DE102020129360B4 - Machine and method for producing workpieces from insulated elongated material with their ends stripped - Google Patents

Abstract

Machine for producing workpieces (12) stripped at their ends (16, 18) from insulated elongate material (4) in the form of wire or flat material, which has a core (36) which is coated with an insulation layer (38), the machine (2) having: - a feed device (6) for feeding the insulated material (4) in a feed direction (8), - a stripping device (10) for stripping sections (45) of the insulated material (4), - a camera device (26) for determining the position of the stripped sections (45) of the elongate material (4), - a cutting device (22) arranged downstream of the stripping device (10) for severing the elongate material (4) in the stripped sections (45), whereby workpieces (12) with stripped ends (16, 18) are separated from the elongate material (4) and- a control device (28) connected to the camera device (26),- wherein the camera device (26) detects the elongated material (4) and- the control device (28) for controlling the machine operation by means of the camera device (26) continuously determines the position of the stripped sections (45), characterized in that- the cutting device (22) has at least two cutting edges (54, 56), none of which completely encloses the material (4), and/or- the machine (2) has a removal device (14) downstream of the cutting device (22) for the elongated, severed workpieces (46).

Description

The invention relates to a machine for producing workpieces with their ends stripped from insulated elongate material in the form of wire or flat material, which has a core that is coated with an insulating layer, the machine comprising: a feed device for feeding the insulated material in a feed direction, a stripping device for stripping sections of the insulated material, a camera device for determining the position of the stripped sections of the elongate material, a cutting device arranged downstream of the stripping device for severing the elongate material in the stripped sections, whereby workpieces with stripped ends are separated from the elongate material, and a control device connected to the camera device, the camera device detecting the elongate material and detecting a length of the elongate material that is preferably smaller than a target length of each stripped section, and the control device for controlling the machine operation continuously determining the position of the stripped sections by means of the camera device.

The invention further relates to a manufacturing method for workpieces stripped at their ends from insulated elongated material in the form of wire or flat material, which has a core that is covered by an insulation layer, comprising the steps of: feeding the insulated material with a feed direction, stripping sections of the insulated material with a stripping device, severing the elongated material in the stripped sections, whereby the workpieces with stripped ends are separated from the elongated material, by means of a cutting device arranged downstream of the stripping device, and detecting the stripped sections by means of a camera device over a length that is preferably smaller than a target length of each stripped section, and determining the positions of the stripped sections.

The WO 2020/200826 A1 describes a device and a method for assembling an electrical connector.

From the EP 0 473 036 A2 A wire bending machine for solid wire provided with electrical insulation is known, which comprises a wire feed station, a bending station with a bending tool, by means of which the wire is bent into a coil, for example, at least one stripping station and a cutting device for separating the bent part from the supplied insulated wire. This known wire bending machine is controlled electronically by means of a program control.

Finally, in the EN 10 2017 200 745 A1 a forming machine of the type mentioned at the beginning and a method for producing a bent part from insulated flat material are described, the latter having a flat electrically conductive carrier material which is covered by an electrically insulating insulation layer. The insulated flat material is stripped in sections and fed to the forming machine, where it is formed into a two- or three-dimensionally bent bent part. The bent part is then separated from the supplied insulated material in a cutting operation. In this machine, the stripping operation is carried out in a continuous process before the bent part is separated from the supplied material and the cutting operation takes place in the stripped section which is directly in front of the bent part. The measuring device for checking the stripping is the CNC leg spring winding machine FTU 2.5 with stripping device FSA 2.5 from WAFIOS Aktiengesellschaft, which is analogous to EN 10 2017 200 745 A1 A measuring clamp is used. The elongated material passes through the measuring clamp and is sensed by means of contacts so that it can be determined whether the insulation is present on the section passing through or not, ie whether there is a stripped section.

It would also be conceivable to capture the stripped section with a camera. However, it has been shown that in an industrial production environment, scattered and disruptive light influences interfere with the image of the wire using a camera to such an extent that stripped sections cannot be reliably detected. The principle of the measuring clamp mentioned above has therefore been established.

The EN 10 2016 122 728 A1 deals with detecting the end of a coaxial cable using an image processing system in such a way that the position of the resting end is determined with sufficient accuracy for a cable assembly device, e.g. using a crimping process. The coaxial cable end is illuminated from behind or in incident light relative to a camera.

The DE 102 44 819 A1 concerns the detection of a fluorescent substance on a technical surface. For this purpose, the surface is illuminated in one excitation spectral range and imaged in another, longer-wave fluorescence spectral range in order to detect whether the fluorescent substance is present. The excitation is carried out with an illumination line and at an angle to the image in order to carry out a layer thickness measurement.

The stripped sections of the elongated material must be of defined lengths at the ends of the workpiece, e.g. a bent part. In the case of a bent part designed as a coil, for example, the connection ends are provided in this way. It is therefore necessary for the stripped sections to have a certain length and to be cut at a certain point so that stripped ends of a certain length are obtained on the workpiece. The exact position and extent of the stripped section is therefore important for the manufacture of the workpiece. If the length and position are not correct, a workpiece must be discarded; scrap is created. There is a need for improvement here, as the known measuring clamps and procedures for cutting the insulated sections are limited in terms of accuracy and working speed.

The invention is therefore based on the object of reducing the reject rate in a machine and a manufacturing process of the type mentioned above.

The invention is defined in the independent claims. The dependent claims relate to preferred developments.

The machine is designed to produce workpieces from insulated, elongated material in the form of wire or flat material. In this material, a core material, e.g. electrically conductive metal, is coated with a sheath, e.g. an electrically insulating insulation layer. The workpieces should be provided with stripped ends. The machine has a feed device for feeding the insulated material along a feed direction. The machine includes a stripping device for stripping sections of the insulating material. The stripping device works in a continuous process. A cutting device is arranged after the stripping device. This serves to cut through the elongated material in the insulated sections. It separates the workpieces because with each cut, one of the workpieces is separated from the remaining elongated material.

The cutting device has two blades that can move relative to each other, neither of which completely encloses the material, but rather stabilizes it at most on one side. In particular, they can move relative to each other with their cutting edges to cut through the material. This is done according to DIN8588 in the version from August 2013 it is referred to as a bite cut and is also called a pliers cut here. A scissor cut is also possible in which the cutting edges run past each other. This is where one-sided stabilization can come into play. Alternatively or in addition to the cutting device, a removal device is arranged downstream of the cutting device to remove the then necessarily rod-shaped workpieces. This is, for example, a rod transfer device which picks up the rod-shaped workpieces separated by the cutting device and moves them on, in particular transversely to the longitudinal direction of the rods.

A camera device is provided to detect the positions and lengths of the stripped sections. A control device is also connected to the camera device and designed to control the production of the workpieces. It synchronizes the cutting and stripping so that the stripped sections have the desired length and are each cut at the predetermined location.

The insulation can be stripped in a continuous process, e.g. by peeling, laser irradiation, brushing or milling on the moving wire. Alternatively, the insulation can be stripped while the wire is at rest for cutting if the stripping device has a drive that moves the stripping influence (e.g. peeling, brushing or milling tool or laser beam focus) along the wire.

In the variant with a pliers cut, a bending station with a bending tool for forming the material into a bent part can be located at the end of the machine. Depending on the bending tool, this takes over the feeding in completely or helps with it. The feeding device is then implemented completely or partially by the bending tool. In embodiments, the bending tool is a winder comprising one or more formers and wire pullers. Depending on the forming process or the shape of the bent part, the feeding can take place intermittently, especially when one end of the elongated material has to be placed in the bending tool, which then forms the bent part while drawing in the material and, after this forming process has been completed, the cutting device cuts through the next stripped section to separate the bent part. The machine with a bending station can be any type of wire forming machine (such as a spring machine, bending machine, etc.) or a coil winding machine, where material provided with an insulating layer is to be stripped in sections.

In the variant with a rod transfer device, any cutting device can be used, in particular the devices for biting or scissor cutting mentioned above. The elongated material preferably remains at rest during cutting. The feed device then works intermittently.

The camera device preferably comprises a monochrome camera and optionally a lighting device. The camera device allows the position and length of the stripped sections to be determined precisely. The camera looks at the elongated material at a right angle, i.e. its viewing axis is arranged at a right angle to the feed direction. The optional lighting device, on the other hand, is at an angle to this, i.e. at an angle to both the feed device and the optical viewing axis. It illuminates the elongated material in the image field captured by the camera. It is particularly preferable for the viewing axis and lighting axis as well as the feed direction to be in one plane, as this results in particularly good reflection differences between stripped, i.e. bare material, and insulated, i.e. coated material. The selected geometry makes the reflection properties of the elongated material relevant for the camera image, so that the camera and/or the control device detects the stripped sections on the elongated material based on the reflection properties. This detection can be carried out at camera level if it already carries out appropriate image processing. Alternatively or in addition, it can also be carried out by the control device, which receives the more or less pre-processed signals from the camera. With the optional lighting device, it is surprisingly insensitive to scattered light, since detection is based on the reflection properties. These are used to detect the stripped sections through the prescribed geometric arrangement of the viewing axis and the lighting axis. Surprisingly, the use of a monochrome camera has proven to be particularly advantageous here. With such a camera, the reflection properties are concise and at the same time particularly easy to determine.

Another advantage of the camera device is that it can be captured in the area of the cutting device, so that the area of the material in which it is being cut is imaged. This is not possible with conventional measuring clamps. The camera device makes it particularly advantageous to capture the area of the elongated material protruding from the guide device and in particular the length of a stripped section or part of it. The camera device therefore indirectly or directly captures exactly that part of the workpiece that is of great importance for the quality of the stripping. In addition to the higher measurement accuracy achieved by the camera device, this also reduces the scrap rate.

The camera device that records the last section to be stripped also has the advantage that any error propagation or latency when setting the point at which the cutting device cuts through the stripped sections is avoided or minimized. This is in contrast to the conventional method in which a measuring clamp recorded the stripped sections at a great distance from the cutting device. A correction could only take effect once the section recorded by the measuring clamp had passed through to the cutting device. This meant that several rejects were unavoidable. If the camera device measures directly at the point of cutting, this problem is avoided, which further reduces the reject rate.

However, it is also possible to record the position and length of the stripped sections on the route to the cutting device. In the variant with a guide device, this can be done, for example, at the other end, i.e. at the inlet end of the guide device. The camera device particularly preferably measures at a location in front of the cutting device where a stripped section is completely in the camera's field of view, and the control device sets the intermittent feed and/or the action of the cutting device so that it cuts the last stripped section at its predetermined location. In embodiments, the camera device records the wire as it moves, i.e. without it being stopped. This is referred to as on-the-fly measurement and allows the camera device to be placed almost anywhere on the route, since there is no need to look for a location where a stripped section is standing still during intermittent feed.

Flying measurements are of course also carried out when the wire is continuously drawn in and are then preferably combined with flying cutting. Since the control device knows the length of the stripped sections through the control or the mode of operation of the stripping device stored there and the control device also controls the cutting device, the camera device makes it possible to control the drawing in of the elongated material and the cutting in such a way that the part of the severed stripped section that remains on the elongated material when it is cut has a predetermined length. This of course also applies equally to the remaining part of the stripped section, which forms a connection terminal on the workpiece, for example.

In further developments, it is possible to use a camera that detects a length of the elongated material that is smaller than a target length of each stripped section. The camera signal is then checked for transitions of the first type, namely from insulated to stripped material, and for transitions transitions of the second type, namely from stripped to insulated material, are monitored. The position and length of the stripped sections are determined from the detection of these transitions. This shows whether the stripped sections have the correct length and/or the correct distance from each other. In a preferred development, the control device detects the feed movement or specifies it in a controlling manner and takes this into account in order to determine the length of the stripped sections and/or their distance from each other. It is not absolutely necessary to determine an absolute length of the stripped sections or an absolute distance between consecutive stripped sections. For control purposes, it may well be sufficient to simply determine deviations from target positions or values.

On-the-fly measurement is particularly simple if the control device records the camera image at trigger times that are selected so that the position of the first type of transition, i.e. from insulated to stripped material, and the position of the second type of transition, namely from stripped to insulated material, can be recognized and determined in the camera image. The length of the stripped sections and/or the distances between successive stripped sections are then determined from the positions of the transitions in the camera image. Preferably, the time interval between the trigger times is also taken into account, as this makes it very easy to obtain an absolute length measurement. Without taking the trigger times into account, a length is obtained in the form of deviations from target values.

In order to be able to use the simplest cameras possible, the camera comprises two camera sub-modules that are arranged at a distance from one another along the feed direction and are each directed at the elongated material at different points with individual image fields. The individual image fields of elongated material preferably capture a section that is shorter than a target extension of the stripped section.

The camera submodules are used to monitor the first and second type transitions, with the camera submodules being read out at different trigger times. The trigger times are chosen so that when the elongated material is pulled in, a first type transition is in the image field of one of the camera submodules, and the second type transition of the same stripped section is in the image field of the second camera submodule - not necessarily at the same time, but at the next trigger time. In this way, the lengths of the stripped sections and/or the distances between successive stripped sections are determined. If the time interval between the trigger times and/or the distance between the camera submodules is taken into account, the lengths and/or the distances can be determined as absolute values. Otherwise, the lengths are obtained in the form of deviations from target values.

It is particularly preferred that the ratio between the extent of the image field (on the wire) and the wire cross-section in the plane of the image field is not more than 15:1, particularly preferably not more than 10:1. This promotes precise detection of the transitions. This can be achieved by making the camera image field smaller than the length of the isolated sections, e.g. by using the submodules mentioned.

Based on the camera device, it is also possible to set the predetermined length of the part of the severed stripped section remaining on the elongated material (and thus in turn also the length of the remaining part that is present on the workpiece) by means of a control. To do this, the control device reverses the feeding of the elongated material if necessary. This can be done by controlling a feeding device accordingly. Alternatively or additionally, a feeding bending tool, e.g. a winder, can be reversed if it is designed to be reservable. It is also possible for the control device to control the stripping device accordingly, especially when it is working on the stationary wire.

A particularly preferred embodiment is one in which the stripping device can be moved and adjusted by motor with regard to its position along the feed direction. The control device then regulates the position on the elongated material at which the cutting device cuts through the stripped sections by adjusting the position of the stripping device. In combination with the reversal of the feed, a two-stage control can then also be carried out in which the feed control and the adjustment of the basic position of the stripping device are used.

When this description refers to the lengths of stripped sections and the distances between consecutive stripped sections or the period with which stripped sections follow one another, this does not necessarily mean an absolute length measurement. Rather, the length can also be determined or specified as a relative length or as a deviation from target values. This can be completely sufficient for controlling the machine.

As already mentioned, the cutting device can cut on the fly, ie on the moving material. It moves during the cutting operation with the material. This is particularly easy with pliers cutting.

Analogous to the machine described so far, a corresponding manufacturing process is provided for workpieces with stripped ends made of insulated elongated material. The above and following description of the machine applies equally to the manufacturing process and vice versa.

The invention is explained in more detail below using embodiments with reference to the accompanying drawings, which also disclose features essential to the invention. These embodiments are merely illustrative and are not to be interpreted as restrictive. For example, a description of an embodiment with a large number of elements or components is not to be interpreted as meaning that all of these elements or components are necessary for implementation. Rather, other embodiments can also contain alternative elements and components, fewer elements or components, or additional elements or components. Elements or components of different embodiments can be combined with one another, unless otherwise stated. Modifications and variations described for one of the embodiments can also be applied to other embodiments. To avoid repetition, identical or corresponding elements in different figures are designated with the same reference numerals and are not explained more than once.

• 1 eine Schemadarstellung einer Maschine zum Erzeugen von Werkstücken aus länglichem Material, hier einem isolierten Draht,
• 2 eine Darstellung einer Maschine mit fliegendem Messen abisolierter Abschnitte,
• 3 eine Teilansicht von Elementen der Maschine der 1 oder 2,
• 4 eine Schemadarstellung zur Erläuterung von Abisolierung des isolierten Drahtes und Abtrennen der Werkstücke,
• 5 eine Schemadarstellung der Maschine der 1 in einer Abwandlung mit Zangenschnitt und optionaler Biegestation,
• 6 die Maschine der 5 in perspektivischer Ansicht,
• 7 eine Schemadarstellung einer Kameraeinrichtung der Maschine und einem unter der Kameraeinrichtung bewegten, abschnittsweise abisolierten Draht und
• 8 eine Ausgestaltung ähnlich der 7, allerdings unter Verwendung einer Kameraeinrichtung mit zwei Kamerasubmodulen.

In the figures show:

• 1 a schematic representation of a machine for producing workpieces from elongated material, here an insulated wire,
• 2 a representation of a machine with flying measurement of stripped sections,
• 3 a partial view of elements of the machine of the 1 or 2 ,
• 4 a schematic diagram to explain stripping the insulated wire and separating the workpieces,
• 5 a schematic representation of the machine of 1 in a variation with pliers cut and optional bending station,
• 6 the machine of 5 in perspective view,
• 7 a schematic representation of a camera device of the machine and a wire that is moved under the camera device and is stripped in sections and
• 8th a design similar to the 7 , but using a camera setup with two camera submodules.

1 and 2 show schematically a machine 2 for producing workpieces from elongated, insulated material, which is made e.g. of metal with an insulating sheath enveloping it. In the exemplary embodiments, this insulated elongated material is an insulated wire 4. This configuration of the elongated material is, however, purely exemplary; it can equally be elongated flat material and/or a thermal insulation layer, for example. The wire 4 is conveyed through the machine 2, with a feed device 6, which has e.g. at least one conveyor carriage, a conveyor roller or wheel, conveyor belt or conveyor tongs, transporting the wire 4 along a feed direction 8 through the machine 2. During the passage through a stripping device 10, which e.g. B. a stripping tool (such as a milling cutter, brush, peeling knife, laser), this removes the sheathing from the wire 4 in sections. The meaning and the position of the stripped sections of the wire 4 thus formed will be discussed later.

The wire 4 is then severed in the stripped sections so that workpieces 12 are produced which have stripped ends 16, 18. The workpieces 12 are in the embodiment of the 1 rod-shaped and are conveyed away as rod material by means of a rod transfer device 20. For cutting, the machine 2 comprises a cutting device 22, which has at least one cutting blade 34 and separates the workpieces 12 from the remaining wire 4. The location on the wire 4 at which the cutting device 22 cuts through the wire 4 is recorded by means of a camera device 26, which has at least one camera 38. It is located in one of the stripped sections.

A control device 28, which comprises, for example, a processor 30 and which is connected to the relevant components, for example, the feed device 6, the stripping device 10, the rod transfer device 20, the cutting device 22 and the camera device 26 via unspecified lines or via radio, controls the production of the workpieces 12 and thus the operation of the components of the machine 2.

The cutting device 22 comprises in the 1 and 3 shown embodiment, a wire guide 32 through which the wire 4 is guided. The wire guide 32 stabilizes the wire 4 when a cutting edge 34, which is driven by a drive 36 controlled by the control device 28, cuts the wire 4 by shearing off the wire 4 protruding from the wire guide 32 transversely to the feed direction 8. The wire guide 32 therefore acts as a counter knife. The exit end of the wire guide 32 determines the point at which the wire 4 is cut. The wire guide 32 and wire 4 are at least at rest relative to one another. If they are absolutely at rest, the wire 4 is transported by the feed device 6 in an intermittent movement. Cutting through moving wire 4 makes it easier to create a straightening device which straightens the wire 4 drawn from a supply. The wire guide 32 and cutting edge 34 then move accordingly with the wire 4. Insofar as the following assumes cutting when the wire 4 is absolutely at rest, the statements apply equally to the relative reference to the moving wire 4 and its cutting.

In the embodiments of the 2 and 5 the cutting device 22 has at least two moving blades 54, 56, which move towards the wire 4 and perform a so-called pliers cut. This is possible on the stationary wire 4, but is particularly suitable for cutting on the fly. A knife 56 can also be stationary, as in 5 shown in dashed lines. This one knife 56 then acts with its cutting edge as a one-sided stabilizing device for the wire 4 when the other knife 54 is moved with its cutting edge transverse to the feed direction towards the wire 4.

The camera device 26 comprises the camera 38, which in the embodiment of the 1 , 3 and 4 the wire 4 is optically detected in the area in which the cutting device 22 cuts it. In the embodiments of the 2 , 5 , 7 and 8th the camera device 22 detects the wire 4 on the conveyor line between the stripping device 10 and the cutting device 22. In all embodiments, the camera device 22 serves to detect and recognize the position of the stripped sections.

The camera 38 has an image field that, as is usual for cameras, extends transversely to an optical viewing axis 40. This is directed essentially perpendicularly to the wire 4. The camera 38 records reflection properties of the wire 4, with an optional lighting device 42 being provided which directs illumination radiation at the point recorded by the camera 38. The illumination radiation is incident along an illumination axis 44 which is at an angle α to the viewing axis 40. As a result, the reflection differences between stripped sections 45 of the wire 4 and sections in which there is still insulation 46 on the core material, here the metallic carrier body 48 of the wire 4 (which can be tinned, for example), can be recognized particularly well based on the reflection properties, i.e. back reflection and/or back scattering. Influences from stray light, etc. are not to be feared with this lighting. Preferably, the angle α is in the range of 45° (variations are possible depending on the installation), and the two axes 30, 32 as well as the wire 4 along the feed direction 8 are preferably in one plane.

When the wire 4 moves intermittently, the camera device 26 is stationary. When cutting through a moving wire 4, the camera device 26 moves synchronously with the cutting device 22 or it is designed in such a way that it allows the position of the stripped sections to be recognized during the feed. It is possible that the image field does not capture the entire length of each stripped section. This will be discussed later.

3 shows an enlarged section of the rear end in the feed direction, i.e. the exit end of the wire guide 32 with the wire 4 guided therein. 3 shows the feed position of the wire 4 during cutting, which is preferably the case when a stripped section 45 protrudes exactly halfway out of the wire guide 32 and the knife 34 consequently cuts through this stripped section 45 exactly in the middle. A different division is possible.

In each stripped section 45, the insulating sheath 46 is removed from the metal wire 48 because the stripping device 10 removes the sheath 46. If one pushes the 3 In the state shown, the cutting edge 34 advances in the direction of the arrow 50, it cuts the wire 4 at the front face of the wire guide 32, which then acts as a counter knife. In order to set the location of the cutting, the control device 28 uses the signals from the camera device 26, from which in 3 only the axes 40, 44 are shown. It should be noted that the viewing axis 40 and the (optional) illumination axis 44 naturally only show the respective optical axis, and that the field of view of the camera 38 or the illumination field of the (optional) illumination device 42 are actually larger, in particular they cover the entire part of the stripped section 45 that protrudes from the wire guide 32. The signals from the camera device 26 are used by the control device 28 to coordinate the cutting device 22 and the feed device 6 and the stripping device 10 so that the stripped section 45 is severed at a predetermined point. This applies equally if the camera device 26 detects the wire 4 at another point (cf. 2 , 5 , 7 and 8th ).

4 shows schematically the wire 4 with stripped sections 45 as it is conveyed in the feed direction 8 after leaving the stripping device 10. After passing through the cutting device 22, in this embodiment it is conveyed away by the rod transfer device 20 as a rod-shaped workpiece 12, e.g. to be further processed. The thicker sections of the wire 4 show the insulation 46; the thinner sections are the stripped sections 45. As in 2 and 4 As can be seen, the workpiece 12 has stripped ends 16, 18, which thus originate from a stripped section 45. The rest of the workpiece 12 is usually sheathed. In order for the ends 16, 18 to have a predetermined length, the (in 4 not shown) control device 28 adjusts the stripping device 10 so that the stripped sections 45 have a length that corresponds to the added length of the ends 16, 18. Furthermore, the control device 28 ensures that the cutting blade 34 cuts through the last stripped section 45, at which the workpiece 12 is still connected to the remaining wire 4, in such a way that the stripped section 45 is halved, for example, as already shown in 4 is shown. In concrete terms, this means for the cutting device 22 with counter knife that the part 52 of the last stripped section 45 protruding from the wire guide 22 is exactly as long as the end 16 should be. This is set by the control device 28, which accesses the camera device 26 for this purpose and evaluates its signals accordingly. Furthermore, the control device 28 also ensures, if necessary, that the movement of the wire 4 in the feed direction 8 is designed in such a way that the last stripped section 45 is severed at the desired location.

For this purpose, in the event that the wire 4 is cut absolutely at rest, depending on the design of the feed device 6, which is in 4 not shown for the sake of clarity, several possibilities. In the case of a feed device which allows the wire movement to be reversed against the feed direction 8, the control device 28 checks in one embodiment whether the location at which the cutting device 22 cuts through the wire 4 is in the right place in the stripped section 45. Reference is preferably made to one end of the stripped section 45, e.g. by ensuring that the part 52 protruding from the counter knife has a predetermined length. By appropriately operating the feed device 6, which may pull the wire 4 back again, i.e. reverse it, the desired location is set or the cutting device 22 is activated for this location (in the case of flying cutting), so that the cutting device 22 cuts through the wire 4 in the last stripped section 45 at the right place. In the case of a feed device that cannot reverse, an embodiment is useful in which the control device 28 changes the feed of the wire 4 when the desired location has not yet been reached, e.g. a maximum length of the stripped section 45 has emerged from the wire guide 32, wherein this maximum length is still smaller than the length of the desired part 52. The wire 4 is then moved further at a reduced speed until the location of the severance is exactly at the point at which the cutting device 22 cuts the wire 4, e.g. until the part 52 protrudes from the wire guide 32 with the desired length. Then the wire is severed.

5 shows another embodiment of a machine 2 for producing workpieces 12 having stripped ends 16, 18. Compared to the 1 , 3 and 4 There are two differences here compared to the embodiment shown. Firstly, the cutting device 22 is designed to perform a bite or so-called pincer cut. It has two blades 54, 56 that are movable relative to one another and which are moved towards the wire 4 in a stripped section 45 and cut through it. The relative movement is in 5 indicated schematically by arrows. A knife can also be at rest; this variant is shown in dashed lines. The pliers cut has the advantage that it can also be carried out on the flying, ie moving, wire 4 if the knives 54, 56 are moving with the wire 4 at the time of cutting. This achieves a particularly preferred mode of operation in which the wire 4 is continuously fed. As already mentioned, this has a particularly advantageous effect on the implementation and operation of the straightening device 39.

A second modification compared to the embodiment of the 1 and 2 is that the bar transfer device 20 is now replaced by a bending station 58, which ensures that the workpieces 12 are bent, in particular coil-shaped, parts with stripped ends 16, 18. This bending station is an alternative to the bar transfer device, which of course is equally suitable in the embodiment of the 5 can be applied.

Optionally, the bending station 58 also has the function of the feed device 6, namely when the bending device feeds in the wire 4 during bending. Likewise, it is possible to participate in the wire feed in addition to the feed device 6.

The number of movable knives in the cutting device that performs a nipper cut is not limited to two. Preferably, three, four or more movable knives can be used, which together cut the wire 4. by moving towards the stripped section 45 and severing the core material.

The same applies, of course, if the rod transfer device 20 participates in the movement of the wire 4 or even causes it. In this case, it is controlled or co-controlled accordingly.

In one embodiment, the control device 28 is guided by the remainder remaining in the wire guide 32, which is set to the length of the stripped end 18. This means that the length of this remainder serves as a control variable. This can lead to the last workpiece 12 produced sometimes having an end 16 that is too short (for example, if there was a deviation in the length of one of the stripped sections 45), but it is then ensured in any case that the next workpiece 12 has an end 16 with the correct length, i.e. will not be a reject. In an alternative embodiment, the control device 28 sets the length of the part 52 protruding from the wire guide 32, thus ensuring the desired length of the end 16.

Neither for the cutting nor for the control does it need to be stationary when measuring. Rather, the cutting device 22 can cut on the fly and/or the camera 38 can measure on the fly. The latter facilitates the arrangement of the camera device 26, which can thus be positioned at almost any point along the wire 4 where it has a clear view of the wire 4. The flying measurement can be combined with cutting the stationary wire 4 and with cutting while the wire 4 is moving and vice versa.

6 shows machine 2 of the 5 in a perspective view with stripping station 10 and a bending station 58, which here is part of a machine 2, e.g. a leg spring winding machine with a bending station 58. The stripping station 10 is preceded by the straightening device (not shown in detail), which ensures that the wire 4 extends as precisely as possible along the feed direction without being wavy, etc. The cutting device is arranged directly upstream of the bending station 58.

As already mentioned, it is possible to detect the position of the stripped sections 45 before entering the cutting device 22, for example if this is easier to implement for reasons of space. This is shown in the 2 and 5 It has the advantage that a stripped section 45 can always be completely in the field of view of the camera 38, which would not be possible, for example, at the exit end of the wire guide 32. This improves control.

Particularly preferred is flying measurements, i.e. at a point in front of the cutting device 22. The camera 38 and (if present) lighting 40 are then set on the wire 4 at a point in front of the cutting device 22. The control device 28 sets the measurement times so that a stripped section 45 is in the camera device 26, i.e. generally in the field of view of the camera 38. Each measurement time is determined, for example, by the control device 28 emitting a trigger signal. For this to happen, it is sufficient for the camera device 26 to detect one end of the stripped section 45. If the end of the stripping is too far to the right or left of a target position in the image obtained at the trigger time, a correction can be made during the remainder of the wire feed, in which the measured section 45 is fed forward to the cutting device 22, e.g. B. by adjusting the feed speed and/or delaying or advancing the actuation of the cutting device 22 accordingly.

The distance between the insulated sections 45, also referred to as the “pitch”, depends on the operation of the stripping device 10. If this operates in a continuous process, i.e. on the moving wire 4, it can only strip the wire 4 while it is being moved through the machine 2. The desired length of the stripped ends 16, 18 determines the length of the stripped section 45 for a given pitch, or vice versa.

In embodiments with bending station 58, the stripping device 10, when working on the stationary wire 4, would have to be spaced from the location at which the cutting device 26 cuts through the wire 4 by an integer multiple of the period specified by the pitch and length of the stripped sections 45, or arranged directly on the cutting device. If the spacing is not correct, it may happen that the wire 4 has to be advanced or reversed further before the cutting process in order to ensure the desired length of the part 52 or the remainder (both can serve as a control variable) and thus of the ends 16, 18. If it turns out that repeated adjustment in one and the same direction (either advance or reversal) is necessary, it can be deduced that the position of the stripping device 10 along the wire 4 is not optimal. A further development therefore provides for a two-stage control system in which the basic position of the stripping device is corrected in order to compensate for a permanent control intervention (feed or reversing) before the cutting process. The term "basic position" expresses the fact that it is about the reference position to the bending tool and not about any movement of a stripping tool that is actively moved for stripping.

This problem does not arise with a pliers cut. It is therefore advantageous to combine the variant with bending station 58 with a pliers cut, which can be carried out comparatively easily on the moving wire 4.

The control concept also takes into account which feed device 6 is present. Examples of possible options are a carriage feed, a roller feed, a belt feed or a pliers feed. In the latter case in particular, reversing, i.e. pulling the wire 4 back into the wire guide 22, is only possible with great effort or not at all. The previously explained concept is used here, whereby the control device 28 positions the wire 4 in a rough setting so that a part that is too short in itself protrudes from the wire guide 32 and then advances it in a fine setting so that the desired length of the part 52 and thus the ends 16, 18 is given. This is particularly easy to do with "on-the-fly" measurement. It is therefore ensured that there is still a residual distance to be advanced before cutting, over which a fine adjustment is then made.

7 shows a possible design for the embodiment according to 2 or 5 , in which the camera device 26 looks at the wire 4 in an area and illuminates it before the wire 4 reaches the cutting device 22. Of course, the wire 4 must be accessible for imaging in this area. The angular position of the lighting and camera mentioned is optional.

Depending on the geometry of the wire 4, it is preferable that the camera 38 is designed in such a way that it does not capture the entire length of the stripped section 45. Especially with thin wires, the problem could otherwise arise that a stripped section 45 is difficult to recognize - despite the optional and advantageous mutual alignment of the viewing axis 30 and the illumination axis 34. It has been shown that a ratio between the length that the camera 38 captures on the continuous wire 4 and the diameter of the wire 4 of 10:1, particularly preferably 15:1, should not be exceeded.

Especially for thin wires, an embodiment as in 7 advantageous. Here, the camera 38 has an image field 62 around its viewing direction 40, which has an extension 64 along the feed direction 8 in the area of the wire 4. This makes it possible to maintain the ratio mentioned particularly well. This size of the image field 62 is smaller than the length a of the stripped sections 45. The camera 38 cannot therefore capture the stripped section 45 in its entirety, but is particularly suitable for thin wires 4. The (in 7 The control device 28 (not shown) therefore reads the camera 38 in such a way that it recognizes the transitions between insulated and stripped material, i.e. the beginning and end of the stripped section 45, based on the reflection properties. In relation to the feed direction 8 along which the wire 4 is moved, each stripped section 45 begins with a first type transition 66, at which the insulation 38 begins to be missing and the bare wire 36 begins. Each stripped section 45 ends in a second type transition 68, from which the bare wire material 36 is again covered with the insulation 38. The distance between the first type transitions 66 and second type transitions 68 defines the length a of each stripped section 45. The distance between the second type transitions 68 and the first type transition 66 defines the remaining part of the period with which the stripped sections 45 follow one another. The period is a plus the length of the insulated sections 70.

To determine the length a of the stripped sections 45 and optionally also to determine the period mentioned, i.e. the distance between transitions of the first type 66 among themselves or between transitions of the second type 68 among themselves, the control device 28 reads the signals from the camera 38 and recognizes the transitions 66 and 68. Together with the movement path of the wire 4, which is usually known to the control device 28 since it controls the retraction of the wire 4, the control device 28 thus determines the length a of the stripped sections 45 and the distances between the stripped sections 45.

In order to be able to determine the occurrence of the transitions 66 and 68 as precisely as possible in time in the case of high feed speeds, it is preferable to design the camera 38 as a line camera.

Irrespective of this, the length a of the stripped sections 40 can be determined by determining the times at which each transition 66 and 68 is at a specific point in the image of the camera 38 or passes through a specific location in the image of the camera 38. Alternatively, it is possible to read the camera 38 at specific times and determine the position of the transition 66, 68 in the image of the camera. An offset from an expected target position then immediately indicates a deviation in the length a.

8th shows a further development of the 7 principle in which the measuring device detects the stripped sections 45 before the wire 4 reaches the cutting device 22, ie before the location at which the wire 4 is severed in the stripped sections 45. 8th uses the same Reference symbols such as 7 , insofar as they refer to the same or corresponding elements.

A special feature is the design of the 8th a camera 38 is used, which has two camera submodules 38a and 38b. These each have an image field 62a and 62b of a size 64a and 64b. The camera submodules are located at a distance c from each other. This is shown as an example in 8th related to the left edge of the image field 62a or 62b. However, it could equally also be related to the viewing axes 40a, 40b.

As in 7 is also in 8th The optional lighting system is not shown for the sake of simplicity.

In the 8th In the embodiment shown, the image fields 62a, 62b are not so large that an entire stripped section 45 could be captured. Therefore, the 7 described principle is applied, whereby now the first camera 38a captures one of the transitions 66, 68 and the second camera 38b the other transition 68, 66. In other words, one of the cameras captures the beginning of each stripped section 45 (relative to the feed direction 8), the other camera the end of the stripped section 45. In the embodiment of the 8th For example, the first camera 38a is directed at the end, ie the transition of the second type 68, and the second camera 38b is directed at the beginning, ie the transition of the first type 66. This can of course be inverted. Of course, however, both cameras must not capture the transition of the same type.

The cameras 38a, 38b are read out at trigger times. I designates a first trigger time and the corresponding position of the stripped section 45 is entered. At trigger time I, the control device 28 determines (in 8th not shown) from the image of the camera 38a an offset d (e.g. to the edge of the image), which indicates the position of the transition of the second type 68. At the second trigger time II, the wire 4 has been moved further along the feed direction 8, and the second camera 38b determines the position of the transition of the first type 66 in the form of an offset e (e.g. to the edge of the image). The length a of the stripped sections 45 can be determined from the known distance c and the positions d, e, since the required dimension b, namely the period with which the stripped sections 45 follow one another, is known from the time interval between the trigger times I and II in connection with the movement sequence of the wire 4 carried out in between, which is controlled by the control device 28.

If the positions e and d denote the distances of the transitions to a fixed and equal reference point in the image, e.g. from the respective image edge, the result is a = (c + e) - (d + b). The positions e and d refer to 8th exemplary on the distance between the transition 66 or 68 and the left edge of the image field of the camera 38a or 38b.

Calibration is possible by pushing a stripped section 45 of known length a through according to the feed movement. In this way, measurement errors for the positions b, e and the distance c can be corrected.

Using the trigger times I and II gives a great deal of freedom in choosing the distance c. In practice, the camera submodules 38a and 38b can be mounted in the machine 2 and the first trigger time I is then selected such that during the movement of the feed, which is controlled by the control device 28, the second type of transition 68 is in the image field 62a of the first camera submodule 38a. Similarly, the second trigger time II is then selected such that the first type of transition 66 is in the image field 62b of the second camera submodule 38b. The exact measure for the distance c can then, as mentioned, be easily determined by a calibration step. In practice, it may also be sufficient to simply ensure that the positions d, e are related to a fixed reference in the image. This then also gives the length of the stripped sections a. If the two layers move in the same way, the length a of the stripped section 45 remains constant. If only one of the positions shifts, the length a has changed by exactly this amount. Neither the camera distance c nor the period b need to be known for this. Likewise, as an alternative, it is possible to record the two positions of the transitions 66, 68 without actually knowing the stripped length a. The measuring device then shows a change in the length a, which results from the change in the sum e + d.

In the embodiments that determine the transitions of the first type 66 and the second type 68, the position of the transitions can be detected at any reference point in the image of the camera 38 or the camera submodules 38a, 38b. It does not necessarily have to be based on an edge of the image field 62.

This design is particularly advantageous if, in practice, a bent part is first set up as a workpiece 12 without taking the measuring device into account. For this purpose, the length a of the stripped sections 45 and their position at a specific time are determined. Then, by means of the camera 38, in particular the camera submodules 38a, 38b monitor the transitions of the first 66 and second 68 type at a specific time. This also indirectly monitors the length a of the stripped sections 45.

Claims (26)

Machine for producing workpieces (12) stripped at their ends (16, 18) from insulated elongate material (4) in the form of wire or flat material, which has a core (36) which is coated with an insulation layer (38), the machine (2) having: - a feed device (6) for feeding the insulated material (4) in a feed direction (8), - a stripping device (10) for stripping sections (45) of the insulated material (4), - a camera device (26) for determining the position of the stripped sections (45) of the elongate material (4), - a cutting device (22) arranged downstream of the stripping device (10) for severing the elongate material (4) in the stripped sections (45), whereby workpieces (12) with stripped ends (16, 18) are separated from the elongate material (4). and - a control device (28) connected to the camera device (26), - wherein the camera device (26) detects the elongated material (4) and - the control device (28) for controlling the machine operation by means of the camera device (26) continuously determines the position of the stripped sections (45), characterized in that - the cutting device (22) has at least two cutting edges (54, 56), none of which completely encloses the material (4), and/or - the machine (2) has a removal device (14) downstream of the cutting device (22) for the elongated, severed workpieces (46). Machine after Claim 1 , characterized in that the control device (28) continuously detects transitions between stripped and insulated material. Machine after Claim 1 or 2 , characterized in that the control device (28) for the stripped sections (40) at trigger times (I, II) in camera images recorded by the camera device (26) in each case determines a position (e) of a transition of the first type (66), namely from insulated to stripped material, and a position of a transition of the second type (68), namely from stripped to insulated material, and determines the lengths (a) of the stripped sections (45) and/or the distances (b) between successive stripped sections (40) from the positions of the transitions (68, 66) in the camera image. Machine after Claim 3 , characterized in that - the camera device (26) has two camera submodules, namely a first and a second camera submodule (38a, 38b), which are arranged along the feed direction (8) at a distance (c) from one another and are each directed at the elongate material (4) with individual image fields (62a, 62b) at different locations, wherein the individual image fields (62a, 62b) of the elongate material (4) preferably capture a length (64) that is smaller than a target length of each stripped section (45), and - the control device (28) for the stripped sections (45) each detects the position (d) of a transition of the second type (68) in the image supplied by the first camera submodule (38a) at a first trigger time (I) and the position (e) of the transition of the first type (66) in the image supplied by the second camera submodule (38b) at a second trigger time (II). and from the layers (d, e) the lengths (a) of the stripped sections (45) and/or the distances (b) between successive stripped sections (45) are determined. Machine according to one of the above claims, characterized in that the control device (28) controls the feed of the elongate material (4) and, on the basis of determined transitions (66, 68) between stripped and insulated material, controls the feed device (6) such that the part (52) of the severed stripped section (45) remaining on the elongate material (4) or on the severed workpiece (12) when the stripped section (45) is severed has a predetermined length, namely that of one of the stripped ends (16, 18). Machine after Claim 5 , characterized in that the control device (28) reverses the feed of the elongated material (4) in order to set the predetermined length of the part (52) remaining on the elongated material (4) or on the workpiece (12). Machine according to one of the above claims, characterized in that the control device (28) controls the cutting device (22) taking into account a distance between the region of the elongate material (4) detected by the camera device (26) and the location of the cutting device (22) such that the cutting device (22) cuts through the stripped section (45) of the elongate material (4) at a predetermined location. Machine according to one of the above claims, characterized in that the stripping device (10) is motor-driven and can be moved with respect to a basic position along the feed direction (8) and can be positioned and the control device (28) regulates the position in the stripped section (45) at which the cutting device (22) cuts through the material (4) by adjusting the basic position of the stripping device (10) and the length of the stripped sections (45). Machine after Claim 8 , characterized in that the control device (28) carries out a two-stage control by controlling the feed device (6) and setting the basic position of the stripping device (10). Machine according to one of the above claims, characterized in that the camera device (26) detects the elongated material (4) before it enters the cutting device (22). Machine according to one of the above claims, characterized in that the camera device (26) has a camera (38) and an illumination device (42), wherein an optical viewing axis (40) of the camera (38) is directed substantially at right angles to the feed direction (8) and an optical illumination axis (44) of the illumination device (42) is directed obliquely to the optical viewing axis (40) onto the elongated material (4), so that the camera (38) and/or the control device (28) detects the stripped sections (45) based on their reflection properties, wherein optionally the optical illumination axis (44) is also directed obliquely to the feed direction (8). Machine after Claim 11 , characterized in that the optical illumination axis (44) is at an angle of 20 to 70 degrees, preferably 30 to 60 degrees, particularly preferably 40 to 50 degrees to the optical viewing axis (40) and/or to the feed direction (8). Machine according to one of the above claims, characterized in that the camera device (26) detects a part (52) of the stripped sections (45) which protrudes from a guide device (32) of the cutting device (22) before the cutting process. Machine according to one of the above claims, characterized in that the camera device (26) detects a length (64) of the elongated material (4) which is smaller than a desired length of each stripped section (45). Manufacturing method for workpieces (12) stripped at their ends (16, 18) from insulated elongate material (4) in the form of wire or flat material, which has a core (36) that is covered by an insulation layer (38), comprising the steps of: - feeding the insulated material with a feed direction (8), - stripping sections (45) of the insulated material with a stripping device (10), - severing the elongate material (4) in the stripped sections (45), whereby the workpieces (12) with stripped ends (16, 18) are separated from the elongate material (4) by means of a cutting device (22) arranged downstream of the stripping device (10), and - detecting the stripped sections (45) by means of a camera device (26) over a length (64) that is preferably smaller than a target length of each stripped section (45), and determining the positions of the stripped sections (45), characterized in that - for severing, a cutting device (22) is used which has at least two cutting elements (54, 56), none of which completely encloses the material (4), and/or - after severing, the workpieces (12) are conveyed away as elongated, severed workpieces by means of a rod holder (20). Manufacturing process according to Claim 15 , characterized in that determining the positions of stripped sections (45) comprises determining transitions (66, 68) between stripped and insulated material. Manufacturing process according to Claim 15 or 16 , characterized in that for the stripped sections (45) at trigger times (I, II) in camera images recorded by the camera device (26) a position (e) of a transition of the first type (66), namely from insulated to stripped material, and a position (d) of a transition of the second type (68), namely from stripped to insulated material, are determined, and the lengths (a) of the stripped sections (45) and/or the distances (b) of successive stripped sections (45) are determined from the positions of the transitions (68, 66) in the camera image. Manufacturing process according to one of the Claims 15 until 17 , characterized in that - for the camera device (26), two camera sub-modules, namely a first and a second camera sub-module (38a, 38b), are arranged along the feed direction (8) at a distance (c) from one another, each of which is directed at the elongated material (4) with individual image fields (62a, 62b) at different locations, and - for the stripped sections (45), the position (d) of the second type of transition (68) in the image supplied by the first camera sub-module (38a) is determined at a first trigger time (I) and the position (e) of the first type of transition (66) in the image supplied by the second camera sub-module (38b) is determined at a second trigger time (II), and the lengths (a) of the stripped sections (45) are determined from the positions (d, e). Sections (45) and/or the distances (b) between successive stripped sections (45) are determined. Manufacturing process according to one of the Claims 15 until 18 , characterized by controlling the feeding of the elongate material (4) on the basis of signals from the camera (38) such that the part (52) of the stripped section (45) remaining on the elongate material (4) or on the workpiece (12) during severing has a predetermined length, namely that of one of the stripped ends (16, 18). Manufacturing process according to Claim 19 , characterized in that a feed of the elongate material (4) is reversed in order to set the predetermined length of the part (52) remaining on the elongate material (4) or on the workpiece (12). Manufacturing process according to one of the Claims 15 until 20 , characterized in that the camera device (26) detects the elongate material (4) before it enters the cutting device (22) and that the feeding and/or the severing is controlled taking into account a distance between the part of the elongate material (4) detected by the camera (38) and the location of the cutting device (22) such that the cutting device (22) severs the stripped section (45) of the elongate material (4) at a predetermined location. Manufacturing process according to one of the Claims 15 until 21 , characterized in that the stripping device (10) is moved and positioned by a motor with respect to a basic position along the feed direction (8) and by adjusting the basic position of the stripping device (10) a position on the elongated material (4) is regulated at which the cutting device (22) cuts through the stripped sections (45). Manufacturing process according to Claim 22 , characterized in that a two-stage control is carried out by controlling the feed and setting the basic position of the stripping device (10). Manufacturing process according to one of the Claims 15 until 23 , characterized in that , in order to determine the position of the stripped sections (45), the elongate material (4) is illuminated with a lighting device (42) along an optical illumination axis (44) and imaged with a camera (38) along an optical viewing axis (40) of the camera (38), wherein the optical viewing axis (40) is directed onto the elongate material (4) substantially at right angles to the feed direction (8) and the optical illumination axis (44) is directed obliquely to the optical viewing axis (40), and the stripped sections (45) are detected on the basis of their reflection properties, wherein optionally the optical illumination axis (44) is also directed obliquely to the feed direction (8). Manufacturing process according to Claim 24 , characterized in that the optical illumination axis (44) is at an angle of 20 to 70 degrees, preferably 30 to 60 degrees, particularly preferably 40 to 50 degrees to the optical viewing axis (40) and/or to the feed direction (8). Manufacturing process according to one of the Claims 15 until 25 , characterized in that the individual image fields (62a, 62b) of the elongated material (4) capture a length (64) which is smaller than a desired length of each stripped section (45).

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