18.09 hours, for a bed 256 mm square covered to roughly seventy percent, parts standing 40 mm, sliced at 20% infill and 0.2 mm layers, running at 100 mm/s. That works out at 200 layers and 449,357 mm³ of plastic.
In other words: start it after dinner and it finishes some time the following afternoon.
Height decides this, not part count
A plate of 40 mm parts takes the same 200 layers whether it holds four objects or forty. Adding parts adds material within each layer; it does not add layers.
So the shape of the job matters more than the quantity:
- Many short parts — fewer layers, more material per layer, and the fastest way to fill a plate.
- Few tall parts — many layers, little material in each, and the head spends most of its time travelling.
- One tall part alone on the plate — the worst case per gram, because the per-layer overhead is paid in full for a nearly empty layer.
That last case is why batching tall parts helps so much: the layer count is already being paid for.
What the estimate leaves out
Travel. A densely packed plate makes the head cross the bed repeatedly within every layer, and those moves are not extrusion time. The model carries a single lumped allowance for travel and acceleration, which is fine for one part and increasingly optimistic as the part count climbs.
Expect a packed plate to run somewhat longer than the figure suggests — the model's stated error band is ±30%, and a crowded plate sits on the slow side of it.
The practical planning question
Whether it fits in the window you can leave it unattended. An 18-hour job is comfortably overnight; a 30-hour one is not, and needs either a shorter plate or a machine you trust to run through a working day without you.
That decision is usually worth more than the exact figure. Print time is a planning number; capacity is a real constraint.
Put your bed area and part height into the print time estimator to schedule your own plate; the money side of the same job is at full build plate cost.