Brico-Info – le blog de Bruno CATTEAU

import FreeCAD as App, Part, math, os

# ================= PARAMETRES =================
D_OUT     = 174.0   # diametre total
ENTRAXE   = 158.0   # entraxe des 2 trous de vis
T         = 5.0     # epaisseur de la grille
D_SCREW   = 6.0     # percage des trous de vis
D_CSK     = 10.0    # diametre d'ouverture du fraisage (tete fraisee 9 mm)
D_CENTER  = 26.0    # diametre du trou central
R_HUB_OUT = 21.0    # rayon exterieur du moyeu plein
RIM_W     = 14.0    # largeur de la couronne exterieure (portee, SANS renfort)
N_RINGS   = 4       # anneaux de fentes
N_WEBS    = 6       # nervures radiales
WEB_W     = 6.0     # largeur des nervures radiales
WALL_R    = 5.0     # nervure circulaire entre deux anneaux
CH_EDGE   = 0.8     # chanfrein du bord exterieur
RIB_H     = 5.0     # hauteur des renforts en sous-face
RIB_W     = 6.0     # largeur des renforts radiaux
RIB_TAPER = 5.0     # longueur du raccord a 45 deg
RIB_MARGIN= 3.0     # retrait des renforts avant la couronne de portee
# ==============================================

R_OUT  = D_OUT/2.0
R_HOLE = ENTRAXE/2.0
R_GRID = R_OUT - RIM_W          # 73.0 : debut de la couronne de portee
R_RIB_END = R_GRID - RIB_MARGIN  # les renforts s'arretent ici
CSK_D  = (D_CSK - D_SCREW)/2.0  # profondeur du fraisage (cone a 90 deg)

name = "Bonde174v3"
if name in App.listDocuments(): App.closeDocument(name)
doc = App.newDocument(name)

pitch  = (R_GRID - R_HUB_OUT) / N_RINGS
slot_w = pitch - WALL_R

def sector(ri, ro, a1, a2):
    pie = Part.makeCylinder(ro, T+4, App.Vector(0,0,-2), App.Vector(0,0,1), a2-a1)
    pie.rotate(App.Vector(0,0,0), App.Vector(0,0,1), a1)
    return pie.cut(Part.makeCylinder(ri, T+8, App.Vector(0,0,-4)))

# ---------- grille ----------
cut = None
for i in range(N_RINGS):
    rm = R_HUB_OUT + i*pitch + WALL_R/2.0 + slot_w/2.0
    half = math.degrees((WEB_W/2.0 + slot_w/2.0) / rm)
    for k in range(N_WEBS):
        a0 = 360.0*k/N_WEBS
        a1, a2 = a0 + half, a0 + 360.0/N_WEBS - half
        s = sector(rm - slot_w/2.0, rm + slot_w/2.0, a1, a2)
        for aa in (a1, a2):
            t = math.radians(aa)
            s = s.fuse(Part.makeCylinder(slot_w/2.0, T+4,
                       App.Vector(rm*math.cos(t), rm*math.sin(t), -2)))
        cut = s if cut is None else cut.fuse(s)

shape = Part.makeCylinder(R_OUT, T).cut(cut.removeSplitter())

# ---------- renforts en sous-face (z = -RIB_H .. 0) ----------
ribs = Part.makeCylinder(R_HUB_OUT, RIB_H, App.Vector(0,0,-RIB_H))      # anneau central
ribs = ribs.cut(Part.makeCylinder(D_CENTER/2.0, RIB_H+4, App.Vector(0,0,-RIB_H-2)))
for k in range(N_WEBS):
    b = Part.makeBox(R_GRID+2, RIB_W, RIB_H, App.Vector(0, -RIB_W/2.0, -RIB_H))
    b.rotate(App.Vector(0,0,0), App.Vector(0,0,1), 360.0*k/N_WEBS)
    ribs = ribs.fuse(b)
ribs = ribs.cut(Part.makeCylinder(D_CENTER/2.0, RIB_H+4, App.Vector(0,0,-RIB_H-2)))
# raccord a 45 deg : on retire tout ce qui sort du cone -> hauteur nulle a R_GRID
outside = Part.makeCylinder(R_OUT+10, RIB_H, App.Vector(0,0,-RIB_H)).cut(
          Part.makeCone(R_RIB_END-RIB_TAPER, R_RIB_END, RIB_H,
                        App.Vector(0,0,-RIB_H), App.Vector(0,0,1)))
ribs = ribs.cut(outside)
shape = shape.fuse(ribs).removeSplitter()

# ---------- percages ----------
shape = shape.cut(Part.makeCylinder(D_CENTER/2.0, T+RIB_H+4, App.Vector(0,0,-RIB_H-2)))
for k in range(2):
    t = math.pi*k
    x, y = R_HOLE*math.cos(t), R_HOLE*math.sin(t)
    shape = shape.cut(Part.makeCylinder(D_SCREW/2.0, T+4, App.Vector(x,y,-2)))

# fraisage : chanfrein sur l'arete des percages, au niveau de la face superieure
ar = [e for e in shape.Edges
      if len(e.Vertexes) == 1
      and abs(e.BoundBox.ZMax - T) < 1e-6 and abs(e.BoundBox.ZMin - T) < 1e-6
      and abs(e.Length - 2*math.pi*(D_SCREW/2.0)) < 0.5]
print("aretes de percage sur la face superieure : %d (attendu 2)" % len(ar))
assert len(ar) == 2, "selection d'aretes incorrecte"
shape = shape.makeChamfer(CSK_D, ar)

def chamfer(sh, r, z, size):
    es = [e for e in sh.Edges if len(e.Vertexes)==1
          and abs(e.BoundBox.ZMax-z)<1e-6 and abs(e.Length-2*math.pi*r)<0.5]
    if not es: return sh
    try: return sh.makeChamfer(size, es)
    except Exception as ex:
        print("chanfrein ignore:", ex); return sh

shape = chamfer(shape, R_OUT, T, CH_EDGE)
shape = chamfer(shape, R_OUT, 0.0, CH_EDGE)
shape = chamfer(shape, D_CENTER/2.0, T, CH_EDGE)

obj = doc.addObject("Part::Feature", "Bonde"); obj.Shape = shape; doc.recompute()

# ---------- controles ----------
print("--- CONTROLE V3 ---")
bb = shape.BoundBox
sec = shape.section(Part.makePlane(400,400, App.Vector(-200,-200, T/2.0)))
print("diametre reel        : %.3f mm" % (2*max((v.Point.x**2+v.Point.y**2)**.5 for v in sec.Vertexes)))
print("hauteur totale       : %.3f mm  (Z de %.2f a %.2f)" % (bb.ZLength, bb.ZMin, bb.ZMax))
print("epaisseur grille     : %.3f mm | renfort : %.3f mm" % (T, -bb.ZMin))
cen = sorted({(round(f.BoundBox.Center.x,2), round(f.BoundBox.Center.y,2)) for f in shape.Faces
              if hasattr(f.Surface,"Radius") and abs(f.Surface.Radius-D_SCREW/2.0)<1e-6})
print("entraxe              : %.3f mm  %s" % (math.hypot(cen[-1][0]-cen[0][0], cen[-1][1]-cen[0][1]), cen))
csk = sorted({round(f.Surface.Radius,3) for f in shape.Faces
              if f.Surface.__class__.__name__=="Cone" and f.BoundBox.ZMax > T-0.01
              and abs(f.BoundBox.Center.x) > 10})
print("--- profil du fraisage (trou a x=+%.0f) ---" % R_HOLE)
for zc in [0.5, 1.5, 2.5, 3.0, 3.5, 4.0, 4.5, 4.95]:
    pl = Part.makePlane(400, 400, App.Vector(-200, -200, zc))
    sc = shape.section(pl)
    rmin = 1e9
    for e in sc.Edges:
        for pt in e.discretize(60):
            d = math.hypot(pt.x - R_HOLE, pt.y)
            if d < 12: rmin = min(rmin, d)
    if rmin < 1e8:
        print("  z=%4.2f mm  ->  diametre du percage = %6.3f mm" % (zc, 2*rmin))
print("attendu : %.1f mm jusqu'a z=%.1f puis elargissement jusqu'a %.1f mm en z=%.1f"
      % (D_SCREW, T-CSK_D, D_CSK, T))
# la couronne de portee doit etre strictement plane en sous-face
under = [f for f in shape.Faces if abs(f.BoundBox.ZMax) < 1e-6 and abs(f.BoundBox.ZMin) < 1e-6]
rmin_under = min((min((v.Point.x**2+v.Point.y**2)**.5 for v in f.Vertexes)) for f in under)
low = [f for f in shape.Faces if f.BoundBox.ZMin < -1e-6]
rmax_rib = max(max((v.Point.x**2+v.Point.y**2)**.5 for v in f.Vertexes) for f in low)
print("renfort : rayon max  = %.3f mm   (cible %.1f, couronne a %.1f)" % (rmax_rib, R_RIB_END, R_GRID))
print("retrait reel avant la couronne : %.3f mm" % (R_GRID - rmax_rib))
print("sous-face plane de r=%.3f a r=%.1f mm  -> disque exterieur intact : %s"
      % (rmax_rib, R_OUT, rmax_rib <= R_RIB_END + 1e-6))
print("solide valide        : %s | solides : %d | faces : %d" % (shape.isValid(), len(shape.Solids), len(shape.Faces)))
print("volume               : %.1f cm3" % (shape.Volume/1000.0))

out = r"C:\chemin\vers\ton\dossier"
doc.saveAs(os.path.join(out, "bonde_v3_174_entraxe158.FCStd"))
import MeshPart
m = MeshPart.meshFromShape(Shape=shape, LinearDeflection=0.04, AngularDeflection=0.15, Relative=False)
m.write(os.path.join(out, "bonde_v3_174_entraxe158.stl"))
print("STL : %d triangles" % m.CountFacets)
try:
    import FreeCADGui as Gui
    d = r"C:\chemin\vers\dossier"
    v = Gui.activeDocument().activeView()
    v.viewAxonometric(); Gui.SendMsgToActiveView("ViewFit"); v.saveImage(d+r"\v3_haut.png", 1200, 1000, "White")
    v.viewRear(); v.viewAxonometric()
    import FreeCAD
    v.setCameraOrientation(App.Rotation(App.Vector(1,0,0), 200).multiply(App.Rotation(App.Vector(0,0,1), 30)))
    Gui.SendMsgToActiveView("ViewFit"); v.saveImage(d+r"\v3_bas.png", 1200, 1000, "White")
except Exception as ex: print("vue:", ex)