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My model is too big for the print bed

Published · How we check our guides

Short answer

First try turning it: a model that is too long often fits diagonally or standing up. If it still doesn't fit and must stay full size, cut it into parts with alignment pins, print them separately and glue them together.

1. Turn it before you cut it

Slicers place a model the way it was drawn. A long part often fits once you turn it:

  • Diagonally. A 256 × 256 mm bed is about 360 mm corner to corner, so a thin part up to roughly 340 mm can fit on the diagonal (leave room for the skirt or brim).
  • Standing up. Many printers are taller than they are wide. A part that stands safely (wide base, nothing hanging over) can use the height instead.

In most slicers, select the model and rotate it 45° around Z; Bambu Studio and OrcaSlicer also have an Auto orient button.

2. Scale it down, if size doesn’t matter

For a figure or a decoration, printing at 80% is often the easy answer. For anything that has to fit something else (a bracket, a case, a replacement part), keep it at 100% and split it instead. If the model is far too big, check it wasn’t drawn in the wrong unit: see STL in inches vs millimetres.

3. Split it into parts that line up

  1. Open the STL splitter, drop your model and pick your printer. It works out how many cuts are needed so every part fits.
  2. Move the cuts to sensible places: flat areas, hidden faces, places where a seam won’t show. Avoid cutting through thin walls or small details.
  3. Keep the alignment pins on. They add round pins to one side of each cut and matching holes to the other, so the parts can only go together one way.
  4. Download the parts, print them, then glue.

The model is cut in your browser; nothing is uploaded.

Getting the joints right

  • Fit: the default gap between pin and hole is 0.15 mm on each side, which suits most well-tuned FDM printers. If pins are too tight, raise it to 0.2–0.25 mm; if they wobble, lower it.
  • Glue: superglue (cyanoacrylate) works for PLA and PETG and sets in seconds. Two-part epoxy fills gaps and is stronger. For ABS and ASA, an acetone weld melts the parts together.
  • Print the faces down: cut faces are flat, so they print well on the bed, with no supports, and come out accurate.

How big is your bed?

Look up your printer in the 3D printer bed sizes table, which also lists the longest part that fits on the diagonal. Leave a few millimetres spare: slicers keep a margin at the edges, and a skirt or brim needs room too.