Bending machines are essential tools in metal fabrication, allowing for the precise bending of metal sheets into various shapes. This comprehensive guide provides step-by-step instructions on operating a bending machine, including the use of different molds and adjustment techniques.
Operating a bending machine requires a good understanding of its various components and proper techniques. From selecting and installing the right molds to making precise adjustments and performing specific bending operations, this guide covers everything you need to know to efficiently use a bending machine.
Understanding Mold Types and Installation
Fixed Step Molds
Fixed step molds have a constant double-fold corner step dimension, providing consistency in bends without the need for frequent adjustments.
Adjustable Step Molds
Adjustable step molds consist of an upper mold and a lower mold. To ensure accurate bending:
1. Align the centers of the upper and lower molds.
2. Adjust the gap between the molds as needed for the specific bend.
Upper Mold Installation
The upper mold installation in a bending machine is similar to that of a standard press brake. Ensure the mold core faces the operator for easy access and adjustment.
Lower Mold Installation
For the lower mold:
1. Place the mold core inside the bending machine.
2. Secure it properly to ensure stability during operation.
Adjustments and Settings
Front and Rear Material Stops
Adjusting the front and rear material stops is essential for accurate bending. Use:
- Electric Quick Adjustments for rapid changes.
- Manual Fine Adjustments for precise control.
The adjustment process is similar to that used in a guillotine shear.
Pressure Measurement
To measure the bending pressure:
1. Place the workpiece in the center of the hydraulic bending machine table.
2. Use the machine's built-in pressure gauge to ensure the correct amount of force is applied.
Bending Operations
Basic Bending Steps
1. Press the foot switch to initiate the bending process.
2. Release the foot switch to stop the operation.
3. Press the switch again to continue bending.
Arc Bending
For bending arcs:
1. Position the area to be bent under the bending machine.
2. Activate the switch to lower the machine.
3. Gently lift the workpiece to form a slight angle.
4. Raise the machine and advance the sheet forward.
5. Repeat these steps 3 or more times, depending on the desired arc size.
Calculating Each Knife Feed
For a sheet thickness of 2 mm, bending angle of 120 degrees, external bending radius of 30, and neutral layer radius of 29:
1. Unfold the sheet to determine the neutral layer arc length.
2. Calculate the number of bending steps and the angle per step based on the neutral layer arc length.
3. The distance from the neutral layer to the edge is half the sheet thickness.
Bending a 90° Arc
Required Tools and Settings:
1. Select appropriate molds or tools that match the desired arc radius.
2. Set the bending angle accurately to ensure precise end point alignment.
3. Adjust machine parameters such as pressure and feed speed according to the material.
Material Placement and Operation:
1. Place the material flat on the machine bed.
2. Monitor the shape changes closely to ensure accuracy.
Case Study: Bending a Stainless Steel Sheet into a 90° Arc
Material: Stainless Steel Sheet
Steps:
1. Choose a mold with a suitable radius.
2. Set the machine pressure and feed speed.
3. Place the stainless steel sheet flat on the machine.
4. Start the bending machine.
5. Adjust parameters as necessary or stop the operation to check progress.
6. Achieve a precise 90° arc.
Conclusion
Operating a bending machine involves understanding the types of molds, making precise adjustments, and following proper bending procedures. By adhering to the guidelines provided in this article, you can ensure accurate and efficient bending operations. Whether you're working with simple bends or complex arcs, these steps will help you achieve the desired results in your metal fabrication projects.
