Bending machines are essential tools in metal fabrication, enabling the precise bending of metal sheets into desired shapes. This guide will walk you through the process of adjusting a bending machine to accommodate different angles and sheet thicknesses.
Bending machines play a crucial role in metalworking, allowing for the precise shaping of metal sheets. Proper adjustment of these machines is essential to achieve accurate bends and maintain high productivity. This guide provides detailed instructions on how to adjust a bending machine, considering different bending angles and sheet thicknesses.
Understanding the Basics of Bending Machine Adjustment
What Is a Bending Machine?
A bending machine, also known as a press brake, is a machine used to bend metal sheets into various shapes. It consists of a flat surface where the metal sheet is placed, a clamping bar that holds the sheet in place, and a bending tool that applies force to create the bend.
Adjusting the Slide Upper Limit
Why Adjust the Slide Upper Limit?
Adjusting the slide upper limit ensures that the slide stops at the desired top dead center (TDC) position. This adjustment is crucial for reducing slide travel distance, thus shortening the working time and improving efficiency.
How to Adjust:
1. Locate the adjustment block II on the machine.
2. Adjust its position to set the slide at the desired TDC.
3. Verify the adjustment by performing a test run.
Adjusting the Upper and Lower Die Gap
Importance of Die Gap Adjustment
The gap between the upper and lower dies is critical for achieving precise bends. This gap must be larger than the sheet thickness initially and then finely adjusted according to the desired bend angle.
Steps to Adjust:
1. Bring the slide to the TDC.
2. Press the button on the lower right corner of the workbench.
3. Follow the direction indicated on the machine label to adjust the gap.
4. Use the handwheel for fine adjustments, with each increment shown on the display (0.1 mm per unit).
Adjusting for Different Angles at the Ends of the Workpiece
Problem: Varying Angles at Workpiece Ends
If the angles at the ends of the workpiece differ, adjustments are necessary to ensure uniformity.
Adjustment Procedure:
1. Loosen the positioning pin.
2. Move the connecting rod to the left, disconnecting the left and right rotation linkage.
3. Turn the handwheel (up or down) to change the mechanical limit gap at one end.
4. After adjustments, reinsert and tighten the positioning pin to prevent mechanical accidents.
Adjusting for Different Angles in the Middle of the Workpiece
Problem: Varying Angles in the Middle of the Workpiece
If the middle angle of the workpiece differs from the ends, the upper die requires fine-tuning.
Adjustment Steps:
1. Bring the upper die close to the lower die slot.
2. Slightly loosen the screws on the middle section of the upper die connecting template and adjustment block (ensure the upper die does not fall off).
3. Tap the adjustment wedge at the top middle section (left or right) to slightly protrude the upper die in the area with a smaller angle.
4. Tighten the positioning pin.
5. Conduct a test bend to ensure the entire length of the workpiece meets the required angle.
Adjusting Hydraulic Bending Force
Calculating Bending Force
To adjust the bending force, you need to calculate the required force for bending the sheet metal. This is typically expressed in kilonewtons (kN).
Bending Force Calculation Formula:
\[ P = \frac{1.42 \times t^2 \times L \times \sigma }{V} \]
Where:
- \( P \) = bending force (kN)
- \( t \) = sheet thickness (mm)
- \( L \) = bend length (m)
- \( \sigma \) = tensile strength of material (N/mm²)
- \( V \) = die opening (mm)
Steps to Adjust Hydraulic Bending Force:
1. Calculate the bending force using the formula or reference table.
2. Find the indicated pressure value (P).
3. Adjust the overflow valve handwheel 8 to slightly exceed the calculated kN value.
Common FAQs about Bending Machine Adjustment
How do I adjust the bending machine for different sheet thicknesses?
Adjust the upper and lower die gap initially larger than the sheet thickness and fine-tune it based on the desired bending angle using the handwheel.
What should I do if the workpiece angles are inconsistent at the ends?
Loosen the positioning pin, adjust the connecting rod and handwheel to change the mechanical limit gap at one end, and then secure the positioning pin.
How can I correct different angles in the middle of the workpiece?
Loosen the screws on the middle section of the upper die, adjust the upper die using the adjustment wedge, and tighten the screws after achieving the desired angle.
How do I calculate the bending force required for different materials?
Use the bending force formula provided, considering the sheet thickness, bend length, tensile strength, and die opening.
What is the importance of adjusting the slide upper limit?
Adjusting the slide upper limit reduces travel distance, shortens working time, and improves overall efficiency.
How do I ensure the upper and lower die gap is correctly set?
Use the display to monitor fine adjustments and ensure the initial gap is larger than the sheet thickness, fine-tuning it as needed.
Conclusion
Adjusting a bending machine is a crucial skill for achieving precise metal bends and maintaining high productivity in metal fabrication. By understanding and following the steps outlined in this guide, you can ensure your bending machine is properly adjusted for various angles and sheet thicknesses. Proper adjustments not only enhance the quality of your work but also improve the efficiency and safety of your operations.
