Sheet Metal Brake Dies

• Machinery manufacturing

• Sheet metal fabrication

• Hardware production

• Cabinet making

Core Components & How They Work

Upper Die

• Mounted on the moving slider of the bending machine

• Applies pressure to the sheet

• Its shape decides the outer shape of the finished part

• Common shapes: straight edge, sharp angle, gooseneck, arc

Lower Die

• Fixed on the machine workbench

• Usually has a V‑shaped groove (V‑groove)

• V‑groove width affects bending force, corner radius, and forming quality

Sectionalized Tooling

• Provides various length combinations (e.g., 10mm, 20mm, 100mm)

• Meets the bending needs of workpieces with different widths

Working Principle

1. Place the metal sheet on the lower die

2. The slider pushes the upper die down

3. The sheet bends and takes the shape of the dies

4. Once the set pressure is reached, the upper die lifts up

5. Remove the finished workpiece

Main Features of Sheet Metal Brake Die

High rigidity & wear resistance

Customizable

Good compatibility

Standardized & serialized

Common Types of Sheet Metal Brake Die

By shape

• Standard straight edge die: For general bending, most widely used

• Sharp angle die: For small angles and springback compensation

• Gooseneck die: For deep U‑shaped parts, avoids interference

• Arc die: For rounded corners and curved shapes

• Irregular die: Custom for special workpiece shapes

• Sectionalized Tooling: For workpieces of different widths, with adjustable length combinations

By application

• Standard bending dies: For mild steel, galvanized steel

• High‑strength steel dies: For stainless steel and hard alloys

• Thin sheet dies: Precision design to avoid warping or scratches

By machine interface

• Amada / Promecam type

• Trumpf / Wila type

• New Standard type (fits most domestic machines)

How to Choose the Right Sheet Metal Brake Die

1. Match material properties

• Mild steel has little springback

• Stainless steel springs back more — use an 85° punch to compensate

• Choose dies based on sheet thickness to avoid cracking or damage

2. Follow the “8x rule” for V‑groove width

• Thin sheets (under 3mm): use V = 6T

• Thick sheets (over 8mm): use V = 10T–12T to reduce pressure

3. Respect pressure tonnage limits

• Never overload the die

• Keep a 10–15% safety margin

• For thick or strong steel, use thickened dies or hardened steel segments

• For workpieces of different widths, choose Sectionalized Tooling to ensure flexible and accurate bending

4. Choose the right punch shape

• Standard punch: general straight bending

• Sharp‑angle punch: small angles and springback control

• Gooseneck punch: deep U‑shapes

• Custom punch: round or irregular parts

• Sectionalized Tooling: For flexible adaptation to different workpiece widths

5. Check machine compatibility

• Make sure the die shank fits your machine’s clamping system

• Die height must match the slider stroke

• Wrong size leads to installation failure or incomplete bending

Important Tips When Choosing Dies

• Don’t ignore springback — it causes wrong angles

• Follow the 8x rule to prevent cracking and die damage

• Always check compatibility with your bending machine

• Choose Sectionalized Tooling when you need to bend workpieces of different widths

The Power of Material: Why We Use 42CrMo (4140)

• 42CrMo / 42CrMo4 alloy steel

  Balances high hardness and great toughness

• Full hardening

  Strong inside and outside, prevents breaking

• Laser or induction hardening

  Working surface reaches HRC45–50

  Maintains precision even after thousands of bends