# Building a living-hinge heart box

> a living-hinge heart box that curves all the way around

A heart box looks tricky but it is just three parts: a heart top, a heart bottom, and one long wall that wraps the whole heart. Because a heart curves everywhere, the entire wall is a living hinge, a field of fine slits that lets a rigid sheet bend into a smooth curve. This generator draws the heart, sizes the wall to the exact perimeter, and cuts the hinge for you. The Assembled 3D tab shows the parts in place so you can judge the size before spending a sheet.

## What you need

- **Laser cutting:** 3 mm plywood or MDF bends best for the living hinge. Measure the actual sheet thickness with calipers, it is rarely exactly 3 mm.
- **3D printing:** any rigid filament for the flat plates and wall; the living hinge is a laser feature.
- **Glue:** PVA wood glue for plywood, plus a couple of clamps or elastic bands to hold the wrap while it cures

## Step 1 - Heart size



**Size** sets the overall width of the heart, and **Height** sets how tall the wall is. **Thickness** must match your sheet, because the living-hinge slits are tuned to bend a sheet of that thickness.

## Step 2 - Tune the hinge



- **Hinge slit spacing** sets how close the slits sit. Closer slits bend more easily but leave a weaker wall.
- Thin plywood around 3 mm bends far better than thick stock, so keep the wall material thin.
- Run a short test strip first to confirm your material wraps the tight lobes of the heart without cracking.

## Step 3 - Check the assembly



Switch to the **Assembled 3D** tab and orbit the heart box to judge the height against the width. The **Export Preview** tab shows the flat sheet with each part in its own colour.

## Laser cutting

### Before you cut



1. Measure your sheet with calipers and set **Thickness** to what you measured, not what the label says.
2. Cut the living-hinge slits before the wall outline where your software lets you choose, so the wall does not shift once it is free.
3. Test the hinge first: cut a short strip and bend it around the tightest part of the heart before committing the whole sheet.

### Wrap and glue



1. Dry wrap the wall around one heart plate first so you know where the seam lands.
2. Glue the wall to the edge of the bottom plate a little at a time, following the curve, and hold it with elastic bands.
3. Cap it with the top plate once the wall is set, or leave the top loose as a lift-off lid.

## 3D Printing

### Slice and print



1. The 3D download is a zip with one part per piece: two heart plates and the wall band.
2. Every part is already extruded to the **Thickness** value. Do not scale the parts in the slicer.
3. Lay each part flat on the bed. The wall prints as a straight strip that you can heat-bend, or scale the box up and print the wall in short arced segments.
4. Print at 0.2 mm layers with 3 or more perimeters so the plates and wall come out strong.

## Make it yours

- Engrave a name or a short message on the top heart before cutting.
- Line the inside with felt so the box cradles jewellery or a ring.
- Cut the plates in a contrasting wood or acrylic from the wall for a two-tone keepsake.

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Open the Heart Box Generator: https://www.mylasertools.com//heart-box-generator
Read online: https://www.mylasertools.com//learn/guides/heart-box-generator