Method for manufacturing and processing a frame composed of steel profiles

Abstract

Method for manufacturing and processing a frame composed of steel profiles using a welding and grinding robot, characterized in that a) the cut frame parts to be joined are clamped onto the welding table using adjusting corners and screw clamps, b) the coordinate profiles of the weld seams to be produced on the front and back of the frame are loaded onto the robot control server by transferring the data identifying the start and corner points and the designation of the parts list from the software storing the design documents,c) by capturing a code on the parts list of the design software using a camera connected to the welding robot, the designation of the parts list is captured and compared by the robot control with the designation stored in the server for identity; and d) upon confirmation of the identity of the designations, the software for controlling the welding and grinding processes is started, wherein the software-supported control of the welding and grinding robots for the purpose of carrying out the welding and grinding processes is carried out as follows: i) for the production of the first weld, the data of the start and end point of the weld and the profile height stored in the server are used to control the movement of the welding robot to the start and end point of the weld to be produced; ii) the camera system of the welding robot first captures the start point, and the coordinates of the start point are stored.iii) The endpoint of the weld is then captured and stored using the camera system, and the robot control system calculates the weld and the profile height. iii) The welding robot tacks the frame at the endpoint of the weld, and then the welding process is carried out from the start to the endpoint. iv) After completion of the welding process, the welding robot is moved to the second corner, the calculation of the second weld is carried out in the same way, and the welding process is carried out as with the first corner. v) After the welding robot has reached the start point of the second weld, the grinding robot calculates the grinding path of the first weld using the stored start and end points of the first weld path, and the physical height of the profile is measured using a force sensor attached to the grinding robot, and the following is determined from the measured values:how many times the grinding robot must grind over the weld seam to achieve the physical height of the profile in order to grind the weld metal flush with the frame, vi) during the grinding process, the second corner of the frame is welded and then the grinding robot moves to the third corner of the frame, vii) subsequently, the welding and grinding operations are carried out on the third and fourth corners in the same sequence, viii) after completion of the welding and grinding operations on one side of the frame, the welding table is rotated 180°, ix) all the aforementioned process steps are then carried out on the other side of the frame in the same sequence, and x) after completion of all welding and grinding operations, the welding table is rotated back to its starting position, the frame is removed and fed into further processing operations.

Description

The invention relates to a method for producing and machining a frame composed of steel profiles by means of welding and grinding robots. In particular, the method serves for the production of square frames and the processing of hollow steel profiles required for this by welding and grinding.The methods known from the prior art are intended for the machining of large and / or complicated workpieces. Thus, EP 2 711 120 A1 describes a method and apparatuses serving to carry out the method, which are suitable for automatic machining, in particular welding, of very large workpieces. For this purpose, the workpieces are scanned by a robot and a three-dimensional data image is generated. Welding and grinding robots are used for the machining. The workpieces to be machined are composed of several layers which justifies the high technical outlay. For the production and machining of simple workpieces such as frames composed of steel profiles, for example, these methods are too time-consuming and technically complicated.Furthermore, DE 20 2012 012 973 U1 discloses a system for adaptive fill welding using an image recording, in which the respective distances between the edges to be joined are detected by means of a camera along the path of a weld seam to be produced. For this purpose, images of the width of the weld seam to be produced are captured successively by the camera. Starting from the respective following captured images, parameters for a welding torch are determined by means of apparatuses used for this purpose. The welding torch introduced on a welding robot is caused to weld the weld seam according to the determined parameters. However, the disadvantage of this system is the exclusive use for the production of welded seams and a camera-related detection provided for this purpose of the different distances of the materials to be connected along the welding path.DE 40 31 033 A1 describes an off-line teaching method for industrial robots, whereby a transmission of execution data is facilitated. Among other things, transmission error is prevented from occurring.It is known (for example from "Die CAM software for the programming of welding robots-almaCAM Weld, ALMA GmbH, 2016") to use CAD / CAM systems which generate control commands for robots from CAD data of structures.EP 3 296 051 A2 discloses a method for controlling a welding device. Application papers and piece lists can be identified by means of bar codes.DE 694 18 625 T2 describes an apparatus for the automatic cleaning of smoldering burners and wire cutting in nozzles.DE 10 2014 108 956 A1 discloses a device for deburring an object with a visual sensor and a force sensor.The object of the invention is therefore to provide a method for the production and machining of frames joined from steel profiles, which method requires less time and tooling complexity and thereby increases the safety of the technological process sequence.This object is achieved with the method provided according to the descriptive features of patent claim 1 Advantageous refinements of the method are described by the features of patent claims 2 to 5.The invention thus relates to a method for producing and machining a frame composed of steel profiles by means of welding and grinding robots, characterized in that a) the cut frame parts to be connected are clamped onto the welding table by means of adjusting corners and screw clamps, b) the coordinate profiles of the welds to be produced on the front and rear side of the frame are loaded onto the server of the robot controller by transferring the data characterizing the starting and corner points and the designation of the list of pieces from the software storing the construction bases, c) by detecting a code applied to the list of pieces of construction software by means of a camera connected to the welding robot, detecting the designation of the list of pieces and comparing it by the robot controller with the designation for identity stored in the server, and d) starting the software for controlling the welding and grinding operations upon determination of the identity of the designations, wherein the software-supported control of the welding and grinding robots for carrying out the welding and grinding operations is carried out in such a way thati) for the production of the first weld seam, the data of the start and end points of the weld seam stored in the server and the profile height are used for controlling the movement of the welding robot to the start and end point of the weld seam to be produced,ii) the camera system of the welding robot first captures the starting point, the coordinates of the starting point are stored, then the end point of the weld seam is captured and stored with the camera system and then the robot controller calculates the weld seam and the height of the profile,iii) the welding robot score the frame at the end point of the weld, and then the welding operation is performed from the beginning to the end point.iv) the welding robot is moved to the second corner in a controlled manner after the end of the welding operation, the calculation of the second weld seam is carried out in the same manner and the welding operation is carried out as in the case of the first corner.v) after the welding robot has reached the starting point of the second weld seam, the grinding robot calculates the grinding path of the first weld seam, including the stored starting and ending points of the first weld path, and the physical height of the profile is measured by means of a force measuring sensor attached to the grinding robot and it is determined from the measured values how often the grinding robot has to grind over the weld seam in order to reach the physical height of the profile in order to grind the weld material flush with the frame,vi) during the time of grinding, the second corner of the frame is welded, and thereafter the grinding robot is moved to the third corner of the frame,vii) Subsequently, in the same sequence, the welding and grinding operations are carried out at the third and fourth corners, vii),viii) After completion of the welding and grinding operations on the one side of the frame, the welding table is rotated by 180°,ix) all the above-mentioned method steps are then carried out on the other frame side in the same sequence andx) after carrying out all welding and grinding processes, the welding table is rotated back into the starting position, the frame is removed and fed to further processing sequences.The method according to the invention is explained in more detail below with reference to an exemplary embodiment. The drawing shows FIG. 1 : selected machining positions of the grinding robot along the grinding seam, and FIG. 2 is a schematic illustration of the torques and force profiles occurring during the grinding operation.Process FlowAs a result of the completed planning of the welding construction, an electronic data record of the construction based on a construction program is present before the beginning of the method sequence.As a first method step, the cut-to-size and welding-ready structural components of the welding construction are aligned on the base plates with clamping corners and foldable stops. For this purpose, the parts are clamped onto the welding table by means of screw clamps.The electronic data set of the construction is transferred to the robot controller via an interface. This data set contains, for example, geometric data such as profile cross sections, contours, start and end points of the welds, dimensions for all 3 coordinate axes and planes of the construction, as well as electronic data such as piece list names and position numbers.On the parallel printed list of pieces of construction, a barcode or QR code is applied. This is used as a first safety barrier in the matching of the program with the inserted construction. The respective code is read out by a camera system. The robot controller then compares the names of both piece lists. If there is a match, the main program then starts.In the following process step, the welding robot moves to the wire cutter and gas nozzle cleaner. The welding table is in a predetermined horizontal or horizontally rotated application-dependent position for welding the upper plane and the vertical contours of the steel structure.The calculation of the weld positions and the welding of the welds in the upper plane are performed by the dedicated programs in the robot controller. For this purpose, the data from the electronic data record transmitted to it is used. The robot controller calculates the theoretical starting and ending points (vector) and the planes of the individual welds, including the data set.Subsequently, the welding robot travels with the camera system to the theoretical start and end point of the welds determined in an order. Here, the welding robot uses the "vision process" to determine the physical vector from the start and end points of the respective weld seam. Specifically, for this purpose, the camera system records the start and end points of the weld seam by means of the "vision process" and stores these points as physical coordinates.The welding robot then welds the weld using the determined physical vector and the vertical contour of the steel structure.Thereafter, this process is repeated for all welded joints in the upper level of the construction.In a subsequent method step, the grinding robot refers to the stored physical coordinates and calculates the required grinding paths. In a functional connection of the force measurement sensor to the grinding unit of the grinding robot, the physical height of the profile is sensed. The control of the grinding robot then calculates the grinding cycles on the basis of the parameters in order to meet the requirements for the surface of the steel construction.After completion of all welding and grinding processes in the upper plane, the welding table rotates to a plane again predetermined to it.After the end of the process, the welding table is rotated back into the original position. The steel structure can be further machined and subsequently removed.The illustration in FIG. 1 schematically represents selected machining positions of the grinding robot along the grinding seam. Individual machining positions are shown in which the grinding robot 1 is connected to the grinding device 2 via the force measurement sensor 4. During the movement of the grinding robot 1 along the grinding seam 3, the respective currently present contact pressure of the grinding device 2 is detected by the force measurement sensor 4. This value is compared by the grinding robot 1 with previously stored desired values and the control of the grinding process is adapted accordingly.The schematic illustration of FIG. 2 shows the force and torque profiles occurring during the automated grinding process. In this application, the internal program of the robot controller controls the grinding robot with four contour programs. Two programs are used to measure the profile height with a table rotation from 0° to 180°. With the other two programs, the robot receives information about the contact pressure, the torques (M x, M y, M z) and the forces (F x, F y, F z). The force measurement sensor 4 arranged between the grinding robot 1 and the grinding device 2 serves as a sensor for this purpose. The force measurement sensor 4 measures the forces and moments occurring, which are achieved during the measurement of the profile height and during the grinding, evaluates these in order to begin with further processes or to end these processes.The grinding process is carried out in a manner analogous to the welding process on the front and rear sides of that of the steel construction.Reference numerals denote reference numerals1 Robot Grinding 2 Grinding Device 3 Grinding seam 4 Force measurement sensor

Claims

Method for producing and machining a frame composed of steel profiles by means of welding and grinding robots, characterized in that a) the cut frame parts to be connected are clamped onto the welding table by means of adjusting corners and screw clamps, b) the coordinate profiles of the welds to be produced on the front and rear side of the frame are loaded onto the server of the robot controller by transferring the data characterizing the starting and corner points and the designation of the list of pieces is loaded from the software storing the construction bases, c) by recording a code applied to the list of pieces of construction software by means of a camera connected to the welding robot, recording the designation of the list of pieces and comparing it by the robot controller with the designation stored in the server for identity, and d) starting the software for controlling the welding and grinding processes when the identity of the designations is determined, wherein the software-supported control of the welding and grinding robots for carrying out the welding and grinding processes is carried out in such a way that i) for producing the first weld seam, the data of the starting and end points of the weld seam stored in the server and the profile height are used for controlling the movement of the welding robot to the starting and end points of the weld seam to be produced, ii) the camera system of the welding robot first records the starting point, the coordinates of the starting point are stored, subsequently, the end point of the weld seam is detected and stored with the camera system and thereafter the robot controller calculates the weld seam and the height of the profile, iii) the welding robot points the frame at the end point of the weld seam and then the welding process is carried out from the start point to the end point. iv) the welding robot is moved in a controlled manner to the second corner after the end of the welding process, the calculation of the second weld seam is carried out in the same manner and the welding process is carried out as in the case of the first corner. v) after the welding robot has reached the start point of the second weld seam, the grinding robot calculates the grinding path of the first weld seam by including the stored start point and end point of the first weld path, and the physical height of the profile is measured by means of a force measuring sensor attached to the grinding robot and is determined from the measured values, The number of times the grinding robot must grind over the weld seam in order to achieve the physical height of the profile in order to grind off the material to be welded flush with the frame, vi) during the time of grinding the second corner of the frame is welded and then the grinding robot is moved to the third corner of the frame, vii) the welding and grinding operations are then carried out at the third and fourth corners in the same sequence, viii) after the end of the welding and grinding operations on the one side of the frame the welding table is rotated by 180°, ix) all the previously mentioned method steps are then carried out on the other side of the frame in the same sequence and x) after the carrying out of all the welding and grinding operations the welding table is rotated back into the starting position, the frame is removed and fed to further processing sequences.Method according to claim 1, characterised in that the welding robot is controlled for the purpose of producing the welded connections on the vertical contour of the frame to the wire cutter and gas nozzle cleaner.Method according to claim 1, characterised in that the force measurement sensor (4) detects the contact pressure along the grinding seam (3) during the grinding process and feeds it to the grinding robot (1), which compares the respectively detected value with the calculated values and triggers corresponding correcting controls of the grinding process.Method according to claim 1, characterised in that the data of the starting and ending points for the welds to be applied to the front and rear sides of the frame are automatically stored on the server from the design program.Method according to claim 1, characterised in that the piece lists taken from the construction program are each provided with a code which, when used, is captured by the camera system, decoded and the data are sent to the robot controller, after which a comparison of the decoded data with the data of the server is carried out and, if they match, the main program is automatically started.

Images