Machining
3D Printing
FDM and resin printing for home cockpit parts — materials, profiles, and finishing for the Qidi Plus 4 and Elegoo Mars 4 DLP.
FDM vs Resin for Cockpit Parts
Home cockpit builds use both technologies for different roles. FDM (filament) printers handle large structural parts; resin printers produce the fine detail needed for switch guards, legends, and instrument bezels. Knowing which technology suits a part saves material, time, and frustration.
| Property | FDM — Qidi Plus 4 | Resin — Elegoo Mars 4 DLP |
|---|---|---|
| Build volume | 305 × 305 × 280 mm | 153 × 77 × 165 mm |
| Layer resolution | 0.1–0.3 mm typical | 0.05 mm typical (35 µm XY) |
| Surface finish | Visible layer lines; needs sanding | Near-smooth; minimal post-processing |
| Strength | Good–high (PLA+, PETG, ABS, ASA) | Moderate; brittle under impact unless ABS-like resin |
| Best cockpit use | Structural brackets, enclosures, panel frames, large bezels | Switch knobs, legends, lettering panels, instrument details |
| Post-processing | Remove supports, sand if needed | Wash (IPA / wash station), UV cure, remove supports |
| Running cost | Low (filament ~€20–30/kg) | Moderate (resin ~€30–50/kg; PPE, wash solution) |
Qidi Plus 4 — FDM Settings for Cockpit Parts
The Qidi Plus 4 is a high-temperature enclosed FDM printer with an active heated chamber (up to 65 °C). This makes it suitable for engineering-grade materials — ABS, ASA, and PA (nylon) — that warp badly on open-frame printers. For cockpit panels that live in a warm room or near a projector, ASA is the preferred material.
Printing indoors? PLA and PLA+ are the safest filaments to use without dedicated ventilation. They are made from cornstarch-derived polylactic acid and emit minimal harmful particles at printing temperatures. ABS, ASA, and Nylon all release styrene or other VOCs and should only be printed with an enclosure and active carbon filtration or proper room ventilation. For a home cockpit room without a fume extraction setup, PLA+ covers the majority of parts with no health concerns.
Material selection
| Material | Nozzle temp | Bed temp | Chamber | Best for |
|---|---|---|---|---|
| PETG | 235–245 °C | 70–80 °C | Not needed | Everyday structural parts, ESP32 enclosures, cable guides — easy to print, good layer adhesion |
| ABS | 240–255 °C | 100–110 °C | 45–55 °C | Panel frames, glareshield — good heat resistance, paintable, sandable |
| ASA | 245–260 °C | 100–110 °C | 45–55 °C | Outdoor-exposed or projector-adjacent parts — UV resistant, better than ABS for long-term colour stability |
| PA (Nylon) 6/12 | 255–270 °C | 70–90 °C | 55–65 °C | Gear levers, throttle linkages, load-bearing hinges — excellent toughness and wear resistance |
| PLA+ indoor safe | 215–235 °C | 55–65 °C | Not needed | Recommended starting material for indoor builds. Safer fumes than ABS/ASA, easy to print, no enclosure required. PLA+ (toughened grade) is noticeably less brittle than standard PLA and handles snap-fits and light structural loads well. Heat resistance peaks at ~55–60 °C — avoid panels directly under a projector lamp or in a very warm room; use PETG or ASA there |
Recommended slicer profiles (Qidi Slicer / OrcaSlicer)
| Setting | Structural parts (PLA+ / PETG / ABS) | Fine detail parts (PLA+ / PETG) |
|---|---|---|
| Layer height | 0.2 mm | 0.1 mm |
| Perimeters / walls | 4 | 4–6 |
| Infill | 30–40 % gyroid | 40–60 % gyroid |
| Top / bottom layers | 5 / 5 | 6 / 6 |
| Support style | Tree (auto) at 45 ° | Tree (auto) at 40 ° |
| Print speed | 150–200 mm/s | 80–120 mm/s |
| Seam position | Rear or aligned | Aligned (hidden behind features) |
For panel faces and bezels that will be sanded and painted, orient the part so the visible face is on the print bed (first layer). The PEI bed surface leaves a near-smooth finish on the bottom layer, saving significant sanding time.
Cockpit-specific tips
| Tip | Why |
|---|---|
| Add 0.2 mm tolerance to any hole that receives a bolt, insert, or shaft | FDM holes shrink slightly due to perimeter overlap — undersized holes require drilling out |
| Design switch cutouts 0.3–0.4 mm larger per side than the datasheet | Panel cutouts for toggle switches and pushbuttons need clearance for the switch body to pass through |
| Use heat-set inserts (M2–M4) instead of printing threads | Printed threads strip quickly; a brass heat-set insert pressed in with a soldering iron provides metal threads that last indefinitely |
| Print mounting tabs with the grain (perimeters) running along the tab length | Tabs loaded across the layer lines delaminate easily — orient so the stress runs along the perimeters |
| Pause print at layer 2–3 to embed a nut or magnet | Allows captured hardware without drilling or gluing after the print |
Brass Heat-Set Inserts
Printed threads strip after a handful of cycles and are too weak for anything held together under tension. Brass heat-set inserts solve this permanently: a heated soldering iron melts the surrounding plastic, the insert sinks flush into the hole, and on cooling you have a metal thread embedded in the part. This is the standard method for all repeatable panel fixings on a cockpit build.
Insert sizing
| Thread size | Insert OD (typical) | Hole diameter in CAD | Typical cockpit use |
|---|---|---|---|
| M2 | 3.2 mm | 3.0 mm | PCB standoffs, small display mounts, sub-panel fixings |
| M2.5 | 3.8 mm | 3.5 mm | Raspberry Pi / ESP32 enclosure lids, thin panel overlays |
| M3 | 4.6 mm | 4.2–4.3 mm | Most common. Panel-to-frame fixings, MCP face plate, overhead panel sections |
| M4 | 5.6 mm | 5.2 mm | High-load fixings: gear lever pivot housings, throttle quadrant mounts |
The hole diameter in your CAD model should be 0.2–0.3 mm smaller than the insert outer diameter. Too loose and the insert spins in the hole; too tight and the plastic cracks instead of flowing around the knurls.
Installation steps
| Step | Detail |
|---|---|
| 1. Set soldering iron temperature | PLA / PLA+: 180–200 °C · PETG: 220–240 °C · ABS / ASA: 240–260 °C. Use a dedicated insert tip or a blunt flat tip — not the fine point used for soldering |
| 2. Place insert on hole | Rest the insert flat over the hole opening by hand — no need to press |
| 3. Apply gentle downward pressure | Press the iron tip onto the top of the insert and apply slow, steady downward pressure. The insert should sink smoothly in 3–6 seconds. Do not force it — if it resists, the iron is too cool |
| 4. Stop flush with the surface | Remove the iron when the insert top is level with or 0.1 mm below the surface. Pushing too deep weakens the thread engagement on the far side |
| 5. Press flat while cooling | Immediately press a flat metal plate (or the flat of a calliper jaw) over the insert for 5–10 seconds while it cools. This prevents the insert from tilting as the plastic re-solidifies |
| 6. Test thread | Run the correct bolt in by hand before assembling the part. A well-installed insert will thread smoothly with no wobble |
Material compatibility
| Filament | Insert compatibility | Notes |
|---|---|---|
| PLA+ | Excellent | Low iron temp, slow sink — most forgiving material for first installs |
| PETG | Excellent | Slightly stringy melt; wipe iron tip between inserts |
| ABS / ASA | Good | Higher temp needed; fumes during install — ventilate |
| PA (Nylon) | Good | Nylon absorbs moisture which can cause bubbling around the insert; dry filament before printing |
| Resin (cured) | Not suitable | Heat-set inserts crack cured resin — use CA glue-in inserts or press-fit threaded brass nuts for resin parts instead |
Design tips for insert bosses
| Tip | Why |
|---|---|
| Make the boss wall at least 2× the insert OD | Thin walls crack when the insert displaces plastic outward during installation |
| Add a 0.5 mm chamfer to the hole entry | Guides the insert straight and prevents tearing the top surface as it enters |
| Make boss height equal to insert length + 0.5 mm | Leaves material below the insert for the bolt tip to bottom out against without punching through |
| Orient bosses vertically in the slicer | Perimeters wrap around the boss continuously — a horizontal boss relies on layer-to-layer adhesion which is weaker |
| Use 4+ perimeters on any boss wall | Dense perimeters around the insert give the knurls more material to grip |
Elegoo Mars 4 DLP — Resin Settings for Cockpit Parts
The Mars 4 DLP uses a projector light source rather than an LCD mask, giving it sharper XY resolution (35 µm) and faster layer cure times than MSLA printers. It is the right choice for anything with fine engraved lettering, crisp switch legends, or thin walls that would be too fragile in filament.
Resin selection
| Resin type | Characteristics | Best for |
|---|---|---|
| Standard (e.g. Elegoo Standard) | Easy to print, low odour versions available, brittle | Display masters, legends, non-structural details |
| ABS-like (e.g. Elegoo ABS-Like) | Higher impact resistance, less brittle, slightly flexible | Knobs, switch guards, instrument bezels, anything handled regularly |
| Water-washable | Washes with water instead of IPA — easier cleanup | Rapid prototyping; detail quality slightly below standard resin |
| 8K / high detail | Formulated for maximum sharpness at fine layer heights | Engraved panel lettering, instrument face replicas, master moulds |
Exposure settings (Mars 4 DLP, 35 µm XY)
| Setting | Standard resin | ABS-like resin |
|---|---|---|
| Layer height | 0.05 mm | 0.05 mm |
| Normal exposure time | 1.5–2.5 s | 2.0–3.0 s |
| Bottom layers | 4–6 | 4–6 |
| Bottom exposure time | 25–35 s | 30–40 s |
| Lift speed | 40–60 mm/min | 40 mm/min |
| Rest time after lift | 0.5 s | 0.5 s |
Always run a Resin Exposure Calibration (e.g. the CHITUBOX or Lychee built-in test, or a community calibration print like the Ameralabs Town) when switching resin brands or opening a new bottle. Exposure times vary significantly between batches.
Orientation and supports for cockpit parts
| Part type | Recommended orientation | Support strategy |
|---|---|---|
| Flat legend panel | 45 ° angle off the build plate | Light auto supports; detailed face away from supports |
| Round knob / cap | Upright, flat base down | No supports needed if base is flat |
| Switch guard (hinged) | Hinge axis vertical | Medium supports under overhangs; touch point on non-visible surfaces only |
| Engraved face plate | Engraved face up, 10–15 ° tilt | Rafted with light supports at corners; prevents suction cup delamination |
Elegoo Mercury Plus — Wash & Cure Workflow
Resin prints must be washed to remove uncured resin from surfaces and cavities, then UV cured to reach full mechanical strength. The Elegoo Mercury Plus combines both steps in one unit. Skipping or rushing either step results in tacky surfaces, warped parts, or prints that are brittle and chip easily.
Step-by-step workflow
| Step | Duration | Notes |
|---|---|---|
| 1. Remove from build plate | — | Wear nitrile gloves and eye protection. Uncured resin is a skin and eye irritant |
| 2. Drain excess resin | 1–2 min | Hold over the vat and let resin drip back in before moving to the wash station |
| 3. Wash in Mercury (IPA / wash solution) | 3–5 min | Use the basket agitation cycle. Do not over-wash — longer than 8 min in IPA can cause standard resin to go cloudy or swell |
| 4. Air dry | 5–10 min | Allow solvent to fully evaporate before UV curing. Curing with trapped IPA causes fogging |
| 5. Remove supports | — | Remove supports before UV curing while the print is still slightly flexible — much easier than after full cure |
| 6. UV cure in Mercury | 2–4 min | Rotate platform for even exposure. ABS-like resins need longer cure time (3–5 min) than standard resin |
| 7. Final check | — | Surface should be dry and non-tacky. If still sticky, cure for another 1–2 min. Persistent stickiness indicates under-exposure during printing |
Never pour IPA or resin waste down the drain. Expose spent wash solution in a clear container to direct sunlight until all resin particles cure and settle, then dispose of the solid waste and pour the clarified IPA through a filter for reuse. Check local regulations for final disposal.
Wash solution maintenance
| Indicator | Action |
|---|---|
| Solution turns cloudy or dark brown | Cure and filter before the next session — heavily contaminated IPA leaves resin residue on parts |
| Resin flakes visible in solution | Filter through a paper coffee filter before reusing |
| Parts feel tacky after washing | Solution is saturated — replace with fresh IPA |
Post-Processing & Finishing
Raw prints from both FDM and resin printers rarely look finished. The steps below turn a print into a convincing cockpit component.
FDM finishing sequence
| Step | Material / tool | Notes |
|---|---|---|
| Remove supports | Flush cutters, needle files | Cut flush; file any nubs on visible surfaces |
| Fill layer lines | Filler primer (rattle can) or XTC-3D epoxy coat | Apply 2 light coats, let cure fully before sanding |
| Sand | 120 → 240 → 400 grit wet/dry | Work through grits; 400 grit is fine enough for a paint base |
| Prime | Filler primer (grey or white) | Reveals remaining surface defects; sand again at 400–600 grit |
| Paint | Rattle can or airbrush — RAL or aviation-matched colour | For 737 panels: RAL 7047 (Telegrey 4) or Boeing grey. For Cessna: flat dark grey |
| Legends & markings | Laser printer decal paper or resin-printed inserts | Apply decals before clear coat; seal with matte lacquer |
| Clear coat | Matte or satin lacquer | Matte finish is most accurate for cockpit panels; satin for knobs |
Resin finishing sequence
| Step | Material / tool | Notes |
|---|---|---|
| Remove supports & nubs | Flush cutters, micro files, scalpel | Resin is hard after cure; work carefully to avoid chipping |
| Light sanding (optional) | 400–800 grit | Only necessary on support contact points — resin faces are typically smooth enough to paint directly |
| Prime | Rattle-can primer (adhesion promoter recommended) | Resin can be slippery for paint — an adhesion primer prevents flaking |
| Paint & seal | Acrylic or enamel; matte lacquer top coat | Thin coats to preserve engraved detail |
Which Technology for Which Part?
| Cockpit component | Recommended technology | Material | Notes |
|---|---|---|---|
| MCP / FCU panel frame | FDM — Qidi Plus 4 | ABS or ASA | Large flat part; print face-down on PEI for smooth front surface |
| Glareshield / coaming | FDM — Qidi Plus 4 | ASA (UV stable) | Near projector light; ASA resists yellowing better than ABS |
| Switch guard covers | Resin — Mars 4 DLP | ABS-like resin | Fine hinge detail and snap-fit tabs require resin resolution |
| Rotary knobs (large) | FDM — Qidi Plus 4 | PETG | Concentric knurling prints well at 0.15 mm layers; sand lightly |
| Rotary knobs (small, detailed) | Resin — Mars 4 DLP | ABS-like resin | Sub-10 mm knobs with detailing need resin resolution |
| Instrument bezel | Resin — Mars 4 DLP | Standard or 8K resin | Sharp corners and crisp text impossible to achieve with FDM |
| Engraved legend plate | Resin — Mars 4 DLP | 8K or high-detail resin | Fill engraving with white paint pen, wipe back for recessed text effect |
| ESP32 / PCB enclosure | FDM — Qidi Plus 4 | PETG | Heat-set inserts for lid screws; vent slots for airflow |
| Gear lever housing | FDM — Qidi Plus 4 | PA (Nylon) | Nylon handles the lever pivot load without cracking over time |
| Cable routing clips | FDM — Qidi Plus 4 | PETG | Print in bulk; small and fast to produce |