Probably not a complete list Outstanding issues Bonding problems when gluing the top face sheet Observed in stave 12 M issing bond in area close to the EOS between the foam blocks foam blocks seem to be bonded and thermal FEA agrees ID: 487446
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Slide1
Outstanding Issues in Stave Core Assembly
Probably not a complete listSlide2
Outstanding issues
Bonding problems when gluing the top face sheet
Observed in stave #12:
Missing bond in area close to the EOS between the foam blocks, foam blocks seem to be bonded and thermal FEA agreesAt the time attributed to incomplete QC after core grindingAgain present in stave #11 (which was completed after #12), but much smallerPossibly related to issue of glue application on honeycomb – this is still not a very controlled processNeeds to be understood and fixedDimensional variations of cooling pipe and cooling pipe wiggleSo far we have not had one cooling pipe with the insulating breaks at the correct locationRequires development of correct jiggingWe never had a pipe with the wiggleIn principle that should not be a problem, but we need to play it throughIntegration of QC into assembly and data storage in DBNeed definition of QC, then write procedure listsWaiting for DB student from Prague to visit to discuss implementation of stave build related dataAccurate process timingNeeded for production planningScaling for productionPrepare adequate areaTraining
2Slide3
Things to be done, but don’t expect a problem
Move to 14 modules and 2x/2x stereo
angle
New tooling, but no differences in the processDecision on epoxy filler material – BN or graphiteWe have used both and seen no obvious problems with either Co-curing of Cu strips for groundingWe have co-cured Cu strips on the top of the EOS area in the past, David wants another strip on bottom, should not be a problemWe might need to increase the tape thickness to create a better transmission lineI don’t think this has major implications for the stave build (other than adjustment of jig thicknesses)3Slide4
Issues being addressed
Improve gluing of thermistor flex
We have to decided to do
this as a standalone step before the pipe is glued inTooling is being developed and we want to use this for the next staveCover layer for tape during stave buildTo prevent CF contamination of bond areasMaterial has been identified and samples are availableWill use for build of next stave4Slide5
Things I still want to try out
Co-cure with perforated release film
It is obvious that there is a lot of excess resin using the current
prepreg: knobbly back surface – also confirmed by Tony’s facesheet sectionsWould like to see if we can suck up excess resin using perforated release filmSamples of perforated release film are being procured5Slide6
Non-issues (aka red herrings)
Any discussions of turning around the lay-up of the
facesheets
Any discussions of covering tape cut-outs with flashbreaker tapeWe never had any problems with height variations in the back of the tapeWhen Carl was here he had to admit that he doesn’t see any problems with the facesheets we producedNot clear why he is still going on about thisIt will be interesting to see the results with the perforated release film6