Press brake punch and die selection is critical for achieving precision, efficiency, and safety in bending operations. Follow this systematic approach:
Type: Steel, stainless steel, aluminum, etc. (e.g., stainless steel has higher springback than mild steel).
Thickness (T): Dictates die load capacity (e.g., 2mm sheet requires narrower V-die than 10mm).
Length: For workpieces >1.5m, use segmented or extended dies to prevent deflection.
Bend Angle: Sharp angles (<90°) need acute-angle punches; obtuse angles (>90°) require gooseneck punches.
Complex Shapes: Hemming, offset bends, or radii demand specialty dies (e.g., flattening dies + offset dies).
Parameter | Guideline |
Tip Radius (R) | R = 0.8–1.2 × T (e.g., T=3mm → R=2.4–3.6mm) |
Angle (α) | Standard: 86°, 88°, 90°. Use 30° acute punches for sharp bends. |
Shoulder Height | Must exceed flange height (H ≥ flange height + 2mm). |
Parameter | Guideline |
V-Opening (V) | Key Formula: V ≈ 6–12 × T (Mild steel: 6–8T; Stainless/Al: 8–12T) |
Angle (β) | Match punch angle (standard 90°±2°). |
Strength | For thick plates (T>6mm), use multi-V dies (e.g., V12/V20) to handle varying loads. |
Critical Rule: Minimum flange height ≥ V/2 + T + R (to avoid interference).
Die Type | Application | Pros/Cons |
Straight Punch | 90° bends, box-shaped parts | Cost-effective, versatile |
Gooseneck Punch | Clearing obstacles (e.g., flanges) | Enables closed shapes; lower rigidity |
Acute-Angle Punch | Sharp bends (30°–60°) for electronics/aesthetics | Requires high tonnage; wears faster |
Segmented Die | Localized/long-part bending | Flexible; demands precise alignment |
Radius Die | Tubes, curved surfaces | No marks; superior surface finish |
Die-rated tonnage ≥ 60% of press brake force (e.g., 100T machine → ≥60T dies).
For thick plates, use V/T > 8 to reduce bending force by 30%.
Material: Cr12MoV tool steel (HRC 58-62) outperforms standard alloy steel (3–5× lifespan).
Coating: TD coating (wear resistance) > Chrome plating (anti-rust) > Uncoated.
Material Hardness & Tooling Longevity
Technical Insight: The durability of your press brake dies is directly tied to the material being processed. When bending high-tensile strength steels like Hardox, Weldox, or Armor plate, standard Cr12MoV dies often experience premature surface wear or deformation due to the extreme friction and pressure.
For consistent precision over 100,000+ bends, LISTEN recommends 42CrMo Alloy Steel dies with localized Laser Hardening (HRC 60+). This process hardens only the working radius of the punch and the V-edges, maintaining a tough, shock-absorbing core while providing a diamond-hard contact surface.
Pro Tip: If your production involves more than 30% stainless steel or high-strength alloys, upgrading to laser-hardened tooling can reduce your annual replacement costs by up to 40%.
Punch height must fit within machine’s shut height (standard: 290–570mm).
Die height matches press brake table groove (common: 85/100/125mm).
Confirm shank size (e.g., 20/30/40mm) compatibility with quick-clamp toolholders.
Segmented dies: Verify alignment pin spacing (EURO: 50mm; JIS: 100mm).
High-use dies (e.g., V10/V20): Prioritize premium brands (WILA, ROJEK).
Custom shapes: Opt for local suppliers (cost ≈ 1/3 of imports).
Avoid "universal dies" for all thicknesses – accelerates wear.
Inspect straightness regularly (>0.05mm/m deviation requires regrinding).
Error-Proofing: Color-code V-openings (e.g., blue=V16, yellow=V25).
Quick Change: Use hydraulic clamping (changeover <5 mins).
Collision Avoidance: Set die protection zones in CNC systems.
Material/Thickness
Calculate V/R
Choose Die Type
Verify Force & Compatibility
Select Material/Coating
Cost Analysis
Test Bend
MANDATORY TEST: Perform springback compensation on first-piece trial (e.g., bend to 92° for 90° target). Record parameters for process library.
Safety Warning: A common mistake in the workshop is assuming that if the press brake is rated for 100T, the dies can also handle 100T. This is incorrect. >Never exceed the Point Load Limit of your tooling. Using a narrow V-die to bend thick plates concentrates the entire force onto a very small surface area, which can lead to catastrophic die cracking or permanent damage to the machine’s ram.
How to stay safe:
Check the T/m Rating: Always verify the Tons per Meter (T/m) capacity laser-engraved on every LISTEN die.
Avoid "Over-Tonnage": If your required bending force exceeds 80% of the die’s rated capacity, switch to a wider V-opening to distribute the load.
The 8T Rule: For heavy-duty bending, aim for a $V \geq 8 \times T$ ratio to reduce the required tonnage by approximately 30%, protecting both your operators and your investment.
Share part drawings with suppliers for collaborative selection.
For complex geometries: Request sample bending before full procurement.
Prioritize ISO-certified dies (e.g., DIN 55220, JIS B 5063) for guaranteed tolerances.
Adhering to these principles reduces trial costs by ≥20% and ensures consistent bend quality.
A: The standard industry formula is $V = 6 \sim 8 \times$ material thickness (T) for mild steel, and $V = 8 \sim 12 \times T$ for stainless steel or aluminum. Selecting a V-opening that is too narrow increases bending pressure and risks cracking the die, while a V-opening that is too wide can lead to inconsistent bend angles and larger internal radii.
A: Yes. Our dies are designed to be universal and support major clamping standards, including EURO (Amada/Promecam style), JIS, and New Standard (Wila style). We provide various shank sizes (e.g., 13mm, 20mm) and heights to ensure seamless integration with your existing hydraulic press brake holders.
A: Standard alloy steel dies (HRC 45-50) wear down quickly when processing abrasive materials like stainless steel or Hardox. Our laser-hardened 42CrMo dies feature a surface hardness of HRC 60+ on the working edges. This extends the tooling life by 3–5 times, maintains bending precision over 100,000+ hits, and reduces the frequency of regrinding.
A: While "universal" dies exist, using them for a wide range of thicknesses is not recommended. It accelerates localized wear and compromises the bend quality of thinner sheets. For optimal results and safety, we suggest a modular set of segmented dies that can be quickly reconfigured for different job requirements.
