Lightburn MasteryModule 2.2~7 min read

Material Library Files (.clb): Save, Share, Migrate

The single most underused Lightburn feature for production shops. The Material Library lets you save validated settings per material (e.g., "Polar Camel powder coat, 30oz tumbler") and apply them with two clicks instead of re-keying speed/power/passes/interval every job. The .clb file is how you back up, share, or migrate that library between machines and computers.

Why this matters

Without the Material Library: every job, you re-enter Speed/Power/Passes/Frequency/Pulse/Interval from a sticky note or your memory. Mistakes are inevitable. Settings drift. New employees can't onboard.

With it: you spend 10 minutes the first time you cut a new material to test and dial settings. You save those settings to the Library with a clear name. Every subsequent job for that material: pick from the Library, apply, run. Same outcome, every time, every operator.

How the Library works

Open via Window → Library (or the Library tab in the right-side panel stack). The Library has three components:

Categories: top-level folders. Typical structure: Wood, Acrylic, Metal-Stainless, Metal-Brass, Leather, Tumblers, Slate, Tile.
Entries: one row per validated material+goal combination. Naming convention matters; see below.
Settings: each entry stores Speed, Power, Min Power, Frequency, Q-Pulse Width (galvo), Image Mode (if image), DPI / Line Interval, Number of Passes, Z step, and other layer-specific values.

Naming convention (the part most people get wrong)

Bad library names: "Wood", "Acrylic settings", "Tumbler". Within 3 months you can't tell what material, what goal, what machine.

Good library names follow a material · finish · goal · controller pattern:

Maple plywood 6mm / engrave dark / CO2 50W
Cast acrylic 3mm / cut clean edge / CO2 50W
Polar Camel powder 30oz / reveal stainless / CO2 50W
Brass 360 coin / black mark / Fiber MOPA 60W 70mm
Stainless 304 / color blue / Fiber MOPA 60W 150mm
Veg-tan leather 4oz / dark engrave / Diode 20W

Including the controller / power / lens means the same Library can serve a multi-machine shop without confusion.

Saving settings to the Library

Run a test grid for the material (see the Material Test guide). Pick the cell that hits your goal.
Set the layer in your active project to those settings.
Open the Library panel. Right-click the category you want to save into → Add Current to Library. (Or click the layer first, then the "save to library" button on the Library panel.)
Name the entry per the convention above.
Verify: open a fresh project, drag the Library entry onto a new layer, run on scrap. Same result confirms the entry is saved correctly.

Applying a Library entry to a job

Drag the entry onto an existing layer in the Cuts/Layers panel, applies the settings to that layer.
Double-click the entry: applies to the currently-selected layer.
Right-click → Apply: same as above.

Backing up and sharing: the .clb file

Lightburn stores the Material Library in a .clb (Cut Library) file. This is just a structured XML/JSON-like file with all your category definitions and entries. You can:

Export your entire library to a single .clb file, Library panel menu → Save Library As.
Import another shop's library: Library panel menu → Open Library. Replace your current library or merge.
Sync between computers: keep the .clb file in Dropbox / OneDrive / iCloud Drive. Open the same file on each computer; changes save back to that shared location.
Send a starter library to a new employee on day one. They open the file, get the shop's validated settings, and start running production same week.

Cloud-synced library = single source of truth

Save the .clb to a cloud-synced folder (Dropbox / OneDrive / Google Drive). Every machine in your shop opens the same file. When you validate a new setting, save it once and every other machine has it within minutes. This eliminates the "did everyone update their settings?" problem that kills multi-machine shops.

Migrating between machines

Settings don't transfer 1:1 between machine classes. A 50W CO2 RF tube and a 100W glass tube need different speeds for the same engrave depth. Treat the Library as per-machine, per-lens:

Within the same machine class (e.g., upgrading from 50W to 60W same model line), settings will be in the ballpark but verify with a test grid before production. Power tends to scale roughly linearly; speed can stay the same.
Across machine classes (e.g., new fiber MOPA replaces old galvo, or 100W CO2 replaces 50W), start over from a fresh test grid. Don't trust the old library.
Per-lens on a galvo, different lenses have different spot sizes and field sizes. Keep separate Library entries (or even separate .clb files) per lens.

Hygiene rules (the difference between a great library and a useless one)

Every entry was validated by you on a test piece. Don't add settings you haven't run successfully. Untested entries pollute the library.
Date the entry in the description field: "Validated 2024-09-15." Materials and machines drift. Old entries get re-validated.
Delete entries that aren't used. A 200-entry library nobody can navigate is worse than a 30-entry library where every entry is golden.
One entry per material + goal combination. "Maple plywood / light engrave" and "Maple plywood / dark engrave" are two entries, not "Maple plywood / engrave (varies)".
Add notes to the entry: Lightburn's library entries support description fields. Use them for "mask with Oramask 813 first" or "wipe with IPA after engrave" or per-material masking guidance.

Library settings vs Material Test built-in

Lightburn also has a Material Test tool (Laser Tools menu) that runs a parameter grid on a material. Don't confuse this with the Material Library, Material Test is a one-shot test grid generator; the Library is permanent saved settings. Use Material Test to find good settings; save the winners to the Library.

Where to get pre-made `.clb` material libraries

Honest answer: there's no centralized, community-maintained .clb repository. The LightBurn forum has discussed it repeatedly; there's never been a definitive shared archive. Here's what does exist, ranked by usefulness:

Build your own with LightBurn's built-in Material Test (the recommended path; the Material Test guide gives ranges per material). Run a power × speed grid on the material, pick the cell that hits your goal, save to your Library with the naming convention above. This is what experienced LightBurn forum members tell new users to do when they ask the same question. Reason: every machine, lens, batch of material, and exhaust setup is different, even a "perfect" downloaded library will need a verification grid run anyway.
Manufacturer-supplied starter libraries. Some laser manufacturers ship a starter .clb with their machine (xTool, Glowforge alternatives, OneLaser, Aeon). Check your manufacturer's downloads page or original USB stick. These are decent baselines for the manufacturer's specific machine + their recommended materials. Always verify with a test patch before production, the manufacturer's "starter" was tuned in their lab, not your shop.
Paid libraries on Etsy. Search "LightBurn material library [your machine model]" and you'll find machine-specific paid downloads ($5-25). Quality varies wildly. Worth it only if (a) the seller's machine spec exactly matches yours (same wattage, same controller, same lens), and (b) you treat the file as a starting point for your own validation, not a finished library. Examples that exist: OMTech 60W CO2 libraries, Commarker B6 20W MOPA libraries, xTool D1 Pro libraries.
LightBurn Forum threads. forum.lightburnsoftware.com users occasionally post .clb attachments in technique threads (rotary tumbler settings, slate photo settings, etc.). Search the forum for your specific use case. Free but ad-hoc; no quality guarantee.
Manufacturer-curated downloadables. Some specialty material vendors (laser-grade plywood suppliers, slate suppliers, Cerakote distributors) publish suggested .clb files for their material lines. These tend to be more reliable than generic third-party libraries because the vendor controls the material consistency.

Don't pay for a library that doesn't match your machine

A $20 "OMTech 60W CO2 material library" on Etsy is useless on a Thunder 80W or a 50W K40, the wattage and controller differ, so the speeds and powers don't translate. Verify the seller specifies your exact machine class (controller + wattage + lens) before buying. If they're vague, skip it; build your own with Material Test instead.

The shortcut that pays for itself

If you're new and want SOMETHING to start from while you build your own validated library: download a free or cheap library from a shop running your same machine class, treat every entry as a starting point for a verification grid, and replace each entry with your own validated settings as you confirm them. Within 6-8 weeks of regular use you'll have a fully-validated library, and the original downloaded entries you replaced were just scaffolding.

Common mistakes

Treating the Library like a wish list. Saving "what I think might work" instead of "what I tested and verified" creates a useless library.
No machine identifier in entry names. A multi-machine shop ends up with "Wood Engrave" entries that mean different things on different machines. Always include controller / power / lens.
Not exporting / not backing up. The .clb lives in Lightburn's user folder. If you reinstall the OS or move computers without exporting, the library is gone. Export to cloud storage from day one.
Sharing settings without warning. Sending another shop your .clb is generous, but they need to know it was validated on YOUR machine and lens. Add a "validated on [your machine spec]" note in the file's description / readme.
Using a single library across radically different jobs. A production tumbler shop and a one-off custom-piece shop have different libraries. Don't merge.