Stave Tooling & Plans for Future Stave-building

(Tim)

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)

First Trials

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