Implement util class for HGR rail

utils.py

@@ -0,0 +1,78 @@
+import cadquery as cq
+
+# pixel coordinates based on a picture in the Hiwin's
+# linear rail guidebook
+
+hgr_profile = [
+    (0, 0),
+    (37, 0),
+    (37 + 6, 6),
+    (96 - 6, 6),
+    (96, 0),
+    (186-17, 0),
+    (186, 17),
+    (186, 76),
+    (129, 133),
+    (129, 59 + 133),
+    (129 + 20, 59 + 133 + 20),
+    (31, 129 + 20 + 31, 133 + 20 + 31),
+    (186 - 6, 316 - 42 - 25 - 6),
+    (186, 316 - 42 - 25),
+    (186, 316 - 42),
+    (186 - 6, 316 - 42 + 6 - 1),
+    (31, 186 - 6 - 31, 316 - 6 - 1),
+    (143 + 6, 316 - 6),
+    (143, 316),
+    (0, 316)
+    ]
+
+scale = (10/186*17/316)**0.5
+
+scaled_profile = [tuple((scale * v for v in vals)) for vals in hgr_profile]
+
+class HGR20:
+    def __init__(self, base, l):
+        self.base = base.workplane()
+        self.l = l
+        
+    def holes(self, w):
+        pts = [(0, x-self.l/2) for x in range(20, self.l, 60)]
+        print("points", pts)
+        w = (w.copyWorkplane(self.base)
+             .transformed(offset=(0,0,17))
+             .pushPoints(pts)
+             .hole(5))
+        return w
+    
+    def rail(self): # workplane or face to use, length of rail
+        # TODO rotate w
+        xy = cq.Workplane().copyWorkplane(self.base)
+        w = xy.transformed((90, 0, 0), (0, self.l/2, 0))
+        for v in scaled_profile[1:]:
+            if len(v) == 2:
+                w = w.lineTo(*v)
+            else:
+                w = w.lineTo(*v[1:3]) # TODO draw an arc instead
+        w = w.mirrorY()
+        w = w.extrude(self.l)
+        pts = [(0, x-self.l/2) for x in range(20, self.l, 60)]
+        print("points", pts)
+        w = (w.copyWorkplane(xy)
+             .transformed(offset=(0,0,17))
+             .pushPoints(pts)
+             .hole(5)) # TODO replace with counterbore and get proper diameter
+        return w
+
+plate = (cq.Workplane("XY")
+         .rect(200, 200)
+         .extrude(10)
+         .faces(">Z")
+         .workplane()
+         .tag("railmount")
+         .end()
+         )
+hgr20 = HGR20(plate.workplaneFromTagged("railmount"), 300)
+plate2 = hgr20.holes(plate)
+hgrtest = hgr20.rail()
+show_object(plate2)
+show_object(hgrtest)