Press line control assembly, manufacturing unit comprising such a control assembly, and method for controlling a press line

Abstract

A press line control assembly, a manufacturing unit comprising such a control assembly, and a method for controlling a press line. The invention relates to a control assembly (1) for a press line for manufacturing a part (7) comprising a stamping die, said control assembly comprising a system for identifying defects in said part, including: - a vision system (3) for acquiring images of said part, - electronic management equipment (5) comprising a computer (23) for receiving and processing said images and a programmable logic controller (27). According to the invention, the programmable logic controller is programmed, when a manufacturing defect in said part is identified, to emit an alert signal and perform corrective action on said stamping die involved in said defect. The invention also relates to a manufacturing unit and a control method implemented by said control assembly.Figure 1.

Description

Title of the invention: Press line control assembly, manufacturing unit comprising such a control assembly, and method for controlling a press line technical field

[0001] The invention falls within the field of artificial vision systems used in the execution of automatic operations in a motor vehicle manufacturing line.

[0002] More particularly, the present invention relates to a control assembly for a press line for the manufacture of a part.

[0003] The invention also relates to a manufacturing unit comprising such a control assembly and a method for controlling a press line implemented by said control assembly. Previous technique

[0004] The production of the different models of motor vehicles involves the production of parts, in particular metallic ones.

[0005] A metal part can be manufactured by stamping, also called pressing, a process which involves the use of a hydraulic stamping press in order to shape a final form from a sheet of metal.

[0006] The stamping process also includes, in particular, cutting, in order to remove excess sheet metal and, when necessary, punching, to pierce the formed sheet metal parts.

[0007] The stamping process can be carried out in a single operation or by following a series of steps by means of a progressive stamping press line, which performs the mechanical operations of stamping, cutting and punching during which the sheet metal is subjected to a compression load between two molds to form parts, to cutting to remove excess sheet metal and to punching by means of punches to pierce the formed sheet metal parts.

[0008] The production of the different models of motor vehicles involves the production of metal parts with different appearances and functions, which requires the forming of a variety of reference metal parts.

[0009] For this purpose, stamping molds are generally designed in a configurable manner to be able to adapt to different part references, by being able to move and configure parts of the stamping mold to activate or deactivate the punches according to the reference to be manufactured.

[0010] These configuration changes of the stamping presses define a This critical moment can lead to manufacturing failures of the metal part. Conformity issues appear in the first units produced after the configuration change.

[0011] In normal operation, a quality control is carried out visually at the end of the line by an operator to detect any defects on the manufactured part.

[0012] First of all, carrying out quality control at the end of the line implies that no defects can be detected on the manufactured parts before they leave the line.

[0013] Furthermore, the fact that the inspection is carried out visually by an operator increases the time required to complete it and depends to a large extent on the experience and knowledge of the operator carrying out the inspection, as well as on his visual acuity, fatigue and dexterity.

[0014] Furthermore, the parts are not necessarily inspected as a unit. Thus, defective parts sometimes continue in the production process, which increases the manufacturing cost.

[0015] Industrial vision solutions applied to quality control are also known, which use a visual inspection system by means of cameras.

[0016] Unlike the human eye, such solutions allow for uninterrupted monitoring and decision-making based on the information received.

[0017] Such a visual inspection system makes it possible to guarantee the homogeneity of the manufactured part or to reveal manufacturing defects such as cracks.

[0018] The use of hyperspectral cameras is also known, which make it possible to know the composition of materials or of anomalous elements which slip into the production line.

[0019] However, the use of visual inspection systems requires a lengthy development process.

[0020] Also, the automatic inspection of large and complex parts is not carried out in its entirety but only in the areas considered to be problematic.

[0021] Furthermore, image analysis is not simple because the inspection of metallic surfaces is complex due to their highly reflective nature. The large amount of reflections and shadows in the images tends to obscure defects. Description of the invention

[0022] The present invention aims to overcome the aforementioned drawbacks, and to this end relates to a control assembly for a press line for manufacturing a part, said press line comprising at least one stamping die having at less a configurable moving part equipped with at least one position sensor, said control assembly including a system for identifying defects in said part manufactured by said press line, comprising: - a vision system adapted to acquire images of said manufactured part, - electronic management equipment, including a computer equipped with vision software adapted to receive and process said images acquired by said vision system, said electronic management equipment further including a programmable logic controller communicating with said computer and with said stamping mold, said control assembly being notable in that said programmable logic controller is programmed, when a manufacturing defect of said manufactured part is identified by said vision software, to emit an alert signal and to perform at least one corrective action on said stamping mold involved in said detected manufacturing defect.

[0023] The programmable logic controller of the control assembly is programmed, when a manufacturing defect of said manufactured part is identified by said vision software, to emit an alert signal and to execute at least one corrective action on said stamping mold involved in said detected manufacturing defect.

[0024] Thus, it is possible to detect if manufacturing errors have occurred in the manufacture of a part and, if so, to trigger an alert to stop the press line and to remove the defective part.

[0025] In addition, corrective action is carried out on the stamping mold which is recognized as being involved in the manufacturing defect of the manufactured part.

[0026] In this way, thanks to the present invention, changes in the operation of the stamping mold are specifically controlled, preventing defective parts from proceeding to subsequent stages of the production line. This increases the production rate and the profitability of the production line.

[0027] The control assembly is advantageously configurable according to the different types of parts and stamping molds.

[0028] According to optional features of the control assembly according to the invention: - said corrective action consists of sending said position sensor of said stamping mold involved in said manufacturing defect detected a position check order of said configurable moving part and, where appropriate, an order to move said configurable moving part to an appropriate position dependent on said part to be manufactured; - in an embodiment, said configurable movable part of said stamping mold includes at least one punch and at least one carriage whose movement or configuration allows said punch to be activated or deactivated, and said manufacturing defect is a punching defect; - the control system includes a visual warning device communicating with said programmable logic controller and being activated when said warning signal is emitted by said programmable logic controller; - in an embodiment, the control assembly includes a human-machine interface comprising a display panel, and the detected manufacturing defect is displayed on the said display panel of the said human-machine interface.

[0029] The invention also relates to a one-part manufacturing unit comprising a press line and a piloting assembly for said press line, notable in that said piloting assembly is according to the invention.

[0030] In one embodiment, said vision system of said control assembly is mounted at the output of said press line.

[0031] In one embodiment, the manufacturing unit includes a robot positioned at the exit of said press line and a conveyor belt adapted to carry said manufactured part to said vision system of said control assembly, said robot being configured to transfer said manufactured part from the exit of said press line to said conveyor belt.

[0032] The invention also relates to a method for controlling a press line, implemented by a control assembly according to the invention, remarkable in that it comprises the following steps aimed at: - acquire a set of images of the said manufactured part, - perform an image processing operation, - to make decisions based on the results from said step aimed at executing an image processing operation.

[0033] In one embodiment, said decision-making step aims to, when a manufacturing defect of said manufactured part is identified by said vision software, issue an alert signal to warn of the need to stop the press line and to perform at least one corrective action on said stamping mold involved in said detected manufacturing defect. Brief description of the drawings

[0034] Other features, purposes and advantages of the invention will become apparent from the following detailed description, for the understanding of which reference should be made to the accompanying drawings in which:

[0035] [Fig-1] shows a control assembly for a press line according to the invention.

[0036] [Fig.2] illustrates the steps of the press line control process implemented by the control assembly according to the invention. Description of the implementation methods

[0037] In the following description, elements having an identical structure or analogous functions are designated by the same reference.

[0038] Reference is made to [Fig.1] showing a control assembly 1 for a press line (not shown) according to the invention.

[0039] The press line includes at least one stamping mold designed in a configurable manner to be able to adapt to different part references and to perform mechanical stamping, cutting and punching operations by means of punches to pierce the formed sheet metal parts.

[0040] In order to allow the stamping mold to adapt to the different part references to be manufactured, the stamping mold includes one or more configurable moving parts, typically configurable carriages or slides, whose movement or configuration allows, in particular, the activation or deactivation of punches according to the part reference to be manufactured.

[0041] Each configurable moving part of the stamping mold is equipped with at least one suitable position sensor to detect whether the configurable moving part occupies the ordered place according to the reference of the part to be manufactured.

[0042] The control assembly 1 includes a fault identification system comprising a vision system 3 and an electronic press line management equipment 5.

[0043] The assembly formed by the press line and by the pilot assembly 1 defines a manufacturing unit.

[0044] In an embodiment of the manufacturing unit, the vision system 3 of the control assembly 1 is, for example, mounted at the exit of the press line.

[0045] For example, a robot (not shown) is positioned at the exit of the press line and is configured to transfer a finished part 7 to a conveyor belt 9 which leads the part 7 to the vision system 3.

[0046] The vision system 3 comprises a set of cameras, including for example upper cameras 11, mounted above the conveyor belt 9 and side cameras 13a, 13b positioned on either side of the conveyor belt 9.

[0047] The upper cameras 11 of the vision system 3 are for example mounted on an upper gantry 15 while the side cameras 13a, 13b are for example mounted respectively on side gantries 17a, 17b.

[0048] The cameras of the vision system 3 are adapted to withstand extreme vibration conditions and the aggressive working environment where the production rate is high.

[0049] Also, the cameras of the vision system 3 and the robot, which transfers the manufactured part 7 to the conveyor belt 9, are positioned so that there is no interference with the robot during image capture.

[0050] The set of captured images includes the entire manufactured part 7 with a resolution suitable for detecting defects in punched parts.

[0051] The control unit 1 is configurable. Each type of part 7 manufactured is associated with a specific program based on the characteristics of the part.

[0052] The vision system 3 further includes a suitable lighting system to illuminate the shooting area in order to obtain good quality images.

[0053] The lighting system includes, for example, a central lighting group 19, for example mounted above the conveyor belt 9, for example on the upper gantry 15, and lateral lighting groups 21a, 21b mounted on either side of the conveyor belt 9, for example on the lateral gantries 17a, 17b.

[0054] Lighting groups 19, 21a, 21b include, for example, LED lamps.

[0055] The electronic management equipment 5 of the control unit 1 of the press line includes a computer 23 equipped with vision software adapted to receive and process the images acquired by the vision system 3.

[0056] The electronic management equipment 5 may further include a human-machine interface 25 comprising a display panel, adapted to display a set of information, including information relating to the reference of the part being processed, image processing from the acquired images, etc.

[0057] The electronic management equipment 5 also includes a programmable logic controller 27, or automaton, frequently called "PLC" for "Programmable Logical Controller" in English.

[0058] The programmable logic controller 27 is a control system which automates the process of controlling the press line, designed to make decisions based on the results from image processing carried out by the vision system 3.

[0059] The cameras 11, 13a, 13b communicate with the computer 23 and the human-machine interface 25 to transfer the acquired images.

[0060] Also, the programmable logic controller 27 communicates with the cameras 11, 13a, 13b to transfer a signal indicating the reference of the part to be analyzed.

[0061] Communication between the cameras 11, 13a, 13b and the computer 23 and between the programmable logic controller 27 and the cameras 11, 13a, 13b can for example be carried out by wired means, for example via the Ethernet protocol.

[0062] The control assembly 1 further includes a visual warning device capable of communicating with the programmable logic controller 27. The visual warning device includes, for example, a set of light beacons, for example green, yellow, red.

[0063] According to the invention, the programmable logic controller 27 is programmed, when a manufacturing defect in the manufactured part 7 is identified by the computer vision software 23, to emit an alert signal.

[0064] The warning signal alerts the operator to the need to stop the press line. The warning signal activates the visual warning device. For example, the warning signal may involve flashing the red indicator on the visual warning device. Stopping the press line allows for the removal of the defective part.

[0065] In one embodiment, the electronic management equipment 5 of the control assembly 1 is programmed so that, when a manufacturing defect of the part 7 is detected, the defect that has occurred is displayed on the display panel of the human-machine interface 25.

[0066] According to one embodiment of the invention, the manufacturing defect is a punching defect in a manufactured part 7. However, other types of defects may be detected.

[0067] According to the invention, the programmable logic controller 27 is also programmed, when a manufacturing defect of the manufactured part 7 is identified by the computer vision software 23, to execute one or more corrective actions on the stamping mold of the press line which is involved in the detected manufacturing defect.

[0068] For this purpose, the programmable logic controller 27 and the stamping mold each include a means of communication enabling communication to be established between the programmable logic controller 27 and the stamping mold.

[0069] In one embodiment, the corrective action consists of sending to the position sensor of the stamping mold involved in the detected manufacturing defect a position check order for the configurable moving part and, if necessary, an order to move the configurable moving part to an appropriate position depending on the part to be manufactured.

[0070] Reference is made to [Fig.2] to describe the press line control method implemented by the control assembly 1.

[0071] The part 7 manufactured by the press line is conveyed to the vision system 3 of the control assembly 1 by means of the conveyor belt 9 and the robot which transferred the part from the exit of the press line to the conveyor belt 9. The movements of the robot and the parts 7 exiting the press line are synchronized according to the production rate.

[0072] When the manufactured part 7 arrives at the vision system 3, the piloting process executes a step El aimed at acquiring a set of images of the manufactured part.

[0073] The number and nature of the images to be acquired is indicated by the indication signal of the reference of the part to be analyzed transmitted by the programmable logic controller 27 of the fault identification system, which communicates with the cameras 11, 13a, 13b.

[0074] The image acquisition time does not slow down the pace of the press line. Also, the shooting area is constantly illuminated by the lighting system of the vision system 3, in order to obtain good quality images.

[0075] The images acquired during step E1 are then transferred to computer 23, equipped with vision software which performs an image processing operation during a step E2.

[0076] The regions of interest used for evaluating defects in the manufactured part 7 are specific to each part reference and are managed according to the computer vision software 23.

[0077] The acquired images are compared to a pre-established reference model for each reference, in order to identify any deviation from the reference model.

[0078] Once the images have been processed to determine whether or not the parts have defects, the computer 23 sends the result to the programmable logic controller 27.

[0079] In a step E3, the programmable logic controller 27 makes decisions based on the results from the image processing step E2.

[0080] When a manufacturing defect in the manufactured part 7 is identified by the computer vision software 23, the programmable logic controller 27 emits an alert signal to warn of the need to stop the press line.

[0081] An operator can then intervene to stop the press line and remove the defective manufactured part 7.

[0082] When such an alert signal is issued, the visual alert device is activated. The display panel of the human-machine interface 25 shows the results of the process, including the presence or absence of defects in the manufactured parts 7, the part number being processed, etc. In particular, when an alert signal is issued, the defect that occurred is displayed on the display panel of the human-machine interface 25.

[0083] Furthermore, the programmable logic controller 27 executes one or more corrective actions on the stamping mold of the press line which is involved in the detected manufacturing defect also programmed when a manufacturing defect of the manufactured part 7 is identified.

[0084] For example, the corrective action consists of sending to the position sensor of the stamping mold involved in the detected manufacturing defect a position check order for the configurable moving part, for example the carriage or slide, and, if necessary, sending a movement order for the configurable moving part to an appropriate position depending on said part to be manufactured.

[0085] The critical moment of failure occurs on the first part after a change of operation of the stamping mold.

[0086] For example, the first parts produced after a change of operation of the stamping mold may be defective because the position of the configurable parts of the mold may not be correctly adjusted to the new geometry of the part to be manufactured.

[0087] Thus, according to a provision of the press line control method implemented by the control assembly 1, a unit check of the configurable parts of the stamping mold that have undergone a change of operation is performed, and a general scan of the manufactured part is carried out on a predetermined number of parts manufactured following the change of operation, before performing a check of the manufactured parts at a predetermined frequency which can be parameterized.

[0088] For example, two parts manufactured consecutively from the change of operation are subjected to a general scan before switching to a control mode for parts manufactured at a predetermined frequency.

[0089] The press line driven by the control assembly according to the invention is, for example, intended for manufacturing metal parts for the automotive industry. However, the control assembly according to the invention is applicable to driving press lines used in any other type of industry.

[0090] As will be understood, the present invention is not limited to the only embodiments of this press line control assembly, of this manufacturing unit comprising such a control assembly and of this method of controlling said press line, described above solely by way of illustrative examples, but on the contrary it encompasses all variants involving the technical equivalents of the means described as well as their combinations if these fall within the scope of the invention.

Claims

Demands

1. A control assembly (1) for a press line for manufacturing a part (7), said press line comprising at least one stamping die having at least one configurable moving part equipped with at least one position sensor, said control assembly (1) comprising a system for identifying defects in said part (7) manufactured by said press line, comprising: - a vision system (3) adapted to acquire images of said part (7) manufactured, - electronic management equipment (5), comprising a computer (23) equipped with vision software adapted to receive and process said images acquired by said vision system (3), said electronic management equipment (5) further comprising a programmable logic controller (27) communicating with said computer (23) and with said stamping die,said control assembly (1) being characterized in that said programmable logic controller (27) is programmed, when a manufacturing defect of said manufactured part (7) is identified by said vision software, to emit an alert signal and to perform at least one corrective action on said stamping mold involved in said detected manufacturing defect.

2. Control assembly (1) according to claim 1, characterized in that said corrective action consists of sending said position sensor of said stamping mold involved in said detected manufacturing defect a position check order of said configurable moving part and, where appropriate, a movement order of said configurable moving part to an appropriate position dependent on said part (7) to be manufactured.

3. A pilot assembly (1) according to any one of claims 1 or 2, wherein said configurable moving part of said stamping mold comprises at least one punch and at least one carriage whose movement or configuration enables said punch to be activated or deactivated, characterized in that said manufacturing defect is a punching defect.

4. Control assembly (1) according to any one of claims 1 to 3, characterized in that it comprises a visual warning device com- communicating with said programmable logic controller (27) and being activated when said alert signal is emitted by said programmable logic controller (27).

5. Control assembly (1) according to any one of claims 1 to 4, comprising a human-machine interface (25) including a display panel, characterized in that said manufacturing defect detected is displayed on said display panel of said human-machine interface (25).

6. A one-part manufacturing unit (7) comprising a press line and a pilot assembly (1) of said press line, characterized in that said pilot assembly (1) is according to any one of claims 1 to 5.

7. One-part manufacturing unit (7) according to claim 6, characterized in that said vision system (3) of said control assembly (1) is mounted at the output of said press line.

8. A manufacturing unit for a part (7) according to any one of claims 6 or 7, characterized in that it comprises a robot positioned at the exit of said press line and a conveyor belt (9) adapted to carry said manufactured part (7) to said vision system (3) of said control assembly (1), said robot being configured to transfer said manufactured part (7) from the exit of said press line to said conveyor belt (9).

9. A method for controlling a press line, implemented by a control unit (1) according to any one of claims 1 to 5, characterized in that it comprises the following steps aimed at: - acquiring (step E1) a set of images of said manufactured part (7), - performing (step E2) an image processing operation, - making decisions (step E3) based on the results from said step aimed at performing an image processing operation.

10. Control method according to claim 9, characterized in that said decision-making step (step E3) aims to, when a manufacturing defect of said manufactured part (7) is identified by said vision software, issue an alert signal to warn of the need to stop the press line and to perform at least one corrective action on said stamping mold involved in said detected manufacturing defect.

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