barrel trt straw wire support assembly and insertion

Click here to load reader

Post on 09-Feb-2016

30 views

Category:

Documents

1 download

Embed Size (px)

DESCRIPTION

Barrel TRT Straw Wire Support Assembly and Insertion. K. McFarlane Hampton University DOE/NSF Review, BNL March 2001. Wire Support Steps. Clean parts Assemble parts with epoxy Inspect a sample Insert CWS in rough-cut straw, gluing in place with epoxy - PowerPoint PPT Presentation

TRANSCRIPT

  • Barrel TRT Straw Wire Support Assembly and InsertionK. McFarlaneHampton UniversityDOE/NSF Review, BNL March 2001

    Hampton U ATLAS-TRT project

  • Wire Support StepsClean partsAssemble parts with epoxyInspect a sampleInsert CWS in rough-cut straw, gluing in place with epoxyInspect position and adhesion after curingInspect interior of final-cut straw.

    Hampton U ATLAS-TRT project

  • Ultem Part CleaningWe use a water-based ultra-sonic cleaning procedure, with multiple rinses in distilled water, and a final oven drying.

    Hampton U ATLAS-TRT project

  • Wire Support Assembly

    Hampton U ATLAS-TRT project

  • Center Wire Support Insertion

    Hampton U ATLAS-TRT project

  • CWS gluing methodA drop of epoxy is dispensed in the center of a 1480mm strawThe CWS is then pushed down the straw, over the drop.Positioning rodDispenserCWS

    Hampton U ATLAS-TRT project

  • Problems (1)At the beginning of production, it often happened that the drop was not dispensed, so the process was adjusted to ensure dispensingProblems were found in October, 2000 by Duke, coincidentally with our switching to a new batch of epoxy with less viscosity. There were glue spots in the straw, often very manyCWS insertion was shut down for several weeks while the problem was studied and adjustments made.

    Hampton U ATLAS-TRT project

  • Problems (2)Rejection was high, running above 50% for some batchesAbout 700 straws were lost due to excessive glueAs a result, a full interior inspection begun, using an angioscope.

    Hampton U ATLAS-TRT project

  • Comparison of InteriorsCleanSmall glue spots

    Hampton U ATLAS-TRT project

  • ChangesThe problem seems to arise from an interaction between glue viscosity, pressure and vacuum in the dispenser, and electrostatic forces between the glue and the straw.Changes were made in straw tip shape and spacing from the straw, pressure and vacuum used in dispensing, and the gluing fixtureWith rejection rates on interior inspection about 1%, the problem is being controlled

    Hampton U ATLAS-TRT project

  • More interiorsTwisterThis plow effect puts glue on wire-joint side

    Hampton U ATLAS-TRT project

  • ConclusionsRejection rate is still high (~1%)Work will continue to be done to reduce this rate through changes in the processMay require additional changes, including changing to inserting the CWS first; this will result in more glue in the straw at the wire joint side. This would affect the physics

    Hampton U ATLAS-TRT project