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Stave Tooling & Plans for Future Stave-building. (Tim). Stave Assembly Tool Update. Development of 2 nd generation Stavelet assembly tool CF / Nomex sandwich construction Brass inserts for dowels & threaded holes Steel plates for magnetic chuck Vacuum channel formed in FR4
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Stave Assembly Tool Update • Development of 2nd generation Stavelet assembly tool • CF / Nomex sandwich construction • Brass inserts for dowels & threaded holes • Steel plates for magnetic chuck • Vacuum channel formed in FR4 • Ground CF top plate
Trial Assembly Studies • Stave Components • Facesheets • K13D2U/RS3 panels 1.3m x 0.31m (0/90/0) • Cut out on pattern cutter • Honeycomb • Nomex grade N636 (Korex replacement) • http://www.compositematerialsltd.com/pdfs/nomex_honeycomb/cormaster_n636.pdf • 4.8mm cell / 28kg.m-3 (1.75 lbs/cuft) • Laser cut (1st go as a trial) • ‘C’-channels • Original manufacturing tool – slight lip on open edges (need to re-make tool to improve) • End Close-outs • Peek (from QMUL)
Laser-cut N636 Honeycomb • Honeycomb is not as ‘uniform’ as Ultracor CF • Stress-free cutting results in good edge definition & perpendicularity • Slight charring of edges
C-channel Jig • 2 C-channels loaded into Jig • Jig located on assembly tool using locator blocks • Holes match !!!
Next Steps • Manufacture of dummy stave • No cooling tube, no Allcomp foam • Steps (start tomorrow) • End close-outs • Honeycomb • Grind • Attach 2nd side • Manufacture of 1st full stave • Cooling tube (from RAL) • Poco foam (have some left) • Steps • Full assembly sequence
Low-density Adhesives / Stencils • Single (few) use laser machined stencil from thin plastic (eg Perspex) • 3/8” CF honeycomb has good cell uniformity so maybe glue can be applied to facesheet using a stencil • Trial stencil manufactured from 0.5mm thick Perspex • Area coverage 23% • Glue volume = 10cc / stavelet • Low viscosity of neat Hysol 9396 means glue easily flows between stencil & CF face sheet • Looking into glass micro-balloons to increase viscosity & reduce glue mass (ρ≈0.67gcm-3)
Possible Extension • Multi-use pattern • Thermal foam • ‘C’-channels & honeycomb • Alternative Patterns • Corrugated core
Summary • Aim to manufacture 1 or 2 dummy staves (<4 weeks) • General ‘training’ (assembly techniques & machining) • Flatness measurements • 3 point bending • Move to Full Stave (4-6 weeks) • Use remaining Pocofoam • Need cooling tube • Maybe new ‘C’-channel jig ? • Further investigations of stenciling • Thinner material (eg. 0.35mm Mylar) • Probably only applicable to large cell & very uniform honeycomb