Using a CNC Press Brake equipped with a Delem DA-53T controller to perform large R arc bending requires careful calculations and precise adjustments to guarantee accuracy and high-quality results. This guide clearly illustrates essential steps and considerations.
Large R Arc Bending Example: Achieving a 90-Degree Arc
To better understand the Large R Arc Bending process visually, we recommend viewing our short demonstration video first:
If you prefer reading detailed instructions or don't want to watch the video right now, please continue with the step-by-step guide below:
Taking a metal sheet with a thickness of 1.5 mm as an example, aiming for a large arc of 90 degrees with a radius of 60 mm, follow these steps:
1. Initial Calculation and Analysis:
- With a sheet thickness of 1.5 mm, the effective radius is 60 mm + 1.5 mm/2 = 60.75 mm.
- Calculate the total arc length using the formula: arc length = radius × π ÷ 2, which results in approximately 95.43 mm.
- Divide the total arc length into 9 equal segments. Each segment's bending interval is 95.43 ÷ 9 ≈ 10.60 mm.
2. Challenges Encountered During Actual Bending:
- The selected lower mold (V-slot width of 16 mm) exceeds the calculated bending interval (10.60 mm). As a result, significant angle deviations occur during bending.
- After first trials, the arc angle drops significantly below the target of 90 degrees after only 6 bends. This large deviation makes the result unacceptable.
3. Software Compensation Limitations:
- Attempting to correct the angles through software compensation in the Delem DA-53T controller results in a required single-bend compensation exceeding 5 degrees.
- Applying such significant compensation would cause the first and last bending angles (initially set at 175 degrees) to surpass 180 degrees, making simple software angle compensation impractical.
4. Overcoming Issues with Physical Compensation:
- Adjust the input sheet thickness parameter from the original 1.5 mm to 1.85 mm. This adjustment decreases the Y-axis displacement each time, thus reducing the angle created per bend, effectively functioning as physical compensation.
- After implementing this change, the total arc angle measures 82 degrees after completing 10 bends. This still results in an 8-degree deviation from the intended 90-degree target.
5. Achieving Target Angle Using Combined Compensation Strategy:
- Considering the 8-degree deviation after 10 bends, calculate the required global angle compensation per bend: 8 degrees ÷ 10 = 0.8 degrees per bend.
- Enter this global compensation value into the Delem DA-53T controller. After another bending test, the large arc reaches exactly the desired 90-degree angle upon completion of 10 bends.
Conclusion:
Performing large R arc bending tasks using a CNC Press Brake demands careful attention to mold choice, sheet thickness, bending intervals, and angular accuracy. If software compensation alone does not solve angle deviations, strategically adjusting physical parameters (such as input sheet thickness) combined with moderate software angle compensation provides a best solution. Employing this combined compensation method ensures correct, efficient, and high-quality bending results, successfully meeting production aims.
