Eliminate difficult geometry in angle joint

nhf/materials.py

@@ -90,6 +90,7 @@ class Material(Enum):
     ACRYLIC_TRANSLUSCENT = 1.18, _color('ivory2', 0.8)
     ACRYLIC_TRANSPARENT = 1.18, _color('ghostwhite', 0.5)
     STEEL_SPRING = 7.8, _color('gray', 0.8)
+    STEEL_STAINLESS = 7.8, _color('gray', 0.9)
     METAL_AL = 2.7, _color('gray', 0.6)
     METAL_BRASS = 8.5, _color('gold1', 0.8)
 

nhf/touhou/yasaka_kanako/onbashira.py

@@ -68,21 +68,22 @@ class Onbashira(Model):
     section1_gohei_loc: float = 30.0
     gohei_bolt_diam: float = 6.0
 
-    # Joints between two sets of side panels
+    # The angle joint bridges between two sets of side panels.
+
+    # Extra thickness beyond the onbashira's body
     angle_joint_thickness: float = 10.0
     # Z-axis size of each angle joint
     angle_joint_depth: float = 50.0
     # Gap of each angle joint to connect the outside to the inside
     angle_joint_gap: float = 8.0
     angle_joint_bolt_length: float = 50.0
-    angle_joint_bolt_diam: float = 6.0
+    angle_joint_bolt_diam: float = BOLT_COMMON.diam_thread
     angle_joint_bolt_head_diam: float = 13.0
     angle_joint_bolt_head_depth: float = 3.0
     # Position of the holes, with (0, 0) being the centre of each side
     angle_joint_bolt_position: list[float] = field(default_factory=lambda: [
         (40, 10),
     ])
-    angle_joint_flange_thickness: float = 7.8
     angle_joint_flange_radius: float = 23.0
     angle_joint_conn_thickness: float = 4.0
     angle_joint_conn_depth: float = 15.0
@@ -110,7 +111,7 @@ class Onbashira(Model):
     bearing_disk_thickness: float = 25.4 / 8
 
     rotor_inner_radius: float = 40.0
-    rotor_bind_bolt_diam: float = 6.0
+    rotor_bind_bolt_diam: float = BOLT_COMMON.diam_thread
     rotor_bind_radius: float = 78.0
     rotor_spacer_outer_diam: float = 15.0
     stator_bind_radius: float = 135.0
@@ -126,6 +127,7 @@ class Onbashira(Model):
     material_bearing_ball: Material = Material.ACRYLIC_TRANSPARENT
     material_barrel: Material = Material.ACRYLIC_BLACK
     material_brace: Material = Material.PLASTIC_PLA
+    material_fastener: Material = Material.STEEL_STAINLESS
 
     def __post_init__(self):
         assert self.n_side >= 3
@@ -320,6 +322,9 @@ class Onbashira(Model):
         return outer - inner
 
     def assembly_barrel(self) -> Cq.Assembly:
+        """
+        The assembly with gun barrels
+        """
         z_lower = -self.bearing_disk_gap/2 - self.bearing_disk_thickness
         a = (
             Cq.Assembly()
@@ -611,6 +616,34 @@ class Onbashira(Model):
 
         return result
 
+    @target(name="chamber-back", kind=TargetKind.DXF)
+    def profile_chamber_back(self) -> Cq.Sketch:
+        return (
+            Cq.Sketch()
+            .regularPolygon(self.side_width - self.side_thickness, self.n_side)
+            .reset()
+            .regularPolygon(
+                self.stator_bind_radius, self.n_side,
+                mode="c", tag="bolt")
+            .vertices(tag="bolt")
+            .circle(self.rotor_bind_bolt_diam/2, mode="s")
+        )
+    def chamber_back(self) -> Cq.Workplane:
+        sketch = self.profile_chamber_back()
+        result = (
+            Cq.Workplane()
+            .placeSketch(sketch)
+            .extrude(self.side_thickness)
+        )
+        # Mark all attachment points
+        for i in range(self.n_side):
+            angle = (i+0.5) * math.radians(360 / self.n_side)
+            x = self.stator_bind_radius * math.cos(angle)
+            y = self.stator_bind_radius * math.sin(angle)
+            result.tagAbsolute(f"holeF{i}", (x,  y, self.side_thickness), direction="+Z")
+            result.tagAbsolute(f"holeB{i}", (x,  -y, 0), direction="-Z")
+        return result
+
     def assembly_chamber(self) -> Cq.Assembly:
         a = Cq.Assembly()
         side = self.chamber_side_panel()
@@ -761,11 +794,11 @@ class Onbashira(Model):
             .reset()
             .regularPolygon(self.side_width_inner, self.n_side, mode="i")
             .finalize()
-            .extrude(self.angle_joint_flange_thickness)
+            .extrude(self.angle_joint_gap)
-            .translate((0, 0, -self.angle_joint_flange_thickness/2))
+            .translate((0, 0, -self.angle_joint_gap/2))
         )
         ri = self.stator_bind_radius
-        h = self.angle_joint_flange_thickness
+        h = self.angle_joint_gap
         cyl = Cq.Solid.makeCylinder(
             radius=self.rotor_bind_bolt_diam/2,
             height=h,
@@ -899,19 +932,19 @@ class Onbashira(Model):
             .reset()
             .regularPolygon(self.side_width_inner, self.n_side, mode="i")
             .finalize()
-            .extrude(self.angle_joint_flange_thickness)
+            .extrude(self.angle_joint_gap)
             .translate((0, 0, -flange_z))
         )
         ri = self.stator_bind_radius
-        h = self.angle_joint_flange_thickness
+        h = self.angle_joint_gap
         cyl = Cq.Solid.makeCylinder(
             radius=self.rotor_bind_bolt_diam/2,
             height=h,
             pnt=(ri * math.cos(th), ri * math.sin(th), -flange_z),
         )
         result = result + flange - cyl
-        result.tagAbsolute("holeStatorL", (ri * math.cos(th), ri * math.sin(th), -flange_z+h/2), direction="+Z")
+        result.tagAbsolute("holeStatorO", (ri * math.cos(th), ri * math.sin(th), -flange_z), direction="-Z")
-        result.tagAbsolute("holeStatorR", (ri * math.cos(th), ri * math.sin(th), -flange_z-h/2), direction="-Z")
+        result.tagAbsolute("holeStatorI", (ri * math.cos(th), ri * math.sin(th), -flange_z+h), direction="+Z")
         return result
 
     @target(name="angle-joint")
@@ -1044,11 +1077,11 @@ class Onbashira(Model):
                 .reset()
                 .regularPolygon(self.side_width_inner, self.n_side, mode="i")
                 .finalize()
-                .extrude(self.angle_joint_flange_thickness)
+                .extrude(self.angle_joint_gap)
-                .translate((0, 0, -self.angle_joint_flange_thickness/2))
+                .translate((0, 0, -self.angle_joint_gap/2))
             )
             ri = self.stator_bind_radius
-            h = self.angle_joint_flange_thickness
+            h = self.angle_joint_gap
             cyl = Cq.Solid.makeCylinder(
                 radius=self.rotor_bind_bolt_diam/2,
                 height=h,
@@ -1135,7 +1168,7 @@ class Onbashira(Model):
             )
             .add(
                 self.assembly_ring(self.angle_joint_chamber_front()),
-                name="chamber_front",
+                name="ring3",
             )
             .add(
                 self.assembly_chamber(),
@@ -1143,32 +1176,52 @@ class Onbashira(Model):
             )
             .add(
                 self.assembly_ring(self.angle_joint_chamber_back()),
-                name="chamber_back",
+                name="ring4",
             )
-            .add(self.assembly_barrel(), name="barrel")
+            .addS(
+                self.chamber_back(),
+                name="chamber_back",
+                material=self.material_side,
+                role=Role.STRUCTURE | Role.DECORATION,
+            )
+            #.add(self.assembly_barrel(), name="barrel")
         )
         for i in range(self.n_side):
             j = (i + 1) % self.n_side
             for ih in range(len(self.angle_joint_bolt_position)):
                 a = a.constrain(
                     f"chamber/side{i}?holeFPI{ih}",
-                    f"chamber_front/side{i}?holeRSO{ih}",
+                    f"ring3/side{i}?holeRSO{ih}",
                     "Plane",
                 )
                 a = a.constrain(
                     f"chamber/side{i}?holeBPI{ih}",
-                    f"chamber_back/side{i}?holeLSO{ih}",
+                    f"ring4/side{i}?holeLSO{ih}",
                     "Plane",
                 )
                 a = a.constrain(
-                    f"barrel/stator2?holeB{i}",
+                    f"ring4/side{i}?holeStatorO",
-                    f"ring1/side{i}?holeStatorR",
+                    f"chamber_back?holeB{i}",
                     "Plane",
                 )
+
+                name_bolt =f"chamber_back{i}boltFPI{ih}"
+                a = a.addS(
+                    BOLT_COMMON.generate(),
+                    name=name_bolt,
+                    material=self.material_fastener,
+                    role=Role.CONNECTION,
+                )
+                a = a.constrain(
+                    f"chamber_back?holeF{i}",
+                    f"{name_bolt}?root",
+                    "Plane",
+                    param=0,
+                )
                 for (nl, nc, nr) in [
                         ("section1", "ring1", "section2"),
                         ("section2", "ring2", "section3"),
-                        ("section3", "chamber_front", None),
+                        ("section3", "ring3", None),
                 ]:
                     a = a.constrain(
                         f"{nl}/side{i}?holeBSO{ih}",