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SpeakCAD for the Prusa MK4S
Custom parts for the Prusa MK4S: describe them, download G-code sliced for it
Prusa's current bed slinger with the Nextruder, a 250 x 210 x 220 mm volume and PrusaLink over Wi-Fi. SpeakCAD ships the Prusa MK4S's own OrcaSlicer profile: describe a part in plain English, watch it render on a virtual 250 x 210 mm bed, edit it by chat, and download a .gcode file, ready for the SD card, the USB stick or the printer's own upload page. Or take the STL or 3MF to your usual slicer. Runs in Safari and Chrome, on a phone or a computer, nothing to install.
How it works
From a sentence to the MK4S's SD card
The slicer runs on our side with the same profiles OrcaSlicer ships for the Prusa MK4S. You choose the print profile and the filament; the printer settings are already right.2
Check it on the MK4S's bed
The part renders on a virtual bed the size of the MK4S's. The first render usually appears within a minute or two: a new part goes to the strongest models, which reason through the geometry, and small edits land in seconds. Turn it, tap a face to read a size, open the dimensions panel, and see whether it has overhangs that need supports. Anything wrong is one sentence to fix.3
Pick the Prusa MK4S and its profile
In the download dialog choose the Prusa MK4S (0.25 nozzle, 0.3 nozzle, 0.4 nozzle, 0.5 nozzle, 0.6 nozzle, 0.8 nozzle), one of its print profiles (0.05 mm, 0.07 mm, 0.1 mm, 0.12 mm…), a filament, then infill, walls, supports and adhesion. The printer and its last settings are saved to your account.4
Download and print
You get a .gcode file, ready for the SD card, the USB stick or the printer's own upload page, with the estimated print time and filament weight. Re-slicing a design you already downloaded does not spend the 10 credits again; without Pro or Unlimited each slice still spends 5 credits.The Prusa MK4S profile SpeakCAD slices with
| Setting | Value |
|---|---|
| Printer | Prusa MK4S (Prusa) |
| Printable area in the profile | 250 x 210 x 220 mm |
| Nozzle variants | 0.25 nozzle, 0.3 nozzle, 0.4 nozzle, 0.5 nozzle, 0.6 nozzle, 0.8 nozzle |
| Layer heights in the print profiles | 0.05 mm, 0.07 mm, 0.1 mm, 0.12 mm, 0.15 mm, 0.16 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.32 mm, 0.4 mm, 0.55 mm |
| Filament profiles | PLA, PETG, ABS, ASA, TPU, PLA-CF, PETG-CF, PC, PA, PA-CF, plus the OrcaSlicer filament library |
| Download | G-code, or STL and 3MF for your own slicer |
| Slicer | OrcaSlicer, run on our servers with the printer's official profile |
Prompts sized for the MK4S
Copy one, change the numbers to yours. Each opens in the editor with the text already typed.“A nozzle swap caddy for a Prusa MK4S: holds four Nextruder nozzles in 12 mm bores 25 mm apart, 3 mm walls, a lid that slides in side grooves, fits a 100 x 40 mm footprint.”
Open this prompt in the editor“A frame-mounted tool holder for the MK4S: clips on the 30 mm aluminium extrusion with 0.2 mm clearance, three 8 mm holes for hex keys and a 20 mm slot for the spatula.”
Open this prompt in the editor“A print sheet wall rack for three MK4S steel sheets (254 x 240 mm) in 4 mm slots, two countersunk screw holes 150 mm apart, 2.4 mm walls.”
Open this prompt in the editorWhy MK4S owners do not need a slicer on the phone
Slicing is the step that keeps 3D printing on the desktop: a design made anywhere still has to pass through Bambu Studio, PrusaSlicer or Cura on a computer. SpeakCAD runs OrcaSlicer on its own servers with the profile OrcaSlicer ships for the Prusa MK4S, so the phone that typed the description also downloads G-code. The desktop slicer stays the better choice for arranging many parts on one bed or for exotic settings; for one part at a time, the download dialog covers the profile, the filament, infill, walls, supports and adhesion.
Parts that fit the MK4S
The Prusa MK4S's 250 x 210 mm bed and 220 mm height are what the virtual bed in the viewer shows, so a part that looks too big is too big. Ask for a part to be split into two halves with alignment pins when it does not fit, or for a flat print orientation when it would need supports. The examples above and the library parts below all fit.
Parts that fit the first time
The Prusa MK4S prints slightly differently from the next printer, which is why holes come out tight and lids loose. Fit Check cuts a five-minute test slice from the interface that must fit, you report too tight, perfect or too loose, and every model after that is built with the clearance your MK4S needs. The test slice downloads free as STL or 3MF. How Fit Check works.
Ready-made parts for the MK4S in the library
Prusa MK4 nozzle storage box for Nextruder and V6 nozzlesA hinged box that keeps Prusa Nextruder nozzles, the V6 adapter nozzles and a couple of Obxidian and high-flow nozzles sorted by size instead of loose in a bag.Prusa MK4 filament runout guide with PTFE fittingA guide arm that bolts to the top of the Prusa MK4 or MK3.9 frame and routes filament from the spool holder into the Nextruder through a short length of PTFE…Prusa MK4S ObXidian nozzle-swap caddyA bench caddy that holds six MK4S / Nextruder nozzles (Cht, ObXidian, brass) in 10 mm hex pockets 12 mm deep plus a 8 mm well for the nozzle wrench.Prusa MK4S print-sheet wall rackA rack that hangs three MK4S 250 × 210 mm sheets on a wall so they are not stacked on the printer.Prusa MK4S frame tool holderA tool holder that clips onto the side of the MK4S aluminium frame, which is about 6 mm thick, with slots for the Prusa hex keys, a nozzle wrench, a spatula…Prusa MK4S frame webcam mountAn arm that clamps to the top of the MK4S frame, about 6 mm thick, and holds a webcam with a 1/4-20 screw, for timelapses or remote monitoring through PrusaC…Prusa MK4S LED light bar frame mountA pair of mounts that hang a 10 mm LED strip channel from the top of the MK4S frame, about 6 mm thick, lighting the bed for the camera and first-layer checks.
Questions
Yes. The Prusa MK4S is one of the 380+ printers in the slicer catalog, with 6 nozzle variants and the print and filament profiles OrcaSlicer ships for it. Pick it in the download dialog and download G-code; it is saved to your account for next time.
No. SpeakCAD slices on its servers and gives you a .gcode file. Copy it to the SD card or USB stick the MK4S takes, or upload it through the printer's own web page or app. If you prefer your own slicer, download the STL or 3MF instead.
The print profile (layer height and speed presets from the Prusa MK4S's profile), the filament profile (the printer's own and the OrcaSlicer library: Generic PLA, PETG, ABS, ASA, TPU, carbon-fibre blends and hundreds of branded filaments), infill, wall count, supports and bed adhesion. Nozzle temperature, bed temperature and speeds come from the profiles you pick.
The virtual bed in the viewer is sized from the Prusa MK4S's profile (250 x 210 mm), so you see it before slicing. Ask for the part to be split into two pieces with alignment pins or a dovetail, or for a different orientation; each is one sentence.
Sliced downloads are included in Pro ($9.99 a month, 200 credits) and Unlimited ($24.99 a month); with Starter credits ($5 once for 75 credits, no subscription) a sliced download spends 5 credits on top of the usual 10. Re-slicing a design you already downloaded does not spend the 10 credits again; without Pro or Unlimited each slice still spends 5 credits. STL and 3MF downloads are always available.
Yes. The editor runs in Safari on iPhone and iPad and in Chrome on Android; the file lands in Files or Downloads, ready for the card or the printer's app. The same project opens later on a desktop.
Read more
All 380+ printersEvery printer the slicer has a profile for, by brand.From a phone to the slicerGetting the file from Files or Downloads onto the printer.Exporting to slicersSTL vs 3MF, units, and what the slicer does with the file.The AI 3D editor on your phoneDescribe, render, edit and download from a phone browser.From a ChatGPT description to a filePaste the spec ChatGPT wrote and get the file it could not make.