How tall can your box be?

The design principle

Punch height is not box height.

A box wall can fit below a tall punch when the part is upright and still run out of room as the part tilts during bending. The upper holder occupies space above the tool, and an already-formed wall can reach back toward the punch body.

This calculator separates those two questions: how much height the upper tool and holder allow, and how tall the opposing wall can be before it touches the selected punch at the final 90° position. The lower result controls the estimate.

“Box height” here means the inside height from the inside floor to the top edge, using theoretical sharp inside corners. It is not the outside overall height, the flat flange length, or the tool’s stamped height. The live section shows the last bend of a simple U-shaped section through the box.

How to use the calculator

1. Enter your inside width and target height. Width W is the inside floor distance between opposing walls. Height H is the wall height you want. Open “Box dimensions” to see the measurement convention.
2. Choose a punch, or compare the inventory. Automatic selection picks the highest planning result. “View” in the table lets you inspect another tool. It does not select tooling for material strength, tip radius, die opening, or tonnage.
3. Check orientation. On asymmetric punches, turning the relief toward the existing wall can change the clearance. Automatic orientation takes the clearer side. OW203/S uses a fixed orientation because the inventory marks it as non-flippable.
4. Confirm the holder assumption. Replace B with the installed holder’s centerline-to-edge dimension when known. Keep a height reserve appropriate to your design; the 2 mm default is an editable planning allowance.
5. Read the controlling limit. If your target is above the estimate, reduce the wall height, try more inside width, or compare another punch. A wider base can help punch-profile clearance; it does not increase the holder-based limit.
6. Check the other direction and the full sequence. A rectangular box has two base dimensions. Run both, keep the more restrictive result, then review the complete formed model and tooling setup.

A result within the estimate means these two simplified checks leave room. It does not certify a four-sided box for production.

Where the maximum comes from

1. Upper holder reference

TRUMPF publishes this relationship for inside box height. OWH is punch height and B is the distance from the press-beam centerline to the outer edge of the Modufix holder.

Using B = 25 mm gives about 63.8 mm for a 120 mm punch, 131.0 mm for a 220 mm punch, and 184.8 mm for a 300 mm punch. These are formula results before the extra reserve or a tighter punch-profile limit. The reference offset has not been measured on Xeon’s holder.

Source: TRUMPF bending tools catalog, “Calculation of the maximum nest height,” printed page 299. The calculator retains the published 1.414 and 0.95 factors.

2. Opposing wall against the punch

The second check uses the same imported punch outlines as Xeon’s 2D bend simulator. At a 90° final bend, the inside floor is drawn at 45° to horizontal. Starting at its far inside corner, the model extends the already-formed wall until its inside face first meets the punch outline. That contact distance is the profile limit.

The displayed sheet is a line representing its inside faces. Thickness, corner radii, springback, overbending and the path through the stroke are outside this check. The upper holder is drawn schematically; its formula is a separate constraint.

The displayed maximum rounds down. The extra reserve reduces allowable height; it is not a measured minimum gap around every surface.

Which Xeon punch should you try?

The calculator reads Xeon’s existing tooling inventory and the simulator’s profiles. The five current punches are OW202/K (120 mm), OW202/S (220 mm), OW200/S (220 mm), OW300/S (300 mm), and OW203/S (220 mm).

The taller tools can provide more room below the holder. A gooseneck can provide relief for an opposing wall, but the useful clearance depends on width and orientation. A 300 mm punch does not mean a 300 mm box, and a gooseneck does not automatically clear every narrow channel.

OW203/S has a 4 mm tip radius; the other four inventory punches have 1 mm tips. A tool that wins this height comparison may still be unsuitable for your intended inside radius or material. Use the tooling selection guide and current tooling library alongside the result.

The 5170S still needs room to open.

Xeon uses a TRUMPF TruBend 5170S. TRUMPF lists a 615 mm usable open height for the 5170 (S). This is a machine reference, not an available box-height allowance; the installed tool stack occupies some of that space. See TRUMPF’s Series 5000 technical data.

A part also needs room to load, rotate between bends and come off the punch after forming. A taller punch uses more of the open space. Die height, adapters, the actual holder, stroke and the removal path must be checked together.

This calculator does not subtract an assumed die height from 615 mm or issue a removal-clearance verdict. The final setup should be checked against the actual machine configuration and the complete folded part.

Before you release the box design

Use this page to compare geometry early. The full job still needs:

• Material, thickness, bend radius, die support and tonnage checks.
• Clearance through the entire stroke, including any overbend for springback.
• Actual upper holder, machine, die and backgauge clearance.
• Tool segment lengths, box corners and side walls along the bend line.
• A workable bend sequence and a way to load and remove the part.

For more detail, open the bend simulator, check reverse-bend clearance, or review part-on-part collision. Provide the folded model with the intended dimensions when the design goes to Xeon for review.