Completed and independently corrected: The base, loose-slip lid, EN plunger body, IO0 plunger body, and reusable post-assembly top-stop cap are Build123d assets. They are represented by six independently toggleable root-level model nodes: base, lid, two plunger bodies, and two cap instances.
Prototype validation still required: terminal-tool access, OLED visible-area fit, J4 cable/wire clearance, wall-screw fit, wireless performance near PCB retention hardware, and temperature rise in the unvented enclosure.
Design Basis
Process/material: FDM, PETG, 0.4 mm nozzle.
PCB geometry used: custom 89 × 99 mm outline, 1.50 mm thickness.
Shared datum: PCB centre (0,0), PCB top z=0; project/root placement (45 mm, -50 mm, 0 mm).
Ordinary PCB-to-wall clearance: 1.0 mm per side.
Wall thickness: 3.0 mm.
Floor and lid plate thickness: 2.4 mm.
Interior wall plan: 91 × 101 mm.
Main exterior shell plan: 97 × 107 mm.
Maximum base plan including four wall-mount ears: 119 × 107 mm.
Base vertical extent: z=-12.0 to 18.5 mm (30.5 mm).
Lid vertical extent: z=15.5 to 20.9 mm (5.4 mm including tongue).
Plunger-cap top: z=23.4 mm; total assembled extent is approximately 119 × 107 × 35.4 mm.
Soft rectangular corner radius: 9.7 mm on the main exterior.
Shadow line: 0.5 mm deep × 1.0 mm high immediately below the lid seam.
No vents were added; no thermal adequacy or ingress-protection claim is made.
Base
Floor exterior is the intended print-bed face.
PCB bottom is 8.1 mm above the floor top, exceeding the requested 2 mm underside clearance.
Two PCB bosses align with the existing 3.5 mm mounting holes at PCB-local coordinates:
(-38.7108, -43.1043) mm
(39.0551, -43.1043) mm
Boss body: 5.8 mm diameter with a 4.7 mm PCB contact pad.
Pilot bore: 2.3 mm diameter, 5.8 mm engagement, blind bottom retained.
Boss roots use verified 1.0 mm fillets; only the final PCB-facing 1.5 mm is tapered.
Intended PCB fastener: 2 × ST2.9 × 8 mm thread-forming screws. Prefer nonconductive hardware at the ESP32-side hole; if metal is used, verify Wi-Fi performance on the assembled prototype.
Four external wall ears keep wall-screw hardware outside the PCB footprint. Each ear is 12.0 mm wide around the provisional 8.0 mm keyhole head, leaving 2.0 mm nominal material per side. Every ear overlaps the shell wall by 1.0 mm. The eight actual concave post-union ear-to-shell vertical root edges are topology-selected and receive true 1.0 mm fillets; the Build123d source rejects unless exactly eight matching edges are found. The current provisional keyhole envelope accepts an approximately 8.0 mm screw head and 4.5 mm shank.
The four relay-side windows are now independently centred from the nested J7/J8/J10/J9 body transforms rather than relay-module or component placement origins. Each finished window is 15.50 mm wide × 13.10 mm high: the measured 15.00 × 12.60 mm terminal-block interface plus the existing 0.25 mm FDM clearance per side.
Window vertical limits are z=-0.25…12.85 mm, centred at z=6.30 mm. This leaves 2.65 mm below the lid-tongue zone at z=15.5 mm, 5.65 mm below the seam, and 11.75 mm of wall below the opening.
The remaining wall webs between adjacent windows are 3.1645, 2.9396, and 2.5659 mm, all above the 1.2 mm structural-feature minimum.
The DC-input window is on the opposite side wall, centred at PCB-local Y=-17.8063 mm, with a 16.5 mm horizontal opening.
Lid and Interface Alignment
Lid retention is loose slip only; there are no snaps, screws, or clips.
Locating tongue depth: 3.0 mm.
Tongue clearance: 0.40 mm total XY relative to the base opening.
OLED viewing windows: 24 × 14 mm, centred at PCB-local (-18.2, -12.5) and (19.5, -12.5) mm.
Four LED holes: 3.0 mm diameter, centred at PCB-local:
(9.5512, -46.0357) mm
(15.4732, -46.0357) mm
(21.5066, -45.9607) mm
(27.5676, -45.9607) mm
EN/IO0 guide bores: 4.0 mm diameter, centred at PCB-local:
EN (-40.2481, 0.6270) mm
IO0 (-40.2480, -8.1982) mm
J11 top-access opening: 6 × 19 mm, centred at PCB-local (-39.1952, -26.0627) mm.
Relay Terminal Interface Measurements
The relay modules are nested layouts, so J7–J10 placement origins were not treated as housing centres. Each J-body rectangle was transformed through its parent relay-module rotation/translation. The terminal model/footprint corresponds to Phoenix Contact 1935789 / PT 2,5/3-5,0-H: 15.0 mm housing width and 12.6 mm height above the PCB.
Table
Interface
PCB-local centre X/Y (mm)
Root/world centre X/Y (mm)
Housing X extent, world (mm)
Cutout X extent, world (mm)
J7
(-22.6024, 40.0383)
(22.3976, -9.9617)
14.8976…29.8976
14.6476…30.1476
J8
(-3.9379, 40.0383)
(41.0621, -9.9617)
33.5621…48.5621
33.3121…48.8121
J10
(14.5017, 40.0383)
(59.5017, -9.9617)
52.0017…67.0017
51.7517…67.2517
J9
(32.5676, 40.0383)
(77.5676, -9.9617)
70.0676…85.0676
69.8176…85.3176
All four housing/interface Z extents are 0.00…12.60 mm; all four cutout Z extents are -0.25…12.85 mm. The projected mating-face centres and the cutout centres therefore coincide independently in horizontal X and vertical Z, with 0.25 mm perimeter clearance.
Plunger Kinematics and True Downward Stops
The installed PTS636 SM43J SMTR LFS switch is 4.3 mm high, has a 3 mm actuator, and has 0.25 ± 0.1 mm total travel.
Rigid plunger stem: 3.2 mm diameter inside a 4.0 mm lid guide, providing 0.80 mm diametral / 0.40 mm radial clearance to avoid guide binding.
Lower captive shoulder: 6.2 mm diameter with a 45° lower transition for support-free vertical printing. This shoulder is retained for assembly and is no longer claimed as the downward stop.
Unpressed actuator gap: exactly 0.25 mm; the contact tip remains at z=4.55 mm above the z=4.30 mm switch top.
True downward stop: a separately printed, post-assembly 6.2 mm diameter × 2.0 mm top cap is pressed onto a 2.6 mm stepped peg. Its underside is at z=21.40 mm, exactly 0.50 mm above the z=20.90 mm lid top.
Maximum downward motion is therefore exactly 0.50 mm. After the first 0.25 mm closes the unpressed gap, the remaining 0.25 mm equals the nominal switch travel; the cap then contacts the lid top and blocks additional downward motion.
Positive axial seating is provided by the step from the 3.2 mm guide stem to the 2.6 mm cap peg at exactly z=21.40 mm; the cap underside bottoms on this annular shoulder and cannot be installed at an arbitrary height.
Cap retention uses a 2.40 mm blind press-fit bore with a 2.80 mm lead-in on the 2.60 mm peg. Bore depth remains exactly 1.00 mm and the 2.00 mm cap retains exactly 1.00 mm solid top material above the bore. The plunger is captive after installation and remains service-removable by pulling off the replaceable cap. The interference fit is provisional pending the first PETG print coupon.
Connector Evidence and Remaining Mechanical Unknowns
TE 282837-3 is a three-position, 5.08 mm-pitch side-entry terminal block. The drawing row indicates 15.24 mm overall length, but that dimension was not machine-verified and should be treated as provisional.
The terminal housing width/height and the rendered mating-face alignment are now documented, but the exact screwdriver and conductor-bend envelopes remain installation-dependent. Verify all four 15.50 × 13.10 mm windows with the installed terminals, conductor ferrules, and intended screwdriver.
The OLED windows are based on installed model geometry; verify the physical modules' visible active area before final production.
Verify the J4 window with the intended wire gauge, ferrules, and bend radius.
Wall keyholes are parameterized but provisional until the selected wall screw is known.
Print and Assembly Notes
Print the base with the exterior floor on the build plate. The four now-closed relay-window roofs span 15.5 mm and are the only new support/bridge concern; the geometry report identifies four down-facing roof faces. Use localized removable support or a validated 15.5 mm bridge profile while keeping support away from the side and bottom fit surfaces.
Print the lid with its exterior top face on the build plate (rotate 180° in the slicer); the tongue then prints upward.
Print both plunger bodies vertically with the switch-contact tip on the build plate. Their 45° shoulder transitions are support-free.
Print two copies of the shared stop cap with the exterior top face on the build plate so the blind press-fit bore opens upward. The geometry report flags a 4.5239 mm² down-facing annulus only in its assembled source orientation; the stated print orientation removes that support requirement from the fit bore.
Insert each plunger body from the lid underside, then press one cap onto each exposed stem until fully seated. Confirm 0.50 mm free downward motion before lid contact and free return without rubbing.
Seat the PCB on both bosses and install the two PCB screws without overtightening.
Fit the lid by loose slip; no retention force is intentionally provided.
Perform first-article checks for connector access, button release, cap retention, display visibility, wall-mount engagement, RF range, and internal temperature.
Assets
3D Model
3D Model
3D Model
3D Model
3D Model
In-Project Model Nodes
Wall Enclosure Base — PETG — UID e1624f1e-3622-4d57-a788-d32b786cb9e0
Wall Enclosure Lid — Loose Slip — UID c2c8ba18-99c6-4ca8-994f-22dcb59084a4
EN Captive Plunger — UID 1913eeed-10ae-4e16-9e9d-7ff58e65d103
EN Plunger Top Stop Cap — UID a179e753-c380-4ba3-af9b-ffe4863aed3b
IO0 Plunger Top Stop Cap — UID e55dae70-80c2-44cf-8cf8-d58546d362b4
The base, lid, and plunger-body assets retain the shared (45 mm, -50 mm, 0 mm) placement. The reusable cap is centred in its own XY frame and instantiated at root positions (4.7519 mm, -49.3730 mm, 0 mm) for EN and (4.7520 mm, -58.1982 mm, 0 mm) for IO0. All six nodes use scale 1, Z-up, physical materials, and visible edges.
Verification Evidence
Relay-aligned base compile: 119 × 107 × 30.5 mm, 55,157.2419 mm³, one solid, 116 faces. The shell envelope, floor, 3.0 mm walls, bosses, ear-root fillets, DC opening, shadow line, lid interface, datum, and overall styling are unchanged. The geometry report identifies only the four expected down-facing relay-window roof faces, totaling 186.0273 mm².
Lid compile: 97 × 107 × 5.4 mm, one solid.
Each final plunger-body compile: 6.2 × 6.2 × 17.85 mm, 177.8173 mm³, one solid, nine faces. The added 3.2-to-2.6 mm step visibly forms the positive axial seating shoulder at z=21.40 mm.
Final stop-cap compile: 6.2 × 6.2 × 2.0 mm, 55.7063 mm³, one solid, six faces. Parameters enforce a 1.00 mm blind bore and exactly 1.00 mm solid top roof. Its only reported finding is a 4.5239 mm² down-facing annulus in assembled orientation; printing top-face-down keeps the blind bore vertical and support-free.
The revised base, plunger body, and cap were visually rendered from isometric, top/front, and underside directions at correct physical scale and orientation.
A relay-side orthographic render was compared against the matching board relay-side render. J7, J8, J10, and J9 each align to its own terminal-block centre; every window provides 0.25 mm perimeter clearance, and the narrowest neighboring wall web remains 2.5659 mm.
Scene-tree read-back confirms the original base and plunger nodes plus both new cap nodes. The existing nodes were explicitly refreshed to their revised asset names.
The board-level renderer did not display root-level enclosure nodes even though node read-back and individual asset rendering succeeded; combined visual fit remains a first-article/in-editor check.
Existing PCB routing congestion and keepout findings were not modified and remain outside this enclosure task.
Independent-Review Must-Fix Resolution
Button plungers — final pass: both assemblies retain the exact 0.25 mm unpressed gap, exactly 0.50 mm downward travel, 0.80 mm diametral guide clearance, and removable post-assembly installation. The cap is now 2.00 mm thick with a 1.00 mm blind bore, 1.00 mm roof, and a positive axial shoulder that deterministically seats its underside at z=21.40 mm.
Wall mounting ears — final pass: all four ears remain 12.0 mm wide with 2.0 mm nominal side material around the 8.0 mm keyhole head. The buried triangular additions were removed; all eight actual post-union concave roots now carry verified, visible 1.0 mm fillets selected by topology with an expected-count rejection.
Status
Design Basis
Base
Lid and Interface Alignment
Relay Terminal Interface Measurements
Plunger Kinematics and True Downward Stops
Connector Evidence and Remaining Mechanical Unknowns