Manual Press Brake Operation Goes from Bottle Neck to “Lights Out” with Robotics
Mid-West Machine Products, Inc., a precision sheet metal and fabrication shop, converted their manual press brake operation to a fully automatic Motoman® robotic system. What was a bottle neck in the manual operation now runs “lights out” and produces parts with tighter tolerances.
A 35% increase in equipment utilization with an average labor savings of $159,750 per year were realized, providing a payback in fewer than 20 months. Due to the tight integration of the Motoman robotic system and the Mid-West Machine engineered components to the press brake, the programming time was reduced by an average of 60% over the traditional robotic press brake systems. In fewer than six months, the robotic press brake system was loaded to greater than 100% of production capacity. The system only requires one hour of operator time to load the parts for an eight-hour robotic production run.
Project Goals and Challenges
- Design a system that is capable of running high part mix with minimal labor.
- Reduce initial programming time by at least 50% per part over traditional methods.
- Implement the robotic system without installing a riser under the press brake (a costly and limiting move).
- Design the system to handle parts weighting up to 120 pounds and 4 X 10 feet blanks without a track under the robot.
- Eliminate need for a traditional squaring table.
- Ability to run small to large part mix.
- Develop flexible automatic part following and unloading stacking patterns
Mid-West Machine Products designed and implemented a Motoman robotic system that exceeded all project goals. The system includes:
- Motoman ES165 robot
- AccurPress Accell model 515012
- HMI cell controller
- One automatic laser sheet stack finder
- ATI Tool Changer
- Five production grippers
- Intelligent robotic back gauging
- Reposition tables that automatically change to 1 of 4 positions
- Intelligent robotic subroutine programs
- Flexible unloading programs
System Feature and Benefits
Until now, programming a family of parts on a traditional robotic press brake cell might take weeks. With the intelligent robotic back gauges, the programmer only needs to provide the rough part position, and the back gauges drive the robot to the correct location, ensuring an accurate bend. Intelligent robot subroutines also provide the programmer with a full library of different operational sequences needed to complete the program for a given family of parts in a fraction of the time required versus traditional robotic press brake systems. During a bend, the robot automatically follows the part as the result of calling a preprogrammed sequence. The programmer has an automatic 4-position table available to set down the part and re-grip in a different orientation if needed. This table is mounted between the press brake and robot to help reduce cycle time, and is fully retracted to the floor during the normal braking operation. At the completion of the part programming, the programmer enters 13 sets of data in the HMI that define the unloading pattern, and the system is ready to run production.
To start a production run, the operator places skids of parts in the cell and closes the safety door. The system takes over by having the Motoman robot pick up the automatic laser sheet stack finder. After the robot completes the scanning pattern over the skids of parts, the stack height and orientation is known for each skid. A gripper change-out occurs, and the robot will pick the first sheet loaded in the production sequence. Because the sheet orientation is known, the robot does not need to set the sheet down on a traditional squaring table, reducing overall cycle time. Secondary processes such as cross bends and punch press operations can be easily handled because of the robot’s large working envelope. During the “lights-out” production run, the Motoman robotic system neatly stacks each completed part on the proper skid for the next operation.As a result of the complete system performance, the part tolerances are much tighter and more consistent for downstream operations. The welders in the fabrication shop noticed a significant improvement with part fit, and other fabrication operations such as assembly have also benefited from the new system. Due to the success of this system, Mid-West Machine Products is already planning for the next Motoman robotic press brake system.
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