Transfer lines for sheet metal production
PROBLEM
great flexibility and high productivity are essential requirements in the sub-supply of the appliance industry. Accuracy and repeatability are taken for granted, particularly in the sector of production of sheet metal parts.
SOLUTION:
the setting given to the automatic system is that of a transfer line, where the processes to be carried out are arranged in sequence. The metal tape is unwound from coil and fed to a mechanical press for the first forming and then cut into pieces according to the required size. The pieces are then advanced along the various phases (shearing, punching, and folding) by 4 Cartesian units. Each operating machine is mounted on linear guides and is adjustable in position with a servo-motor: this feature allows the system to change its configuration and automatically adapt to the settings given by the operator. With this system setting, the operator is only required to enter the construction dimensions obtained from the technical drawing of the piece and each operating unit moves to the correct working position: a few seconds and production can be started. The software allows to adjust the working positions of the single units also online (with the machine running) to improve the precision of the pieces produced. For the format change, only the replacement of the tools and the selection of the code to be produced are required.
ADVANTAGES:
it is possible to highlight some strengths of our line: -high precision of the workings: ± 0.05mm; -high flexibility: workpiece lengths from 400m up to 1200mm and adjustment of the position of the operating heads; -high productivity: 700 pieces / hour; – low labor demand, only for loading and unloading operations.
DESCRIPTION:
this transfer line was conceived to make metal sheet parts with high production cadence. Starting from coil, the first operation is to feed the belt to the mechanical press at a rate of 110 strokes per minute: a linear motor (equipped with a hydraulic gripper) drags the belt into the press synchronizing with the mold. The maximum cumulative error for the longest piece (1200mm) is reduced to ± 0.05mm. The tape is then cut to size by a cutting-off machine and the pieces are transported to the subsequent work stations by 4 Cartesian robots: a shear cuts them according to the desired angle giving them a first trapezoidal shape, a shear punches holes for assembly and finally two press brakes give the final shape. High translation speed (10m / s @ 3g) and machining precision (± 0.05mm) are combined with easy management of all the individual processing phases: without stopping production, it is possible to change the working position of the operating machines and the inclination of the grippers (during picking or release), to adapt the work cycle to the characteristics of the single sheet metal strip (actual thickness, presence of oil, annealing state of the material, …). To train a new format, it will be sufficient for the operator to specify the machining dimensions read directly on the construction drawing: both the dimensions of the translation units and the position of the operating machines will be automatically generated.
