Patent Application
20210205872
From CN 104551538 B a device and a method for separating flexibly rolled strip material are known. The strip material is fed from a coiler via a first clamping roller and a strip straightening device into a strip buffer. Behind the strip buffer there are two further clamping rollers with integrated length measurement, between them a strip thickness measurement, and behind them a hydraulic shear for separating the strip material.
From EP 3 181 248 A1 a process and an apparatus for producing a sheet metal blank are known. The process comprises the steps: flexible rolling of a strip material, wherein a thickness profile with different sheet thicknesses is generated over the length of the strip material; determining a measured thickness profile of several successive regions of the strip material; calculating a desired position in the strip material for a sheet blank to be cut out of the strip material depending on the generated measured thickness profile of at least two successive regions of the strip material; cutting the flexibly rolled strip material by means of at least one cutting device along the desired position to produce the sheet blank.
The production of shape-cut or rectangular blanks from flexibly rolled metal strip, also known as tailor rolled shapes or tailor rolled blanks, is usually carried out using a suitable cutting device. Depending on the length and thickness profile of the blanks to be produced, efficient production is difficult. In particular, components of variable sheet thickness with end sections of varying thickness (in this case also referred to as A-B rolling) cannot be produced or can only be produced with considerable scrap. The scrap is caused by the fact that a transition ramp has to be rolled into the strip material between the end thickness of a first blank and the beginning thickness of the following blank, which forms a scrap.
The present disclosure relates to a process and an apparatus for manufacturing a product from flexibly rolled strip material. Flexibly rolled strip material has a variable thickness profile in the longitudinal direction of the strip. The separation of flexibly rolled strip material therefore requires an exact positioning of the separation region in order to obtain blanks with a defined nominal thickness profile.
The present process and an apparatus for producing products from flexibly rolled strip material enables an efficient production of blanks with high manufacturing accuracy even if the thickness profiles in the strip material are not uniform. A corresponding apparatus which enables fast and cost-efficient processing with high manufacturing accuracy can produce products from flexibly rolled strip material.
A method of producing a product from flexibly rolled strip material, comprises: providing a flexibly rolled metallic strip material having a thickness profile with a variable thickness along the length of the strip material; determining a measured thickness profile of the strip material along the length of the strip material; and calculating a desired cutting position for a blank to be produced from the strip material depending on the determined measured thickness profile of the strip material and an associated desired thickness profile of the blank to be cut therefrom; cutting off a blank from the strip material along the desired cutting position; rotating the blank depending on the determined measured thickness profile such that the blank is positioned with its thickness profile in a defined processing position which differs from the cutting position; and processing the blank in the processing position by means of a processing unit, the blank being processed into a product.
This method allows blanks with variable thickness profile (Tailor Rolled Blanks), which have different sheet thicknesses at the opposite ends, and/or those with an asymmetrical sheet thickness profile, or products made therefrom, to be produced efficiently and with high manufacturing accuracy. The blanks are correctly positioned before entering the contour cutting tool so that the sheet thickness profile always matches the shape and/or cutting contour in the tool. The correctly aligned raw blanks are indexed into the following tool where they are further processed into shaped cuts. Because the blanks, which have a greater length than width in the rolling direction, are rotated before further processing, the feed lengths of the blanks into the tool and during transport through the tool are shortened, so that shorter cycle times are achieved.
The raw blanks are further processed into a product in the following processing unit. In the context of the present disclosure, the term product shall include any intermediate or end product that starting from the blank has undergone a shape-changing further processing. These may be shape cut parts, for example, if the further processing includes pure shape cutting, or formed parts, if the further processing includes a forming process, or combinations thereof, if the further processing includes shape cutting and forming.
Separation is performed in particular in such a way that blanks with a length of less than 2500 mm (millimetres), in particular less than 2000 mm, are separated from the strip material. Alternatively or additionally, blanks with a length of more than 400 mm, in particular more than 600 mm, can be separated from the strip material. According to a possible embodiment, the raw blanks can be separated from the strip material in such a way that a longest length of the raw blank in the feed direction of the strip is greater than the width of the strip material. It is to be understood that, depending on the technical requirements of the finished product and/or for tooling reasons, raw blanks can also be cut off whose length in the desired cutting position, i.e. in the feed direction of the strip, is equal to or less than the width of the strip. In this disclosure, the desired cutting position is understood to be the position to which the strip is advanced and positioned in accordance with the measured thickness profile in order to cut off the respective blank. The position and/or orientation of the blank after cutting and before rotating is also called the cut-off position.
The strip material can have alternating strip regions with different or equal, symmetrical or asymmetrical strip thickness profiles over the length.
According to a first embodiment, the strip material can have a first strip region with a first thickness profile and an adjoining second strip region with a second thickness profile over the length, with the first and second thickness profiles differing from one another in the strip material, wherein a first blank is separated from the strip material from the first strip region and a second blank is separated from the strip material from the second strip region, wherein the first blank and the second blank are rotated in such a way that the first thickness profile and the second thickness profile are aligned in the same way in the processing position. The first thickness profile in the strip can be mirror-symmetrical to the second thickness profile with respect to a parting plane lying between the two strip regions. In the strip, the two thickness profiles are different over the length, i.e. not congruent, but after cutting and rotating they coincide. In the rotated state, the two blanks with their respective thickness profiles are aligned identically and can be fed to the tool for further processing. For this purpose, the first blank can be rotated in a first direction of rotation depending on the measuring thickness profile and the second blank in an opposite second direction of rotation depending on the measuring thickness profile. This also applies to each subsequent first and second blank.
Another possibility is that the successive strip regions and the blanks to be produced therefrom can also have front and end sections of equal thickness, but with an asymmetrical sheet thickness profile with respect to a feed length center. In this case, too, the blanks are rotated with respect to the thickness profile so that they have the same orientation before entering the processing tool and in the tool, respectively. Of course, blanks with a symmetrical thickness profile can also be processed. Here, the blanks can always be rotated in the same direction.
According to an embodiment, it is intended that the blank starting from the initial position after having been cut off from the strip, is rotated by 80° to 100°, in particular 90°. As described above, the rotation takes place in the first or opposite second direction of rotation around a vertical axis of the blank, depending on the thickness profile.
After rotation, the identically aligned blanks, which still have straight side edges after separation, are fed to the processing tool and cut to the desired shape and, as the case may be, formed. The processing device may comprise, for example, one or more stamping tools and/or one or more beam cutting tools and/or one or more forming tools or combinations thereof.
The method may further comprise feeding the strip material from a buffer device by means of a feeding device, in particular by a first feeding unit and a second feeding unit. The measuring thickness profile can be determined, for example, during the strip feed by continuously measuring the thickness of the strip material by a thickness measuring unit and continuously measuring the length of the strip material by a length measuring device. The thickness is preferably measured in the feed direction of the strip material before the first feed unit, and the length is measured in the feed direction of the strip material behind the first feed unit. On the basis of the determined measuring thickness profile and comparison with an associated desired thickness profile of the blank, a feed length for the blank to be separated from the strip material can be determined. The strip material is then fed to the separating device by means of the first and second feed unit on the basis of the calculated feed length.
According to an embodiment, the strip material can be pulled out of the strip buffer by the position-controlled feeding device. The flexible rolled strip can be continuously measured by the thickness measuring unit with regard to its thickness. The thickness measuring unit evaluates on the basis of the measured thickness, under consideration of the associated length measurement values, whether or not the flexible rolled strip meets the required thickness tolerances. The comparison of the determined actual thickness profile with the specified desired thickness profile is carried out in particular also under consideration of the associated tolerances of the desired thickness profile, which can be represented by an envelope profile. In this case, it is verified by calculation whether the determined actual profile lies within the envelope profile of the desired profile. From the result of the comparison the feed length for the strip or the blank to be separated can be calculated. The strip is divided into regions that are OK (so-called OK parts) and those that are not OK (so-called not OK parts). The position and length of these individual regions in the strip is passed on from the thickness measuring unit to the first feed unit. The first feed unit, and the second feed unit coupled to it, can then carry out the feeds instructed by the thickness measuring unit and position the reference edges of the individual feed lengths accurately to the separation point of the separating device. The feed unit can then transmit the information to the other apparatus components as to whether the feed length is a feed length with an OK thickness profile or a not OK thickness profile.
According to an embodiment, the first length measuring device of the first feed is referenced at the starting point with the thickness measurement with regard to length. This can be done by continuous transmitting the measured length value from the first length measuring device to the thickness measuring device. Transmitting the length measuring values can be effected absolute or incremental. The thickness measurement scales the thickness measurement values based on the transmitted length measurement values over the strip length. In this way both measuring devices can work from exactly the same strip length zero point. According to an embodiment, the length measuring device can generate trigger signals and pass them on to the thickness measuring device, wherein the trigger signals serve as triggers for carrying out thickness measurements of the thickness measuring device.
According to an embodiment, a fixed distance can be set between the thickness measuring unit and the first feed unit. This distance is measured precisely, preferably with an accuracy of up to +/−0.2 mm, and is maintained during operation of the line. In this way, the length reference between the thickness measurement on the one hand and the feed respectively length measurement on the other hand can be reliably ensured over the entire length of the strip material.
For accurately positioning a reference edge of a feed length on a reference separation point of the separating device, a fixed distance can be set between the thickness measuring device and the separating device according to a possible embodiment. This distance is measured precisely, preferably with an accuracy of up to +/−0.2 mm, and maintained during operation of the apparatus.
According to an embodiment, the second feed unit is operated synchronously with the first feed unit, in particular with the same length scale as the first feed unit and the thickness measuring unit. By controlling the second feed unit such that it moves slightly ahead of the first feed unit, the second feed unit produces a slight strip tension in the strip portion that is within the measuring section, which ensures a smooth strip run.
To solve the above mentioned object, an apparatus for producing a product from flexibly rolled metallic strip material is also proposed, comprising: a feeding device for feeding flexibly rolled metallic strip material, which has a thickness profile with different sheet thicknesses over the length of the strip material, wherein successive regions of the flexibly rolled strip material each correspond to an associated desired thickness profile of a shaped blank to be produced therefrom; a measuring device for determining the thickness of the strip material over the length of the strip material; a separating device for producing individual blanks from the flexibly rolled strip material, wherein the separating device has a distance from a part of the measuring device which amounts to at least twice the distance of a blank to be cut off; a rotating device for rotating a separated blank into a desired processing position, the rotating device being controllable by an electronic control unit in order to rotate a separated blank into the desired processing position depending on the determined measuring thickness profile of the blank; a processing device which is designed to produce a product, in particular a shaped cut part, from the blank in the processing position.
There are similar advantages for the device as for the process. The device enables blanks with a variable thickness profile (Tailor Rolled Blanks), which have different sheet thicknesses at the opposite ends and/or those with an asymmetrical sheet thickness profile, to be produced efficiently and with high production accuracy. It is to be understood that all method-related features are analogously applicable to the apparatus, and vice versa, all apparatus-related features are applicable to the method.
The electronic control unit can be configured to determine a first rotary motion from a first strip region with a first thickness profile, and a second rotary motion from a second strip region with a second thickness profile, which deviates from the first rotary motion. For example, the control unit can derive on the basis of the determined measured thickness profile of the metal strip, respectively the thickness profile of the blank separated therefrom, how the blank is to be aligned relative to the subsequent tool to be further processed to the desired product.
The processing device may include one or more cutting groups that cut the shaped blank from the raw blank in one or more successive stages and/or one or more forming tools to form the blank into a sheet metal formed part.
The apparatus may also include a transport device for transporting the strip material through the measuring device and the cutting device to the rotating device. The transport device can have a variety of rolling elements on which the strip material rests and is guided further.
A buffer device for temporarily buffering the flexibly rolled strip material can also be provided upstream of the feeding device. The feeding device may comprise a first feed unit, which is arranged behind the buffer device in the feeding direction of the strip material, and a second feed unit, which is arranged downstream the first feed unit and upstream the separating device. The first and second feed units are configured to move the strip material from the buffer device to the separating device in dependence on the thickness measurement and the length measurement. The measuring device may comprise at least one length measuring unit for continuously measuring the length of the strip material, and one thickness measuring unit for continuously measuring the thickness of the strip material along the length. The thickness measuring unit is preferably arranged between the buffer device and the first feed unit in the feed direction of the strip material. The length measuring unit is preferably arranged behind the first feed unit in the feed direction of the strip material.
Upstream of the buffer device, the apparatus may also include a decoiler for uncoiling the flexibly rolled strip material and one or more straightening units arranged in series for straightening the flexibly rolled strip material. In particular, it is intended that the feeding device for the separation of the strip material into blanks is controlled independently of the feed of the coiler and the straightening unit.
Overall, the apparatus and the method are advantageous for inspecting, precise positioning and separation of flexibly rolled strip material into tailored rolled blanks and subsequent further processing into shaped cuts and/or pressed parts.
Preferred embodiments are explained below using the drawing figures. Herein shows:
A flexible rolled strip material is understood to be a metal strip that has a variable sheet thickness over its length. A variable sheet thickness profile can be produced by rolling a strip material with a substantially constant starting sheet thickness by rolling with dynamical variation of the roll gap. The strip material is given different thicknesses D3 over the length L3 in the rolling direction. After flexible rolling, the strip material 3 can be wound up into a coil 1 so that it can be fed to the next processing step.
The feeding device 10 can have one or more feed units 11, by which the strip material is moved in feed direction R3. A feed unit can have two feed rollers between which the strip material 3 is fed through and moved in the feed direction by rotatingly driving the feed rollers 11.
The measuring device 20 may comprise at least a length measuring unit 21 for continuously measuring the length L of the strip material 3, and a thickness measuring unit 22 for continuously measuring the thickness D3 of the strip material 3 along its length. The calculation of the desired cutting position for the blank 4 to be separated is then carried out depending on the determined measurement thickness profile D3 of the strip material 3 and the associated desired thickness profile of the blank 4 to be cut therefrom. The length measuring unit 21 can comprise a measuring wheel 23, which is in contact with one side of the strip material 3, and optionally a support wheel 24, which is in contact with the opposite side of the strip material 3 as a counter support for the measuring wheel.
The length measuring unit 21 and the thickness measuring unit 22 can be coupled with each other in a measuring-technical manner. For a reliable maintaining the length reference over the strip length between the thickness measurement 22 on the one hand and the first feed unit 11 and/or the first length measurement 21 on the other hand, a fixed distance A1 is set between the thickness measuring unit 22 and the first feed unit 11. This distance A1 is measured precisely, preferably with an accuracy of up to +/−0.2 mm, and maintained during operation of the line. In this way, the length reference between the thickness measurement on the one hand and the feed and/or length measurement on the other hand can be reliably ensured over the entire length of the strip material. During operation of the apparatus 2, the length measuring unit 21 can generate 21 trigger signals B1 and transmit them to the thickness measuring unit 22. Each trigger signal B1 serves as a trigger for a thickness measurement, so that with each trigger signal of the length measuring unit 21 a thickness measuring value is generated and assigned to a corresponding length measuring value. In this way, data sets of pairs of length and thickness values are generated, from which the actual thickness profile of the blank 4 to be cut out of the strip material 3 can be determined.
The separating device 30 can be selected according to the requirements of the flat product 4 to be separated and can comprise, for example, a cut-to-length shear 31, as shown schematically, or a cut-to-length beam cutting unit, in particular a laser cutting unit. The separation of a raw blank 4 from the strip material 3 is performed along a nominal cutting edge 32 in the desired cutting position P30, into which the strip has been advanced and positioned by the feeding device 10. In particular, the present method and apparatus are used to produce blanks 4 whose longest length L4 is greater than the width B3 of the strip material 3, which corresponds to the width B4 of the blank 4 to be cut off. In particular, it is further provided that blanks 4 with a length L4 of less than 2500 mm, in particular less than 2000 mm, and/or with a length of more than 400 mm, in particular more than 600 mm, are separated from the strip material.
The distance A2 between the thickness measuring unit 22 and the separating device 30 is preferably at least twice the blank length L4 of the blank 4 to be cut out of the strip material 3. In particular, the distance A2 is at least twice the blank length plus the feed path covered by the strip material 3 during the computing time for a blank 4 to be cut out.
In particular, the apparatus and/or method is configured such that the thickness profiles determined by the measuring device 20 are compared with the desired nominal thickness profile. The control unit 26 evaluates whether or not the flexible rolled strip 3 meets the required thickness tolerances. From the result of the comparison, the feed length for the strip 3, respectively the blank 4 to be cut out therefrom can be determined. The strip can be divided into regions that are OK (so-called OK parts) and those that are not OK (so-called not OK parts). The position and length of these individual regions in the strip 3 is transmitted by the thickness measuring device 20 to the feeding device 10, which carries out the instructed feeds accordingly and positions the reference edges of the individual feed lengths accurately to the separation point 32 of the separating device 30. The feeding device 10 can transmit the information to the other apparatus components (30, 40, 50) as to whether the feed length has an OK thickness profile or not.
After the blank 4 has been cut off, it is rotated about a vertical axis A40 in the rotating device 40. The rotating device can be designed and configured to meet the requirements of the blanks to be rotated. For example, the rotating device 40 can comprise a number of suction cups 41, which are attached to a movable carrier 42. Using the rotating device 40, the blank 4 is rotated from the starting position P30 after cutting from the strip 3, in which the blank 4 is still aligned in the direction R3 of strip 3, depending on the measured thickness profile D3 so that it is aligned with its thickness profile D4 in a defined processing position P50. In particular, it is intended that one or more tools of the further processing device 50 are aligned transversely to the strip feed direction R so that the blanks 4 are each rotated by 90° from the cut-off position P30 to the processing position P50.
After rotating S40, the equally aligned raw blanks 4 are fed to the further processing device 50. The processing device 50 is selected according to the requirements of the product 5 to be manufactured. In an embodiment shown in
According to a second embodiment, which is shown in
Strip material 3 can have alternating strip regions with different or equal, symmetrical or asymmetrical strip thickness profiles D3 over the length L3.
With the method and apparatus, blanks 4 with variable thickness profile (Tailor Rolled Blanks), which have different sheet thicknesses at the opposite ends and/or those with an asymmetrical sheet thickness profile, can be produced efficiently and with high production accuracy. The blanks 4, 4A, 4B are correctly aligned before entering the contour cutting tool so that the sheet thickness profile always matches the shape or cutting contour in the tool. The correctly aligned blanks 4 are fed into the following tool 50 and processed there into shaped cuts or press-formed parts. As the blanks 4, 4A, 4B, which have a greater length L4 than width B4 in the rolling direction, are turned before further processing, the feed length of the blanks into and/or through the tool is shortened so that shorter cycle times are achieved overall.
An uncoiling and straightening group 60, a buffer device 70 and an example of a downstream feed and separation group 15 are shown. The starting material is a coil 1 of flexibly rolled metal strip which is unwound from a decoiler 61 and then passes through a straightening unit 62 with a plurality of rolls. Between the decoiler 61 and the straightening unit 62, an infeed driver 63 can be provided to pull the strip material 3 from the decoiler and feed it to the straightening unit 62. A take-off roller 64 can be arranged in the processing direction behind the straightening unit 62, which take-off roller 64 transmits a feed force to the strip material 3. The operation of the apparatus components, i.e. the decoiler, infeed driver, straightening unit and take-off roller, can be synchronized with each other via controllers and operated in speed control or torque control mode. Each of the units can be operated individually, i.e. independently of the others, in a generator or motor mode.
In the strip feed direction behind the uncoiling and straightening group 60, a buffer device 70 is provided, which is designed to temporarily store a respective section of strip 3. This decouples a feed movement of the uncoiling and straightening group 60 from a feed movement of the following apparatus components (10-50). The uncoiling and straightening group 60 conveys the strip 3 to the strip buffer 70, which makes the flexibly rolled strip 3 available for further processing in the separation group 15. The conveying and/or unwinding speed of the uncoiling and straightening group 60 can be controlled by a level sensor 71 of the strip buffer 70. The level sensor 71 can, for example, include an ultrasonic sensor or an optical sensor which senses the depth of the strip loop hanging in the strip buffer and transmits a corresponding signal to the controller for the uncoiling and straightening group.
Behind the buffer device 70, the apparatus components already described above are the feeding device 10, measuring device 20 and separating device 30. In the present embodiment, the feeding device 10 comprises a first feed unit 11 and a second feed unit 12, which are arranged at a distance from each other. Furthermore, the measuring device comprises a further length measuring unit 25 in addition to the thickness measuring unit 22 and the length measuring unit 21. It can be seen that the thickness measuring unit 22 for continuous measurement of the thickness D3 of the strip material 3 is arranged in front of the first feed unit 11, and that the first length measuring unit 21 for continuous measurement of the length L3 of the strip material 3 is arranged behind the first feed unit 11. The second length measuring unit 25 is assigned to the second feed unit 12 and arranged behind same in feed direction R10.
The two feed devices 11, 12 are operated synchronously and are designed to move the strip material 3 from the buffer device 70 to the separation device 30 in dependence on the thickness measurement and the length measurement. The two feeds 11, 12 each exert a feed force on the strip material to move it. To ensure that the strip material is held flat between the two feed devices 11, 12, the second feed device 12 can be driven with a slight advance relative to the first feed device 11.
| Number | Date | Country | Kind |
|---|---|---|---|
| 18174010.1 | May 2018 | EP | regional |
This application is a national stage of, and claims priority to, Patent Cooperation Treaty Application No. PCT/EP2019/061598, filed on May 6, 2019, which application claims priority to European Application No. EP18174010.1, filed on May 24, 2018, which applications are hereby incorporated herein by reference in their entireties.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2019/061598 | 5/6/2019 | WO | 00 |
