24° U-Groove Two-Stage Hemming Die for 1.5 mm Sheet Metal
A custom 24° U-groove press brake hemming die designed for two-stage bending and flattening of thin sheet metal. The first operation forms the sheet to approximately 24°, while the second flattening operation is completed using the same 12 mm U-shaped die groove. Unlike spring-loaded or pneumatic hemming systems, this tooling uses a fixed die structure without an integrated spring or air-powered flattening mechanism. The tooling shown is designed for 1.5 mm sheet metal and has a maximum rated load capacity of 100 ton/m. This type of U-groove hemming tool is mainly used for light-gauge sheet metal applications where both pre-bending and flattening can be completed with the same punch and die set.
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Description
24° U-Groove Two-Stage Hemming Die for Thin Sheet Metal
This custom press brake hemming die is designed for thin sheet metal parts that require an acute pre-bend followed by a final flattening operation.
The tooling uses a fixed U-shaped lower die groove rather than a spring-loaded flattening plate or pneumatic hemming mechanism.
Both forming stages are completed with the same punch and the same lower die groove.
During the first operation, the sheet is bent to approximately 24°.
During the second operation, the pre-bent workpiece is repositioned into the same U-groove and compressed further until the required flattened or hemmed edge is formed.
This tooling concept provides a simple and compact solution for selected thin-sheet hemming applications.
Two-Stage Hemming Process
First Operation – 24° Acute Pre-Bending
In the first stroke, the punch forms the workpiece to approximately 24°.
The punch uses an R0.5 tip radius, while the lower die incorporates a 12 mm wide U-shaped groove.
This acute pre-bend creates the intermediate geometry required for the following flattening operation.
Second Operation – Flattening in the Same Groove
After the first bend, the workpiece is repositioned for the second forming stage.
The bent edge is placed back into the same 12 mm U-groove.
The press brake then continues the compression process until the required flattened or hemmed profile is achieved.
No separate flattening station is required within the tooling set.
Key Features
24° Acute Pre-Bending
The tooling is designed to form an approximately 24° acute bend before final flattening.
Same Groove for Both Operations
Both the pre-bending stage and the flattening stage use the same U-shaped die groove.
12 mm U-Groove
The lower die shown features a 12 mm groove width, matched to the required material thickness and hemming process.
Fixed Tooling Structure
The design does not rely on a moving spring-loaded flattening plate.
No Pneumatic Mechanism
The hemming process does not require an air cylinder or pneumatic control system.
Designed for 1.5 mm Sheet Metal
The tooling shown is designed for 1.5 mm sheet thickness, which is near the upper end of the typical application range for this specific U-groove hemming structure.
Maximum Load Capacity: 100 ton/m
The tooling is rated for a maximum load of 100 ton/m, subject to actual working length, material strength and application conditions.
Technical Specifications
| Parameter | Specification |
|---|---|
| Tool Type | U-Groove Two-Stage Hemming Die |
| Tooling Function | Acute Pre-Bending + Flattening |
| Pre-Bending Angle | 24° |
| Punch Tip Radius | R0.5 |
| Punch Total Height | 158 mm |
| Punch Effective Height | 128 mm |
| Punch Width | 27 mm |
| Lower Die Height | 80 mm |
| Lower Die Width | 60 mm |
| U-Groove Width | 12 mm |
| Designed Sheet Thickness | 1.5 mm |
| Typical Application Range | Thin sheet up to approx. 1.5 mm |
| Maximum Load | 100 ton/m |
| Hemming Method | Two-stage hemming in the same groove |
| Spring Mechanism | Not required |
| Pneumatic Mechanism | Not required |
| Custom Dimensions | Available |
| Custom Mounting Systems | Available |
Working Principle
This U-groove hemming tool performs the forming process in two press brake operations.
In the first stroke, the punch creates a 24° acute pre-bend.
In the second stroke, the pre-bent section is returned to the same U-shaped lower die groove and compressed further to create the final flattened edge.
The complete process therefore combines acute bending and final flattening in one tooling groove, without requiring a separate spring-loaded or pneumatic flattening mechanism.
Advantages of the U-Groove Hemming Structure
Simple Mechanical Construction
The fixed tooling structure contains fewer moving components than many integrated spring-loaded hemming systems.
Same Tooling for Two Forming Stages
The same punch and die set can be used for both acute bending and final flattening.
Compact Tooling Design
The lower die does not require a separate flattening section or internal moving mechanism.
Suitable for Light-Gauge Sheet Metal
This tooling concept is intended mainly for thin sheet metal applications requiring closed, folded or flattened edges.
Easy to Customize
The groove width, punch angle, tip radius, tooling height, mounting interface and other dimensions can be adapted to the actual workpiece.
Typical Applications
This special press brake hemming tool can be used for thin sheet metal parts requiring folded or flattened edges, including:
- Electrical enclosures
- Control cabinets
- Sheet metal housings
- Equipment covers
- Cabinet doors
- Stainless steel panels
- Appliance panels
- Light-gauge fabricated components
- Sheet metal boxes
- Industrial equipment panels
- Decorative sheet metal parts
- Custom enclosure fabrication
Suitable Materials
Depending on material strength, ductility and the required hem geometry, this tooling can be designed for:
- Mild steel
- Stainless steel
- Galvanized steel
- Aluminum sheet
- Pre-painted sheet metal
- Other light-gauge metal materials
Actual groove width, hemming clearance and working tonnage should be confirmed according to the sheet thickness, material grade and final part geometry.
Custom Press Brake Hemming Tooling
The Tool Shown Is Only One Example
The tooling shown on this page is one custom solution designed for a specific 1.5 mm sheet metal hemming application.
It does not represent the full range of hemming tools that we can manufacture.
We can customize:
- Pre-bending angle
- Punch height
- Effective tooling height
- Punch width
- Punch tip radius
- U-groove width
- U-groove depth
- Hemming clearance
- Tooling length
- Segmentation
- Load capacity
- Mounting interface
- Tooling material
- Heat treatment
- Surface treatment
The tooling can be designed according to the customer's finished part drawing, press brake configuration and required bending process.
Compatible Press Brake Tooling Systems
This U-groove hemming die can be manufactured with different mounting interfaces according to the customer's press brake or tooling system.
Available configurations include:
AMADA Type
TRUMPF Type
WILA Type
LVD Type
Bystronic Type
and other press brake tooling systems.
Custom mounting profiles can also be produced according to customer drawings, tooling samples or machine specifications.
Custom Tooling Design Service
For special sheet metal bending and hemming applications, standard tooling may not always provide the required forming result.
Customers can send us:
- Finished part drawings
- Sheet thickness
- Material grade
- Required hem dimensions
- Bend length
- Press brake model
- Tool mounting interface
- Available machine tonnage
Our engineering team can evaluate the forming sequence and recommend a suitable custom press brake tooling solution.
Important design factors include:
- Acute pre-bending angle
- Sheet thickness
- Material tensile strength
- Springback
- Hemming clearance
- U-groove width
- Punch tip radius
- Final hem geometry
- Tooling strength
- Press brake tonnage
- Workpiece interference
Related Press Brake Hemming Solutions
Depending on the application, different hemming structures can be selected, including:
- U-Groove Hemming Dies
- Two-Stage Hemming Dies
- Spring-Loaded Hemming Tools
- Pneumatic Hemming Tools
- Flattening Dies
- Acute Angle Punches
- Custom Hemming Punches
- Special Thin-Sheet Hemming Tooling
The appropriate tooling structure should be selected according to material thickness, material strength, bend length, required hem geometry and production conditions.
