"""Full OTA part library — every part modelled, positioned for assembly. Units mm. Positions are in ASSEMBLY space: tube axis = Z, primary vertex at Z=41. """ import math from build123d import * def vane_cutter(thk=1.1, extra=4.0): """A thicker copy of the vane, same footprint - cuts a guaranteed-fit slot.""" L = VANE_TIP - VANE_ROOT with BuildPart() as b: Box(thk, L + extra, 22 + extra, align=(Align.CENTER, Align.MIN, Align.CENTER)) return b.part # ═══════════════ MASTER PARAMETERS ═══════════════ D, FRATIO = 200.0, 4.0 F = D * FRATIO # 800 SEC_MINOR, SEC_MAJOR, SEC_THK = 80.0, 114.0, 18.0 SEC_OFFSET = SEC_MINOR / (4*FRATIO) # 5.0 MIR_DIA, MIR_THK = 200.0, 24.0 TUBE_OD, TUBE_WALL = 250.0, 1.5 TUBE_ID = TUBE_OD - 2*TUBE_WALL # 247.0 TUBE_LEN = 720.0 CELL_STANDOFF = 30.0 Z_PRIMARY = 41.0 # primary front face Z_SPIDER = 560.0 Z_RING1, Z_RING2 = 210.0, 450.0 Z_GLASS_FRONT = 29.0 + 17.0 + 24.0 # pads + glass thickness Z_VANE = 560.0 + 70.0 # vane plane, skyward of the secondary STALK_BOT = 560.0 + 34.0 # clear of the tilted holder's rear face STALK_TOP = Z_VANE - 13.0 # hub underside # ── TOLERANCE / FIT SCHEDULE (single source of truth) ── FIT = { "mirror_radial": (0.50, 1.00), # glass OD to cell wall, per side "clip_standoff": (0.30, 0.50), # clip face above glass front "cell_to_tube": (0.30, 0.80), # cell OD to tube ID, per side "vane_slot": (0.05, 0.15), # vane thickness to hub slot "sec_seat": (0.20, 0.60), # secondary edge to holder seat "ring_to_tube": (0.10, 0.40), # ring bore to tube OD, per side "focuser_bore": (0.25, 0.75), # drawtube to board bore, per side "print_clearance": (0.20, 0.35), # FDM mating clearance, per side "envelope_min": (60.0, None), # optics swept envelope to tube ID } PRINTED = {"secondary_holder", "mirror_clip", "edge_roller", "fan_shroud", "dew_shield_half", "cable_guide"} # tube_ring deliberately NOT printed: 285 mm PA-CF warps on the plate and creeps # under sustained load, and the rings carry the whole OTA into the dovetail. H2C = (305.0, 320.0, 325.0); H2C_MARGIN = 5.0 # ═══════════════ PARTS ═══════════════ def p_tube(): with BuildPart() as b: Cylinder(TUBE_OD/2, TUBE_LEN, align=(Align.CENTER,Align.CENTER,Align.MIN)) Cylinder(TUBE_ID/2, TUBE_LEN, align=(Align.CENTER,Align.CENTER,Align.MIN), mode=Mode.SUBTRACT) with Locations(Location((0,0,Z_SPIDER),(0,90,0))): Cylinder(30.5, TUBE_OD, mode=Mode.SUBTRACT) tube = b.part for a in (45,135,225,315): # slot cut from a thicker copy of the vane, same position c = vane_cutter().translate((0, VANE_ROOT, 0)).rotate(Axis.Z, a) \ .translate((0, SEC_OFFSET, Z_VANE)) tube = tube - c return tube def p_mirror_cell(): OD = TUBE_ID - 2*0.55 # cell_to_tube fit, mid of band with BuildPart() as b: Cylinder(OD/2, 12) Cylinder(60, 12, mode=Mode.SUBTRACT) with PolarLocations(OD/2-14, 3): Cylinder(6, 20, align=(Align.CENTER,Align.CENTER,Align.MIN)) with PolarLocations(70.71, 3, start_angle=60): Cylinder(11, 17, align=(Align.CENTER,Align.CENTER,Align.MIN)) with PolarLocations(OD/2-14, 3): Cylinder(2.55, 26, mode=Mode.SUBTRACT) with PolarLocations(OD/2-4, 3, start_angle=30): Box(9, 5.5, 20, mode=Mode.SUBTRACT) return b.part def p_primary(): with BuildPart() as b: Cylinder(MIR_DIA/2, MIR_THK) return b.part def p_mirror_clip(): # PRINTED PAHT-CF with BuildPart() as b: Box(26, 14, 6, align=(Align.CENTER,Align.MIN,Align.MIN)) with Locations((0,4,6)): Box(26, 6, 5, align=(Align.CENTER,Align.MIN,Align.MIN)) with Locations((0,8,0)): Cylinder(1.7, 20, align=(Align.CENTER,Align.CENTER,Align.MIN), mode=Mode.SUBTRACT) return b.part def p_edge_roller(): # PRINTED PAHT-CF, PTFE roller pocket with BuildPart() as b: Box(16, 14, 14, align=(Align.CENTER,Align.CENTER,Align.MIN)) with Locations((0,0,14)): Cylinder(5.2, 24, rotation=(90,0,0), mode=Mode.SUBTRACT) with Locations((0,0,3)): Cylinder(2.2, 20, mode=Mode.SUBTRACT) return b.part def p_spider_hub(): with BuildPart() as b: Cylinder(22, 26) Cylinder(5.0, 34, mode=Mode.SUBTRACT) for a in (45,135,225,315): # vane slots, 0.62 for a 0.5 vane (0.06/side) with Locations(Location((0,0,0),(0,0,a)) * Location((0,18,0))): Box(0.62, 10, 22, mode=Mode.SUBTRACT) return b.part VANE_ROOT = 14.0 # starts inside the hub slot, clear of the hub bore VANE_TIP = 126.0 # reaches into the tube-wall slot at OD/2 = 125 def p_spider_vane(): L = VANE_TIP - VANE_ROOT with BuildPart() as b: Box(0.5, L, 22, align=(Align.CENTER,Align.MIN,Align.CENTER)) with Locations((0,L-8,0)): Box(4, 10, 4, mode=Mode.SUBTRACT) return b.part def p_secondary(): with BuildPart() as b: Cylinder(SEC_MINOR/2, SEC_THK) scale(by=(SEC_MAJOR/SEC_MINOR, 1, 1)) return b.part def p_secondary_holder(): # PRINTED PAHT-CF with BuildPart() as b: Box(SEC_MAJOR+12, SEC_MINOR+12, 24, align=(Align.CENTER,Align.CENTER,Align.MIN)) with BuildPart(mode=Mode.SUBTRACT): with Locations((0,0,(SEC_THK+2)/2)): Cylinder((SEC_MINOR+2*0.4)/2, SEC_THK+2) scale(by=((SEC_MAJOR+2*0.4)/(SEC_MINOR+2*0.4), 1, 1)) with PolarLocations(SEC_MAJOR/2-4, 3): Cylinder(1.7, 24, align=(Align.CENTER,Align.CENTER,Align.MIN), mode=Mode.SUBTRACT) with Locations((0,0,24)): Cylinder(11, 8, align=(Align.CENTER,Align.CENTER,Align.MIN)) Cylinder(5.2, 34, align=(Align.CENTER,Align.CENTER,Align.MAX), mode=Mode.SUBTRACT) return b.part def p_secondary_stalk(): L = STALK_TOP - STALK_BOT with BuildPart() as b: Cylinder(7.5, L, align=(Align.CENTER,Align.CENTER,Align.MIN)) Cylinder(4.2, L+8, align=(Align.CENTER,Align.CENTER,Align.MIN), mode=Mode.SUBTRACT) return b.part def p_focuser_board(): with BuildPart() as b: Box(120, 120, 14) with Locations((0,0,-7)): Cylinder(TUBE_OD/2, 140, rotation=(0,90,0), align=(Align.CENTER,Align.CENTER,Align.MIN), mode=Mode.SUBTRACT) Cylinder(30.75, 40, mode=Mode.SUBTRACT) with PolarLocations(46, 4, start_angle=45): Cylinder(2.6, 30, mode=Mode.SUBTRACT) return b.part def p_tube_ring(): # PRINTED PAHT-CF (checked against H2C envelope) BORE = TUBE_OD + 2*0.25 with BuildPart() as b: # MACHINED aluminium, not printed Cylinder(BORE/2+13, 26) Cylinder(BORE/2, 30, mode=Mode.SUBTRACT) with Locations((0,-(BORE/2+11.0),0)): Box(60, 22, 26) with Locations((0,-(BORE/2+11.0),0)): with GridLocations(40,0,2,1): Cylinder(3.3, 34, mode=Mode.SUBTRACT) with Locations((0, BORE/2+6, 0)): Box(30, 14, 26, mode=Mode.SUBTRACT) # hinge/clamp gap return b.part def p_dovetail(): with BuildPart() as b: Box(74, 14, 320, align=(Align.CENTER,Align.CENTER,Align.CENTER)) return b.part def p_fan_shroud(): # PRINTED PETG with BuildPart() as b: Cylinder(66, 18, align=(Align.CENTER,Align.CENTER,Align.MIN)) Cylinder(60, 24, align=(Align.CENTER,Align.CENTER,Align.MIN), mode=Mode.SUBTRACT) with GridLocations(105,105,2,2): Cylinder(2.3, 24, align=(Align.CENTER,Align.CENTER,Align.MIN), mode=Mode.SUBTRACT) return b.part def p_dew_shield_half(): # PRINTED PETG, split because Ø250 x 300 exceeds H2C with BuildPart() as b: Cylinder(TUBE_OD/2+3.2, 300, align=(Align.CENTER,Align.CENTER,Align.MIN)) Cylinder(TUBE_OD/2+1.0, 320, align=(Align.CENTER,Align.CENTER,Align.MIN), mode=Mode.SUBTRACT) with Locations((TUBE_OD/2+20,0,150)): Box(TUBE_OD+40, TUBE_OD+40, 320, mode=Mode.SUBTRACT) return b.part def p_cable_guide(): # PRINTED PETG with BuildPart() as b: Box(30, 16, 10, align=(Align.CENTER,Align.CENTER,Align.MIN)) with Locations((0,0,10)): Cylinder(5, 34, rotation=(0,90,0), mode=Mode.SUBTRACT) with Locations((0,0,0)): Cylinder(2.2, 16, align=(Align.CENTER,Align.CENTER,Align.MIN), mode=Mode.SUBTRACT) return b.part def p_focuser_body(): # bought-in envelope with BuildPart() as b: Cylinder(38, 35, align=(Align.CENTER,Align.CENTER,Align.MIN)) with Locations((0,0,35)): Cylinder(30.0, 42, align=(Align.CENTER,Align.CENTER,Align.MIN)) return b.part def p_imaging_train(): # corrector + drawer + OAG + camera envelope with BuildPart() as b: Cylinder(30, 62, align=(Align.CENTER,Align.CENTER,Align.MIN)) with Locations((0,0,62)): Cylinder(43, 48, align=(Align.CENTER,Align.CENTER,Align.MIN)) return b.part def p_fan(): with BuildPart() as b: Box(120, 120, 25, align=(Align.CENTER,Align.CENTER,Align.MIN)) Cylinder(58, 30, align=(Align.CENTER,Align.CENTER,Align.MIN), mode=Mode.SUBTRACT) return b.part # ═══════════════ ASSEMBLY ═══════════════ def assembly(): """[(name, solid, printed?)] — every position derived from a mating datum.""" # datums Z_CELL_BASE = 29.0 Z_PAD_TOP = Z_CELL_BASE + 17.0 # cell pad face Z_GLASS_BOT = Z_PAD_TOP # glass SITS on the pads Z_GLASS_TOP = Z_GLASS_BOT + MIR_THK Z_CLIP_BOT = Z_GLASS_TOP + 0.40 # clip standoff fit R_ROLLER = 100.75 + 10.6 # roller inner face 0.75 off the glass OD Y_RING_FOOT = -(TUBE_OD/2 + 0.25 + 11.0 + 11.0) A = [] def add(n, s_, printed=False): A.append((n, s_, printed)); return s_ add("tube", p_tube()) add("mirror_cell", p_mirror_cell().translate((0,0,Z_CELL_BASE))) add("primary", p_primary().translate((0,0,Z_GLASS_BOT + MIR_THK/2))) for i,a in enumerate((90,210,330)): r = math.radians(a) add(f"mirror_clip_{i+1}", p_mirror_clip().rotate(Axis.Z, a-90) .translate((104*math.cos(r), 104*math.sin(r), Z_CLIP_BOT)), printed=True) for i,a in enumerate((225,315)): r = math.radians(a) add(f"edge_roller_{i+1}", p_edge_roller().rotate(Axis.Z, a) .translate((R_ROLLER*math.cos(r), R_ROLLER*math.sin(r), Z_CELL_BASE+12)), printed=True) add("fan_shroud", p_fan_shroud().translate((0,0,Z_CELL_BASE-6-18)), printed=True) add("fan", p_fan().translate((0,0,Z_CELL_BASE-6-18-25))) add("spider_hub", p_spider_hub().translate((0,SEC_OFFSET,Z_VANE))) for i,a in enumerate((45,135,225,315)): v = p_spider_vane().translate((0, VANE_ROOT, 0)).rotate(Axis.Z, a) add(f"spider_vane_{i+1}", v.translate((0,SEC_OFFSET,Z_VANE))) add("secondary_holder", p_secondary_holder().rotate(Axis.X, 45) .translate((0,SEC_OFFSET,Z_SPIDER)), printed=True) _pz = (SEC_THK + 2.0)/2.0 # pocket centre, holder-local add("secondary_stalk", p_secondary_stalk().translate((0,SEC_OFFSET,STALK_BOT))) add("secondary", p_secondary().rotate(Axis.X, 45) .translate((0, SEC_OFFSET - _pz*math.sin(math.radians(45)), Z_SPIDER + _pz*math.cos(math.radians(45))))) add("focuser_board", p_focuser_board().rotate(Axis.Y, 90).translate((TUBE_OD/2+7,0,Z_SPIDER))) add("focuser_body", p_focuser_body().rotate(Axis.Y, 90).translate((TUBE_OD/2+14,0,Z_SPIDER))) add("imaging_train", p_imaging_train().rotate(Axis.Y, 90).translate((TUBE_OD/2+91,0,Z_SPIDER))) add("tube_ring_1", p_tube_ring().translate((0,0,Z_RING1))) add("tube_ring_2", p_tube_ring().translate((0,0,Z_RING2))) add("dovetail", p_dovetail().translate((0, Y_RING_FOOT - 7.0, (Z_RING1+Z_RING2)/2))) add("dew_shield_half_1", p_dew_shield_half().translate((0,0,TUBE_LEN-40)), printed=True) add("dew_shield_half_2", p_dew_shield_half().rotate(Axis.Z,180).translate((0,0,TUBE_LEN-40)), printed=True) for i,z in enumerate((330,520)): add(f"cable_guide_{i+1}", p_cable_guide().rotate(Axis.X,-90) .translate((0,-(TUBE_OD/2+14.0),z)), printed=True) return A