A printed enclosure, a knob, and a slicer run that checks its own work

.github/workflows/ci.yml

@@ -111,6 +111,7 @@ jobs:
                      '*.cpp' '*.h' '*.md' '*.sdoc' 'CMakeLists.txt' '*/CMakeLists.txt' \
                      'firmware/controller/**/Kconfig*' 'firmware/controller/*.csv' 'firmware/controller/sdkconfig.*' \
                      'tools/*.sh' 'tools/*.py' '.github/workflows/*.yml' 'strictdoc.toml' \
+                     '*.scad' 'hardware/enclosure/*.ini' 'hardware/enclosure/*.sh' \
                    | grep -v '^LICENSE' \
                    | grep -vE '^fixture/(board|firmware)/')
             # fixture/board and fixture/firmware are generated verbatim by

.gitignore

@@ -71,3 +71,7 @@ firmware/supervisor/latex/
 # Python bytecode from the tools/ scripts.
 __pycache__/
 *.pyc
+
+# Rendered STLs and sliced G-code: generated by hardware/enclosure/slice.sh,
+# reproducible from the .scad and the profile, and large.
+hardware/enclosure/build/

docs/03_hardware_req.sdoc

@@ -382,6 +382,38 @@ RELATIONS:
   VALUE: SYS-HW-24
   ROLE: Refines
 
+[REQUIREMENT]
+UID: HWR-24
+TITLE: The board has mounting holes
+STATEMENT: >>>
+The PCB shall carry **four M3 mounting holes**, 4 mm in from each corner of the 100 × 70 outline, plated or with keep-out to the nearest copper.
+
+There are none today. Nothing fixes the board to anything, so the enclosure's standoffs ([`hardware/enclosure`](../hardware/enclosure/README.md)) are a proposal the board has to adopt rather than a fit to something that exists. A controller held in place by its own wiring is a controller whose terminal blocks take the weight of the loom.
+
+The positions are the enclosure's, not the other way round, because the enclosure is printed from a parameterised model and the board is not.
+<<<
+PRIORITY: M
+VERIFICATION: I
+RELATIONS:
+- TYPE: Parent
+  VALUE: SYS-HW-05
+  ROLE: Refines
+
+[REQUIREMENT]
+UID: HWR-25
+TITLE: Every footprint is inside the outline
+STATEMENT: >>>
+Every footprint shall sit inside the board outline, and the placement shall be reviewed against it before routing continues.
+
+**14 of 125 do not**, measured 2026-10-11 against the `gr_rect` at 50,40 to 150,110: `U4` (the second MAX31856) at y = 117.9 and `J7` (the second thermocouple terminal) at y = 73.2 are the two that matter, with a cluster of decoupling capacitors and test points beside them. A part outside the outline is not placed at all: it will not be fabricated where it appears, and the netlist that routes to it is routing into free space.
+<<<
+PRIORITY: M
+VERIFICATION: I
+RELATIONS:
+- TYPE: Parent
+  VALUE: SYS-HW-10
+  ROLE: Refines
+
 [[/SECTION]]
 
 [[SECTION]]

hardware/enclosure/README.md

@@ -0,0 +1,99 @@
+<!--
+SPDX-FileCopyrightText: 2026 Bitcrush Testing
+SPDX-License-Identifier: GPL-3.0-or-later
+-->
+
+# Enclosure
+
+Panel-mount housing for the Safe Kiln Controller, in three printed parts.
+
+```sh
+./slice.sh              # render and slice all three for PLA
+./slice.sh knob         # just one
+./slice.sh --stl-only   # STLs only, slice them yourself
+```
+
+| Part | Size | 0.2 mm PLA | Prints |
+|---|---|---|---|
+| `shell` | 54 × 81 × 115 mm | 8 h 49 m | open face up, no support |
+| `bezel` | 70 × 97 × 7 mm | 1 h 40 m | face down, no support |
+| `knob` | 25 × 25 × 16 mm | 27 m | bore up, no support |
+
+Panel cut-out **54.4 × 81.3 mm**; outside size 70 × 97 × 115 mm.
+
+## ⚠ PLA is probably the wrong material here
+
+PLA softens at **55 to 60 °C**. This box bolts to the panel of a kiln, and
+`SWR-SAF-11` exists because that panel can get hot enough to matter: the
+firmware raises a fault on enclosure over-temperature at a configurable limit
+whose default is well inside PLA's softening range.
+
+So print PLA for **fit, feel and review**, which is what the knob's bore and
+the panel cut-out need, and it is cheap and accurate. Before a real
+installation, measure the panel at temperature, and if it runs warm use PETG
+or ASA. Both slice from the same profile with their own filament settings;
+nothing in the geometry assumes PLA.
+
+A softened enclosure is not a safety failure on its own: nothing in the
+protection chain depends on the plastic. It is a mounting failure, which means
+a board hanging off a hot panel by its wiring.
+
+## Print it in this order
+
+1. **The knob**, alone, and try it on the encoder. `knob_bore` is 6.15 mm,
+   which suits a splined EC11E shaft on a well-calibrated machine; if it is
+   tight or loose, change that one number. Four minutes, and it saves
+   discovering the same error at the end of an 8 hour print.
+2. **The bezel**, which is the part you look at. Check the display window
+   against the module you actually bought before printing the shell: the three
+   `CHECK` parameters in the `.scad` are the common 0.96″ variant and modules
+   differ.
+3. **The shell**, last, because it is the long one.
+
+## What the design is built around
+
+Every dimension comes out of `hardware/safekiln.kicad_pcb`, not from a guess,
+and the board's own placement decides the shape:
+
+- the outline is **100 × 70 mm**;
+- **SW3, the rotary encoder, is on the board** at its left edge, so that edge
+  is the operator's face and the board stands on edge behind the panel;
+- `J1` (5 V in) and `J2` (USB-C) are on that same edge, under the knob;
+- six 5 mm terminal blocks leave the **right** edge (coil, SSR, lid, CT and
+  the two thermocouples), so that edge faces into the back of the box, which
+  is where the kiln's wiring belongs;
+- `J5` is an OLED module **on a cable**, so the display is the one thing free
+  to go where it should.
+
+The display sits in its own lane beside the board's column rather than above
+the knob, because the front face is only as wide as the board's thickness plus
+that lane, and the first version of this model put a 27 mm module on a 23 mm
+face. The render caught it; see the note at `in_w` in the `.scad`.
+
+## Before this can be screwed together
+
+**The PCB has no mounting holes.** Nothing fixes the board to anything, so the
+four M3 standoffs in the shell are a *proposal* the board has to adopt: holes
+4 mm in from each corner of the 100 × 70 outline. Tracked as `HWR-24`.
+
+The supervisor's SWD tag-connect (`J4`) needs a probe to reach it through the
+shell's side opening. That opening is positioned from `J4`'s coordinates, but
+a TC2030 needs the probe held square to the pads, so check the clearance with
+the probe in hand before trusting it (`HWR-19`).
+
+## Files
+
+| | |
+|---|---|
+| `safekiln-enclosure.scad` | all three parts, parameterised, `-D part="…"` |
+| `pla-0.2mm.ini` | PrusaSlicer configuration, flat so `--load` applies it |
+| `slice.sh` | render, slice, and verify the profile was actually used |
+
+`slice.sh` checks more than it looks like it should, and each check is there
+because the failure it catches is silent: a render that is not a closed solid,
+a G-code file too small to be a part, a slicer that exits **zero** while
+refusing a configuration and writing nothing, and a profile that was ignored.
+The last one happened: the first `pla-0.2mm.ini` used `[print:]`-style
+sections, which makes it a config *bundle*, and `--load` ignored it without a
+word and sliced at 0.3 mm with a cold bed. The script now reads the settings
+back out of the finished G-code.

hardware/enclosure/pla-0.2mm.ini

@@ -0,0 +1,147 @@
+; SPDX-FileCopyrightText: 2026 Bitcrush Testing
+; SPDX-License-Identifier: GPL-3.0-or-later
+;
+; PrusaSlicer configuration for the Safe Kiln Controller enclosure in PLA, on
+; a 0.4 mm nozzle at 0.2 mm layers. Load it in the GUI or let
+; tools/slice.sh use it.
+;
+; ===========================================================================
+; WHY THESE VALUES AND NOT THE STOCK PROFILE
+; ===========================================================================
+; The stock 0.2 mm SPEED profile prints this enclosure perfectly well. The
+; departures below are deliberate and each has a reason tied to this part
+; rather than to a general preference for quality:
+;
+;   PERIMETERS = 3. The walls are 2.4 mm, which is exactly three extrusions at
+;   0.45 mm. Two would leave a gap filled with infill, and the part that gets
+;   handled is the wall a terminal screw is torqued against.
+;
+;   TOP/BOTTOM = 5/4. The bezel's visible face is a bottom surface and the
+;   display window's chamfer is a top surface, both of which show every
+;   missing layer.
+;
+;   NO SUPPORT. The geometry is drawn so that nothing needs it: the shell
+;   prints open-face-up and its standoffs grow off the floor, the bezel prints
+;   face-down, the knob prints bore-up. If a future change needs support, the
+;   change is wrong rather than the profile.
+;
+;   BRIM 3 mm ON THE SHELL ONLY, set by the script per part. The shell is
+;   115 mm tall on a 54 x 81 footprint, which is exactly the aspect ratio that
+;   lets a knock mid-print take it off the bed.
+;
+;   FAN 100 % after the first layers. PLA in a part with small bosses and thin
+;   ribs needs the cooling more than it needs the layer adhesion, and this
+;   enclosure is not structural.
+;
+; What this profile is NOT for: anything that gets hot. PLA softens around
+; 55 to 60 degC, and an enclosure bolted to a kiln's panel can exceed that.
+; See the warning in README.md before printing this in PLA for real use.
+;
+; ===========================================================================
+; WHY THIS FILE IS FLAT AND NOT A BUNDLE
+; ===========================================================================
+; No [print:...] / [filament:...] / [printer:...] sections. Those make it a
+; config BUNDLE, which the GUI imports and which `--load` silently ignores:
+; the first version of this file had them, PrusaSlicer accepted it without a
+; word, and sliced at 0.3 mm layers, 200 degC and a cold bed. The G-code was
+; 891 kB and looked perfectly healthy.
+;
+; `--load` wants a flat configuration, which is what the GUI's "Export Config"
+; writes. slice.sh now reads the settings back out of the finished G-code and
+; fails if they are not these, because a profile that is quietly not applied is
+; indistinguishable from one that is until the print is on the bed.
+
+layer_height = 0.2
+first_layer_height = 0.25
+perimeters = 3
+top_solid_layers = 5
+bottom_solid_layers = 4
+fill_density = 20%
+fill_pattern = gyroid
+top_fill_pattern = monotonic
+bottom_fill_pattern = monotonic
+solid_infill_every_layers = 0
+infill_every_layers = 1
+ensure_vertical_shell_thickness = 1
+thin_walls = 0
+gap_fill_enabled = 1
+support_material = 0
+support_material_auto = 0
+brim_width = 0
+brim_type = outer_only
+skirts = 1
+skirt_distance = 2
+skirt_height = 1
+seam_position = aligned
+external_perimeters_first = 0
+perimeter_speed = 45
+external_perimeter_speed = 25
+infill_speed = 80
+solid_infill_speed = 80
+top_solid_infill_speed = 40
+travel_speed = 180
+first_layer_speed = 20
+bridge_speed = 25
+bridge_flow_ratio = 1
+extrusion_width = 0.45
+first_layer_extrusion_width = 0.42
+external_perimeter_extrusion_width = 0.45
+perimeter_extrusion_width = 0.45
+infill_extrusion_width = 0.45
+solid_infill_extrusion_width = 0.45
+top_infill_extrusion_width = 0.4
+elefant_foot_compensation = 0.2
+; Holes print undersize. 0.1 mm of compensation gets an M3 clearance hole to
+; actually pass an M3 and the knob's bore onto the shaft, and is the one
+; setting most likely to need adjusting for a particular machine.
+hole_size_compensation = 0.1
+xy_size_compensation = 0
+
+filament_type = PLA
+filament_diameter = 1.75
+temperature = 210
+first_layer_temperature = 215
+bed_temperature = 60
+first_layer_bed_temperature = 60
+fan_always_on = 1
+cooling = 1
+min_fan_speed = 100
+max_fan_speed = 100
+bridge_fan_speed = 100
+disable_fan_first_layers = 2
+slowdown_below_layer_time = 8
+min_print_speed = 15
+filament_retract_length = nil
+filament_colour = #FF8000
+filament_settings_id = "SafeKiln PLA"
+
+printer_technology = FFF
+printer_model =
+nozzle_diameter = 0.4
+; A generic Prusa i3 envelope: MK3S is 250 x 210 x 210 and MK4 250 x 210 x 220,
+; so this is the smaller of the two and every part fits either.
+bed_shape = 0x0,250x0,250x210,0x210
+max_print_height = 210
+z_offset = 0
+retract_length = 0.8
+retract_speed = 35
+deretract_speed = 25
+retract_before_travel = 1.5
+retract_layer_change = 1
+wipe = 1
+use_relative_e_distances = 1
+; Required with relative E, and PrusaSlicer refuses to slice without it:
+; relative extrusion accumulates floating-point error unless the position is
+; reset each layer. Worth knowing how it refuses -- it printed the reason and
+; exited ZERO, writing no file, which is why slice.sh checks that the G-code
+; exists and contains a plausible number of moves rather than trusting the
+; exit status.
+layer_gcode = G92 E0
+gcode_flavor = marlin2
+; Deliberately minimal: the real start sequence belongs to the machine's own
+; profile, and a start G-code copied into a project file is a start G-code
+; that goes stale. The script warns when it is slicing with this one.
+start_gcode = M115 U3.13.2 ; tell the firmware the slicer version\nG28 ; home\nG29 ; mesh bed level (ignored by firmware that does not have it)\nM104 S[first_layer_temperature] ; set nozzle\nM140 S[first_layer_bed_temperature] ; set bed\nM109 S[first_layer_temperature] ; wait nozzle\nM190 S[first_layer_bed_temperature] ; wait bed\nG92 E0 ; zero the extruder
+end_gcode = M104 S0 ; nozzle off\nM140 S0 ; bed off\nG1 X0 Y200 F3000 ; present the part\nM84 ; motors off
+between_objects_gcode =
+printer_settings_id = "SafeKiln Prusa 0.4"