the cross-sections of the sub-distribution 29 can with regard to the flow resistance, to the heat transfer from the contour plate 20th in the hot gas and / or with regard to the manufacturability by means of a 3D printing process.

The following are embodiments of the contour plate 20th described, the reference numerals already used for the description of the same or functionally equivalent parts being used to describe them.

In 4th is a further embodiment of the contour plate 20th shown. The nozzles 22nd this embodiment have two opposite guide plates 26th on. These baffles 26th are on the outside of the nozzle 22nd , which runs largely parallel to the welding line, above the nozzle outlet opening 24b arranged. The baffles 26th protrude along the vertical plane 41 up from the nozzle 22nd and have a constant opening cross-section. The baffles 26th can in the rib to be welded with a corresponding geometry of the plastic part 18th immerse. This creates a uniform build-up of heat in this area. The baffles 26th are individually adjustable in the transverse direction to the welding line. The smaller their curvature perpendicular to the direction of bending 38 is, the easier it is to move the baffles towards 38 the manufacturing tolerances of the component 18th to adjust. A fine adjustment of the flow ratio of the hot protective gas can therefore also be carried out.

5 FIG. 11 shows a plan view of the section along the line I - I of FIG 4th . The upper edges of the baffles 26th stand above the nozzle outlet opening 24b . An almost continuous and coherent outlet opening is thus formed. The protective gas of the individual nozzles 22nd can through the baffles 26th not so easy on the side of the plastic part 18th flow past. This build-up of heat can create an even, homogeneous weld line without dimples on the plastic part 18th be generated.

6th shows a further embodiment of the contour plate 20th . The nozzle 22nd points in the area of a nozzle head 30th at its end a plateau 28 on. This plateau 28 runs horizontally. On the plateau 28 are baffles 26th arranged. This plateau becomes in a 3-D printing process 28 supported by means of supporting webs, not shown. These support webs are then removed mechanically. The advantage of this embodiment is that the baffles 26th on the plateau 28 exactly the curvature of the component 18th can follow, with the lower nozzle area 34 does not have to follow the curve. As a result, the lower nozzle area is in the direction of 38 more flexible than if the entire nozzle 22nd the curvature of the component 18th would follow.

In 7th is a further embodiment of the contour plate 20th shown. The nozzle 22nd points in the area of the nozzle head 30th the plateau 28 on, which also has a maximum opening angle of 45 °. Therefore, in this embodiment, no support webs are required in the manufacturing process. It thus represents a geometry that is optimized for production using 3D printing processes.

In 8th Figure 3 is a top plan view of the contour plate 20th shown. The curvature of the guide bleach 26th is aligned exactly to the weld line or the curvature of the rib in the illustration shown.

9 shows a further embodiment of the nozzle 22nd on a contour plate 20th . This shows in the lower nozzle area 34 the nozzle 22nd a constant cross-section. The upper nozzle area 32 has a funnel-shaped configuration. This increases the cross-section of the sub-distribution 29 the nozzle 22nd up to the nozzle outlet opening 24b the nozzle 22nd constant. A maximum opening angle of 45 ° is not exceeded.

10 shows an embodiment of the contour plate 20th with a nozzle 22nd . The lower nozzle area 34 of the nozzle 22nd is stable and the upper nozzle area 32 of the nozzle 22nd can with the baffles 26th adjusted. The upper nozzle area 32 the nozzle 22nd does not have a closed cross-section, the outer surfaces are in the horizontal plane 42 separated into at least two areas.

11 shows a further embodiment of the contour plate 20th with a nozzle 22nd on. The wall thickness of the nozzle 22nd is in the lower nozzle area 34 variable; in particular, in the present exemplary embodiment, it steadily decreases from the surface 23 the contour plate 20th in the direction of the outlet opening of the nozzle 22nd down. This results in a bending line without a pronounced notch effect at the transition 36 .

List of reference symbols

10

Hot gas welding device

12th

Heating plate

14th

Heat exchanger plate

16

Gas control system

18th

Plastic part

20th

Contour plate

22nd

jet

23

Surface of the contour plate

24a

Nozzle inlet opening

24b

Nozzle outlet opening

25th

Nozzle outer surface

26th

Baffle

28

plateau

29

Sub-distribution of the contour plate

30th

Nozzle head

32

upper nozzle area

34

lower nozzle area

36

crossing

38

Adjustment direction

41

vertical plane

42

horizontal plane

43

frontal plane

Claims (15)

Contour plate (20) for applying hot gas along a welding line of a plastic part (18), for use in a device (10) for welding plastic parts (18), which has a heating plate (12), on the opposite sides of which a heat exchanger plate ( 14) is arranged, which has a gas control system (16) for the hot gas, wherein the contour plate (20) is arranged on the outside of the heat exchanger plates (14) and has nozzles (22) for delivering the gas to the welding line, characterized in that A plurality of protruding nozzles (22) are provided on the surface (23) of the contour plate (20) which have a nozzle inlet opening (24a) and a nozzle outlet opening (24b), a cross section of the nozzle outlet opening (24b) being larger than a cross section of the Nozzle inlet opening (24a). Contour plate (20) Claim 1 , characterized in that a cross section widens from the nozzle inlet opening (24a) to the nozzle outlet opening (24b). Contour plate (20) Claim 1 or 2 , characterized in that the nozzles (22) have a lower nozzle area (34) which is rectangular. Contour plate (20) according to one of the preceding claims, characterized in that an upper nozzle area (32) of the nozzles (22) runs along a welding line. Contour plate (20) according to one of the preceding claims, characterized in that adjacent nozzles (22) are spaced apart by a uniformly narrow gap, the gap running in the plane perpendicular to a welding line. Contour plate (20) according to one of the preceding claims, characterized in that the nozzles (22) are designed to be adjustable in the transverse direction to the welding line. Contour plate (20) according to one of the preceding claims, characterized in that the nozzles (22) have a radius in the region of the transition (36) to the surface (23) of the contour plate (20). Contour plate (20) according to one of the preceding claims, characterized in that the nozzles (22) have opposite guide plates (26) at the nozzle outlet opening (24b). Contour plate (20) Claim 8 , characterized in that the alignment of the guide plates (26) is adjustable. Contour plate (20) according to one of the Claims 8 or 9 , characterized in that the guide plates (26) are omitted at the intersection of the welding lines. Contour plate (20) according to one of the Claims 8 to 10 , characterized in that the nozzle head (30) has at least one protruding plateau (28) on which at least one guide plate (26) is arranged. Method for producing a contour plate (20) according to one of the preceding claims, characterized in that the contour plate (20) is produced in a 3-D printing process. Procedure according to Claim 12 , characterized in that the nozzle outer surfaces (25) have an inclination of up to a maximum of 45 °. Procedure according to Claim 12 or 13th , characterized in that the contour plate (20) is made of a metal, in particular steel or aluminum. Device (10) for welding plastic parts (18), in particular for connecting plastic parts (18) along a welding line, which has a heating plate (12), on the opposite sides of which a heat exchanger plate (14) is arranged, which has a gas control system (16) for the hot gas, wherein a contour plate (20) is arranged on the outside of the heat exchanger plates (14) and has nozzles (22) for delivering the gas to the welding line, characterized in that a contour plate (20) according to one of the Claims 1 to 11 and / or a contour plate (20) produced according to one of the Claims 12 to 14th is provided.

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