Press Brake Die Load Ratings by V-Opening: Data From 517 Catalog Tools

This page analyzes the maximum rated loads published on 517 COVO press brake tool pages: 314 dies and 203 punches. Across the catalog, the rated load rises with die opening: dies with a V-opening of 4–8 mm have a median rating of 350 kN/m, while dies with a V-opening of 70–200 mm have a median of 1,500 kN/m. Under the common V = 8 × thickness rule, mild steel air bending needs about 10.0 kN/m per millimeter of V-opening, so the safety margin between the required force and the lowest-rated die shrinks as the V-opening grows.

Key findings

• Coverage: 517 of 585 catalog products are punches or dies with a published rating in kN/m. 225 dies state a single V-opening; 18 multi-V dies state several.
• Ratings rise with V-opening: the median rating grows from 350 kN/m in the V 4–8 mm band to 1,500 kN/m in the V 70–200 mm band.
• Required force rises faster than the ratings: at V = 8 × thickness the required force grows in proportion to V, about 10.0 kN/m per millimeter for mild steel and 15.9 kN/m for stainless steel. From V 6 to V 100 mm the required force grows about 17×, while the median steel die rating grows about 3.8×.
• Where to check most carefully: for stainless steel at V = 8 × thickness, the lowest-rated steel system die has less than a 1.5× margin at V 12, 24, 25, 40, 50, 80, 100 mm, and less than the required force itself at V 80, 100 mm. Large-V work in stainless steel needs a deliberate rating check rather than a default die choice.

Die load ratings by V-opening

Dies with a single stated V-opening, all systems and constructions. Values are maximum rated loads in kN per meter of tool length.

The spread inside each band is wide because the band mixes single-V blocks, multi-station dies, mark-free dies and heavy-duty sections. A low value is not a defect: it tells you which tool needs a shorter loaded length or a larger V-opening for the job.

Ratings by tool type and system family

"-style" means the tool is made for that documented clamping interface; it is not an original-equipment part. Radius punches whose page does not state a system are grouped separately. Mark-free and adjustable dies are shown as their own families because their construction differs from solid steel dies.

Planning check: required force versus catalog rating

The table compares the force needed for air bending at V = 8 × thickness with the ratings of steel system dies at the same V-opening (V-openings with at least five such dies). Required force uses the constants of the COVO bending force calculator: F = 0.065 × S² × L / V tonnes for mild steel, multiplied by 1.6 for stainless steel, converted to kN/m. Margin = lowest catalog rating ÷ required force; the COVO tooling workbench asks for at least 1.5×.

⚠ marks a margin below 1.5×. The required force scales with thickness squared, so the V-to-thickness ratio matters: bending thicker material in the same V (V = 6 × thickness) raises the force by about 78 %, while the V = 10 × or 12 × thickness often used for heavy plate lowers it by about 36 % or 56 %. Bottoming and coining need several times the air-bending force and are outside this comparison. Short parts concentrate the load: always convert kN/m to the force allowed over the length actually in contact.

How to use a kN/m rating

1. Find the rating for the exact tool. Read it from the product page or drawing of the punch and of the die; use the lower of the two.
2. Multiply by the loaded length. Allowed force (kN) = rating (kN/m) × length under load (m). Segmented tools are rated per meter too, but every section in the stack must carry its share.
3. Compare with the required force. Estimate it with the bending force calculator using the real tensile strength from the material certificate, then keep at least a 1.5× margin.
4. Check the rest of the stack. Holders, adapters, the machine's own limits and off-center loading can be more restrictive than the tool rating.

Method and limits

Source: every active product on chinacovo.com, read through the public catalog on 2026-10-28. Included: products tagged as punch or die whose specification states a numeric maximum load in kN/m (517 tools). Excluded: 42 forming tools and adapters, and 26 punches or dies without a published rating. The system family comes from the stated tooling system or compatible brand; the first system listed is used when several are named. Values are taken as published and have not been re-tested for this analysis.

The data will be refreshed when the catalog changes. Cite as: COVO Precision Tooling, "Press brake die load ratings by V-opening", catalog snapshot 2026-10-28, https://www.chinacovo.com/blog/press-brake-die-load-ratings-by-v-opening.

Download the data

Download the CSV (517 rows: product URL, model, tool type, system family, V-opening, angle, maximum rated load, snapshot date).

FAQ

What load rating do press brake dies typically have?

In COVO's catalog snapshot of 2026-10-28, dies with a V-opening of 4–8 mm have a median maximum rated load of 350 kN/m (range 150–1,000), while dies with a V-opening of 70–200 mm have a median of 1,500 kN/m (range 1,000–3,400). Always use the rating published for the exact tool, not a typical value.

What does a load rating in kN/m mean?

It is the maximum force the tool may carry per meter of loaded tool length. Multiply it by the length actually under load to get the allowed force for that setup. A 1,000 kN/m die loaded over 0.5 m may carry 500 kN, not the full press capacity.

How much force does air bending need per millimeter of V-opening?

With the constants used by the COVO bending force calculator and the common rule V = 8 × thickness, mild steel needs about 10.0 kN/m for every millimeter of V-opening, and stainless steel about 15.9 kN/m. These are preliminary planning values; confirm them with the material certificate and a test bend.

Can I download the COVO load-rating data?

Yes. The CSV at https://www.chinacovo.com/data/covo-press-brake-tool-load-ratings.csv lists every tool in this analysis with its product page, model, system family, V-opening, angle and published maximum rated load.

Next step

Send the part, material, thickness, bend length and machine and COVO will propose a punch and die whose published rating covers the job, or explain which limit needs a different setup.

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