Curved enclosure corners
A 90° honeycomb corner in 3 mm birch needs a 49.48 mm hinge zone at R 30. Wrap all four corners of a box instead.
Hinge box generator →Living Hinge Generator
Pick one of 7 kerf patterns, set sheet thickness, bend angle, inner radius and kerf, and the cut path, the 3D bend and the R_min check redraw as you type. No sign-up for the live studio, the proof PNG or the formula TXT.
Lattice cut length · bridge · row spacing
Fills row spacing 0.6t, cut length 5t + 5 (12–60 mm) and bridge 0.8t from the thickness.
Panel size · legs · margin
- Bend zone W
- 49.48 mm
- Corner zone W90
- Wrap strip
- Pattern open area
- Web
- R_min estimate
- 17.4 mm
- Bend check
- Safe
Inner cuts · 1stBend guides · no cutOutline · last
Too tight.
Links too thin.
Web too thin.
Cast acrylic is brittle. Acrylic living hinges crack after a few bends; use it for flat vent panels, or cut a swatch before any hinge.
Very dense. The preview draws the first 120,000 cut-outs; the numbers count every one.
Proof preview · not a cut file
Free proof
Pro · cut-ready files of this design
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Proof saved. The cut-ready version of this design is in the Pro pack below.
Readout
- Panel open area
- Flat panel
- 169.48 × 100.00 mm
- Slit rows
- 28 rows
- Hinge zones
- Top + bottom plates
- Net link
- 1.65 mm
- Min link
- 0.90 mm
- Cut-outs
- Hole range
- Total cut length
- 2.86 m
R_min, laser time and open area are estimates from the torsion and area models. Confirm the bend with the 5-strip swatch before a full cut.
Pro pack · built for the design above
Production Laser DXF/SVG & 3D STEP CAD Pack
Layered, de-duplicated, cut-ordered DXF R12 and LightBurn SVG with correct kerf handling, a STEP + STL solid of this hinge, and a 5-step swatch that follows your own design.
| You get | Free | Pro |
|---|---|---|
| Every pattern, live 2D/3D, W, R_min, open area | Yes | Yes |
| Proof PNG (≤ 1000 px) + formula TXT | Yes | Yes |
| Kerf-compensated DXF R12 + LightBurn SVG | — | Yes |
| STEP AP214 + binary STL solid | — | Yes |
| 1:1 swatch + datasheet PDF | — | Yes |
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Ready-made designs
Worked examples
Click one to load it into the studio above; every value stays editable.
How to use it
Four steps from sheet to cut file
No Generate button: every step redraws the 2D path, the 3D bend and the numbers at once.
- 01Start from a presetPick one of the four presets or switch to Hinge Box or Perforated Panel. Every value stays editable.
- 02Describe the sheetEnter thickness, kerf and material. Suggest lattice fills row spacing, cut length and bridge for that thickness.
- 03Set the bendAngle and inner radius give the hinge zone W = π(R + t/2)θ/180 and the flat panel with both legs.
- 04Check, then exportKeep R above R_min, save the free proof PNG and TXT, then take the Pro DXF, SVG, STEP or swatch.
Reference
Minimum bend radius by sheet
Straight Slit, suggested lattice, typical CO2 starting kerf.
R_min falls as the links get longer and thinner. The table uses the lattice the Suggest button gives for each thickness (row spacing 0.6t, cut length 5t + 5, bridge 0.8t) and the Straight Slit pattern. Honeycomb, chevron and auxetic need a larger radius; wave and cross-link need less.
| Material | t (mm) | Starting kerf (mm) | Row spacing / cut length / bridge (mm) | Net link (mm) | Min link (mm) | R_min estimate (mm) |
|---|---|---|---|---|---|---|
| Baltic birch plywood | 3.0 | 0.15 | 1.8 / 20 / 2.4 | 1.65 | 0.90 | 15.4 |
| Baltic birch plywood | 4.0 | 0.18 | 2.4 / 25 / 3.2 | 2.22 | 1.20 | 22.4 |
| Baltic birch plywood | 6.0 | 0.22 | 3.6 / 35 / 4.8 | 3.38 | 1.80 | 37.3 |
| Basswood plywood | 3.0 | 0.15 | 1.8 / 20 / 2.4 | 1.65 | 0.90 | 12.6 |
| MDF | 3.0 | 0.15 | 1.8 / 20 / 2.4 | 1.65 | 0.90 | 26.6 |
| MDF | 6.0 | 0.20 | 3.6 / 35 / 4.8 | 3.40 | 1.80 | 64.5 |
| Cast acrylic | 3.0 | 0.15 | 1.8 / 20 / 2.4 | 1.65 | 0.90 | 40.7 |
Model estimate for Straight Slit with the suggested lattice and a typical CO2 starting kerf; empirical, confirm with the 5-step swatch.
Patterns
Which pattern bends furthest
η scales the allowed twist of each link.
All seven hinge topologies share the same rows, cut length and bridge, so you can switch pattern without losing the lattice. η is the flex factor against Straight Slit in the torsion model: R_min scales roughly with 1/η, which is why the 3 mm honeycomb corner reads 17.4 mm while the same sheet in Sinusoidal Wave reads 13.3 mm.
| Pattern | η (flex vs straight) | Curvature | Feel | Good for |
|---|---|---|---|---|
| Straight Slit | 1.00 | Single | Even, predictable | Box corners, book spines |
| Sinusoidal Wave | 1.15 | Single | Softest single bend | 180° spines, cylinder wraps |
| Honeycomb Hex | 0.90 | Single | Firmer, holds shape | Enclosure corners |
| Chevron | 0.80 | Single | Resists side shear | Lids, panels with side load |
| Diamond | 0.75 | Single | Firm, decorative | Decorative panels |
| Cross-Link | 1.10 | Single, both directions | Springy | Sleeves, soft wraps |
| Auxetic | 0.70 | Double (dome, saddle) | Stiff in one bend, stretches in two | Lamp shades, domes |
Perforated mode
Open area formulas for vents and grilles
Perforated Panel mode places only whole holes inside the outline minus the margin, then reports two numbers: the pattern open area from the formula below and the panel open area, which is total hole area over the whole panel. The web between holes is checked against max(0.8 mm, 0.4 × t).
| Pattern | Formula | Worked example |
|---|---|---|
| Staggered Round 60° | OA = 90.69 × (d/p)² % | d 5, p 7 → 46.3% |
| Hexagonal Vent | OA = 100 × (s/p)² % | s 7.9, p 10 → 62.4% |
| Obround Slot | OA = 100 × ((L − w)w + πw²/4) / (px × py) % | 20 × 4 at 26 × 8 → 36.8% |
| Radial Speaker Grille | OA = 100 × N × d² / D² % | Ø100, 341 × 3 mm → 30.7% |
| Attractor Gradient | OA = mean of per-cell ratios | hex 4.0–7.9 mm graded |
Cutting notes
From living hinge SVG generator to LightBurn, Glowforge and xTool
The live 2D view uses LightBurn colours, so what you check here is what your laser software shows after import: blue inner slits cut first, green bend guides are never cut, and the red outline cuts last so the part does not shift while slits are still being burned.
| Layer | Colour | ACI | Cut order | Holds |
|---|---|---|---|---|
| INNER_KERF_SLITS | #0000FF blue | 5 | 1 (first) | Slits and holes |
| BEND_CENTERLINES | #00AA00 green | 3 | never cut | Bend start, end and centre lines; perforated field boundary |
| OUTER_PERIMETER | #FF0000 red | 1 | 2 (last) | Part outline offset by kerf/2 |
| SPEC_NOTES | black | 7 | never cut | Parameter text (DXF only) |
LightBurn
Import the SVG or DXF in millimetres at 100%. Set the green layer to Output off, put the blue layer above red in the cut list and use the same power for both. Start around 20 mm/s for 3 mm birch on a 40–60 W CO2 tube and adjust from the swatch.
Glowforge
Upload the SVG; each colour becomes a step. Set blue and red to Cut, ignore green, and drag the red step to the bottom. Proofgrade 1/8 in plywood is close to the 3 mm presets; keep the kerf at about 0.15 mm.
xTool Creative Space
Import the SVG, keep the scale lock, and assign Cut to blue and red with the outline processed last. Diode lasers cut slower, so the laser time estimate here is a lower bound for a 10–20 W diode.
Where it fits
Use cases and related tools
Real jobs makers cut with these numbers, and the tool page that fits each one.
Lamp shades and domes
Auxetic cells stretch in two directions, so a flat sheet can follow a dome instead of a single cylinder.
Auxetic living hinge →Vents and grilles
Switch to Perforated Panel for hex vents, staggered round holes, obround slots or radial speaker rings.
Perforated panel DXF →Check a radius before cutting
Work out W and the minimum radius for any sheet with the formula explained step by step.
Kerf bending calculator →Send the file to the laser
Layer colours, cut order and import settings for LightBurn, Glowforge, xTool, RDWorks and VCarve.
DXF & SVG guide →Compare every pattern
See all 12 hinge and vent patterns with their flexibility or open-area formula before you choose.
Pattern library →Questions
Frequently asked questions
R_min values are estimates from the torsion model; confirm with a test cut.
What is a living hinge and how does kerf bending work?
A living hinge is a field of parallel cuts that turns a rigid sheet into a flexible strip. The cuts leave thin links of material; when you bend the sheet, each link twists a little, so dozens of links add up to a curve. Plywood, MDF and some plastics bend this way without steaming.
How do I calculate the length of the hinge zone (W)?
Measure the bend at the neutral axis, halfway through the sheet: W = π × (R + t/2) × θ / 180. For 3 mm birch bent 90° around an inner radius of 30 mm, W = π × 31.5 × 0.5 = 49.48 mm. The flat panel is leg A + W + leg B.
What is the minimum bend radius for 3 mm plywood?
With the suggested lattice (1.8 mm row spacing, 20 mm cuts, 2.4 mm bridges) and a 0.15 mm kerf, the Straight Slit estimate for 3 mm Baltic birch is 15.4 mm. Honeycomb is firmer: 17.4 mm with a 2.5 mm bridge. Treat both as estimates and cut the 5-step swatch.
Which pattern bends furthest: straight, wave, honeycomb or auxetic?
In this model Sinusoidal Wave is the most flexible single-bend pattern (η 1.15), then Cross-Link (1.10), Straight Slit (1.00), Honeycomb (0.90), Chevron (0.80), Diamond (0.75) and Auxetic (0.70). Auxetic is the stiffest in one direction but the only one that curves two ways.
Can I make a living hinge in MDF or acrylic?
MDF works but allows less shear strain: the same honeycomb corner that is Safe at R 30 in birch becomes Marginal (R_min 29.9 mm) in MDF. Cast acrylic is brittle; its R_min is about 2.6 times the birch value and repeated bending cracks it, so use it for flat vent panels.
How does kerf compensation work for slits and outlines?
Closed contours are offset by half the kerf: the outer perimeter moves outward and holes move inward, so parts come out at nominal size. Open slits stay where they are and are shortened by kerf/2 at each end, so the burn ends exactly at the drawn length.
How do I import the DXF or SVG into LightBurn, Glowforge or xTool?
Import the SVG at 1:1 in millimetres. In LightBurn the blue layer (inner slits) cuts first, green guides are set to Output off and the red outline cuts last. Glowforge and xTool Creative Space read the same colours as separate steps; keep the outline as the final step.
What open area do I need for a vent or speaker grille?
Vents for passive cooling usually aim for 40 to 60% open area; a 7.9 mm hex at 10 mm pitch gives 62.4%. Speaker grilles are commonly kept above about 30% as a rule of thumb; the 4-inch preset has 341 holes of 3 mm for 30.7%.
What is in the STEP and STL files?
The STEP AP214 file holds two solids: FLAT_PART, the sheet at full thickness with every slit or hole cut through, and BENT_ENVELOPE, the part bent to your angle and radius without slits for fit checks. The binary STL is the bent part with through slits.
Why should I cut the test swatch first?
R_min comes from a torsion model with estimated material coefficients, and real plywood varies between batches and grain directions. The swatch PDF cuts five strips at 0.8 to 1.3 times your row spacing; bend each one and keep the stiffest strip that survives your radius.
Same engine
The rest of the toolkit
Every tool shares one geometry engine, so numbers match between pages and files.