Machining
Laser Cutting
Cutting and engraving acrylic cockpit panels on the Omtech 60W CO₂ laser — materials, settings, paint workflows, and backlit legends.
Omtech 60W CO₂ Laser — Machine Overview
The Omtech 60W is a mid-range CO₂ laser cutter with a 600 × 400 mm work area — large enough to cut a full MCP face plate or an entire overhead panel section in a single job. CO₂ lasers cut and engrave non-metal materials cleanly, making them ideal for the acrylic and MDF panels used in home cockpit builds.
| Specification | Value |
|---|---|
| Laser type | CO₂ glass tube, 10.6 µm wavelength |
| Rated power | 60 W (tube peak ~65–70 W) |
| Work area | 600 × 400 mm |
| Z travel | ~80 mm (manual or motorised depending on variant) |
| Positioning accuracy | ±0.1 mm |
| Controller | Ruida RDC6445G (compatible with LightBurn) |
| Software | LightBurn (recommended) or RDWorks |
| Cooling | External water chiller (CW-3000 or CW-5000) — required |
| Exhaust | Inline fan + active carbon filter, or duct to outside — required |
Never run the laser without the water chiller active. The CO₂ glass tube is cooled by water flow. Running it dry for even a few seconds will permanently damage the tube (€150–300 to replace). Always confirm chiller flow before firing.
Safety & Ventilation
A 60 W CO₂ laser produces hazardous fumes and smoke from every material it processes. Acrylic produces irritating vapours; MDF releases formaldehyde and fine wood dust; painted surfaces add paint fumes to the mix. Adequate extraction is non-negotiable for indoor use.
| Hazard | Source | Mitigation |
|---|---|---|
| Acrylic fumes (MMA) | Cutting / engraving acrylic | Inline exhaust fan + carbon filter, or duct outside; do not cut PVC (produces chlorine gas) |
| MDF / wood smoke | Cutting MDF, plywood | Strong airflow across the bed; clean air assist nozzle to keep optics clear |
| Paint fumes | Engraving painted panels | Same extraction as acrylic; wait for extraction to clear before opening lid |
| Fire risk | Any material, especially MDF | Never leave unattended; keep a CO₂ fire extinguisher within reach; use air assist |
| Reflected / scattered IR beam | Reflective materials, open lid | Always wear OD4+ CO₂ laser safety glasses (190–550 nm + 10 600 nm); never run with lid open |
Paint the inside of the laser enclosure with matte black paint or cover reflective metal surfaces with matte aluminium tape. Reflections from shiny enclosure walls can scatter the beam and damage the lens or tube.
Setting Focus
The CO₂ laser beam converges to its smallest point (the focal point) at a fixed distance below the lens. For clean cuts and crisp engraving the focal point must sit exactly on the material surface. Even 1–2 mm of defocus noticeably widens the kerf and reduces cut depth per pass.
| Focus method | How |
|---|---|
| Focus gauge (included tool) | Lower the Z axis until the acrylic spacer tool just touches the material surface — the standard method |
| Ramp test | Engrave a line across a wedge-shaped piece of scrap; the narrowest line marks the true focal height |
| LightBurn autofocus | If the Omtech variant has a Z probe, LightBurn can probe the material surface automatically |
When engraving a painted panel, focus on the top surface of the paint, not the raw acrylic underneath. The paint layer adds ~0.1–0.2 mm. For most jobs this is negligible, but for very fine engraving it is worth accounting for.
Materials & Cut Settings (Omtech 60W)
Settings below are starting points tested on the Omtech 60W at 600 × 400 mm work area. Always run a small test cut on scrap before committing a finished panel. Tube power degrades over time — older tubes may need 5–10% more power than a new tube for the same result.
Cutting
| Material | Thickness | Power | Speed | Passes | Notes |
|---|---|---|---|---|---|
| Cast acrylic | 3 mm | 55–65% | 12–15 mm/s | 1 | Leave protective film on during cutting; peel after. Flame-polished edge on cast acrylic |
| Cast acrylic | 5 mm | 65–70% | 8–10 mm/s | 1–2 | Air assist essential to prevent melted re-deposit on edge |
| Extruded acrylic | 3 mm | 50–60% | 15–18 mm/s | 1 | Extruded cuts slightly faster but edge is frosted rather than clear; fine for painted panels |
| MDF | 3 mm | 55–65% | 15–20 mm/s | 1 | Strong air assist; heavy smoke — ensure good extraction |
| MDF | 6 mm | 70–75% | 8–10 mm/s | 2 | Flip between passes to reduce char on underside |
| Birch plywood | 4 mm | 60–70% | 12–15 mm/s | 1 | Avoid cheap plywood with voids — the laser drops through glue gaps and scorches |
| Cardboard / mat board | 2–3 mm | 30–40% | 30–40 mm/s | 1 | Useful for templates and fit-check mockups before cutting acrylic |
Engraving
| Material | Power | Speed | DPI / interval | Notes |
|---|---|---|---|---|
| Acrylic (surface frost) | 15–25% | 300–400 mm/s | 254 DPI / 0.1 mm | Frosts clear acrylic to diffuse white — good for edge-lit legends |
| Paint removal (panel legends) | 20–35% | 250–350 mm/s | 254–508 DPI | Removes paint layer to reveal acrylic below — the core cockpit panel technique. Start at 20% and increase until paint clears cleanly without melting acrylic |
| MDF surface engrave | 30–50% | 200–300 mm/s | 254 DPI | Darker wood = deeper engrave; lighter = less power. Mask with transfer tape to reduce char halo |
| Anodised aluminium | 55–70% | 150–200 mm/s | 508 DPI | Removes anodising to reveal bright aluminium — sharp contrast for labels and scales |
Acrylic Panel Workflow — Cut, Prime, Paint & Engrave
The standard technique for backlit cockpit panels uses black or dark-tinted acrylic as the base, sprayed with primer and panel-colour paint, then engraved through the paint to expose the acrylic beneath. An LED strip behind the panel lights the engraved legends from behind, exactly as real aircraft panels work.
Step-by-step workflow
| Step | Detail |
|---|---|
| 1. Cut acrylic to panel size | Use 3 mm black cast acrylic. Leave the protective film on during cutting — it protects the surface from smoke residue and scratches. Cut switch holes, mounting holes, and panel outline in the same job |
| 2. Deburr and clean | Remove the protective film. Scrub the panel face with isopropyl alcohol (IPA) on a lint-free cloth to remove any residue. The panel must be completely clean and grease-free before priming — fingerprints cause paint fisheye |
| 3. Apply adhesion primer | Spray a thin, even coat of plastic adhesion primer (e.g. Rust-Oleum Adhesion Primer or Motip Plastic Primer) from ~30 cm distance. One thin coat is enough — the goal is adhesion, not filling. Let dry fully (30–60 min) before painting. Thick primer fills engraved grooves and blurs fine text |
| 4. Spray paint panel colour | Apply 2–3 thin coats of your panel colour, allowing 15–20 min between coats. Thin coats prevent runs and preserve detail. Let final coat cure for at least 4 hours (ideally overnight) before engraving — soft paint tears rather than ablates cleanly under the laser |
| 5. Engrave legends in LightBurn | Set up text and symbols as a separate engraving layer. Run a power test on a painted scrap piece first. The laser should remove the paint and primer cleanly without melting or frosting the acrylic surface beneath. If the acrylic surface looks milky, reduce power or increase speed |
| 6. Clean after engraving | Wipe the panel with a damp cloth immediately after engraving while residue is still loose. Do not use IPA on fresh paint — it can lift the paint edges around the engraving. Use plain water or a very mild soap solution |
| 7. Optional — fill engraving | For a solid white legend (non-backlit panels), apply white acrylic paint into the engraved grooves with a brush, then wipe back across the surface before it dries. The paint stays in the recess and the panel face cleans up |
| 8. Clear coat | Seal with 1–2 coats of matte lacquer. This locks the paint edges around the engraving and gives a uniform surface sheen. Matte finish is correct for most cockpit panels; use satin for knobs and bezels |
Engraving Annunciator Face Plates
Annunciator tiles are small, individually lit acrylic pieces that sit in an overhead or warning panel. Each tile carries one or two lines of legend text — FIRE, FUEL, MASTER CAUTION — which glows white or amber when the LED behind it is energised and appears as a dim, barely visible label when unlit. Getting readable text at this small scale is the trickiest part of laser engraving for cockpit work.
Choosing the acrylic: opaque vs translucent black
This is the most important material decision for an annunciator tile. Both types are black on the front face — the difference is how they behave with a light source behind them.
| Type | Behaviour unlit | Behaviour lit | When to use |
|---|---|---|---|
| Translucent black (recommended) also called "smoke" or "tinted" acrylic | Deep black face — legend text barely visible as a slightly different sheen in the painted surface | LED light passes through the engraved areas and also softly through the black tint, producing a warm, glowing legend with a slight halo around the text — exactly like real aircraft annunciators | All backlit annunciator tiles. The tint filters and softens the LED rather than blocking it entirely, giving a more natural glow than full cut-outs would |
| Opaque black acrylic | Deep black face — no light passes at all | Light only escapes through the engraved area where the paint was removed. Produces a hard-edged, bright white or amber text on a completely dark background — high contrast but slightly harsh | Acceptable when you want maximum contrast text, or when tiles are mounted close together and you need zero light bleed between them |
Translucent black acrylic is available in different light transmission levels — typically T10, T20, or T40 (percentage of light passed). For annunciator tiles T10–T20 is ideal: dark enough to look black in ambient room light, light enough to glow warmly when the LED fires. T40 starts looking grey under room light and is better suited to gauge backlights.
Tile construction
| Element | Specification | Notes |
|---|---|---|
| Acrylic base | 3 mm translucent black cast acrylic (T10–T20) | Translucent tint produces a natural glow through the full face; cast grade engraves cleaner than extruded |
| Tile size | 20 × 14 mm to 30 × 20 mm typical | Match to your switch or pushbutton cap dimensions; leave 0.5 mm clearance per side for the housing |
| Primer | Plastic adhesion primer, single very thin coat | On tiles this small, one light coat is all that is needed — thick primer blurs fine text completely at 7–9 pt font sizes |
| Paint | RAL 7047 or flat grey, 2 thin coats | Let cure overnight before engraving; soft paint tears at small feature sizes |
| LED colour | White (neutral/cool) or amber | White LED through translucent black reads as bright white legend with soft glow. Amber LED reads as orange-amber — matches Boeing warning colours. Avoid blue or green, which look unnatural on grey panels |
Typography rules for small annunciators
Text that looks fine at 12 pt on screen can completely disappear when engraved at 20 mm wide on 3 mm acrylic. The laser removes paint by ablating it; strokes thinner than about 0.35 mm either fail to clear fully or fuse back together as the surrounding paint shifts. Follow these constraints:
| Rule | Detail |
|---|---|
| Minimum font size | 7–8 pt at 508 DPI engraving resolution. Below 7 pt, stroke widths on most fonts fall under 0.3 mm and become unreadable after engraving |
| Font weight | Use Bold or Medium weight only. Light or Thin weight fonts have strokes under 0.4 mm at small sizes and will not survive the engraving process. Good choices: Helvetica Bold, Arial Bold, Eurostile Bold, B612 Mono Bold (open source) |
| ALL CAPS only | Real aircraft annunciators use all-caps text exclusively. Lowercase descenders (g, p, y) reduce legible height and waste vertical space on a small tile |
| Letter spacing | Add +5 to +10% tracking (letter spacing) in your design software. Tight letter spacing causes adjacent engraved areas to merge, especially in narrow letters like I, L, T |
| Two-line layout | Main label on top line (bold, larger), sub-label or system name on bottom line (slightly smaller, dimmer — reduce DPI or power slightly on the bottom line layer for a two-tone effect) |
| Minimum stroke width | 0.4 mm minimum for reliable engraving. Check in your vector editor at 1:1 scale — if a stroke looks hairline-thin on screen it will not engrave cleanly |
| No serifs | Serif fonts (Times, Garamond) have very thin stroke transitions that disappear at small sizes. Use a clean sans-serif or monospace font |
Engraving settings for annunciator text
| Setting | Value | Why |
|---|---|---|
| DPI / line interval | 508 DPI (0.05 mm interval) | Higher DPI means more laser passes per mm — fills small text completely without gaps between scan lines |
| Power | 20–30% (test first) | Enough to remove paint and primer cleanly. Too high frosts the black acrylic surface, which scatters the LED light and makes the legend look hazy rather than sharp |
| Speed | 200–250 mm/s | Slower than large-panel engraving — gives the beam more dwell time to cleanly ablate the thin paint layer on small features |
| Scan angle | 0° (horizontal) | Horizontal scanning matches the natural reading direction of text. Avoid 45° for text — diagonal scan lines create a visible texture across engraved letter fills |
| Overscanning | 3–5% | Prevents power buildup at the start and end of each scan line, which burns the edge of the first and last letter |
| Bi-directional scan | Enabled (after calibrating scanning offset) | Halves engraving time on small tiles; only use after running scanning offset calibration in LightBurn |
Achieving the dim / unlit look
A real annunciator tile is barely readable when the LED is off — just enough to know what the tile says — and fully bright when lit. With translucent black acrylic, the tinted material itself provides this effect automatically: ambient light shows the legend as a very subtle sheen difference in the painted surface, and the LED brings it fully alive.
| Method | How | Result |
|---|---|---|
| Translucent black + engraved only (recommended) | Laser removes paint to expose the translucent acrylic beneath. No fill. The T10–T20 tint is dark in ambient light but glows warmly when the LED fires through it | Dim: legend barely visible as a slight texture change in the paint. Lit: warm, even glow across the full engraved area — closest to real aircraft appearance |
| White-fill engraving | After engraving, fill the recesses with white acrylic paint or a white paint pen, wipe back while wet. Paint stays in the grooves | Dim: crisp white text visible in all room lighting — always readable. Lit: bright white. Best for non-backlit panels or labels that must be readable without power |
| Opaque black + engraved only | Full opaque acrylic — light only passes through the paint-removed engraving | Dim: invisible recess in dark grey paint. Lit: hard bright text with no surrounding glow. Highest contrast but least authentic appearance |
Backlight diffusion — the annunciator box
A bare LED directly behind a small tile creates an uneven hotspot: bright in the centre, dark at the edges. Real annunciators use a small box behind each tile to spread the light evenly before it reaches the face plate. Replicating this in a home cockpit build makes a dramatic difference to the final look.
| Element | Specification | Why |
|---|---|---|
| White interior box walls | 3D print or laser-cut the annunciator housing in white material (PLA+ white, or white acrylic), or paint the inside of a black housing with flat white spray paint | White walls reflect and bounce light around the interior before it reaches the face plate, filling the full tile area evenly. A black interior absorbs the light and creates the hotspot problem |
| Black exterior | Outside faces of the housing remain black (material colour or black paint) | Prevents light leaking through the housing walls and bleeding into adjacent tiles or onto the panel surface around the annunciator |
| Diffuser plate | 3 mm white opal acrylic or milky acrylic, cut to the inner box dimensions, fitted 5–10 mm behind the face plate | Scatters the LED point source into a broad, even wash of light. Eliminates any remaining hotspot and gives the face plate a completely uniform glow. White opal (e.g. Plexiglas WH02) is the standard diffuser material |
| Air gap between diffuser and face plate | ≥ 5 mm | A small air gap after the diffuser lets the diffused light spread slightly further before hitting the face plate, softening any remaining bright spots at the diffuser surface |
| LED position | Centred on the back wall, pointing straight forward | For small tiles (under 20 × 20 mm) one 3 mm LED or one 5050 SMD LED per tile is sufficient with a diffuser. Larger tiles (MASTER CAUTION etc.) may benefit from two LEDs side by side |
The simplest diffuser plate source is white opaque acrylic offcuts from the same laser cutting session. Cut 3 mm white acrylic to the inner box dimension in the same LightBurn job as the tiles — no extra material order needed. Alternatively, a sheet of printer paper or tracing paper taped inside the box works surprisingly well for test builds.
Always cut the tile outline after engraving, in the same LightBurn job. Cutting first frees the small tile from the sheet — it can shift by 0.5 mm or more, misregistering the engraved text inside the tile boundary. Use a honeycomb bed and place a piece of masking tape across the cut line to hold tiny tiles in place until the job completes.
Panel Colours & Paint Selection
Aviation panels use specific grey tones that vary by aircraft type and manufacturer. Matching the correct colour is one of the details that makes a cockpit look authentic rather than like a grey box.
| Aircraft / panel | Colour reference | Spray paint option | Notes |
|---|---|---|---|
| Boeing 737 MCP / overhead | RAL 7047 Telegrey 4 | Montana Cans RAL 7047, Motip RAL 7047 | Slightly warm light grey — matches real 737 panel colour closely |
| Boeing 737 glareshield | Flat black / Boeing dark grey | Any flat/matte black rattle can | The glareshield is typically flat black to minimise reflections |
| Cessna 172 instrument panel | Flat dark grey (approx. RAL 7021) | Motip RAL 7021, Rust-Oleum dark grey | Slightly darker than Boeing grey; matte finish |
| General aviation (generic) | RAL 7035 Light grey | Widely available in spray cans | Good neutral grey when exact colour match is not critical |
| Annunciator legends (text) | White or amber fill | Tamiya acrylic white / Molotow paint pen | Applied into engraved recesses; wiped back before dry |
Use matte or satin finish paint — gloss paint reflects the backlight and room lighting onto the panel surface, reducing contrast of engraved legends and looking wrong compared to a real cockpit.
LightBurn Setup for Cockpit Panels
LightBurn is the recommended software for the Omtech 60W (Ruida controller). It combines vector cutting and bitmap engraving in one file, making it straightforward to run cut and engrave operations in the correct sequence in a single job.
Layer structure for a typical panel job
| Layer | Colour | Operation | Content |
|---|---|---|---|
| 00 | Black (T0) | Tool / guide only (output off) | Panel outline, reference marks — never fires the laser |
| 01 | Blue | Engrave (Fill) | All legend text, symbols, and annunciator labels |
| 02 | Red | Cut (Line) | Switch holes, indicator cutouts — inner cutouts first |
| 03 | Green | Cut (Line) | Panel outer profile — always last to avoid shifting the workpiece mid-job |
Always run engrave before cut in the layer order. If you cut the panel outline first, the workpiece can shift slightly when freed from the sheet — any subsequent engraving will be misregistered.
Useful LightBurn settings for panels
| Setting | Recommended value | Why |
|---|---|---|
| Start from | Absolute coords | Panel origin is fixed to the machine bed — consistent positioning across multiple jobs |
| Scanning offset (engraving) | Calibrate per speed | Compensates for head inertia at high speeds; prevents shifted left/right passes |
| Overscanning | 2–5% | Allows the head to decelerate outside the job boundary, preventing burned ends on engraving lines |
| Cut inner shapes first | Enabled | Cuts holes before the outer profile so the panel stays registered throughout |
| Kerf offset | 0.1–0.15 mm | Compensates for beam width; apply to cut lines only so hole dimensions match CAD |
| Air assist | On for all cut layers | Blows smoke clear of the lens and helps prevent flare-ups on MDF |
Tips & Troubleshooting
| Problem | Likely cause | Fix |
|---|---|---|
| Acrylic not cutting through cleanly | Defocused, wrong speed, dirty lens, or old tube | Re-focus, slow down by 2 mm/s, clean lens with IPA and lens tissue, check tube power with power meter |
| Melted or bubbly acrylic edge | Speed too slow, air assist off, or extruded acrylic | Increase speed slightly, enable air assist, switch to cast acrylic for clean flame-polished edges |
| Paint not fully removed in engraving | Power too low or paint coat too thick | Increase power by 5% increments on test scrap; ensure paint coats are thin |
| Acrylic surface milky / frosted under engraving | Power too high — laser is melting the acrylic surface | Reduce power or increase speed; the goal is to remove paint only |
| Engraving text is jagged or rough | Scanning offset not calibrated, or speed too high | Run LightBurn scanning offset calibration; reduce engraving speed to 200 mm/s and re-test |
| Black soot halo around engraving on MDF | No masking, air assist insufficient | Cover surface with transfer tape or painter's tape before engraving; peel tape after to reveal clean surface |
| Cut position shifted from engraving | Panel moved between operations, or absolute coords not set | Use absolute coordinates in LightBurn; pin or clamp material to the bed honeycomb |
| Lens fogging after a job | Air assist not running, or exhaust insufficient | Run air assist on all layers; check air pump pressure; clean lens after every session with IPA and lens tissue |