Method for manufacturing a material strand assembly

Abstract

A method for manufacturing a material strand assembly for a vehicle. The method includes: extruding strand material in an extruder so that an extruded material strand is produced; monitoring the quality of the extruded material strand so as to detect faults of the extruded material strand; in case of a detection of a fault, cutting out the fault from the material strand and re-joining cutting end faces, thus producing a joint, so that a faultless material strand is produced. The cutting-out step is conducted such that any two adjacent joints are at a minimum joint distance from each other. The faultless material strand is stored in a storage unit so as to produce the material strand assembly. The extruded material strand is passed through a first strand accumulator between the extruder and the cutting arrangement and through a second strand accumulator between the cutting arrangement and the storage unit.

Claims

1. A method for manufacturing a material strand assembly for a vehicle, including the steps of: extruding strand material in an extruder so that an extruded material strand is produced, monitoring the quality of the extruded material strand so as to detect faults of the extruded material strand, in case of a detection of a fault, cutting out the fault from the material strand, using a cutting arrangement, and re-joining cutting end faces, thus producing a joint, so that a faultless material strand is produced, wherein the cutting-out step is conducted such that any two adjacent joints are at a minimum joint distance from each other, and storing the faultless material strand in a storage unit so as to produce the material strand assembly, wherein the faultless material strand is passed through a second strand accumulator between a cutting arrangement and the storage unit, and wherein the second strand accumulator is adapted to feed an accumulated faultless material strand to the storage unit.

2. The method of claim 1, wherein the cutting step includes the use of at least two cutters that are arranged at an axial cutter distance from each other, wherein the axial cutter distance is axially shorter than the minimum joint distance.

3. The method of claim 1, wherein the cutting step includes the use of at least two cutters that are arranged at an axial cutter distance from each other, wherein the axial cutter distance is axially longer than an average axial fault length.

4. A method for manufacturing a material strand assembly for a vehicle, including the steps of: extruding strand material in an extruder so that an extruded material strand is produced, monitoring the quality of the extruded material strand so as to detect faults of the extruded material strand, in case of a detection of a fault, cutting out the fault from the material strand, using a cutting arrangement with first and second cutters, and re-joining cutting end faces, thus producing a joint, so that a faultless material strand is produced, wherein the cutting-out step is conducted by placing the fault between the first and second cutters and cutting out the fault and the re-joining step is conducted such that any two adjacent joints are at a minimum joint distance or more from each other, and storing the faultless material strand in a storage unit so as to produce the material strand assembly, wherein a feeding step includes at least one of passing the extruded material strand through a first strand accumulator between the extruder and the cutting arrangement and passing the faultless material strand through a second strand accumulator between the cutting arrangement and the storage unit.

5. The method of claim 4, wherein, if a joint is produced, the position of the joint is neither recorded nor marked.

6. The method of claim 4, wherein, if a joint is produced, the position of the joint is marked on the material strand by a single marking which has an axial marking length that is shorter than an axial joint length of the joint.

7. The method of claim 4, wherein, if a joint is produced, the position of the joint is recorded by recording one single axial position that identifies the joint.

8. The method of claim 4, wherein the cutting step includes the use of at least two cutters that are arranged at an axial cutter distance from each other, wherein the axial cutter distance is axially shorter than the minimum joint distance.

9. The method of claim 4, wherein the cutting step includes the use of at least two cutters that are arranged at an axial cutter distance from each other, wherein the axial cutter distance is axially longer than an average axial fault length.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

(1) Exemplary embodiments of the invention are explained in more detail in the following description and are represented in the drawings, in which:

(2) FIG. 1 is a schematic view of a manufacturing apparatus for manufacturing a material strand assembly according to an embodiment of the invention;

(3) FIGS. 2A to 2N are sequences of operation in a method for manufacturing a material strand assembly using a manufacturing apparatus according to another embodiment of the invention;

(4) FIG. 3 shows several schematic views of different types of joints in a faultless material strand; and

(5) FIG. 4 is a schematic view of an apparatus for applying a material strand strip to a vehicle part.

EMBODIMENTS

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

(7) 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.

(8) 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.

(9) 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).

(10) 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.

(11) 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.

(12) 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.

(13) The material strand 20 is typically used for sealing, trimming or fastening body openings in vehicle bodies, typically in the automobile industry.

(14) 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.

(15) 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.

(16) 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.

(17) 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.

(18) The axial distance between the first cutter 42 and the second cutter 44 is shown at L.sub.2.

(19) 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).

(20) 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.

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

(22) The cutting device distance L.sub.C is preferably shorter than L.sub.MIN.

(23) 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.

(24) 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.

(25) 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.

(26) 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.

(27) 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.

(28) 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.

(29) In FIGS. 2A to 2N, 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.

(30) 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.

(31) 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.

(32) 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.

(33) 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.

(34) 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.

(35) 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.

(36) In FIG. 2G, 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.

(37) 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.

(38) 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.

(39) 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.

(40) 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. 2J), which includes the first joint 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.

(41) 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).

(42) Therefore, as shown in FIG. 2L, 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. 2M, 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. 2M. In FIG. 2M, 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. 2N, 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.

(43) 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.

(44) 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.

(45) 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.

(46) 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 0L.sub.520 cm, for example, either upstream or downstream of the joint.

(47) On the other hand, the above joints 46A, 46B, 46C may not be marked at all.

(48) 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.

(49) 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 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.

(50) 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.

(51) 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.

(52) 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.

(53) 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).

(54) 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.

(55) 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.

(56) 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.

(57) 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.

(58) 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 86.sub.3.