The Ultimate Guide to Selecting Press Brake Dies for Flawless Bends
Introduction
In precision sheet metal work, the quality of your bend depends on your tools. The punch controls the inside curve, while the press brake die handles pressure and shapes the outside. Choosing the right bottom die is key to accurate dimensions, protecting your machine, and cutting down on wasted material.
Press Brake Dies: Basics & Core Parts
Press brake dies are special molds used with bending machines. They are the main parts for bending sheet metal, made of two key pieces:
Punch (upper die)
Die (lower die)
How they work: The machine’s ram and worktable move together, pressing the sheet metal between the two dies. This bends the metal into the shape you need (90° angles, U-shapes, V-shapes, etc.). They are used in many fields, including:
Core Components & How They Work
Upper Die (Punch)
Attached to the machine’s moving ram, it applies pressure to the metal. Its shape (straight, sharp-angle, gooseneck, rounded, or custom) decides the outer shape of the bent part.
Lower Die
Fixed to the machine’s worktable, it supports the metal. It usually has a V-shaped groove. The width of this groove affects bending force, inner curve, and overall quality.
Working Principle
Place the sheet metal on the lower die.
The ram moves the upper die down, pressing the metal into the shape of both dies.
Once the right pressure and movement are reached, bending is done.
The upper die moves back up, and you can take out the finished part.
Key Features of Press Brake Dies
Material and Hardening (42CrMo Advantage)
We use 42CrMo (42CrMo4) alloy steel — it balances toughness and durability well.
It can handle high pressure and friction without breaking or bending.
Our dies go through Full Induction Hardening, reaching HRC 48-52 hardness.
This hardening protects the V-groove from wear or damage under heavy pressure, reducing the need for frequent replacements.
Single-V vs. Multi-V Dies
Choose based on your machine type and production needs:
Single-V Dies
Best for CNC machines with automatic clamping.
High precision and easy to change, saving setup time.
Great for high-volume, precise production.
Multi-V Die Blocks
Good for manual or hydraulic machines.
One block has multiple V-grooves of different widths.
No need to change tools often — perfect for small batches or mixed work.
Customization & Compatibility
Punches can be custom-made (rounded, gooseneck, irregular) to fit your needs.
Lower dies can have different V-groove widths (8mm, 16mm, 24mm) or special shapes.
Dies must fit your machine’s clamping system, ram movement, and pressure capacity to avoid installation issues.
Standardization
Standard dies fit major machine brands (Amada, Trumpf, Wila) and can be bought and used right away.
Special dies can be custom-made for your specific needs.
Common Types of Press Brake Dies
By Forming Shape
Standard Straight Die: For regular straight bends (most common).
Sharp-Angle Die: For small angles or fixing springback (high precision).
Gooseneck Die: For U-shaped or deep parts (avoids hitting already bent edges).
Radius Die: For rounded bends (curved parts or smooth transitions).
Irregular Custom Die: Made for unique, non-standard shapes (from your drawings).
By Application
Standard Dies: For common metals (mild steel, galvanized steel) — good value.
High-Strength Steel Dies: Reinforced and hard — for stainless steel or tough alloys.
Thin Material Dies: Precision-made to prevent warping, bending, or scratching thin metal.
By Installation Interface
Amada / Promecam Type: Fits Amada machines.
Trumpf / Wila Type: Fits Trumpf and Wila machines.
New Standard Type: Universal — fits most domestic machines.
How to Choose the Right Press Brake Dies
Choose dies that match your material, bending process, part needs, and machine. This ensures accuracy, efficiency, and long die life.
1. Match Your Material
Mild steel: Low springback — use an 86°–88° punch for 90° bends.
Stainless steel/high-strength steel: High springback — use an 85° punch or adjust the angle.
42CrMo dies work with most materials, reducing the need for multiple die sets.
2. The 8× Rule (V-Opening Size)
For most mild steel: V-opening width = 8 × material thickness (V = 8T).
This ensures smooth bends and prevents cracking.
Adjustments:
Thin metal (T ＜ 3mm): Use V = 6T for smaller curves.
Thick metal (T ＞ 8mm): Use V = 10T–12T to reduce pressure and avoid die damage.
3. Sectionalized Dies for Complex Bends
For custom-length or irregular parts — use sectionalized dies (10mm, 20mm, 100mm segments).
Segments are precise (±0.01mm) and can be combined to make any length.
Saves money: Replace only damaged segments, not the whole die.
4. Pressure & Tonnage Limits
Calculate bending pressure based on material thickness, strength, and V-width.
Do not exceed the die’s pressure limit — leave a 10%–15% safety margin.
For thick/tough materials: Use reinforced or sectionalized dies to spread pressure.
5. Choose the Right Punch Shape
Standard: For regular bends.
Sharp-angle: For small angles or springback.
Gooseneck: For deep U-shapes or boxes.
Rounded/custom: For curved or unique parts.
6. Check Machine Compatibility
Choose the right holder type (Amada, Trumpf/Wila, New Standard).
Ensure die height fits the machine’s ram movement and worktable opening.
Important Selection Tips
Account for material springback to avoid wrong angles and waste.
Follow the 8× rule and adjust for material thickness to prevent damage.
Check that the die fits your machine to avoid installation problems.
Prioritize 42CrMo material and Full Induction Hardening for long die life.
Conclusion
Get the most out of your machine with long-lasting bottom dies. Whether you need a standard 88-degree die or a custom one, our team can help. Download our Tooling Catalog or send us your drawing for a quick quote. The right press brake dies (made of high-quality 42CrMo, precise, and tailored to you) will help you make perfect bends, protect your machine, cut waste, and work more efficiently.
42CrMo International Standard Comparison Table (Essential for Selection)
Country/Standard Organization | Standard Code | Corresponding Grade |
China (GB) | GB/T 3077 | 42CrMo or 42CrMo4 |
USA (AISI/ASTM) | ASTM A29 | 4140 |
International Organization for Standardization (ISO) | ISO 683-1 | 42CrMo4 |
Germany (DIN) | DIN EN 10083 | 1.7225 (or 42CrMo4) |
Japan (JIS) | JIS G4105 | SCM440 |
UK (BS) | BS 970 | 708M40 (EN19) |
Press Brake Die Manufacturer - Durable V-Dies
42CrMo steel press brake die
Why 42CrMo Is More Durable Than Ordinary Carbon Steel？
42CrMo alloy steel offers significantly higher durability compared with ordinary carbon steel, thanks to its alloy composition, heat treatment performance, and mechanical properties.
It contains chromium(Cr), molybdenum(Mo) and manganese, which greatly improve:
Higher hardness and wear resistance
Better strength and toughness
Higher tensile and yield strength
Excellent performance under high pressure and heavy load
Longer service life in industrial applications
Ordinary carbon steel is soft, wears out quickly, and deforms easily under pressure.42CrMo maintains shape, stability even under long-term heavy working conditions, making it the ideal material for press brake toolingand molds.
press brake upper die drawing
press brake lower die drawing