KR20160057975A - Method of connecting metal strips - Google Patents

Abstract

The present invention relates to a method for connecting the terminal end of a first metal strip to the front end of a second metal strip especially in a strip processing line, wherein the terminal end and the front end forming an overlapped part of being vertically overlapped, and forming a plurality of connection points by clinching on an area of the overlapped part are connected to each other without cut. The method according to the present invention forms the first metal strip and/or the second metal strip as a metal strip cool rolled and not being annealed, and at least 20 connection points are formed per a meter of the width of the strips by clinching for connection of the strips.

Description

[0001] METHOD OF CONNECTING METAL STRIPS [0002]

The present invention relates to a strip processing facility in which in particular a strip processing facility in which the distal end and the leading end are positioned one above the other in the overlapping portion and are connected to each other at the connection points in the overlapping portion by no clinching and without clinching, And connecting the distal end of the first metal strip to the distal end of the second metal strip.

In a strip processing facility, also referred to as a strip processing line, the coil-wound strip is generally unwound at the upstream suction end, then extends through one or more processing stations and is rewound at the outlet end, Or alternatively cut into plates. The leading end of the new coil is connected to the distal end of the preceding coil so that the strip need not always be threaded again. Strip connections are particularly important because defective strip connections can negatively affect other processes.

Thus, the most diverse methods for strip connection by, for example, welding, punching and / or gluing are known from the prior art (see for example EP 2 202 025 (US 8,109,428) and EP 1 749 590 (US 2007/029039)].

Indeed, as an alternative to the conventional method, it is known that the strip connection may also be formed by a punching engagement, also referred to as clinching. Clinchening is a method of joining metal strips or metal sheets without the use of additional materials. A clinching tool generally consists of punch (s) and die (s). The strip to be connected is pressed into or against the die by a punch in a manner similar to deep drawing with plastic deformation. In this case, the strips are connected to each other by active bonding (and non-active bonding) without the use of rivets. Because of the configuration of the die and punch, the material flows in a direction that is transverse to, or into, the die, so that active connections are created as in a rivet connection, but not a separate rivet. Within the scope of the present invention, "clinching" means punching without and without breaking.

Such a method of the type described at the outset is known, for example, from WO 2014/033037 A1. In this case, the connection points are formed during the strip connection by clinching, and the plurality of connection points are spaced apart in the direction transverse to the direction of movement of the strip to form one or more rows of connection points. In this case, it is advantageous if the tools or tools are adjusted in a position-controlled manner.

The known method of connecting strips by clinching without separation has proved to be actually successful, but can be further improved. This is the starting point of the present invention.

It is an object of the present invention to form a method by which metal strips can be connected in a simple manner in a universal and high quality manner.

In order to achieve this object, in a general manner, the present invention relates to a method of manufacturing a strip, wherein the first strip and / or the second strip are formed of cold rolled and non-annealed metal strips, The connection point is set by the clinching.

For clinching, the parts to be joined need to have good ductility or good molding ability under compressive stress and tensile stress, or such articles are advantageous. Thus, in practice, it has been assumed that only metal sheets or strips having high elongation so far are suitable. For this reason, when joining aluminum strips, clinching has been limited to annealed aluminum strips so far. Surprisingly, it has now been found through testing that cold-rolled and non-annealed metal strips, for example aluminum strips, can be connected with sufficient quality by clinching. The tests show that even if the elongation at break of A80 is only 6% or less, clinching with good quality can be achieved. For elongation to rupture, the tensile test includes the difference between the measured length after rupture and the initial measured length based on the initially measured length, and the rupture elongation is specified as a percentage. Also, since the value of the tear elongation is determined as the ratio of the measured length to the cross-section of the specimen, the tear elongation is specified in more detail by the corresponding index, in which case the A80 tear elongation is measured in 80 mm Lt; RTI ID = 0.0 > tensile < / RTI > A metal strip having an A80 rupture elongation of 2% to 5%, preferably about 3% to 4% is preferably used. As a result, according to the present invention, satisfactory strip connection is achieved even in the case of cold-rolled and non-annealed metal strips. The metal strip may be, for example, aluminum or an aluminum alloy, or a strip of copper or a copper alloy. In this case, it is particularly important that the strip connection is formed by a plurality of connection points. Preferably, at least 40 connection points, preferably at least 80 connection points, particularly preferably at least 100 connection points, are used for strip connection. Due to the numerous connection points that form the strip connection, tearing of individual clinch points can be tolerated. In this regard, the present invention is based on the perception that it is possible to work in the boundary region where potentially separate clinch points are torn when the cold-rolled metal strips are connected without annealing. However, because of the number of clinch points, the durability of the strip connection is not severely impaired, the method according to the present invention can actually be used in cold-rolled metal strips without being annealed. In this case, a plurality of connection points can be formed in the row of connection points, and the plurality of connection points are distributed back and forth in the strip movement direction on the strip width or particularly preferably in the plurality of rows of connection points in the strip movement direction. In this case, one or more rows of connection points can be formed simultaneously with only one single press stroke. For this, reference can be made to what is disclosed in WO 2014/033037.

Advantageous variants of the invention are described below.

Optionally, the thickness of the distal end of the first metal strip and / or the thickness of the distal end of the second metal strip is measured prior to connection, and the clinching process is controlled or adjusted according to the measured thickness. The clinching consists of a clinching tool with a punch and a die. Thus, the depth of insertion of the punches or punches into the material is controlled or adjusted, e.g., according to the measured thickness of the strip or the specified thicknesses of the strips. In this case, the present invention is based on the recognition that the formation of a connection without cutting, and consequently without a cutting edge, is particularly important for the quality of the strip connection. This assumes that the punch will not penetrate too deep into the material. On the other hand, for the formation of satisfactory and solid connections, it is essential that the punches penetrate into the material to a sufficient depth, so that the penetration depth of the punch into the strip is particularly important. For this reason, it is possible in principle to carry out the joining process in a position-controlled manner. However, in accordance with the present invention, as an alternative to position adjustment or as an alternative to position adjustment, the control or adjustment of the joining process is effected according to the actual thickness of the metal strip. In fact, the thickness of the strip to be connected is known to deviate from or to a specific / hypothesized value. Now, according to the present invention, since the determination of the actual thickness of the metal strip is made, it is ensured that during the bonding process the bonding process is always carried out at an optimum penetration depth. Particularly preferably, both the thickness of the distal end of the first strip and the thickness of the distal end of the second strip are measured. Thickness measurements or thickness measurements can be made, for example, by laser thickness measurements.

In accordance with the present invention, since the thickness measurement is made, it is no longer necessary to precut a distal end or tip that potentially exhibits a greater thickness deviation, for example an excess thickness, but the strip connection can in any case be cut if necessary It can be formed in such a region as to become scrap.

Measurements of strip thickness or strip thicknesses are made before bonding and indeed preferably separately for each two strips. Alternatively, it is within the scope of the present invention to measure the overall thickness of the strips positioned above and below each other (before the bonding process). It is possible to measure the thickness or thicknesses in the vicinity of the coupling device or on the coupling device / coupling device. However, alternatively, the measurement may be made at another location, for example immediately downstream of the decoiler.

According to another aspect of the invention, one or more edge punches may be formed on one strip edge or two strip edges before or after connection of the strip and / or in a manner such that punches of the binding tool do not strike one of the strip edges and / It has been proposed to arrange the distal end and the distal end and / or the clinching tool in such a manner as not to be performed.

In this case, the present invention must ensure that a satisfactory clinch point has to be formed, and that the clinch point is not formed or present in the strip edge, in order to avoid problems when the strip is extended through the various parts of the device It is based on facts. For example, if a clinch point is formed at the edge of an existing strip, at such an inadequate clinch point, depending on the degree of coverage of the strip edge, the punch can form a jagged edge on the strip. In this area, the particles which are later fixed on the rollers, for example, leading to the markings on the strip, are separated during movement through the strip processing line. As a result, according to the present invention, precautions are taken to prevent the formation or presence of clinch points at the strip edges.

Accordingly, there is a possibility to selectively ensure that the punch of the engaging tool can not strike the strip edge during placement of the tip and / or end and / or placement of the tool.

Alternatively or additionally, the present invention proposes that one or more edge punches or stampings are introduced into one strip edge or two strip edges. Stamping from metal strips is basically known in the art. Thus, for example, when the new strip is wider than the existing strip, it is advantageous to edge punch the strip connection of strips of unequal width when the wide edge of the new strip can be secured to the line, for example the squeeze roller . To avoid this, in this case the edges are obliquely cut by stamping using a trapezoidal or semi-circular punching tool. According to the present invention, if the joining point is not cut by punching, there is a possibility of introducing an edge punch after connection of the strip.

Alternatively, it is possible to introduce one or more edge punches already before the connection of the strip. This is advantageous, for example, when there is a risk that the clinching punch will strike the strip edge. In this case, if the tool punch is prevented from striking the strip edge depending on the tool shape and strip width, the edge punch can be introduced before the strip is connected.

Apart from the abovementioned possibility of positioning the tip and the end in the center of the device, it is possible that only one of the strips is centered relative to the other strip. At this point, both ends or both strips lie outside the center of the device. Thereafter, the clinching tool is moved in the width direction so that its central axis corresponds to the distal end portion. Then, in order to prevent the clinch point from being located at the edge of the strip, the above possibility can be used again.

Optionally, it is possible that the clinching tool is present in a fixed state in the center of the device. The position of the two strips relative to the center of the device is measured. In this way, it is known that the clinch point is at the two connected ends. To prevent the clinch point from being punched, an edge punch is now made on each side. When trimming is also carried out on the line, the punching depth on each side also increases correspondingly, but the clinch point is not punched again.

According to another aspect of the present invention, it is proposed to lubricate the strip before and / or during clinching. The lubrication of the parts to be joined during the clinching is principally known to minimize tool wear during clinching and also to maximize the service life. In practice, however, lubrication appears to be disadvantageous to the deep-drawing process during clinching. This relates to the fact that the lubrication reduces the friction of the part or strip to which it is to be joined and that this can have a negative impact on the connection quality or the connection strength. Thus, as a starting point, the present invention now proposes coating only the upper surface of the upper metal strip and the lower surface of the lower metal strip with oil. As a result, according to the present invention, the oil supply is exclusively made on the lower strip from below and on the upper strip from above, so that there is no lubrication between the two strip ends. Thus, the problem that is actually observed can be avoided in a simple and reliable manner. At the same time, tool wear can be minimized and the life span can be maximized.

In an alternative embodiment of the present invention, the strips are connected to each other by a tempered clinching. At this time, the metal strip to be connected is heated before and / or during the connection. To this end, the strip itself may be preheated with a suitable temperature controller and then cleaned. Alternatively or additionally, the temperature adjustment can also be done by the clinching tool itself. For this, there is a possibility of heating the upper tool and / or the lower tool, so that the strip is preheated under contact pressure and then deformed. To this end, it may be advantageous to work with a non-contoured die or amorphous counter tool, and the counter tool and / or punch may be heated. When the strip is heated by one or two tools, it may be advantageous if the strip is pressed together by suitable means prior to clinching or pressing, for example by a clamping device or the like. It is therefore possible to press the strip with the suppression tool against the (heated) corresponding surface, so that heating of the connection area is achieved. Then, clinching is done with the help of punch. However, the contact pressure during heating can also be influenced by the tool or punch itself. In the (first) heating state, only the fixing and heating of the strip are performed, and in the (second) cleaning state, the connection is made.

For tempering type clinching, it is advantageous if the movable tool, for example the top tool, can be adjusted in position, especially when the punch must be placed on the strip in order to preheat the contact in the heated state. In the case of contact preheating, it is advantageous if, with the aid of a tool, the contact pressure (during heating) is adjustable according to the strip.

Tempering (heating) of the metal strip improves formability or molding ability, so that the joining process can be optimized. This is particularly advantageous for the connection of brittle materials because the moldability of the brittle material is improved by tempering. Overall, tempering may be advantageous in the case of certain materials or combinations of materials. The formation of cracks can be avoided.

The method according to the invention may be practiced with an apparatus for connecting metal strips. Such a device is generally a connection press with a press frame, an upper press portion and a lower press portion, wherein the upper tool having at least one punch (or die) for clinching is carried by the upper press portion, A lower tool having at least one die (or punch) is delivered by a lower press portion, and the upper press portion and / or the lower press portion are moved (relative to each other) by one or more drive portions for application of a pressing force, Characterized in that the connecting press is movable. Therefore, there is a possibility to move the upper press portion to the upper tool with the aid of the driving portion with respect to the fixed lower tool, or vice versa. The driving portion may be, for example, a hydraulic pressing cylinder. In this case, an existing design of a punching type connection press may also be used. Since a high pressing force can be applied, it is possible to set up a plurality of connection points at the same time as the individual connection points, in particular one or more complete rows of connection points.

Accordingly, the present invention is a multiple tool with multiple tools (or punches) with multiple tool punches (or punches) on which the lower tool is distributed over a strip width, Lt; / RTI >

It should be noted that, given the fact that the method is adaptable to different strips, in particular to different strip thicknesses, in a simple manner, it is possible to obtain a plurality of strips which can be selectively moved from the working position inside the press to the standby position outside the press, A tool changer having an upper tool and a plurality of lower tools (and consequently a plurality of tool sets) is particularly preferred.

With the aid of a tool changer it is possible to provide a number of clinching tools or tool sets, so that a simple adaptation of the device to particular situations, especially to different strip thicknesses can be made. It is also possible to have additional (conventional) punching tools in the tool changer, so that the device can also be switched to a punching device if necessary.

As mentioned above, tools for clinching generally have a punch on one side and a die on the other. The die can be, for example, a die with a shape or profile that can be adapted to the shape of the punch. However, within the concept of the present invention, the so-called " die-less "clinching method is also included because the" die " may also refer to an irregular flat die and consequently a flat counter tool.

The apparatus may be provided with one or more thickness sensors capable of measuring the thickness of the distal end of the first metal strip and / or the thickness of the distal end of the second metal strip. Furthermore, a control device and / or an adjustment device can be provided, whereby the clinching process can be controlled or adjusted according to the measured thickness or specified thicknesses. It is also possible to provide one or more punching devices capable of effecting one or more edge punching before and / or during connection of the strip. Finally, the device may be equipped with one or more lubricators, whereby lubrication may be effected on metal strips or metal strips and / or tools.

BRIEF DESCRIPTION OF THE DRAWINGS The invention is described in more detail below with reference to the drawings, which show only one embodiment.

1 is a vertical sectional view through the first embodiment.
Fig. 2 is a simplified view in the x-direction of Fig.
3 is a vertical sectional view through the second embodiment.
4 is a side view of the second embodiment of Fig.
Figure 5 is a simplified view in the y direction of Figure 3;
Figure 6 is a simplified view of a clinch connection with a strip thickness measuring part.

The figure shows an apparatus for connecting metal strips, in particular for connecting the ends of a first metal strip to the tip of a second metal strip. Such a device is preferably integrated in a strip handling facility (strip processing line), for example at the upstream suction end of such a strip processing line. The coiled metal strip is unwound at the suction, then extends through the various processing stations, and is coiled again at the downstream outlet end or further processed in some other way. The tip of the new coil is connected to the distal end of the preceding coil so that the metal strip need not always be threaded again. To this end, the distal end and the distal end are located on top of each other in the overlapping section, and are connected to each other at a plurality of connection points of the overlapping section. This connection process is known in principle. The metal strips are not shown in Figs. 1 to 5, only the strip plane E is shown.

According to the present invention, the connection point is formed by clinching without cutting. To this end, the device has, in turn, a connecting press 2 with a press frame 3 having an upper part 4 and a lower part 5. The strip moving direction B is shown in Fig. 4, and in Fig. 1 and Fig. 3, this direction is perpendicular to the drawing plane. The upper tool 6 with a plurality of punches 8 for the clinching is carried by the upper press part 4. The lower tool 7 with a plurality of dies 8 for the clinching is carried by the lower press part 5. The upper tool 6 with the punch 8 and the lower tool 7 with the die 9 form the tool sets 10a, 10b and 10c. The upper tool 6 and the lower tool 7 have multiple tools each having a plurality of punches 8 and dies 9 distributed over a strip width. In the illustrated embodiment, the upper press portion 4 can be moved relative to the stationary lower press portion 5 by the drive portion 11 for application of a pressing force. Here, the driving portion 11 is a hydraulic pressing cylinder 11, the piston of which is connected to the movable upper press portion 4 and is also supported on the stationary upper beam of the press frame 3. Figs. 1 and 3 respectively show a divided press 2 in which one half is closed and the other half is open. The upper press part 4 is guided onto the guide part 15 on the press frame 3.

The illustrated embodiments each have a tool changer 12 having a plurality of tool sets 10a, 10b and 10c each consisting of an upper tool 6 and a lower tool 7, respectively. With the aid of this tool changer 12, the individual tool sets 10a, 10b, 10c can be selectively moved from the working position inside the press to the standby position outside the press and vice versa. In this way, it is possible to replace the tool, and also to adapt the device to the requirements, for example to the respective strip thicknesses. For connection of a particular strip thickness, different tools are preferably used.

Figures 1 and 2, on the one hand, and Figures 3 to 5, on the other hand, illustrate two embodiments with differently configured tool changers 12.

1 and 2, a first embodiment in which the tool 6, 7 is moved by the tool changer 12 in a direction transverse to the strip moving direction B from the working position to the standby position is shown. In this embodiment, the tool changer 12 is laterally adjacent to the press 2 for this purpose. It has an exchange table 14 with a plurality of tool sets 10a, 10b, 10c lying one behind the other in the strip moving direction B. If the tool located in the connecting press 2 is replaced, it is pulled (or pressed) in the direction transverse to the strip moving direction B onto the exchange table 14 from the press. Thereafter, the exchange table 14 is moved by one position, for example, so that another tool can be pressed into (or pulled into) the press 2 in a direction transverse to the strip moving direction B And moves in parallel with the strip moving direction. In the simplified plan view of Figure 2, it can be seen that four different tools or tool sets 10a, 10b, 10c, 10 'are in the tool changer 12 in the illustrated embodiment. Three tool sets 10a, 10b and 10c, to which the first, second and third columns of the connection points can be set, are provided for clinching. As a result, the first tool set 10a has a single row of punches and dies, while the second set of tools 10b has two rows of punches and dies positioned one behind the other in the strip moving direction B, Tool set 10c has three rows of punches and dies that are positioned one behind the other in the strip moving direction so that the tool sets 10a, 10b, and 10c can be selectively moved in one single press stroke, 1, 2, or 3 connection points can be set. Also, provided an additional tool set 10 ', which is a punching tool 10', the press may then be simply switched for a punching connection. It is apparent that for example different tool sets may be used for different strip thicknesses or strip thickness areas, and that the individual tool sets 10a, 10b, 10c generally have different point diameters or punch diameters. For thin strips, small spot diameters are commonly used, and also a relatively large number of connection points are set. For thicker strips, larger spot diameters are used, and generally fewer points are set.

In this case, it can be seen that the upper tool 6 and the lower tool 7 are connected to each other by the guide portion 13 to form the tool set 10a, 10b, 10c. Here, there is a guide post 13 which ensures that the upper tool 6 and the lower tool 7 with punches and dies are moved together satisfactorily at the desired position. In this case, each tool set has four guide poles 13 at its corners. This also applies to the embodiment according to Figures 1 and 2 as well as the embodiment according to Figures 3 and 4. [

Although the tool set 10a, 10b, 10c or 10 has been changed in the direction transverse to the strip moving direction in the embodiment according to Figures 1 and 2, Figures 3-5 illustrate the tool set 10a, 10b, 10c or 10 ) Is moved along the strip moving direction (B) for exchange purposes. The individual tool sets are again in a back and forth position relative to each other in the strip movement direction, but this time they are not offset laterally with respect to the connection press 2 and are offset relative to the connection press 2 in the strip movement direction. Nevertheless, the movement of the metal strip is not disturbed because the upper tool 6 is always on the metal strip or strip plane E or the lower tool 7 is always under the metal strip, (13) is always outside the strip region. In this embodiment, the tool set may also change when the strip is in the machine. 4 shows the punch tool 10 in the machine, for example.

To replace the tool sets 10a, 10b, 10c, 10, a hydraulic drive unit, which is not shown in detail in the drawings, is generally provided as an exchange drive unit.

The tool shown in Figs. 2 and 5 can be formed by a device according to the present invention at the same time that a plurality of connection points spaced in a direction transverse to the strip moving direction B can be formed at the same time, Thereby forming at least one row of connection points extending over the width. As the tool is used, multiple rows of connection points that are positioned one behind the other in the strip movement direction may also be formed at the same time. Thus, even if there are several rows of connection points, there is a possibility to connect the entire strip with one single press stroke. The connecting press provides a sufficient pressing force to the hydraulic cylinder 11.

The principle of the clinch connection according to the present invention is shown by way of example and in a simplified manner in Fig. In this case, the distal end of the first metal strip B1, the tip of the second metal strip B2 and its overlapping portion are shown, and the connection point is obtained by clinching the connection point by the clinching tools 6, 7 Respectively. In this case, a clinch connection without cutting is shown. 6 shows that the thickness D1 of the distal end of the first metal strip B1 is measured by the first thickness sensor 16 and the thickness D2 of the front end of the second metal strip B2, Is measured by the second thickness sensor 17. In this case, These thickness sensors 16,17 can be designed, for example, as optical thickness sensors using laser radiation. These thickness sensors 16 and 17 enable the controller to control the bonding process with or without feedback according to the measured thickness or measured thicknesses D1 and D2. In the illustrated embodiment, the thickness sensor is in the immediate vicinity of the coupling tool and can also be integrated into the coupling tool. However, the present invention also includes embodiments in which the thickness sensor is located at another location inside the strip processing facility, for example, the thickness sensor may be located immediately downstream of the decorrelator to measure the thickness of the leading edge immediately downstream of the decorrel And then the corresponding output signal or corresponding value can be processed during the strip connection.

Furthermore, there is a possibility that the oil is supplied to the strip by the oil feeders 18 and 19. In the illustrated embodiment, only the upper surface of the upper metal strip B2 and the lower surface of the lower metal strip B1 are lubricated at the overlapping portion. Optionally and additionally, there is also the possibility of lubrication to the corresponding tool surface.

The options shown in Fig. 6 may be used individually, or in combination with the apparatus according to, for example, Figs. 1 to 5, but in combination with an apparatus configured differently as an alternative.

Claims (9)

In particular, in a strip processing facility in which the distal end and the distal end are located at the upper and lower sides of each other at the overlapping portion and are connected to each other at various connection points by clinching without separation at the overlapping portion, As a method of connecting to the tip of the strip,
Characterized in that the first strip and / or the second strip are formed as cold-rolled and non-annealed metal strips and at least twenty connection points per meter of strip width for strip connection are set by clinching. Connection method. The method according to claim 1,
Wherein the first strip and / or the second strip is formed as a cold-rolled and un-annealed metal strip made of aluminum, an aluminum alloy, or a copper or copper alloy. 3. The method according to claim 1 or 2,
The material of the metal strip, for example the aluminum strip, has an A80 elongation to rupture of at most 6%, preferably between 2% and 5%, for example between about 3% and 4% Connection method. 4. The method according to any one of claims 1 to 3,
Characterized in that at least 30 connection points, preferably at least 50 connection points, per meter of strip width for strip connection are set by clinching. 5. The method according to any one of claims 1 to 4,
Wherein the thickness of the distal end of the first metal strip and / or the thickness of the distal end of the second metal strip is measured prior to connection, and the clinching process is controlled according to the measured thickness or the measured thicknesses. 6. The method of claim 5,
Wherein the punch of the clinching tool or the insertion depth of the punches is controlled or adjusted according to thickness measurements or thickness measurements. 7. The method according to any one of claims 1 to 6,
The tip and end and / or the clinching tool may be positioned such that the punch of the coupling tool does not strike one of the strip edges and / or one or more edges before or after the connection of the strip punches one strip edge or two strip edges Wherein the metal strips are disposed in such a manner that they are spaced apart from each other. 8. The method of claim 7,
Wherein the edge punch can be introduced prior to the connection of the strip if the tool punch is prevented from striking the strip edge depending on the tool shape, the strip width and the strip position. 9. The method according to any one of claims 1 to 8,
Wherein only the upper surface of the upper metal strip and the lower surface of the lower metal strip are lubricated at the overlapping portion.

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