K-Profiles¶

K-Profiles are BamDude's representation of slicer-grade print parameters tuned per printer — pressure-advance / linear-advance values, nozzle/bed temps, flow ratios, retraction settings. Profiles travel with your install: backed up over Git on a schedule, exported as a single JSON file when you want to migrate, applied per spool from the inventory page.

This page covers the profile mechanics. For the spool side (assigning a profile override to a specific spool / colour) see Spool Inventory.

What is Pressure Advance?¶

Pressure advance (also called "K-factor", "linear advance", or just "K") compensates for the lag between the extruder motor pushing filament and the molten plastic actually leaving the nozzle. The wrong K value shows up at every direction change of the print head — corners, perimeter starts, retract→prime points:

Too low — bulged corners, blobby seams, over-extrusion at perimeter starts. The motor keeps pushing while the head is still decelerating.
Too high — gaps at corners, thin lines, weak perimeter joins. The motor backs off too aggressively and the nozzle starves.
Just right — sharp clean corners, consistent line width across the layer, no blobs at line starts.

Different filaments compress differently — softer/wetter materials (PETG, TPU) need higher K than stiff PLA — so you need a separate value per material, sometimes per brand within a material.

Storage model¶

BamDude keys K-profiles on a 3-tuple composite: printer × filament × nozzle.

Dimension	Why it matters
Printer	Same filament on different printers may need different K — different extruder geometry, different bowden length, different firmware tuning.
Filament	PLA needs different K than PETG, TPU, ABS, PA — material compressibility varies by an order of magnitude.
Nozzle	A 0.2 mm nozzle has a different pressure profile from a 0.6 mm — the K value tracks nozzle diameter, not just material.

So a 3-printer farm running 4 materials at 2 nozzle sizes ends up with up to 3 × 4 × 2 = 24 distinct profiles. The profile picker filters down to the relevant subset for whatever printer/filament/nozzle you're configuring.

Where profiles live¶

Surface	What it does
Profiles in the sidebar	The profile list. Filter by printer model, search by name, edit, clone, import, export.
Spool detail (under Inventory)	"K-profile override" — pick a profile to use whenever this spool is assigned to an AMS slot. Useful for off-spec filaments.
Settings → Backup → Git	Schedule profiles + cloud profile snapshots to GitHub / GitLab.

Cloning vs editing¶

A profile can be in three states:

System default — shipped with BamDude, read-only. Clone to customise.
User-owned — created by you, fully editable.
Imported — pulled in from another install / Git restore. Editable, but the import metadata stays attached so you can tell where it came from.

Cloning a system default produces a user-owned copy with the same parameters; the original system row is untouched. Most BamDude operators end up with one user-owned per (printer model × material) pair.

Dual-nozzle gating¶

H2D / H2D Pro carry a second nozzle; their profiles need to expose two parallel sets of flow / temperature parameters. BamDude detects dual-nozzle at runtime from MQTT telemetry — specifically, when the printer publishes a nozzle_2 key in its temperature stream BamDude flips the printer's dual-nozzle flag. There is no serial-prefix lookup table for this; the detection is purely capability-based, so any future Bambu model that publishes a second nozzle key will be picked up automatically. Once detected, BamDude:

Filters the profile picker to dual-nozzle profiles when the target is a dual-nozzle printer.
Hides the secondary-nozzle UI block on single-nozzle profiles to reduce noise.
Refuses to assign a single-nozzle profile to a dual-nozzle printer (and vice versa) — you'll see a clear error in the UI rather than a silent malfunction during print.

Fetch from Printer / Push to Printer¶

Profiles round-trip with the printer over MQTT. Two directions:

Fetch from Printer¶

Open K-Profiles, select the printer.
Click Fetch from Printer.
BamDude reads the printer's currently-stored K values for every loaded filament and creates / updates the matching profile rows.

Use this after manual on-printer calibration — it pulls the freshly-tuned values straight into BamDude.

Push to Printer¶

Select the profiles you want to send.
Click Push to Printer.
BamDude writes the K values via MQTT command.

Push overwrites the printer's current K

Pushing profiles overwrites the printer's stored K values for the matching filament. If you've been tuning on-printer, fetch first to avoid clobbering uncommitted tuning work.

Saving and deleting wait for the printer's verdict. They used to be fire-and-forget — BamDude reported success the moment the bytes left the process, and the printer's actual answer was thrown away in a debug log. If the printer says no, you now see its own reason.

A printer that stays silent is still treated as success

No answer is not evidence of refusal.

Nozzle size on a profile¶

The printer reports the nozzle size once, on the envelope of its reply. On single-nozzle models the individual profile entries carry no size at all, so a profile's size is read from that envelope.

If you run a 0.6 or 0.8 mm nozzle on a printer older than this release, every profile was listed as 0.4 mm — and it was not only a wrong label:

Editing a profile is delete-and-re-add on single-nozzle printers, and the dialog rebuilds the nozzle fields from what it was shown — so saving an untouched 0.6 mm profile stored it back as 0.4.
Deleting one aimed the command at the wrong nozzle the same way.
Assigning a spool's saved calibration to an AMS slot matches on nozzle size, so on a 0.6 or 0.8 nozzle it never found the printer's own entry and the assignment silently failed to stick.

The H2D was never affected — its firmware does repeat the size per entry.

Flow Type (Standard / High Flow)¶

A K-profile can be Standard or High Flow, but only some firmware stores the choice; the rest accept it and keep Standard whatever you pick. BamDude follows the same rule Bambu Studio uses for its own calibration window, read from the printer definitions it ships:

Flow Type field	Models
Shown	H2 series, X2D, P2S
Hidden	X1, X1 Carbon, X1E, P1P, P1S

This is not the single- versus dual-nozzle split — the P2S is single-nozzle and does offer both flows.

A profile carrying no flow type at all reads as Standard, the way the slicer reads it, rather than the High Flow that used to be assumed on import.

Sync status indicators¶

Each profile shows one of three sync states:

Status	Meaning
Synced	BamDude's value matches the printer's last known K.
Modified	BamDude has local edits that haven't been pushed yet.
New	Profile created in BamDude, never pushed to this printer.

After firmware updates or factory resets the printer's stored K may diverge from BamDude's view — re-Fetch to re-establish ground truth.

Editing K-profiles & value guidelines¶

Click any profile row to edit. The K-factor field accepts a decimal number; typical starting points per material:

Material	Typical K range
PLA	0.02 – 0.04
PETG	0.03 – 0.06
ABS / ASA	0.02 – 0.04
TPU	0.05 – 0.10

Starting points, not absolutes

These are calibration starting points. Actual optimal K depends on your specific printer, filament brand, nozzle diameter, and even ambient temperature. Always run a calibration pass after picking a starting value — see below.

Add a free-form note per profile (brand, purchase batch, tested 2026-04-01, …) so you remember why a value was set the way it is.

Adding K-profiles¶

Three ways to create a profile from scratch:

Manual entry¶

Click Add K-Profile.
Pick the filament family (the same picker the spool form uses — see Filament Families; custom families included), the nozzle diameter, and (if multiple) the target printer.
Enter the K-factor.
Save — sync state lands as New until you push.

Auto-matching between spools and profiles keys on the family — which is what lets a custom filament (your own vendor and name) find its own calibration instead of collapsing onto Generic.

From calibration result¶

After running flow / pressure-advance calibration on the printer:

Note the optimal K reported by the calibration screen.
Either Fetch from Printer (if the printer stored the result) or add it manually.
The profile is now reusable across slicer round-trips.

Bundle import¶

Drop in a previously-exported profile bundle — see Import & export below.

Calibration walkthrough¶

Built-in flow calibration (Bambu Lab printers)¶

Bambu printers ship with a flow / pressure-advance calibration routine:

Load the filament you want to calibrate.
From the printer's Calibration menu (or via Bambu Studio → Calibration → Pressure Advance), run flow calibration.
Inspect the test pattern on the build plate — the optimal K is the one that produces the cleanest corners and most consistent extrusion.
Note the value, then either Fetch from Printer in BamDude (printer-side calibration writes back to the printer's K store) or update the profile manually.

Third-party methods¶

If you prefer to calibrate by eye:

Pressure-advance line test — print a series of single-perimeter lines at increasing K. The cleanest line wins.
Pressure-advance tower — vertical tower with K incrementing per layer, measure the layer where corners are sharpest.
Corner flow test — print a test cube and inspect the four corners under raking light.

Whatever method you use, the resulting K value goes into the BamDude profile via Add K-Profile or by editing the existing row.

Copying profiles between printers¶

Right-click any profile row → Copy to printer…, pick the destination printer. BamDude clones the profile (same K, material, nozzle) onto the new printer with sync status New.

Fine-tune after copying

Different printers — even of the same model — can have subtly different extruder behaviour. Treat a copied profile as a starting point and re-run calibration on the destination if you want best-quality output.

Comparing values across printers¶

The K-profiles page has a Compare view — pick a material + nozzle and BamDude shows a column-per-printer table of the K values stored for that combination. Use this to:

Spot one outlier printer that needs re-tuning,
Decide which printer's profile to use as the canonical "copy from" source,
Audit drift after firmware updates across the farm.

Import & export¶

Three import paths:

Source	Notes
Single profile JSON	The Profiles page accepts an upload of a previously-exported profile.
Bundle import	Profiles + matching spool-overrides as one ZIP; useful when migrating between installs.
OrcaSlicer preset	OrcaSlicer ships filament presets that map cleanly onto K-profile parameters. Drop a folder of `.json` Orca filament presets and BamDude imports them in one click.

Export is the inverse — single profile, full bundle, or "everything modified since X" diff bundle.

Git-backup integration¶

Settings → Backup → Git can push your profile catalogue (plus the BamDude config snapshot) to a GitHub or GitLab repo on a schedule. The repo holds:

A flat directory of profile JSONs under kprofiles/ (one file per profile, named by ID).
A kprofiles_index.json listing every profile by hash + name + printer-model so a partial restore is unambiguous.
The matching spool overrides (spool_kprofiles/).
An audit log entry per scheduled commit.

Restore from Git is partial-by-default: you can pick specific profiles to pull back, or "everything since the last backup". The Git history itself is your version archive — every commit is a profile catalogue snapshot you can roll back to.

Permissions¶

Permission	Effect
`kprofiles:read`	View profile list, see settings. Default for Viewers.
`kprofiles:create`	Make new profiles or clone existing ones.
`kprofiles:update`	Edit user-owned / imported profiles.
`kprofiles:delete`	Remove user-owned profiles (system defaults can never be deleted).

Spool overrides (spool_kprofile) are governed by inventory:update — same surface as editing a spool.

RFID re-tap and live calibration preservation¶

When an AMS slot reads a Bambu RFID tag and the matching spool has a K-profile registered for the same printer + nozzle diameter, BamDude pushes that profile's calibration index to the slot. So any time you re-insert a calibrated spool, the slot snaps back to the correct K immediately — you don't have to re-pick it from the printer screen.

If the spool has no stored K-profile for that specific printer + nozzle combo (you've calibrated this filament on Printer A but just inserted it into Printer B for the first time, or you've changed the nozzle and haven't re-calibrated yet), BamDude preserves the slot's currently-selected calibration instead of letting the firmware silently snap it to slot 0. The exact behaviour:

The slot's live cali_idx (whatever profile was already loaded — manually picked from the printer screen, or carried over from the previous spool in the same slot) is re-issued to the AMS so it sticks.
If the slot has no calibration loaded at all (cali_idx < 0), no command is sent — the firmware default behaviour stands.
A diagnostic log line records No stored K-profile for spool … — preserved live cali_idx=N so the choice is observable in Settings → System → Diagnostics.

Why this matters: prior versions left the slot un-touched on re-tap when no stored profile existed, which on some firmware revisions produced a silent regression to slot 0 that operators only noticed mid-print as a quality drop. The new behaviour is a strict no-op for slots that already have your manually-picked calibration, but a corrective re-issue for the rare slots that would have regressed.

Troubleshooting¶

Fetch from Printer fails

Verify the printer is online and BamDude shows a green status dot.
Make sure the printer isn't mid-print or actively running its own calibration — MQTT commands can be queued behind the active operation.
Check the printer's MQTT logs (Settings → System → Diagnostics) — fetch is a regular MQTT command and surfaces the same way as any other.

Push to Printer fails

Confirm the printer is idle. Some firmware versions reject K-write commands while a job is loaded but not yet started.
Try a known-good profile to rule out a malformed K value (BamDude clamps to sensible ranges, but a manually-imported bundle could theoretically contain garbage).
After firmware updates, the printer may temporarily reject commands until its first reboot completes — wait, retry.

Pushed values don't seem to apply during printing

Re-slice the model after the push — slicer-embedded K values can override printer-side K depending on slicer/firmware version.
Verify the material name in your slicer matches the profile's material — BamDude maps profiles to materials by name, so a mismatch silently bypasses the profile.
Some firmware versions need a printer reboot before K-write takes effect.