OpenSCADBoxes

Parametric laser-cut boxes with living hinges, based on the original designs by Martin Raynsford (msraynsford). All dimensions are in millimetres.

Script	Design	Cutting parts
LivingHinge.scad	Hinge coupon for material/bend calibration	1
FlexBox1.scad	Two panels with perpendicular bends	2
FlexBox2.scad	Continuous wall strip and two oversized lids	3

Quick start

Install OpenSCAD. The regression suite is verified with OpenSCAD 2021.01. Download or clone the whole repository: the entry scripts require lib/common.scad beside them.

1. Open a script and adjust the parameters at its top (or use the Customizer).
2. Leave outputMode = "cut" for the 2D cutting layout.
3. Render with F6, then choose File → Export → Export as SVG or DXF.
4. Import at 1:1 scale into the laser software and verify a known dimension. Cut outlines, including every hinge slot and joint hole; do not fill/engrave the filled areas of the SVG. Do not treat SVG stroke width as beam width.
5. Cut a hinge and joint sample in the intended material before a full box.

The default for all three scripts is now cut; FlexBox1 previously opened a combined 3D display. Output mode is a parameter, so exporting needs no code edits.

Command line

Run these commands from the repository directory:

openscad -o FlexBox1.svg FlexBox1.scad
openscad -o FlexBox2.dxf FlexBox2.scad
openscad -o custom.svg -D 'height=100' -D 'width=120' FlexBox2.scad
openscad -o preview.stl -D 'outputMode="preview"' FlexBox2.scad
openscad -o flat.stl -D 'outputMode="flat"' FlexBox1.scad

In Windows PowerShell, use OpenSCAD's console executable and escaped embedded quotes for string parameters:

& 'C:\Program Files\OpenSCAD\openscad.com' -o box.svg FlexBox2.scad
& 'C:\Program Files\OpenSCAD\openscad.com' -o flat.stl -D 'outputMode=\"flat\"' FlexBox1.scad

cut is 2D and exports to SVG/DXF; flat is a nominal 3D sheet layout; preview shows folded parts. Preview bends are solid schematics without hinge slits, and the default explodeDistance=10 separates parts for inspection. Set it to zero to bring the schematics together. These previews do not simulate material deformation or certify physical fit. STL is for inspection, not the laser cutting path. Kerf compensation applies only to cut.

Parameters and calibration

Parameter	Meaning
height, width, depth	Nominal dimensions used by the original design; not a guaranteed usable internal envelope
thickness	Measured sheet thickness, rather than its catalogue value
cornerRadius	Inner radius of the schematic bend
tabLength	Nominal tab width; complete tab patterns are centred on each straight edge
slotRepeatMin	Minimum spacing of slot rows across the bend length
slotLengthMin	Target minimum slot-column spacing along the hinge height; a narrow panel uses one column
slotLengthGap	Uncut bridge width between staggered slot segments
slotWidth	Nominal width of each rectangular slot
bendAllowance	Multiplier on ideal arc length; defaults are 1.02 for boxes and 1.2 for the coupon
jointClearance	Total extra width/length of mating slots; 0.1 mm for boxes, adjustable independently of kerf
kerf	Measured beam width; 0 disables compensation
partGap	Nominal separation of flat parts; must exceed kerf
explodeDistance	Preview separation; does not change cutting dimensions
angle, radius, hingeHeight	Standalone coupon parameters; signed, nonzero angle in −360…360 degrees
curveSegments	Shared curve resolution in lib/common.scad; integer ≥12, also overridable with -D

Measure thickness and kerf on the actual sheet with the chosen laser settings. With compensation enabled, the material outline expands by half the kerf: outer toolpaths move out and hole toolpaths move in. Do not also apply kerf compensation in the laser software. jointClearance remains the desired total extra slot size after a correctly calibrated cut.

Kerf must be less than slotWidth, otherwise hinge slots disappear. If your beam width is larger, increase the nominal slot width and recalibrate the hinge. Changing slot pattern, sheet grain, thickness, material or bend allowance changes bend behaviour. Test the coupon at the same bend radius and settings as the box; copy its successful settings to the box, including bendAllowance.

The scripts reject nonpositive dimensions, impossible radii/tab patterns, and hinges too short for even one row. Increase radius or reduce slotRepeatMin when a hinge is too short. A small panel width no longer silently loses its slots. FlexBox1 also needs room for its rounded end tabs, and FlexBox2 needs room for tabs on each half of its split wall. Check OpenSCAD's console for assertions; an exit code alone is insufficient on some versions.

The flat layout is a simple separated layout, not a sheet-packing optimiser. Changing dimensions changes its size, but parts remain separate. The existing Pi Case 3.svg is a legacy static drawing, not generated by these parameters.

Development and regression checks

Python 3.9+ and OpenSCAD are sufficient; no Python packages are required:

python -m unittest discover -s tests -v

On Windows, use py instead of python if needed and set the console executable:

$env:OPENSCAD = 'C:\Program Files\OpenSCAD\openscad.com'
py -m unittest discover -s tests -v

Tests render real SVG/STL outputs, reject warnings, check separate part outlines, verify slots on small coupons, measure kerf and clearance changes, exercise signed/full-circle bends, and require explicit failure for invalid inputs. Temporary outputs are removed automatically. Run the suite before submitting a change; keep shared hinges, tab patterns and validation in lib/common.scad. No automatic GitHub Actions workflow is added; tests can run locally without CI minutes. Physical cutting and bending still require material-specific trials.

Origin and licensing

The original design process is described in the Instructables article. This repository descends from daci6920/OpenSCADBoxes. The original project promoted the vanillabox laser cutter; that historical shop is not a dependency or an installation requirement.

Neither the source repository nor this fork declares a licence. See LICENSE.md for the explicit status and the remaining permissions needed before offering a redistribution licence.