The pipeline in six stages
Fused deposition modeling is the technology Bambu Lab lists first in the P1S specification table [1]. Every FDM printer, whatever the brand, runs the same six stages. Vendors give the parts their own names, which is why spec sheets can be confusing. The table shows each stage and the wording each vendor uses on the pages we checked.
| Stage | What happens | Bambu Lab wording | Creality wording |
|---|---|---|---|
| 1. Model | A 3D shape is saved as a file | Model files on the microSD card [1] | Files menu on the printer [9] |
| 2. Slice | Software cuts the model into layers and plans every move | Bambu Studio | Creality Print [9] |
| 3. Send | Instructions reach the printer | Micro SD card, Wi-Fi [1] | USB flash disk, LAN, Creality Cloud [9] |
| 4. Feed and melt | Filament is pushed into a heated zone | Extruder gears (steel), all-metal hot end, 300 °C max [1] | Direct extruder, 300 °C nozzle [2] |
| 5. Move | Motors place the nozzle in X and Y, then step up in Z | 500 mm/s tool head speed [1] | CoreXY frame [2] |
| 6. Cool and hold | Fans set each layer; a heated plate holds the first one | Part cooling fan, auxiliary part cooling fan, 100 °C plate [1] | 100 °C heatbed [2] |
Stages 1 to 3: model, slicer and G-code
A model file describes only the outside of a shape. It says nothing about how thick the walls should be, how hot the nozzle runs or where the printer should start. The slicer adds all of that. You choose a layer height, the number of walls, how much infill goes inside, whether to add supports, and the material profile, and the slicer turns those choices into G-code: thousands of short instructions such as heat the nozzle, move to this point, extrude this much filament.
Because the slicer makes almost every decision, two printers given the same file can produce very different parts. That is also why vendors ship pre-sliced test files: they remove your settings from the first print.
The file then travels to the printer by card, USB stick, local network or the vendor’s cloud. Nothing about the print changes in transit; the printer simply executes the list.
Stage 4: the extruder and hotend
The extruder is a pair of gears that grip the 1.75 mm filament [1] and push a precise length of it forward. In a direct-drive design, as on the K1C [2], the gears sit on the print head right above the hotend, which shortens the path and helps with flexible filament. In a Bowden design the gears sit on the frame and push filament through a long tube.
The hotend is the heated block and nozzle. Filament enters solid and leaves as a molten line about the width of the nozzle opening, usually 0.4 mm on the printers above [1][2]. You can see the temperature step on any printer: Bambu Lab’s A1 heats the nozzle to 250 °C before you push filament in during loading [8]. Each material has a range; Bambu Lab lists 190 to 240 °C for PLA [6].
Molten plastic behaves like a stiff fluid, so pressure builds and lags behind the motor. Firmware features such as pressure advance compensate for that; Klipper’s documentation says it reduces ooze during travel moves and blobbing at corners [7].
Stage 5: the motion system
Two layouts dominate. On a CoreXY printer, such as the K1C [2], the bed moves only down, and two motors share a belt arrangement to move the head in X and Y. Klipper’s documentation shows that each CoreXY motor position is the sum or difference of the X and Y positions [3]. On a bed-slinger the bed itself travels front to back; that is why Bambu Lab asks A1 owners to leave about 695 mm of clearance for heatbed travel [4].
Every move speeds up, cruises and slows down. Klipper models this as a trapezoid and notes that short moves may have no cruising phase at all [3]. That is the reason headline top speeds matter less than they appear: small parts are mostly short moves.
Stage 6: cooling, heating and multicolour
Each layer must be solid enough to carry the next. Part-cooling fans blow on the fresh plastic; the P1S lists a part cooling fan and an auxiliary part cooling fan [1]. Meanwhile the heated plate keeps the first layer warm enough to grip. Materials that shrink a lot as they cool, such as ABS and ASA, also need a warm chamber; Bambu Lab recommends an enclosed printer for them [6].
Multicolour printing adds one more step. Each time the colour changes, the old filament is pushed out of the nozzle until the new colour runs clean, then directed away from the print area [5]. That flushed plastic is why multicolour prints use more filament than the part weighs.
Worked example: a 20 mm cube at 0.2 mm layers
A 20 mm cube printed with 0.2 mm layers is 20 ÷ 0.2 = 100 layers. The slicer decides what happens on each one. The example below assumes a common beginner profile of 2 walls, 3 solid bottom layers, 4 solid top layers and sparse infill. These are illustration choices, not any vendor’s defaults.
Each wall loop around a 20 mm square is about 80 mm long. With a 0.45 mm line at 0.2 mm height, every millimetre of line is about 0.09 cubic millimetres of plastic, so two wall loops are about 160 mm and 14 cubic millimetres per layer. Across 100 layers the walls alone are about 1,440 cubic millimetres. Filament 1.75 mm wide holds about 2.4 cubic millimetres per millimetre, so the walls alone use roughly 0.6 m of filament.
| Layers | What the slicer plans | Why |
|---|---|---|
| 1 | Slower first layer, full solid fill, plate at material temperature | Grip on the plate decides whether the rest succeeds |
| 2 to 3 | Walls plus solid fill | A closed, flat bottom |
| 4 to 96 | Walls plus sparse infill | Saves plastic and time inside the part |
| 97 to 100 | Walls plus solid top fill | Solid fill must bridge the sparse infill below to close the top |
Questions before you decide
What is G-code?
The instruction list a slicer produces: temperatures, moves and how much filament to push for each move. The printer simply follows it, which is why slicer settings matter so much.
Why does the nozzle need to be so hot?
The filament must melt to flow through a 0.4 mm opening. Bambu Lab lists 190 to 240 °C for PLA [6], and the A1 heats to 250 °C while loading filament [8].
What is the difference between CoreXY and a bed-slinger?
A CoreXY printer such as the K1C [2] moves the head in X and Y while the bed only moves down. A bed-slinger such as the A1 moves the bed front to back, which needs about 695 mm of clearance on the A1 [4].
Why do multicolour prints waste filament?
Each colour change pushes the old colour out of the nozzle until the new colour runs clean, and that flushed plastic is discarded [5].
Sources & verification
Product details and prices can change. Check the linked provider before buying.
- Bambu Lab Wiki: Unboxing P1S (includes P1S specification table) Accessed 30 Oct 2026
- Creality: K1C support page and parameters Accessed 30 Oct 2026
- Klipper documentation: Kinematics Accessed 30 Oct 2026
- Bambu Lab Wiki: A1 FAQ Accessed 30 Oct 2026
- Bambu Lab Wiki: Reduce waste during filament change Accessed 30 Oct 2026
- Bambu Lab Wiki: Filament guide - printer, nozzle, build plate and parameters Accessed 30 Oct 2026
- Klipper documentation: Pressure advance Accessed 30 Oct 2026
- Bambu Lab Wiki: A1 first print with an external spool Accessed 30 Oct 2026
- Creality Wiki: K1C / K1C 2025 user manual Accessed 30 Oct 2026
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