What we can bend, what the tooling can reach, and what our preflight checks before the first controlled collision between punch, material, and die.
A press brake does not simply fold a line in a CAD model. It drives a punch, a sheet, and a die through a precisely managed physical event.
The punch defines where force enters. The V-die supports the sheet. The material yields, wraps around the punch tip, and springs back when the load leaves. Change the alloy, grain direction, thickness, inner radius, flange length, or angle and the event changes with it.
That is why bend quality begins before the machine moves. The geometry must be compatible with a real punch and die. Both flanges need support. The formed part needs room to rotate. The tooling must be able to leave after the bend. The sequence has to remain possible from the first stroke to the last.
From one-flange brackets to multi-bend chassis, the shape is not limited by what can be drawn. It is limited by whether the machine can support, reach, form, and release it.
The most direct formed profile: one bend, two open legs, and clear access for straight tooling.
Parallel walls formed in sequence, provided the punch can reach the second wall and the inside span clears the tool.
Two opposing bends create a controlled step. The offset must leave room for the second bend and the selected punch-and-die pair.
Four bends build a rigid raised section. Earlier flanges must remain clear while the final returns enter the tooling.
Deep walls and neighboring flanges make tool access, backgauge contact, and the escape path as important as the target angles.
A broad radius can be built from many controlled bends. Step pitch, tangent quality, and visible tooling marks become design variables.
These are profile families, not standalone machine limits. The final decision still comes from material, thickness, bend length, tooling, flange support, and the complete bend sequence.
Our standard air-bending range is 30° to 135°, with a standard angle tolerance of ±0.5°. Bend lines can reach up to 120 inches when material, thickness, tonnage, and geometry permit.
Those numbers describe the machine's range, not a guarantee that every possible combination can be formed. A 120-inch bend in thin aluminum and the same bend in thick steel are different load cases. A 30-degree acute bend with a long open flange and the same angle inside a closed box create different access conditions.
A flange also has a physical minimum. During air bending, enough material must sit across the die shoulders to remain controlled. As a design starting point, use a formed flange around 4 times the material thickness. The actual minimum is calculated from V-opening, angle, inside radius, and the geometry of the part.
Tolerances are always symmetrical relative to the nominal dimension. A leg called out at 40 mm with a ±0.3 band is accepted anywhere from 39.7 to 40.3. There is no one-sided allowance and no implied bias toward the nominal.
Which letter governs a given dimension depends on how many bends sit between the two faces being measured. Every additional bend contributes its own angular and positional error, so a span measured across two bends carries a wider band than a single leg measured off one.
| S — sheet thickness | A | B | C | D | E — angle | F — precision |
|---|---|---|---|---|---|---|
.118″up to 3 mm | ±.008″± 0.2 mm | ±.016″± 0.4 mm | ±.031″± 0.8 mm | ±.020″± 0.5 mm | ± 0.5° | 15′/100 mmper 3.937″ of bendper 100 mm of bend |
.157″4 mm | ±.012″± 0.3 mm | ±.024″± 0.6 mm | ±.047″± 1.2 mm | ±.024″± 0.6 mm | ± 0.5° | 15′/100 mmper 3.937″ of bendper 100 mm of bend |
.197″ – .236″5 – 6 mm | ±.016″± 0.4 mm | ±.031″± 0.8 mm | ±.063″± 1.6 mm | ±.031″± 0.8 mm | ± 0.5° | 15′/100 mmper 3.937″ of bendper 100 mm of bend |
.315″8 mm | ±.020″± 0.5 mm | ±.039″± 1 mm | ±.079″± 2 mm | ±.039″± 1 mm | ± 0.5° | 15′/100 mmper 3.937″ of bendper 100 mm of bend |
.394″10 mm | ±.031″± 0.8 mm | ±.063″± 1.6 mm | ±.126″± 3.2 mm | ±.063″± 1.6 mm | ± 0.5° | 15′/100 mmper 3.937″ of bendper 100 mm of bend |
Checker platetextured stock | .079″2 mm | — | — | — | ± 1.5° | — |
Hemmingfolded edge | ±.039″± 1 mm | 0 – 0.5 × Sof sheet thickness | — | — | — | — |
Our bending check turns a formed 3D model into a set of physical questions before material reaches the press brake.
Good sheet-metal geometry gives the material room to move and the tooling room to work.
TRUMPF ACB angle measurement lets the press brake respond to the material in front of it. It does not make impossible geometry possible.
During the stroke, non-contact optics measure both flanges and compare the actual angle with the target. The control can compensate for springback and material variation before the ram returns. That makes angle control more consistent across prototypes, batches, and material lots.
Measurement is most effective when both flanges present enough clean surface to read. Very short flanges, perforations at the measurement zone, or unusual geometry may require another verification strategy. The design still has to create a bend the machine can physically see and execute.
The purpose of preflight is not to say no. It is to convert uncertainty into a solvable manufacturing state.
A useful bending platform should let a designer explore complex formed geometry without already being a press-brake operator. It should reveal the same constraints a production engineer sees: the radius that an alloy can survive, the die that can support the flange, the tool that can clear the box, and the sequence that keeps the last bend reachable.
When those constraints are visible early, prototypes become faster, revisions become cheaper, and production becomes predictable. The result is not just a bend that matches an angle. It is a complete part whose geometry survived contact with the real world.
Send a formed 3D STEP model. We will read the bends, validate the tooling envelope, develop the flat, and turn the geometry into a manufacturing plan.
Upload your STEP →