With the increasing degree of automation, the previous automation line mainly produced outer cover products. Nowadays, non-outer cover parts such as door inner panels, door frame parts, and structural parts are gradually popularized to implement automatic stamping production. However, in the process of picking and transferring these non-external covering parts by the robot end picker, due to the low area ratio of the product process layout vacuum suction cup, the process and mold design of this type of product cannot reasonably take into account the robot automatic replacement and the suction cup layout surface. Design problems, there are problems such as downtime caused by material dropping during the grabbing process, product scrapping, and material dropping products blocking the waste pit. Such problems not only restrict the production cycle of the whole line, but also have great uncertain factors.
Current status of stamping automation production of non-outer cover parts
Figure 1 is a digital model diagram of the inner panel of the tailgate of the SUV model. Due to the product process structure and mold design, the design layout of the robot end picker does not take into account the longitudinal height of the equipment end picker branch (H ≤300mm). , Causing the automatic replacement of the robot end picker to interfere with the door post (Figure 2). There is a safety risk of collision between the end picker branch and the door post. Therefore, it can only be manually assembled and disassembled and replaced by stopping the machine. Each manual assembly and disassembly takes 28 hours. At the same time, the vacuum suction cup coverage ratio of the inner product process surface of the tailgate is low, and the vacuum suction cup grabbing and dropping materials often occurs during the production process. It takes 25 minutes to stop the adjustment process; it restricts the production efficiency of the entire line and wastes energy.
Figure 1 Digital model diagram of SUV tailgate inner panel product
Figure 2 The automatic replacement of the end picker interferes with the door post
Application analysis of the magnetic suction cup of the robot end picker
The magnetic suction cup structure includes: ⑴ Clip-on friction washer, which can be used for quick replacement. ⑵Aluminum shell body. (3) Install and connect threaded holes. ⑷ Permanent magnet parts. ⑸With standard threaded holes on the top. Application range of magnetic chuck: (1) Handling of porous metal plates and laser cutting parts with complex geometric shapes. ⑵Transfer magnetic workpieces.
The working principle of the magnetic chuck (Figure 3): ⑴ Relying on the air source to push the permanent magnet parts to move. ⑵The air source pushes the permanent magnet component downward, and it is in the suction state at this time. ⑶ The air source pushes the permanent magnet component upwards, and it is in the released state at this time. ⑷Air pressure requirement: 3.5 to 6 atmospheres can realize rapid switching of magnetic force.
End picker automatic replacement interference solution
In order to solve the above problems, this article provides the application method of the robot end picker of the automated press line using magnetic suction cups to solve the problem of non-external cover parts due to unreasonable product technology and mold design, which cause interference during automatic replacement of the robot and the vacuum suction cup grabbing parts. , The specific plan is as follows:
Figure 3 Working principle of magnetic chuck
Figure 4 Will not interfere with the door post during automatic replacement
⑴According to the digital and analog analysis, adjust the height of the horizontal bar grabbing position downward. This step can reduce the longitudinal height H of the end picker branch. ⑵Analysis in the digital simulation to find out the inner and outer plate profile of the tailgate can be arranged in the end picker suction cup area, and will not interfere with the door post when it is automatically replaced; this analysis step is to find the suction cup that will not interfere with the end picker and the door post Layout location. ⑶ According to the requirements of the equipment automation specification, analyze the position of the suction cup and the type of the suction cup, and find the required suction cup and the matching connecting rod. ⑷Use magnetic suction cups to replace the product location areas where vacuum suction cups are not suitable for layout. ⑸ Modify the compressed air supply joints at both ends of the cross bar of the manipulator, so that the magnetic suction cup adopts two sets of air source connection methods, so that the magnetic suction cup can be connected with the compressed air source at both ends of the cross bar. ⑹Set the parameters of the gripper of the press, and set the start and end angles of the gripper sucker in the vacuum suction cup and workpiece transport setting options of the press control function interface. The angle setting range: 0°～359° (accurate To 1 °).
The solution to the interference problem when the end picker is automatically replaced
The following describes the solution in combination with the analysis plan: (1) Lower the height of the grabbing position of the crossbar, and the minimum distance needs to meet the requirement that the lower surface of the crossbar is 50mm from the highest point of the lower model surface. ⑵ Find out the inner and outer plate profile of the tailgate that can be arranged with the suction cup area of the end picker and will not interfere with the door post when it is automatically replaced (Figure 4). ⑶According to the automation tools required by the equipment, find out the required suction cups and matching connecting rods. ⑷Because the suction cups of the stamping automation line generally use vacuum pump equipment and use the Venturi principle to output a real air source; in the past, the magnetic suction cups were only connected to one path, and the permanent magnet was driven by the pressure difference, and only one atmosphere was established when the magnetic force was established; The air pressure input to the magnetic chuck in parallel is not high, so the magnet moves slowly, and the magnetic chuck releases the parts slowly. There is a phenomenon of belt parts, and the use effect is not good. Therefore, it is necessary to modify the compressed air source joints at both ends of the manipulator crossbar to allow the magnetic chuck to adopt The two sets of air source connection modes enable the magnetic chuck to be matched and connected with the compressed air source at both ends of the crossbar (Figure 5). ⑸By adjusting the magnetic chuck of the end picker + small vacuum chuck, set the compressed air source at both ends of the cross bar to be used, and set the gripper angle function. The compressed air source gripper angle is set 5° ahead of the vacuum source angle ( Image 6).
Figure 5 The magnetic suction cup can be matched and connected with the compressed air source at both ends of the cross bar
Figure 6 The angle of the compressed air source clamping jaws is set 5° ahead of the vacuum source angle
In this paper, combined with on-site production examples, through the use of magnetic suction cups and corresponding rectification measures, the manipulator uses magnetic suction cups to transport workpieces, and separately connects the compressed air source at both ends of the cross bar, which can stably transport porous and complex structure non-outer covering parts. The suction cup layout The position can also have more choices, which effectively solves the problem of interference between the end picker of the automatic assembly and disassembly of the inner and outer panels of the tailgate and the door column; and promotes this application to solve the problem of door inner panels, door frame parts, structural parts, etc. Outer cover parts dropped during the handling process of the manipulator, which achieved remarkable results, improved production efficiency and saved energy consumption.