Different Types of Mark

In sheet metal bending, traditional press brake tools often leave dents, scratches, or other marks on the workpiece. These defects lower product quality and cause material waste. If punches and dies are not well-maintained, they wear faster, leading to downtime and reduced production efficiency. Mark-free press brake toolsaddress these issues using specialized die designs and higher-quality materials, improving efficiency while extending tool life.

In this article, we share proven methods to achieve precise, mark-free bending for your workpieces — ensuring top-quality results every time.

Problems with Traditional Press Brake Tools

Indentations and Strain Marks

When bending sheet metal with traditional press brakes, marks, dents, or even cracks often appear on finished parts. These defects occur because the punch and die apply high localized pressure to the sheet, which can damage the surface and weaken the part.

Old or worn V diesare a common cause—especially when punches and dies are misaligned. Sliding contact between the sheet and tooling increases friction, leaving visible marks. Using double-V dies or mismatched tooling further raises the risk.

Mark-free press brake tools solve these problems by reducing friction and surface damage through optimized die geometry and advanced materials. Companies like CHAOEROoffer a wide range of mark-free solutions, including custom designs to meet strict surface quality requirements.

While conventional bending often leaves unwanted marks, mark-free press brake tooling ensures a flawless surface finish.

Types of Mark-Free Press Brake Tools

1. Roller-Type Mark-Free Press Brake Tools

These dies incorporate hard alloy rollers in the lower die. As bending occurs, the rollers rotate in sync with the sheet movement, converting sliding friction into rolling friction. This greatly reduces scratches and surface marks.
Key Points:

• Feature:Rotating alloy rollers on contact surfaces
• Advantage:Dynamic rolling contact; ideal for ultra-thin sheets (<0.5 mm)
• Typical Applications:Precision electronics, solar panel frames

2. Swing-Plate Type Mark-Free Press Brake Tools

These dies feature a rotating flap mechanismin the lower die. As the punch presses the sheet into place, the flap rotates to maintain face contact without sliding, virtually eliminating pressure marks.
Key Points:

• Feature:Polished chrome surface (Ra ≤ 0.4 μm)
• Advantage:Even force distribution; no surface dragging
• Typical Applications:Stainless steel countertops, elevator panels

Each press brake tool undergoes strict pre-delivery performance testing to ensure accuracy, durability, and safety.

3. Polyurethane Press Brake Tools

These dies use soft, elastic polyurethane inserts that act as a cushion, evenly distributing pressure to prevent marks. Best for soft metals and decorative finishes.
Key Points:

• Feature:Polyurethane or spring ejector in the lower die
• Advantage:Fully eliminates pressure marks; produces uniform bend radii
• Limitations:Not suitable for thick or heavy-gauge workpieces
• Typical Applications:High-gloss aluminum, mirror-finish stainless steel, smartphone frames

4. Other Mark-Free Bending Methods

Additional methods include:

• Protective film:Placed between the die and sheet to protect surfaces; cost-effective and easy to use.
• Adiprene or nylon inserts:Absorb pressure and reduce direct metal-to-metal contact.
• Special die geometries:Larger radii or rotating contact surfaces to minimize friction.

CHAOEROsupplies imported Protective filmfor different sheet thicknesses:https://www.chaoero.com/protective-film/

Comparison of Mark-Free Press Brake ToolsTypes

How to Choose the Right Mark-Free Press Brake Tools

• Match die opening to sheet thickness– For air bending, the V opening is typically 8× sheet thickness.
• Select tooling based on bend type– Acute bends require sharper punches; complex profiles may need gooseneck or multi-V dies.
• Consider bend radius– Smaller radii create higher stress; use wider die openings for thicker sheets.
• Part size and quantity– Large parts may benefit from custom-length tooling for efficiency.
• Material– Soft metals like aluminum work best with polymer-lined or polyurethane dies; nylon inserts suit coated/polished metals.
• Machine capacity– Ensure tooling matches the press brake’s tonnage and safety limits.
• Cost vs. performance– Higher-quality tools last longer and reduce scrap rates.
• Get expert guidance– Consult suppliers like CHAOEROfor optimal tooling solutions.

We keep an extensive stock of flap-type mark-free press brake tools, ready to meet your urgent bending needs.

Choosing the right press brake tooling for each job not only prevents marks on the metal, but also extends the life of the tools. CHAOEROcan help you select the most suitable tooling, or even customize it to your specific requirements.
Browse CHAOERO’sdelivered mark-free press brake tools— customization available.

Explore CHAOERO’s delivered mark-free press brake tools with full customization options.

Standard Swing-Plate Type Mark-Free Press Brake Tools