High-Precision Bending Machine Dies

How to Choose the Right Bending Machine Die

What is a Bending Machine Die?

Main parts:

Upper die (punch) and lower die

How it works:

Squeezes metal sheets to form shapes (90° angles, U-shapes, V-shapes, etc.)

Common uses:

Mechanical manufacturing, sheet metal work, hardware, cabinets

Core Components & How It Works

Upper Die

Shapes: Straight edge, sharp corner, gooseneck, arc

Controls the outer shape of the bent workpiece

Lower Die

Mostly has a V-shaped groove

Groove width affects bending force, fillet size and quality

Working Principle

Place the metal sheet on the lower die

Slider drives the upper die down to squeeze the sheet

Sheet bends into the desired shape (permanent deformation)

Upper die moves back; take out the finished workpiece

Key Features of Good Bending Dies

Strong & Wear-Resistant:

Made of 42CrMo steel, hardened to HRC 45–52; resists pressure and friction

Customizable:

Can be made into different shapes/sizes to match workpiece needs

Compatible:

Fits the press brake’s size, tonnage and clamping system

Standardized:

Works with common press brake brands (Amada, Trumpf, etc.); custom options available

Common Types of Bending Dies

By Forming Shape

Standard Straight Edge: For regular straight bends (most common)

Sharp Angle: For small angles and precise bending

Gooseneck: For U-shaped and deep-channel workpieces (avoids interference)

Arc: For curved or rounded bends

Irregular: Custom-made for special shapes

By Application

Standard: For mild steel, galvanized steel (cost-effective)

High-Strength: For stainless steel, thick alloy plates (reinforced design)

Thin-Material: Prevents warping/scratching of thin sheets

By Installation Interface

Amada/Promecam: Fits Amada press brakes

Trumpf/Wila: Fits Trumpf, Wila press brakes

New Standard: Universal (fits most domestic press brakes)

How to Choose the Right Die

1. Match the Material

1. Mild steel: Small springback (use 86°–88° punch for 90° bends)

2. Stainless/high-strength steel: Large springback (use 85° punch)

3. Choose die size based on sheet thickness

2. Follow the 8× Principle

1. Basic rule: V-groove width = 8 × sheet thickness (V = 8T)

2. Thin sheets (T < 3mm): V = 6T

3. Thick sheets (T > 8mm): V = 10T–12T

3. Check Pressure Limits

1. Press brake tonnage must be less than the die’s rated load (10–15% safety margin)

2. Use reinforced/segmented dies for thick/high-strength sheets

4. Pick the Right Punch Shape

1. Standard: Regular straight bends

2. Sharp angle: Small angles, springback control

3. Gooseneck: Deep channels, U-shapes

4. Arc/custom: Curved or special shapes

5. Ensure Equipment Compatibility

1. Match die shank type to the press brake’s clamping system

2. Die height must fit the press brake’s slider stroke

Precision Advantage

• High-quality dies use CNC precision grinding (ensures accurate angles)

• Vacuum heat treatment keeps dies stable (even for complex shapes)

Conclusion