Files
kicad-zone-resistance/fill_resistance/config.py
T
janik d183bc5fd7 Document that via capping is deliberately not modeled, with error bound
Layer-to-layer the cap (>=15 um plating per fab spec) is parallel to
the annular-ring contact, so it cannot change the DC path. In-plane the
model treats every via mouth as solid layer-thickness copper; the error
is bounded by the dilute-hole correction (~ +2x mouth-area-fraction
locally), partially offset by the unmodeled annular-ring copper, and
typically well under a few percent of total R.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-15 16:11:49 +07:00

85 lines
4.7 KiB
Python

"""All tunable constants. v1 has no GUI dialog: edit here, re-run.
A future version may read overrides from <project>/fill_res_config.json.
"""
# --- Grid sizing ---
# Benchmarked on the VOUT+ plane (147x59 mm): R changes < 0.3% from
# 150 um cells down to 50 um. Accuracy is feature-limited (slots/necks
# narrower than one cell), not plane-limited - override CELL_UM_OVERRIDE
# for boards with sub-cell slots.
TARGET_CELLS = 2_000_000 # auto cell size aims for roughly this many cells
HARD_MAX_CELLS = 16_000_000 # abort above this (see GridSizeError message)
MIN_CELL_UM = 25.0 # clamp for auto cell size
MAX_CELL_UM = 500.0
CELL_UM_OVERRIDE: float | None = None # force a cell size, bypasses auto (not HARD_MAX)
MARGIN_CELLS = 2 # empty guard cells around the copper bbox
# --- Physics ---
RHO_CU_OHM_M = 1.68e-8 # copper resistivity at 20 degC
COPPER_THICKNESS_UM: float | None = None # None -> stackup, fallback 35.0 with warning
FALLBACK_THICKNESS_UM = 35.0
TEST_CURRENT_A = 1.0 # default injected current (dialog/CLI-selectable)
VIA_PLATING_UM = 18.0 # barrel plating thickness (always plated).
# Via capping is NOT modeled: layer-to-layer
# the cap (>=15um per fab spec, thinner than
# the foil) is parallel to the annular-ring
# contact, not in series; in-plane every via
# mouth is treated as solid layer-thickness
# copper (error bound: see README).
INCLUDE_TH_PADS = True # plated through-hole pads stitch layers too
SKIN_SIDES = 1 # skin-effect field config: 1 = plane facing a
# return plane (conservative), 2 = isolated foil
# --- Solder / mask-opening buildup ---
INCLUDE_MASK_BUILDUP = False # OFF by default; dialog-toggleable. Zones on
# F.Mask/B.Mask = mask openings that collect
# solder on the pour underneath
SOLDER_THICKNESS_UM = 50.0 # solder height over opened copper
SOLDER_RHO_OHM_M = 1.32e-7 # SAC305, ~7.9x copper
BUILDUP_EXTRA_CU_UM = 0.0 # optional user-added copper (busbar/wire
# soldered into the opening); dialog-settable
# --- Zone / layer selection ---
INCLUDE_TRACKS = True # the net's traces (straight + arc tracks)
# conduct together with the zone fills;
# dialog-toggleable
TRACK_1D_FACTOR = 3.0 # traces narrower than this many grid cells
# become exact 1D resistor chains along their
# centerline instead of rasterized outlines
# (no discretization error in the trace R;
# 0 = always rasterize)
LAYER_HINT: str | None = None # e.g. "F.Cu" to disambiguate candidate fills
ELECTRODE_POS_LAYER = "User.1" # rectangles on this layer mark V+ contact parts
ELECTRODE_NEG_LAYER = "User.2" # rectangles on this layer mark V- contact parts
ALWAYS_REFILL = False # refill zones even if KiCad says they are filled
# --- Solver ---
CONTACT_MODEL = "uniform" # "uniform": conductor pressed on top injects
# orthogonally with uniform surface density
# (J ramps across the contact); "equipotential":
# ideal bonded lug (Dirichlet). The two bracket
# a real contact: R_equi <= R_real <= R_uniform.
SPSOLVE_MAX_UNKNOWNS = 500_000 # above this, AMG-preconditioned CG (pyamg;
# Jacobi-CG if pyamg is missing). Direct is
# exact and fastest for small grids; measured
# at 1.4M unknowns: spsolve 13 s / ~3 GB,
# AMG-CG 6 s at a fraction of the memory
AMG_TOL = 1e-10 # relative residual of the AMG-CG solve
CG_TOL = 1e-8 # Jacobi-CG fallback (no pyamg)
CG_MAXITER = 50_000 # CG iterations are cheap; large grids need many
# --- Geometry ---
ARC_TOL_FRACTION = 0.5 # arc sagitta tolerance as a fraction of cell size
# --- Plots / output ---
CMAP_POTENTIAL = "viridis"
CMAP_CURRENT = "inferno"
CMAP_POWER = "magma"
POWER_DYNAMIC_RANGE = 1e4 # LogNorm span for the power map (power ~ J^2)
LOG_CURRENT_SCALE = True
CURRENT_DYNAMIC_RANGE = 1e3 # LogNorm vmin = vmax / this
DPI = 150
INTERACTIVE = True # False -> save PNGs only, never open windows
OUTPUT_DIRNAME = "fill_res_results"