r""" Six-component aluminum sting balance - CAD (sizes from ../../analysis/six_component_balance_sizing.py). One piece 7075-T651: front block | FWD neck | block | axial Z-flexure | block | AFT neck | aft block | 0.750 spigot - Necks 0.220 W (y) x 0.510 H (z) x 0.90 L, stations at x = +-1.35 in, cut from all four sides with r 0.06 fillets in both planes (pitch AND yaw bending, roll torsion). - Axial flexure, slots, front-face pattern and spigot details as the 3-component balance. Also builds the matching model puck, instrumented 2.25 in pod (longer) and the 17.45 in sting (clamp flats stay at x = 17..20 in for the roll spindle / pitch sector). Coordinates (inches, exported mm): x aft, y spanwise, z up, BMC at x = 0. Run (from this folder): ..\..\.venv\Scripts\python build_6c_balance_cad.py """ import math import sys from pathlib import Path import cadquery as cq HERE = Path(__file__).resolve().parent sys.path.insert(0, str(HERE.parent / "aluminum_balance")) sys.path.insert(0, str(HERE.parent)) sys.path.insert(0, str(HERE.parents[1] / "analysis")) from build_balance_cad import box, xz_cut # noqa: E402 import pod_instrumentation as PI # noqa: E402 import six_component_balance_sizing as S6 # noqa: E402 IN = 25.4 W, H = S6.BAR_W, S6.BAR_H _, _, NB, NH = S6.size_neck() # 0.220, 0.510 LN, RF = S6.L_NECK, S6.R_FIL XS = S6.a # 1.35 FWD = (-XS - LN / 2, -XS + LN / 2) AFT = (XS - LN / 2, XS + LN / 2) BLOCK_END = 0.75 X_FRONT = FWD[0] - BLOCK_END # -2.55 X_AFT = AFT[1] + BLOCK_END # +2.55 RAIL, T_P, E_P, X_AX, SLOT, R_W = 0.25, 0.025, 0.75, 0.60, 0.012, 0.03 SPIG_D, SPIG_L = 0.75, 1.25 PIN_X = X_AFT + 0.90 STING_D = 0.875 STING_L = 20.0 - X_AFT # flats at x = 17..20 as before PUCK_D, PUCK_T = 1.70, 0.30 POD_D, POD_BASE_D, POD_BORE_R = 2.25, 1.50, 0.8525 def xy_cut(x0, x1, y0, y1, r=0.0, sel=None): """Through-all (z) prism with optional fillets on its z-parallel edges.""" c = box(x0, x1, y0, y1, -2, 2) if r > 0: c = c.edges("|Z").edges(sel).fillet(r) return c def make_balance(with_plates=True): b = box(X_FRONT, X_AFT, -W / 2, W / 2, -H / 2, H / 2) for x0, x1 in (FWD, AFT): b = b.cut(xz_cut(x0, x1, NH / 2, H, RF, "Z")) # pitch flats b = b.cut(xy_cut(x0, x1, NB / 2, 1.0, RF, "Y")) # yaw flats zi = H / 2 - RAIL xa, xb = -E_P / 2, E_P / 2 b = b.cut(xz_cut(xa + T_P / 2, xb - T_P / 2, -zi, zi, R_W)) b = b.cut(xz_cut(-X_AX, xa - T_P / 2, -zi, zi, R_W)) b = b.cut(xz_cut(xb + T_P / 2, X_AX, -zi, zi, R_W)) b = b.cut(xz_cut(-X_AX - SLOT, -X_AX, zi - 0.075, H)) b = b.cut(xz_cut(X_AX, X_AX + SLOT, -H, -zi + 0.075)) if not with_plates: for xc in (xa, xb): b = b.cut(xz_cut(xc - T_P, xc + T_P, -zi - 0.01, zi + 0.01)) # spigot: set-screw flat, 3/16 cross pin, wire bore + exit through the top of the aft block b = b.union(cq.Workplane("YZ").circle(SPIG_D / 2).extrude(SPIG_L).translate((X_AFT, 0, 0))) b = b.cut(box(X_AFT + 0.15, X_AFT + SPIG_L + 0.1, -1, 1, SPIG_D / 2 - 0.075, 1)) b = b.cut(cq.Workplane("XZ").center(PIN_X, 0).circle(0.09375).extrude(1, both=True)) b = b.cut(cq.Workplane("YZ").circle(0.125).extrude(X_AFT + SPIG_L - (X_AFT - 0.25)).translate((X_AFT - 0.25, 0, 0))) b = b.cut(cq.Workplane("XY").center(X_AFT - 0.25, 0).circle(0.094).extrude(1)) # front face: 2x #10-32 tapped (z = +-0.42), 2x 1/8 dowels (z = +-0.17) for z, d, dep in ((0.42, 0.159, 0.5), (-0.42, 0.159, 0.5), (0.17, 0.125, 0.3), (-0.17, 0.125, 0.3)): b = b.cut(cq.Workplane("YZ").center(0, z).circle(d / 2).extrude(dep).translate((X_FRONT, 0, 0))) return b def make_puck(): x0 = X_FRONT - PUCK_T p = cq.Workplane("YZ").circle(PUCK_D / 2).extrude(PUCK_T).translate((x0, 0, 0)) p = p.union(cq.Workplane("YZ").circle(0.25).extrude(0.10).translate((x0 - 0.10, 0, 0))) for z in (0.42, -0.42): p = p.cut(cq.Workplane("YZ").center(0, z).circle(0.098).extrude(1).translate((x0 - 0.5, 0, 0))) p = p.cut(cq.Workplane("YZ").center(0, z).circle(0.16).extrude(0.20).translate((x0 - 0.10, 0, 0))) for z in (0.17, -0.17): p = p.cut(cq.Workplane("YZ").center(0, z).circle(0.0625).extrude(1).translate((x0 - 0.5, 0, 0))) xm = x0 + PUCK_T / 2 for ang in (45, 135, 225, 315): p = p.cut(cq.Workplane("XY").circle(0.068).extrude(0.35).translate((0, 0, PUCK_D / 2 - 0.35)) .rotate((0, 0, 0), (1, 0, 0), ang).translate((xm, 0, 0))) return p.cut(cq.Workplane("YZ").center(0.60, 0).circle(0.094).extrude(1).translate((x0 - 0.5, 0, 0))) def make_sting(): x0 = X_AFT s = cq.Workplane("YZ").circle(STING_D / 2).extrude(STING_L).translate((x0, 0, 0)) s = s.cut(cq.Workplane("YZ").circle(0.3755).extrude(SPIG_L + 0.05).translate((x0, 0, 0))) s = s.cut(cq.Workplane("YZ").circle(0.15).extrude(STING_L).translate((x0, 0, 0))) s = s.cut(cq.Workplane("XZ").center(PIN_X, 0).circle(0.09375).extrude(1, both=True)) for xs in (x0 + 0.40, x0 + 1.10): s = s.cut(cq.Workplane("XY").center(xs, 0).circle(0.1065).extrude(1)) xc = x0 + STING_L - 3.0 s = s.cut(box(xc, xc + 3.1, -1, 1, 0.35, 1)).cut(box(xc, xc + 3.1, -1, 1, -1, -0.35)) for xh in (xc + 0.75, xc + 2.25): s = s.cut(cq.Workplane("XY").center(xh, 0).circle(0.1405).extrude(1, both=True)) return s def pod_geom(): x_puck0 = X_FRONT - PUCK_T return dict(nose_tip=x_puck0 - 2.2, cyl0=x_puck0 - 0.2, cyl1=X_AFT + 0.05, base=X_AFT + 1.80, r=POD_D / 2, rb=POD_BASE_D / 2, bore_r=POD_BORE_R, sting_clear=STING_D / 2 + 0.10, x_cav=x_puck0 - 0.12, x_screw=x_puck0 + PUCK_T / 2, r_bay=0.70) def make_pod(): g = pod_geom() pts = [(g["nose_tip"], 0)] for i in range(1, 13): f = i / 12 pts.append((g["nose_tip"] + f * (g["cyl0"] - g["nose_tip"]), g["r"] * math.sqrt(1 - (1 - f) ** 2))) pts += [(g["cyl1"], g["r"]), (g["base"], g["rb"]), (g["base"], 0)] outer = cq.Workplane("XY").polyline(pts).close().revolve(360, (0, 0, 0), (1, 0, 0)) inner = (cq.Workplane("XY").polyline([(g["x_cav"], 0), (g["x_cav"], g["bore_r"]), (g["cyl1"], g["bore_r"]), (g["base"] + 0.01, g["sting_clear"]), (g["base"] + 0.01, 0)]) .close().revolve(360, (0, 0, 0), (1, 0, 0))) pod = outer.cut(inner) for ang in (45, 135, 225, 315): pod = pod.cut(cq.Workplane("XY").circle(0.09).extrude(0.5).translate((0, 0, g["r"] - 0.45)) .rotate((0, 0, 0), (1, 0, 0), ang).translate((g["x_screw"], 0, 0))) pod, make_pod.report = PI.instrument_pod(pod, g) return pod def nsol(wp): return len(wp.solids().vals()) if __name__ == "__main__": bal = make_balance() print(f"balance: {nsol(bal)} solid (expect 1); plates removed -> {nsol(make_balance(False))} (expect 2); " f"length {X_AFT - X_FRONT:.2f} in + {SPIG_L} in spigot; volume {bal.val().Volume():.3f} in^3 " f"({bal.val().Volume()*0.101:.2f} lb)") print(f"necks {NB:.3f} W x {NH:.3f} H x {LN} L at x = +-{XS}; front face x = {X_FRONT}, aft block end x = {X_AFT}; " f"sting {STING_L:.2f} in") parts = {"balance_6c_7075": bal, "model_puck_6061": make_puck(), "sting_4140": make_sting(), "pod_reference_2.25in_printed": make_pod()} PI.print_report(make_pod.report, "6-component pod") for n, wp in parts.items(): cq.exporters.export(cq.Workplane().add(wp.val().scale(IN)), str(HERE / f"{n}.step")) print(f" {n}.step ({nsol(wp)} solid)") names = list(parts) worst = 0.0 for i in range(len(names)): for j in range(i + 1, len(names)): v = parts[names[i]].val().intersect(parts[names[j]].val()).Volume() if v > 1e-6: print(f" overlap {names[i]} x {names[j]}: {v:.5f}") worst = max(worst, v) print(f"assembly max interference {worst:.5f} in^3") col = {"balance_6c_7075": (0.75, 0.75, 0.8), "model_puck_6061": (0.55, 0.6, 0.9), "sting_4140": (0.35, 0.35, 0.35), "pod_reference_2.25in_printed": (0.2, 0.7, 0.4, 0.35)} asm = cq.Assembly(name="six_component_balance_flight") for n, wp in parts.items(): asm.add(cq.Workplane().add(wp.val().scale(IN)), name=n, color=cq.Color(*col[n])) asm.export(str(HERE / "assembly_6c_flight.step")) print(" assembly_6c_flight.step")