Add angle joint stub, hole in rotor

nhf/touhou/yasaka_kanako/onbashira.py

@@ -3,7 +3,7 @@ from nhf.materials import Role, Material
 import nhf.utils
 
 import math
-from dataclasses import dataclass
+from dataclasses import dataclass, field
 import cadquery as Cq
 
 @dataclass
@@ -13,28 +13,43 @@ class Onbashira(Model):
     # Dimensions of each side panel
     side_width: float = 200.0
     side_length: float = 600.0
-
     side_thickness: float = 25.4 / 8
 
+    # Joints between two sets of side panels
+    angle_joint_thickness: float = 25.4 / 4
+    # 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 = 10.0
+    angle_joint_bolt_length: float = 50.0
+    angle_joint_bolt_diam: float = 10.0
+    # Position of the holes, with (0, 0) being the centre of each side
+    angle_joint_hole_position: list[float] = field(default_factory=lambda: [
+        (20, 20),
+        (70, 20),
+    ])
+
     # Dimensions of gun barrels
     barrel_diam: float = 25.4 * 2
     barrel_length: float = 300.0
     # Radius from barrel centre to axis
-    rotation_radius: float = 75.0
+    rotation_radius: float = 90.0
     n_bearing_balls: int = 24
     # Size of ball bearings
     bearing_ball_diam: float = 25.4 * 1/2
     bearing_ball_gap: float = .5
     # Thickness of bearing disks
     bearing_thickness: float = 20.0
-    bearing_track_radius: float = 120.0
+    bearing_track_radius: float = 135.0
     # Gap between the inner and outer bearing disks
     bearing_gap: float = 10.0
     bearing_disk_thickness: float = 25.4 / 8
 
+    rotor_inner_radius: float = 55.0
+
     rotor_bind_bolt_diam: float = 10.0
-    rotor_bind_radius: float = 50.0
+    rotor_bind_radius: float = 110.0
-    stator_bind_radius: float = 150.0
+    stator_bind_radius: float = 170.0
 
     material_side: Material = Material.WOOD_BIRCH
     material_bearing: Material = Material.PLASTIC_PLA
@@ -47,18 +62,37 @@ class Onbashira(Model):
         assert self.bulk_radius - self.side_thickness - self.bearing_thickness - self.bearing_diam > self.rotation_radius + self.barrel_diam / 2
         assert self.bearing_gap < 0.95 * self.bearing_ball_diam
         assert self.rotor_bind_bolt_diam < self.rotor_bind_radius < self.bearing_track_radius
-        assert self.bearing_track_radius < self.stator_bind_radius
+        assert self.rotor_inner_radius < self.bearing_track_radius < self.stator_bind_radius
+        assert self.angle_joint_thickness > self.side_thickness
 
     @property
     def angle_side(self) -> float:
         return 360 / self.n_side
+    @property
+    def side_width_inner(self) -> float:
+        """
+        Interior side width
+
+        If outer width is `wi`, inner width is `wo`, each side's cross section
+        is a trapezoid with sides `wi`, `wo`, and height `h` (side thickness)
+        """
+        theta = math.pi / self.n_side
+        dt = self.side_thickness * math.tan(theta)
+        return self.side_width - dt * 2
+    @property
+    def angle_joint_extra_width(self) -> float:
+        theta = math.pi / self.n_side
+        dt = self.angle_joint_thickness * math.tan(theta)
+        return dt * 2
+
+
     @property
     def angle_dihedral(self) -> float:
         return 180 - self.angle_side
     @property
     def bulk_radius(self) -> float:
         """
-        Calculate radius of the bulk to the centre
+        Radius of the bulk (surface of each side) to the centre
         """
         return self.side_width / 2 / math.tan(math.radians(self.angle_side / 2))
     @property
@@ -78,7 +112,7 @@ class Onbashira(Model):
     def profile_bearing_stator(self) -> Cq.Sketch:
         return (
             Cq.Sketch()
-            .regularPolygon(self.side_width, self.n_side)
+            .regularPolygon(self.side_width - self.side_thickness, self.n_side)
             .circle(self.bearing_track_radius + self.bearing_gap/2, mode="s")
             .reset()
             .regularPolygon(
@@ -99,6 +133,7 @@ class Onbashira(Model):
         return (
             Cq.Sketch()
             .circle(self.bearing_track_radius - self.bearing_gap/2)
+            .circle(self.rotor_inner_radius, mode="s")
             .reset()
             .regularPolygon(
                 self.rotation_radius, self.n_side,
@@ -143,6 +178,9 @@ class Onbashira(Model):
 
     @target(name="pipe", kind=TargetKind.DXF)
     def pipe(self) -> Cq.Sketch:
+        """
+        The rotating pipes. Purely for decoration
+        """
         pass
 
     @target(name="side-panel", kind=TargetKind.DXF)
@@ -160,6 +198,7 @@ class Onbashira(Model):
             .placeSketch(self.profile_side_panel())
             .extrude(self.side_thickness)
         )
+        # Bevel the edges
         intersector = (
             Cq.Workplane('XZ')
             .polyline([
@@ -174,6 +213,71 @@ class Onbashira(Model):
         # Intersect the side panel
         return result * intersector
 
+    def angle_joint(self) -> Cq.Workplane:
+        """
+        Angular joint between two side panels. This sits at the intersection of
+        4 side panels to provide compressive, shear, and tensile strength.
+
+        To provide tensile strength along the Z-axis, the panels must be bolted
+        onto the angle joint.
+        """
+
+        # Create the slot carving
+        slot = (
+            Cq.Sketch()
+            .regularPolygon(
+                self.side_width,
+                self.n_side
+            )
+            .regularPolygon(
+                self.side_width_inner,
+                self.n_side, mode="s",
+            )
+        )
+        slot = (
+            Cq.Workplane()
+            .placeSketch(slot)
+            .extrude(self.angle_joint_depth)
+        )
+
+        # Construct the overall shape of the joint, and divide it into sections for printing later.
+        sketch = (
+            Cq.Sketch()
+            .regularPolygon(
+                self.side_width + self.angle_joint_extra_width,
+                self.n_side
+            )
+            .regularPolygon(
+                self.side_width - self.angle_joint_extra_width,
+                self.n_side, mode="s"
+            )
+        )
+
+        h = (self.bulk_radius + self.angle_joint_extra_width) * 2
+        # Intersector for 1/n of the ring
+        intersector = (
+            Cq.Workplane()
+            .sketch()
+            .polygon([
+                (0, 0),
+                (h, 0),
+                (h, h * math.tan(2 * math.pi / self.n_side))
+            ])
+            .finalize()
+            .extrude(self.angle_joint_depth*4)
+            .translate((0, 0, -self.angle_joint_depth*2))
+        )
+        result = (
+            Cq.Workplane()
+            .placeSketch(sketch)
+            .extrude(self.angle_joint_depth)
+            .translate((0, 0, -self.angle_joint_depth/2))
+            .cut(slot.translate((0, 0, self.angle_joint_gap/2)))
+            .cut(slot.translate((0, 0, -self.angle_joint_depth-self.angle_joint_gap/2)))
+            .intersect(intersector)
+        )
+        return result
+
 
 
     def bearing_ball(self) -> Cq.Solid: