METHOD AND APPARATUS FOR DETECTING IRREGULARITIES ON A MATERIAL STRAND

Abstract

A method for detecting irregularities on a material strand made of an elastomeric material comprises the steps of: (a) providing a material strand which defines a longitudinal axis along which the material strand is to be conveyed; (b) bringing a detection element in contact with the material strand, wherein at least one of the detection element being movably mounted in a direction of deflection transverse to the longitudinal axis and a force can act on the detection element in a force direction, (c) setting up a relative movement between the detection element and the material strand along the longitudinal axis; and (d) detecting at least one of a deflection of the detection element in the deflection direction and a force acting on the detection element in the force direction, so as to detect irregularities in the material strand.

Claims

1. A method for detecting joints in a sealing profile strand made of an elastomeric material, comprising the steps of: providing the sealing profile strand which defines a longitudinal axis along which the sealing profile strand is to be conveyed; bringing a detection element in contact with the sealing profile strand, wherein at least one of (i) the detection element being movably mounted in a direction of deflection transverse to the longitudinal axis and (ii) a force can act on the detection element in a force direction, setting up a relative movement between the detection element and the sealing profile strand along the longitudinal axis; and using at least one of (i) a travel sensor for detecting a deflection of the detection element in the deflection direction and (ii) a force sensor for detecting a force acting on the detection element in the force direction, so as to detect a joint in the sealing profile strand, when a sensor signal produced by at least one of the travel sensor and the force sensor exhibits a peak.

2. The method according to claim 1, wherein the detection element is mounted on a bearing block, wherein at least one of a deflection of the bearing block in the deflection direction and a force exerted on the bearing block by the sealing profile strand is detected in order to detect irregularities in the sealing profile strand.

3. The method according to claim 1, wherein the detection element is a roller element which is mounted on a bearing block, wherein the roller element is rotatable about a roller axis which is aligned transversely to both the longitudinal axis and at least one of the deflection direction and the force direction.

4. The method according to claim 1, wherein at least one of the deflection and the force is continuously detected and compared with a previously stored characteristic.

5. The method according to claim 4, wherein at least one of the deflection and the force is stored in the form of at least one of a displacement profile and a force profile.

6. The method of claim 1, wherein a peak is detected using a threshold value, wherein a joint is recognized if the sensor signal exceeds the threshold value.

7. The method of claim 6, wherein the threshold value is a basic value plus 10%, wherein the basic value of the sensor signal is the value of the sensor signal when no joint is detected.

8. The method of claim 1, wherein a joint is detected if the axial length of the peak is in a range of 0.5 mm to 80 mm.

9. A method for applying a sealing profile strand strip on a body portion, comprising the steps of: providing a sealing profile strand assembly including a sealing profile strand which might have one or more joints, un-storing the sealing profile strand from the sealing profile strand assembly, wherein a detection element is brought into contact with the sealing profile strand, wherein at least one of (i) the detection element being movably mounted in a deflection direction transverse to a longitudinal axis and (ii) a force may act on the detection element in the deflection direction, detecting a joint in the sealing profile strand by: bringing the detection element in contact with the sealing profile strand, setting up a relative movement between the detection element and the sealing profile strand along the longitudinal axis, and using at least one of (i) a travel sensor for detecting a deflection of the detection element in the deflection direction and (ii) a force sensor for detecting a force acting on the detection element in the force direction, so as to detect a joint in the sealing profile strand, when a sensor signal produced by at least one of the travel sensor and the force sensor exhibits a peak, and cutting off a sealing profile strand strip which has a predefined length, from an end of the sealing profile strand, if no joint has been detected between the end of the sealing profile strand and a cutting location determined by the predefined length.

10. A method for detecting irregularities on a material strand made of an elastomeric material, comprising the steps of: providing the material strand which defines a longitudinal axis along which the material strand is to be conveyed; bringing a detection element in contact with the material strand, wherein at least one of (i) the detection element being movably mounted in a direction of deflection transverse to the longitudinal axis and (ii) a force can act on the detection element in a force direction, setting up a relative movement between the detection element and the material strand along the longitudinal axis; and detecting at least one of (i) a deflection of the detection element in the deflection direction and (ii) a force acting on the detection element in the force direction, so as to detect irregularities in the material strand.

11. The method according to claim 10, wherein the detection element is mounted on a bearing block, wherein at least one of a deflection of the bearing block in the deflection direction and a force exerted on the bearing block by the material strand is detected in order to detect irregularities in the material strand.

12. The method according to claim 10, wherein the detection element is a roller element which is mounted on a bearing block, wherein the roller element is rotatable about a roller axis which is aligned transversely to both the longitudinal axis and at least bone of the deflection and the force direction.

13. The method according to claim 10, wherein the at least one of the deflection and the force is continuously detected and compared with a previously stored characteristic.

14. The method according to claim 13, wherein the at least one of the deflection and the force is stored in the form of a at least one of a displacement profile and a force profile.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Exemplary embodiments of the application are explained in more detail in the following description and are represented in the drawings, in which:

[0059] FIG. 1 is a schematic view of a prior art manufacturing apparatus for manufacturing a material strand assembly;

[0060] FIGS. 2a to 20 are sequences of operation in a prior art method for manufacturing a material strand assembly;

[0061] FIG. 3 shows several schematic views of different types of joints in a faultless material strand;

[0062] FIG. 4 is a schematic view of an apparatus for applying a material strand strip to a vehicle part;

[0063] FIG. 5 is a schematic view of an apparatus for detecting irregularities on a material strand and a portion of a profile of deflection and/or force over a relative travel between the material strand and the detection apparatus; and

[0064] FIG. 6 shows an alternative embodiment of an apparatus for detecting irregularities.

EMBODIMENTS

[0065] In FIG. 1, an embodiment of a manufacturing apparatus for manufacturing a material strand assembly is schematically shown and given the reference numeral 10.

[0066] The manufacturing apparatus 10 includes an extruder 12, which is adapted to receive strand material 14. The extruder 12 may include a heater 16 and comprises a die 18. In operation, the extruder 12 produces a material strand 20 that moves at an extrusion speed v.sub.E out of the die, along a moving direction 21.

[0067] Downstream of the extruder 12, the manufacturing apparatus 10 includes a first strand accumulator 22, a monitoring device 24, a first cutting device 26, a joining device 27, a second cutting device 28, wherein the first cutting device 26 and the second cutting device 28 form a cutting arrangement 29, a second strand accumulator 30 and a storing device 31.

[0068] The first strand accumulator 22 and the second strand accumulator 30 allow for movement speeds of the material strand between the accumulators 22, 30 that differ from the movement speed upstream of the first strand accumulator 22 and/or downstream of the second strand accumulator 30. Typically, the storing device 31 may be adapted to store a material strand at the same speed as the extrusion speed (v.sub.E).

[0069] The storing device 31 is adapted to store a material strand in a storage unit 32. The storage unit 32 may have a reel 34 which is supported rotatably in a reel carrier 36, e.g., a reel box.

[0070] The material strand that is stored in the storage unit 32 is a faultless material strand 37, wherein any faults of the extruded material strand 20 have been cut out.

[0071] As soon as a predefined length of faultless material strand 37 is stored in the storage unit 32, thus forming a material strand assembly 38, the material strand assembly 38 can be transported to another site where the material strand of the material strand assembly 38 is processed, e.g., an application site at an OEM.

[0072] The material strand 20 is typically used for sealing, trimming or fastening body openings in vehicle bodies, typically in the automobile industry.

[0073] The first cutting device 26 may include a single cutter for preparing right-angled cutting end faces, as for example shown in FIG. 3, left side.

[0074] In the present case of FIG. 1, the first cutting device 26 includes a first upstream cutter 42 and a second downstream cutter 44. The first cutter 42 and the second cutter 44 are provided so as to prepare complementary cutting edges, as for example shown in FIG. 3, middle or right side.

[0075] The first cutter 42 and the second cutter 44 are adapted to cut out any extrusion fault 48 that has been detected by the monitoring device 24, thus producing a scrap piece 50. The joining device 27 is adapted to re-join the remaining material strand at its opposite cutting end faces (not shown in FIG. 1). The joining process conducted by the joining device 27 leads to a joint 46, two of which are shown at 46.sub.1 and 46.sub.2 in FIG. 1. The faultless material strand 27 does not include any faults 48, but may include a number of joints 46.

[0076] A distance between the monitoring device 24 and the first cutting device 26 is shown at L.sub.1. The distance L.sub.1 is chosen such that, at a typical maximum speed of the material strand 20, there is sufficient time for the first cutting device 26 to be operated when a fault 48 is detected by the monitoring device 24.

[0077] The axial distance between the first cutter 42 and the second cutter 44 is shown at L.sub.2.

[0078] The length L.sub.2 may, for example, correspond to an average axial fault length. In the present embodiment, L.sub.2 is chosen to be in a range from 50 cm to 150 cm, for example 1 m (100 cm).

[0079] An axial distance between the first cutter 42 and the second cutting device 28 (which may include a third cutter) is shown in FIG. 1 at L.sub.C.

[0080] The length L.sub.C (the cutting device distance) corresponds preferably to a minimum joint distance L.sub.MIN, explained below.

[0081] The cutting device distance L.sub.C is preferably shorter than L.sub.MIN.

[0082] The ratio of L.sub.C to L.sub.2 is preferably in a range from 7:1 to 3:1, preferably in a range from 4.5:1 to 6:1.

[0083] If the movement speed of the material strand downstream of the first strand accumulator 22 is set to be smaller than the extrusion speed v.sub.E, the first strand accumulator 22 can be loaded, as shown at 52. On the other hand, if the material strand speed downstream of the first strand accumulator 22 is set to be higher than the extrusion speed v.sub.E, the first strand accumulator 22 can be unloaded as shown at 54.

[0084] Similarly, the second strand accumulator 22 can be loaded, as shown at 56, if the material strand speed upstream of the second strand accumulator 30 is higher than the material strand speed downstream of the second strand accumulator 30. On the other hand, if the speed relation is reversed, the second strand accumulator 30 can be unloaded, as shown at 58.

[0085] The cutters 42, 44 may include knifes or notching devices, and can be operated online, i.e. while the material strand moves along the first cutting device 26. On the other hand, it is also possible to stop the material strand when conducting the cutting-out step.

[0086] When the scrap piece 50 is cut out from the material strand, two opposing cutting end faces 60, 62 are produced, which can be re-joined in the joining device 27, thus producing a joint 46.

[0087] The joining device 27 is preferably a stationary device. Similarly, the cutters 42, 44 and the second cutting device 28 are stationary. In other embodiments, however, these elements can be axially movable devices, so that these devices can be moved synchronously with the material strand.

[0088] In FIG. 2a to 20, a sequence of operation of a manufacturing apparatus 10 is shown, which corresponds with respect to construction and function to the manufacturing apparatus 10 of FIG. 1. Similar elements are given the same reference numerals. In the following, the operation is explained in detail.

[0089] In FIG. 2a, a situation is shown where the material strand 20 is moved in moving direction 21, wherein a fault 48.sub.1 is detected by the monitoring device 24.

[0090] In FIG. 2b, the fault 48.sub.1 has been moved into the area axially between the first cutter 42 and the second cutter 44.

[0091] In FIG. 2c, the first cutter 42 and the second cutter 44 are operated simultaneously, thus cutting out a scrap piece 50.sub.1 on which the fault 48.sub.1 is located, thus producing two opposing cutting end faces 60.sub.1, 62.sub.1 in the area of the cutters 42, 44.

[0092] In FIG. 2d, the first strand accumulator 22 is unloaded (schematically shown at 54), so that the material strand downstream of the first strand accumulator 22 moves with a speed v.sub.1 which is larger than v.sub.E, such that the two cutting end faces 60.sub.1, 62.sub.1 are approaching each other.

[0093] In FIG. 2e, the cutting end faces 60.sub.1, 62.sub.1 are close to each other and are located in the area of the joining device 27, which is stationary, so that the material strand is brought to a standstill, such that the material strand speed v.sub.2=0. In this case, the first strand accumulator 52 is loaded, as shown at 52 in FIG. 2e. The joining device 27 is operated so as to stitch overlapping ends of the cutting end phases 60.sub.1, 62.sub.1. In the joining device 27, therefore, a first joint 46.sub.1 is produced.

[0094] In FIG. 2f, it is shown that the material strand is moving again at the extrusion speed v.sub.E, so that the accumulators 22, 30 are neither loaded nor unloaded. The first joint 46.sub.1 has moved into the direction of the second cutting device 28.

[0095] In FIG. 2f, it is shown that the joint 46.sub.1 has reached an axial distance from the monitoring device 24, which is L.sub.MIN, which is a minimum joint distance. Namely, the faultless material strand 37 that is to be stored in the storage unit 32 may have joints, but any two adjacent joints must be at the minimum joint distance L.sub.MIN from each other. The distance L.sub.MIN is preferably in a range from 3 m to 10 m, particularly in a range from 4 m to 7 m, preferably in a range from 4.5 m to 6 m.

[0096] In FIG. 2f, it is shown that no further fault 48 has been detected within the minimum joint distance L.sub.MIN, so that the process can be continued by moving the material strand and storing the faultless material strand 37 in the storage unit 32.

[0097] FIG. 2g shows a different situation. Here, a second fault 48.sub.2 has been detected by the monitoring device 24 at a distance from the first joint 46.sub.1, which is less than or equal to L.sub.MIN. Here, a distance between the first joint and a second joint for the second fault 48.sub.2 would be axially shorter than the minimum joint distance L.sub.MIN.

[0098] Therefore, the process continues with the situation of FIG. 2h, where the second fault 48.sub.2 is located between the first and the second cutter 42, 44. The first joint 46.sub.1 is still located upstream of the second cutting device 28 in this case.

[0099] As shown in FIG. 2i, the first cutter 42 and the second cutting device 48 are operated simultaneously, so that a second scrap piece 50.sub.2 is produced (as shown in FIG. 2k), which includes the firstjoint 46.sub.1 and the second fault 48.sub.2. Further, two opposing cutting end faces 60.sub.2, 62.sub.2 are produced at the locations of the first cutter 42 and the second cutting device 28, respectively.

[0100] In order to bring the opposing cutting end faces 60.sub.2, 62.sub.2 into the area of the joining device 27, the first strand accumulator 22 is unloaded, as shown at 54, and, further, the second strand accumulator 30 is unloaded as shown at 58. The unloading of the first strand accumulator 22 has the effect that the material strand speed v.sub.1 downstream of the first strand accumulator 22 is higher than the extrusion speed v.sub.E. The unloading 58 of the second strand accumulator 30 has the effect that the cutting end face 62.sub.2 is moved in a direction opposite to the moving direction (extrusion direction), so that the material stand that is moved out of the second strand accumulator 30 is moved at a speed v.sub.2 which is smaller than zero (negative speed).

[0101] Therefore, as shown in FIG. 2m, the cutting end faces 60.sub.2, 62.sub.2 meet at the joining device 27, so that, at a material strand speed of v=0, a second joint 46.sub.2 is produced. As shown in FIG. 2n, the second joint 46.sub.2 has moved beyond the second cutting device 42, without that another fault having been detected in the monitoring device. Thus, the second joint 46.sub.2 is at the minimum joint distance from any upstream joint, and the second joint 46.sub.2 can be fed into the second strand accumulator 30 as shown at 56 in FIG. 2n. In FIG. 2n, the speed with which the faultless material strand 37 is stored in the storage unit 32 is preferably less than v.sub.E. As shown in FIG. 20, a third fault 48.sub.3 is detected after the second joint 46.sub.2 has passed the second joining device 28. The third fault 48.sub.3 will be dealt with in a manner identical to what has been described with respect to FIGS. 2a to 2f.

[0102] In FIG. 3, three different types of joints 46 are shown. On the left hand side in FIG. 3, a joint 46A of a faultless material strand 37A is shown, wherein a material dissimilar from the material of the material strand 37A is inserted between the cutting end faces 60, 62, wherein the joining material is for example a thermoplastic elastomer material or any other thermoplastic joining material which, by way of heating, produces a thermoplastic weld at the cutting end faces 60, 62.

[0103] In the middle portion of FIG. 3, a joint 46B is shown, wherein the cutting end faces 60′, 62′, produced by special cutters 42, 44, have complementary shapes. For example, the cutters 42, 44 can be formed by L-shaped notching elements. Therefore, these L-shaped cutting end faces are complementary to each other and overlap axially, such that a stitching 63 can be produced in the joining device 27, so as to join the material strand portions of the faultless material strand 37B together. As an alternative to the stitching 63, the cutting end faces portions that are aligned parallel to the longitudinal direction, could be connected by adhesive or the like, so that the portions of the cutting end faces 60′, 62′, that are arranged transverse and at the outer border of the material strand 37B, could be distant from each other and present gaps that can be easily detected.

[0104] In FIG. 3, the joint 46C includes cutting end faces 60″, 62″, that are complementary to each other by having complementary slopes, thus, again, producing a faultless material strand 37C.

[0105] As shown in the left hand part of FIG. 3, any joint 46A (or 46B, 46C or any other joint) can be marked by a marking 64, wherein an axial length L.sub.4 of the marking 64 is shorter than an axial length L.sub.3 of the joint. Further, the marking 64 may have an axial distance L.sub.5 from the joint 46A, wherein 0≤L.sub.5≤20 cm, for example, either upstream or downstream of the joint.

[0106] On the other hand, the above joints 46A, 46B, 46C may not be marked at all.

[0107] As a third alternative, an axial position of each of the joints 46A, 46B, 46C may be recorded in a recording device, which is assigned to the material strand assembly 38. As explained later, at an assembly site, such recording device can be used in order to identify the positions of joints of the faultless material strand 37.

[0108] In FIG. 4, an apparatus for applying a material strand strip to a vehicle part is schematically shown and is given reference 66. The production apparatus 66 includes an inspection device 68. The inspection device 68 is designed to inspect the faultless material strand 37 that is un-stored or un-wound from the material strand assembly 38, at a production speed v.sub.P. The inspection device 68 is preferably a camera-based inspection device that is able to clearly identify joints, wherein the joints may have been produced by a mirror weld joining step, either with or without material between cutting end faces. The inspection device may, however, also be another type of inspection device, e.g. a metal detection device. Downstream of the inspection device 68, the production apparatus 66 includes a separation device 70 which is adapted to separate or cut the material strand.

[0109] Between the material strand assembly 38 and the inspection device 68, optionally, a production accumulator 71 can be provided which has a function similar to that of the first strand accumulator 22 of the manufacturing apparatus 10 of FIG. 1.

[0110] The separation device 70 is adapted to cut off strand strips 72 from the endless and faultless material strand 37, which strand strips 72 have an axial length L.sub.D which is a predefined strip length adapted to the application purpose.

[0111] The production apparatus 66, further, includes an applying device 74. The applying device 74 is designed to apply a strand strip 72 to a vehicle part, in particular to a body opening of a vehicle body. As shown schematically in FIG. 4, the applying device 74 may be adapted to apply a strand strip 72 to a window opening 78 of a vehicle door 76.

[0112] The applying device 74 is preferably adapted to apply the strand strip 72 automatically, using at least one robot. In FIG. 1, two robots are shown at 80, 82. A first robot 80 may be used to handle the strand strips 72. A second robot 82 may be adapted to handle and three-dimensionally move the vehicle part (vehicle door 76).

[0113] In general, it is possible to provide an applying device 74, wherein the strand strip 72 is applied to the vehicle part while the strand strip 72 is still attached to the faultless material strand 37 (up until to the last portion). In FIG. 4, however, it is shown that strand strips 72 are cut off in advance before being applied to the vehicle part.

[0114] FIG. 4 also shows that the faultless material strand 37, when un-stored from the storage unit 32, has a downstream end 86. When the downstream end 86 has reached the distance L.sub.D from the separation device 70, the separation device 70 is operated, so as to cut off the strand strip 72, and producing a new downstream end of the material strand 37.

[0115] In FIG. 4, left hand side, a situation is shown where a joint 46 is located at a distance L.sub.F from a downstream end 86.sub.1, which distance L.sub.F is shorter than the predefined strip length L.sub.D.

[0116] Therefore, in a second step, the joint 46 is moved passed the separation device 70, and the separation device 70 is operated, so that a second downstream end 86.sub.2 is produced. The strand portion 88 between the first downstream end 86.sub.1 and the second downstream end 86.sub.2, including the joint 46, is discarded as waste.

[0117] Finally, it is shown that the second downstream end 86 has then again moved at the production speed v.sub.P to a location, where it is located at the distance L.sub.D from the cutting device 70 and wherein no joint is arranged within this distance, so that the separation device 70 can again be operated, so that another strand strip 72 can be cut off and used for applying it to the vehicle part, creating a third downstream end 863.

[0118] FIG. 5 shows a situation similar to FIG. 4, wherein a material strand 37 is un-stored from a material strip assembly 38 at a certain speed V.sub.P. In order to identify or detect joints, the production apparatus 66 of FIG. 4 may, in addition to the inspection device 68 shown in FIG. 4 or as an alternative thereto, include an apparatus 100 for detecting irregularities.

[0119] The apparatus 100 is preferably a stationary apparatus. The material strand 37 is conveyed along a longitudinal axis 102. The movement of the material strand 37 is also shown in FIG. 5 at s.

[0120] The apparatus 100 includes a detection element 104 that is brought into contact with a surface of the material strand 37. Particularly, the detection element 104 is arranged at a bearing block 106. Here, the bearing block 106 is mounted movably in a deflection direction d on a housing 108. Further, the bearing block 106 is biased in a direction toward the material strand 37 by means of a spring 110.

[0121] The detection element 105 may be a low-friction surface element so that only little heat is produced during the relative movement between the detection element 104 and the material strand 37.

[0122] A deflection d of the bearing block 106 can be detected by means of a deflection sensor 112 which is typically an electro-mechanical travel sensor which is connected (via A) to a controller 114.

[0123] As an alternative and/or in addition to the deflection sensor 112, a force sensor 116 can be provided. In this case, the bearing block 106 does not need to be movable in a direction transverse to the longitudinal axis 102. In contrast, the bearing block 106 and the force sensor 116 may be stationary.

[0124] In any case, during the movement of the material strand 37, the deflection sensor 112 and/or the force sensor 116 will produce a sensor signal which essentially corresponds to a basic force by means of which the detection element 104 is pressed against the material strand 37.

[0125] FIG. 5 also shows a diagram of the deflection d and/or of the force F over the travel s.

[0126] Normally, if no irregularities are detected, the signal of the sensor(s) is at a basic value d.sub.0. In case of detecting an irregularity, the deflection and/or force increases. If the deflection d and/or force F exceeds a certain threshold value T and if the axial length Δs of the peak is within a typical range of the axial joint length, an irregularity in the form of a joint in the faultless material strand is detected. The axial length Δs of the peak is preferably in a range of 0.5 to 80.0 mm, particularly 0.5 to 8.0 mm. A typical axial joint length is in a range of 0.1 to 1.0 mm. The threshold may be set on the basis of the basic value d.sub.0. For example T=d.sub.0+0.1×d.sub.0, i.e. 10% above the basic value d.sub.0.

[0127] The sensor signals can be detected and recorded. Preferably, the sensor signals are output continuously and compared with a previously stored characteristic which reflects the shape of a peak when a joint is detected.

[0128] Joints 46a, 46b are for example shown in FIG. 5 as well in the material strand 37.

[0129] FIG. 6 shows an alternative embodiment, wherein the detection element is a roller element 104′ which is mounted rotatably on a bearing block 106′ about a roller axis 118 which is aligned transversely to both the longitudinal axis 102 and the deflection direction d.

[0130] In FIG. 6, it is further shown that the roller element 104′, by means of a spring 110, is slightly pressed into the elastically deformable material strand 37 by a deflection amount D.sub.0, which corresponds essentially to the basic value d.sub.0 in the diagram of FIG. 5.

[0131] The material strand which the detection element contacts, is preferably manufactured by a method and/or an apparatus according to any one of the following clauses, wherein reference is made in this context to document EP 3 431 250 A1 the disclosure which is incorporated herein by reference: [0132] Clause 1. A method for manufacturing a material strand assembly (38) for a vehicle, particularly for sealing a body opening (78) of a vehicle part (76), including the steps of: [0133] extruding strand material (14) in an extruder (12) so that an extruded material strand (20) is produced, [0134] monitoring the quality of the extruded material strand (20) so as to detect faults (48) of the extruded material strand (20), [0135] in case of a detection of a fault (48), cutting out the fault (48) from the material strand (20), using a cutting arrangement (29), and re-joining cutting end faces (60, 62), thus producing a joint (46), so that a faultless material strand (37) is produced, wherein the cutting-out step is conducted such that any two adjacent joints (46) are at a minimum joint distance (L.sub.MIN) from each other, and [0136] storing the faultless material strand (37) in a storage unit (32) so as to produce the material strand assembly (38),
wherein the extruded material strand (20) is passed through a first strand accumulator (22) between the extruder (12) and the cutting arrangement (29) and/or wherein the faultless material strand (37) is passed through a second strand accumulator (30) between the cutting arrangement (29) and the storage unit (32). [0137] Clause 2. The method of Clause 1, wherein, if a joint (46) is produced, the position of the joint (46) is neither recorded nor marked. [0138] Clause 3. The method of Clause 1, wherein, if a joint (46) is produced, the position of the joint (46) is marked on the material strand (20; 37) by a single marking (64) which has an axial marking length (L.sub.4) that is shorter than an axial joint length (L.sub.3) of the joint (46). [0139] Clause 4. The method of any of Clauses 1 or 3, wherein, if a joint (46) is produced, the position of the joint (46) is recorded by recording one single axial position that identifies the joint (46). [0140] Clause 5. The method of any of Clauses 1-4, wherein the cutting step includes the use of at least two cutters (42, 44) that are arranged at an axial cutter distance (L.sub.2) from each other, wherein the axial cutter distance (L.sub.2) is axially shorter than the minimum joint distance (L.sub.MIN) and/or wherein the axial cutter distance (L.sub.2) is axially longer that an average axial fault length. [0141] Clause 6. A manufacturing apparatus (10) for manufacturing a material strand assembly (38), particularly for conducting a method for manufacturing a material strand assembly (38) according to any of Clauses 1-5, comprising: [0142] an extruder (12) for producing an extruded material strand (20), [0143] a monitoring device (24) for monitoring the quality of the extruded material strand (20), such that faults (48) of the extruded material strand (20) can be detected, [0144] a cutting arrangement (29) for cutting out detected faults (48) from the extruded material strand (20), such that cutting end faces (60, 62) are created, [0145] a joining device (27) for re-joining the cutting end faces (60, 62), thus producing a joint (46), so that a faultless material strand (37) is produced, wherein the cutting arrangement (29) is adapted to conduct the cutting-out step such that any two adjacent joints (46) are at a minimum joint distance (L.sub.MIN) from each other, and [0146] a storing device (31) for storing the faultless material strand (37) in a storage unit (32). [0147] Clause 7. The manufacturing apparatus of Clause 6, wherein the cutting arrangement (29) comprises a first cutting device (26) and a second cutting device (28), wherein the joining device (27) is arranged axially between the first cutting device (26) and the second cutting device (28). [0148] Clause 8. The manufacturing apparatus of Clause 7, wherein a cutting device distance between the first cutting device (26) and the second cutting device (28) corresponds to the minimum joint distance (L.sub.MIN). [0149] Clause 9. The manufacturing apparatus of Clause 7 or 8, wherein the first cutting device (26) comprises a first cutter (42) and a second cutter (44), which are arranged at an axial cutter distance (L.sub.2), wherein the axial cutter distance (L.sub.2) is axially longer than an average axial fault length and/or wherein the first cutter (42) and the second cutter (44) are operable independently from each other. [0150] Clause 10. The manufacturing apparatus of Clause 9, wherein the first cutter (42) and the second cutter (44) are adapted to produce complimentary cutting end faces (60′, 62′), wherein the second cutting device (28) comprises a third cutter which is adapted to produce the same cutting end face (62′) as the second cutter (44). [0151] Clause 11. The manufacturing apparatus of any of Clauses 6-10, wherein a second accumulator (30) is adapted to feed an accumulated faultless material strand to the joining device (27).

[0152] It is to be understood that the foregoing is a description of one or more preferred exemplary embodiments of the invention. The invention is not limited to the particular embodiment(s) disclosed herein, but rather is defined solely by the claims below. Furthermore, the statements contained in the foregoing description relate to particular embodiments and are not to be construed as limitations on the scope of the invention or on the definition of terms used in the claims, except where a term or phrase is expressly defined above. Various other embodiments and various changes and modifications to the disclosed embodiment(s) will become apparent to those skilled in the art. All such other embodiments, changes, and modifications are intended to come within the scope of the appended claims.

[0153] As used in this specification and claims, the terms “for example,” “e.g.,” “for instance,” “such as,” and “like,” and the verbs “comprising,” “having,” “including,” and their other verb forms, when used in conjunction with a listing of one or more components or other items, are each to be construed as open-ended, meaning that the listing is not to be considered as excluding other, additional components or items. Other terms are to be construed using their broadest reasonable meaning unless they are used in a context that requires a different interpretation.