Choosing the right tools for a press brake is critically important for the quality and efficiency of bending operations. Here is the most accurate and structured step-by-step approach to tooling selection:
1. Material Analysis
* Type of material: steel, stainless steel, aluminum, etc.
* Material thickness: important for determining the V-opening width and the required force.
* Tensile strength (σ): the higher it is, the more force is needed.
2. Determining the Required Bending Geometry
* Bending angle: sharp, right, or obtuse.
* Bend radius: essential for selecting punches.
* Minimum distance between bends: affects tool shape (standard, narrow, etc.).
3. Choosing the Bottom Tool (Die / V-opening)
* Rule of thumb: V = 6 to 12 times the material thickness
- For aluminum – V = 6×t
- For steel – V = 8×t
- For stainless steel – V = 10×t
Example:
For 2 mm steel → V = 16 mm
* Check whether the die suits the desired radius and angle.
4. Choosing the Top Tool (Punch)
* Must match the desired inner bend radius.
* For sharp bends, use narrow punches; for thick materials, use stronger punches with a larger radius.
* Take into account punch height if there are clearance limitations on the machine.
5. Checking the Bending Force
* Use the following formula or a force chart to calculate the required tonnage:
P = (1.42 × σ × t² × L) / V
Where:
P - force in kN
σ – material strength in N/mm²
t – material thickness (mm)
L – bending length (mm)
V – V-opening width (mm)
* Compare the result with the machine’s capacity.
6. Considering Specific Part Features
* If the part has protrusions, holes, or special contours – use specialized or segmented tooling.
* For complex bends – multiple-step operations may be necessary.
7. Compatibility and Mounting
* Tools must be compatible with the machine's clamping system (e.g. Promecam, Trumpf, Wila, etc.).
* Ensure the tools allow for quick changeover and easy setup.
Final Tips
* Use CAD/CAM simulation if available – helps avoid errors.
* Choose hardened tools for frequent use.
* Maintain accuracy through regular inspection for wear.
We are always available to support you with information or advice regarding the correct use of “Karmet Bulgaria” Ltd. machines or the tools used with them.