Do all 3D printers poop? Which ones do and why

No. Only printers with a purge chute or purge wiper “poop”, the name owners give the blobs of purged filament these machines drop out the back or side. Printers without one, such as the Prusa MK4S, the Prusa Core One and Ender-3 style machines, prime the nozzle with a short purge line on the bed instead.

Do all 3D printers poop?

No. A printer poops only if it has a place off the bed to purge: a chute or purge wiper that drops the blob outside the print area. Bambu Lab’s X1, P1, A1 and H2D series, Creality’s K2 Plus and the Flashforge AD5X have one. The Prusa MK4S, Core One and Ender-3 style printers purge onto the bed.

Which printers poop, and how much they purge before a print

The start purge figures come from each printer’s start G-code in the slicer profile. Grams assume 1.75 mm PLA (polylactic acid) at 1.24 g/cm³, the density in OrcaSlicer’s PLA profile. AMS is Bambu Lab’s Automatic Material System, its filament changer.

Printer	Where the purge goes	Purge in the start G-code	PLA
Bambu Lab X1 Carbon	Waste chute at the back	105 mm	0.31 g
Bambu Lab P1S	Purge chute at the back	105 mm	0.31 g
Bambu Lab A1, A1 mini	Purge wiper	105 mm with an AMS lite attached	0.31 g
Bambu Lab H2D	Purge wiper above the left inner liner	45 mm (0.4 mm nozzle)	0.13 g
Creality K2 Plus	Waste chute beside the nozzle wiper	Firmware routine, plus a 30 mm line on the bed	0.09 g (line)
Flashforge AD5X	Waste eject system	18 mm line on the bed	0.05 g
Prusa MK4S	Line along the front of the bed	19 mm	0.06 g
Prusa Core One	Line along the front of the bed	17 mm	0.05 g
Ender-3 (Cura’s Creality start G-code)	Two lines along the left edge of the bed	30 mm	0.09 g

Bambu Lab’s store describes the X1 and P1 purge chute as an assembly on the back of the printer that cleans the nozzle and slides “the excess filament out of the printer.” The H2D’s purge wiper, per Bambu Lab’s wiki, expels “waste filament generated during filament changes and other scenarios outside the printer.” Creality’s wiki shows the K2 Plus nozzle wiper mounted on the side of its waste chute. Flashforge lists a redesigned waste eject system among the AD5X’s upgrades.

The Creality K2 Plus and Flashforge AD5X do both. They draw a purge line on the bed at the start of a print and send purge through the chute when the filament changes. The K2 Plus also runs Creality’s own START_PRINT routine from the printer firmware. The slicer profile doesn’t show how much that routine extrudes.

Why does a 3D printer poop during a single-color print?

Because the printer primes its nozzle before every job. The start routine pushes filament through until fresh plastic fills the nozzle, then wipes the blob off over the chute instead of onto the bed. Bambu Lab’s X1 and P1 start G-code extrudes 105 mm of filament there, about 0.31 g of PLA.

Bambu Lab’s wiki says the X1 uses its waste chute “when printing with multiple colors using the AMS, but also when starting a new print, to ensure that the filament inside the nozzle is fresh.” One blob at the start of each print is normal, even in one color.

What the start routine does

On the P1S profile the sequence runs:

1. Heat the nozzle to 250 °C, a common flush temperature.
2. Extrude 50 mm, then another 50 mm while the nozzle cools toward print temperature, then 5 mm with the part fan on.
3. Drop the temperature 20 °C so the filament shrinks a little, retract 0.5 mm, then shake and wipe the blob off over the chute.
4. Wipe the nozzle again before homing and bed leveling.

With an AMS attached, the same routine first loads the print’s filament from the AMS.

The A1 and A1 mini run the same 50, 50 and 5 mm sequence at the purge wiper when an AMS lite is attached. When flow dynamics calibration is switched on, the A1 extrudes another 10 mm at the same spot before it calibrates. The H2D’s 0.4 mm profile extrudes 45 mm toward its trash bin before wiping both nozzles.

Other single-color poops

• Loading filament. Bambu Lab’s loading guide tells you to watch for extruded filament “to ensure the extruder is purging correctly” and to retry the load if nothing comes out.
• Pause and resume. Bambu Lab’s store says the A1 purge wiper gathers and dislodges waste “during different stages, including printer setup, pause and resume operations, and filament changes for multi-color printing.”

When do 3D printers poop?

A chute printer poops at the start of every print, when filament loads, and at every color or material change. Bambu Lab adds pause and resume to that list for the A1. Color changes make by far the most.

When	Typical amount	PLA
Start of a print (X1, P1)	105 mm of filament	0.31 g
Each color change	280 mm³, OrcaSlicer’s default purging volume	0.35 g
Each color change, Bambu Lab’s four-color test cube	83 g over 153 changes, prime tower included	0.54 g

Bambu Studio and OrcaSlicer set the color-change flush for each pair of colors. Per Bambu Lab’s wiki, darker colors need more flush to switch to lighter ones. A model with a change on every layer repeats it hundreds of times. Bambu Lab’s four-color test cube wasted 83 g, as much as about 265 single-color starts on an X1 or P1. The multi-color waste calculator totals the grams, cost and added time for your own change count.

How much filament does one poop waste?

The start purge of 105 mm on an X1 or P1 comes to about 0.31 g of PLA, or about $0.006 at $19.99 a kilogram. Convert any purge length the same way:

purge volume mm³ = purge length mm × 2.405 mm²   (cross-section of 1.75 mm filament)
purge grams      = purge volume mm³ × density g/cm³ ÷ 1000

Worked example, the Bambu Lab X1 or P1 start purge in PLA:

purge volume = 105 × 2.405         = 252.5 mm³
purge grams  = 252.5 × 1.24 ÷ 1000 = 0.31 g
per print    = 0.31 g × $0.020/g   = $0.006
200 prints   = 62.6 g              = $1.25

The price is Polymaker’s US list price for a 1 kg spool of PolyLite PLA. Put your own spool price into the filament cost calculator, or convert a different purge length with the filament length and weight converter.

Is there a 3D printer without poop?

Yes. Any printer that primes with a purge line on the bed instead of a chute makes no poop. That includes the Prusa MK4S, the Core One and Ender-3 style printers. Their purge line is the same waste in a different place: a strip of 0.05 to 0.09 g that you peel off the bed.

For multi-color printing without poop, the options are:

• A wipe tower instead of a chute. Prusa’s MMU (Multi-Material Unit) and other single-nozzle systems without a chute purge into a wipe tower printed beside the model. Prusa’s knowledge base says the tower’s size depends on the number of color changes, not on the size of the object. The waste stays, as a printed block instead of loose blobs.
• A toolchanger. Each filament keeps its own nozzle, so a color change swaps tools instead of flushing one. Prusa Research lists the XL+ with “zero purge waste” because “each toolhead keeps its own nozzle.” Snapmaker advertises “minimal purge” and “up to 85% less waste” for the U1.

If a chute printer makes no poop at the start of a print, filament isn’t reaching the nozzle. Bambu Lab’s loading guide says to retry the load when nothing comes out.