Sheet metal has four steps from raw material to finished product, of which bending is the second step. Most bending machines have to be equipped with manual labor to do the work, but as bending machine automation continues to evolve, automated bending technology is slowly becoming more reliable and economical.This situation of relying on a large number of manual operations for production is gradually changing, and people have been looking for faster and better ways of sheet metal processing, thus robot bending automation technology has gradually attracted widespread attention.
- Principle of sheet bending and molding:
In metal fabrication manufacturing, most of them use bending machines, the core of which is the upper and lower molds.The lower tool (lower mold) has a “V” shaped cross section (v-groove); the upper tool (upper mold) has a mating wedge or angle profile. The sheet is placed between the two, and the wedge presses it down into the “V”-shaped groove, creating a bend.
- The process of bending manually with a bending machine:
The worker picks up a cut sheet from the bin, positions it, slides the sheet between the upper and lower cutters until it hits the back stop, and finally steps down on the control panel to lower the upper mold mechanism, thus bending the sheet.If another bend is required, it means that the sheet needs to be reclaimed, reoriented and repositioned; sometimes the sheet needs to be turned over to bend the sheet in the other direction. This is a very hard job, especially for large, heavy sheets, and sometimes requires more than one person to work together.And manual labor in the high intensity of physical labor is easy to fatigue, thus generating errors. Manual operation of an inattentive may put the wrong bending position or formed the wrong angle, and even completely ignored the machine is working. And because of the high labor intensity, the workplace environment is harsh, employees need to stop often to take a break to continue to work, the production efficiency greatly reduced.
- Automation of CNC bending robots for sheet metal：
To be precise, it is the automation of the entire sheet metal production line. A large number of companies have proved that for many manufacturing plants, flexible sheet metal bending lines, which make full use of CNC bending machines equipped with high-quality tooling, as well as dedicated bending systems.In an automated robotic bending machine system, a bending robot replaces the operator. A sheet is placed next to the robot, which sucks up the sheet in sequence from top to bottom and places it on the bending machine for follow-on bending.
- Automated bending processes:
General bending robot placed in front of the bending machine fixed position can not be moved at will. This is to ensure that the iron plate is controlled, the bending robot is usually first sucked up to the alignment table to adjust the position of the plate; and then the robot again sucked up the plate, and then placed on the bending machine to carry out bending work.Detailed description, only when the sheet is in position to be placed by the robot into the designated position within the bending machine, the bending machine machine will follow to make the bend. If multiple passes need to be processed, the robot will reposition the sheet as needed. When the bending is complete, the bending robot can either stack it up in the finished product area or place it on a chute or conveyor belt for transportation to the next process.
Sheet metal processing work is mainly divided into six processes: loading, picking up, centering, flipping, bending and stacking:
Loading: Manually place the whole pallet of boards to be processed onto the loading table, which is installed with a board detection switch to prevent the robot from gripping the pallet after all the boards have been processed.
Material picking: the robot runs to the position of the loading table, detects the height of the plate through the ultrasonic sensors installed on the gripper, according to the detection data, it automatically runs to the appropriate position for the gripping of the plate, after the plate is gripped, the thickness of the plate is measured through the thickness measuring device, to avoid gripping more than one plate at a time, which will result in processing failures, and after passing the thickness measurement, it is ready to be centered.
Alignment: The robot runs to the position of the positioning table, places the sheet on the table for accurate positioning, and after positioning, grabs the sheet again to prepare for bending.
Turning: According to the process requirements to determine whether the use of turning shelf, if necessary, the robot will run to the position of the turning shelf, the sheet will be placed on the turning shelf, the robot to loosen the sheet, avoiding, waiting for the completion of the turning of the sheet gripping.
Bending: The robot runs to the position of the bending machine, flattens the sheet to the lower mold of the bending machine, and accurately locates it through the sensor at the back of the bending machine, after the positioning is completed, the robot sends the bending signal to the bending machine and cooperates with the bending machine to complete the bending action, and determines whether it is necessary to bend the sheet again to determine if it is to be bended continuously.Bending is the key link, the technical difficulties of bending is the robot and the bending machine with the action, that is, bending follow. Robot clamping or support plate bending, plate deformation, the robot needs to follow the plate according to a specific trajectory algorithm to do the arc action, and always maintain a relatively fixed position with the plate.
Palletizing: The robot runs to the position of the lower material table, and due to the difference in the forming of the workpieces, there are many kinds of palletizing process actions, such as conventional matrix palletizing, single and double layer cross-palletizing, positive and negative interlocking palletizing and so on.
6-axis or 7-axis robot with 6+1 or (7+1, 8+1) axis CNC bending machine. Fully automatic bending machine for sheet metal, equipped with accessories such as centering table and flip bracket to meet the demand for automatic bending. Advantages: labor saving, no safety hazards, suitable for long time continuous operation, good consistency of workpiece accuracy.
6-Currently on the market, whether it is a general-purpose standard six-axis robots, or robot arm span or shape optimized for the bending process of bending special robots, need to follow the bending algorithm to support, do not follow the bending of the situation is very few.Without good following effect, the fixture or suction cup gripper will pull the workpiece due to poor following trajectory, forming sheet wrinkles and affecting the forming quality. Establishing an accurate robot bending following motion model helps to establish a good following trajectory algorithm to obtain excellent following effect.
