Clear Fiber Cable Light Tightening

1
Clear Fiber Cable Light Tightening

• Howard Budd
• University of Rochester
• MINERnA PMG Meeting
• Nov 14 2007

2
Outline

• Old Process
• RD Saga
• Fabrication Procedure
• QC tests
• Fire
• Transmission ratio, after boot/before boot
• Light tightness
• From here to production
• Schedule

3
Boots, Old Process

• Problems with Process in May 2007
• Ferrule positioned in mold off polished end, but
  the length of the polished end changed causing a
  path for the mold material to flow to the front
  of the connector.
• Material flowed easily, including places we
  didnt want, like the polished fiber end the
  clips
• Material flowed into mold ejection parts, jamming
  them up.
• In trying to make the boot fire resistant, the
  boot would expand and be too wide.
• ESH impact of the material, chemical
  hood(polyurethane, Al(OH)3 fire retardant)
• Remediation
• New mold new mold material

4
Mold Redesigned Simplified
Old mold
New mold
5
New Mold

• Use sliding clamp to press connector against mold
  to prevent mold material from flowing to front of
  connector
• The Alumilite polyurethane did not flow into
  around the connector to the polished fibers as it
  was doing with the old mold
• No extraction pins which got gummed up in
  previous mold
• Use straps put in the boot
• Mold cost cut in half
• We have successfully made bootswith new mold and
  our originalmolding material, Alumilitepolyureth
  ane

6
New Boot Mold
Features Simplified reduced cost by
50 Increased draft for easier part removal Mold
cavity is plated polished for easy part
removal No ejector pins or moving plates Modular
design to allow for future changes Added slides
to account for molded connector size
fluctuations Cavity sealing improved to stop
leakage of watery molding materials
7
Mold Material The Search

• We research materials for mold
• Worked with PPD ESH on the material
• The requirements are
• Viscosity 1000-15000 cps
• Can be pulled out of mold after 1.5 hours at the
  latest
• Light tight
• Use mixing nozzle, preferably with prepackaged
  cartridges
• Durameter A of 90 or harder, RTV doesnt work
  here
• Fire resistant to UL94
• Like to avoid using a chemical hood for the
  molding
• After an extensive search, we found nothing which
  satisfied all these criteria.
• But we have solution which passes the tests

8
Hiegl MP5405bk Epoxy the Winner

• Hardens in 15 minutes, this will make production
  efficient
• Viscosity OK, but it cant be more viscous
• Comes in 50 ml 2 component packages for mixing
  gun
• No chemical hood needed,
• Probably has the least ESH problems when you
  look at the MSDS
• Not fire resistant will address later
• Problem, the black material transmits red light
• See the red light from a flash light through a
  thick sample, ½ inch thick
• Heigl is eager to work with us to satisfy our
  criteria
• Heigl sent us one 50ml tube of HP5405bk with
  additional carbon black
• Needed to use a custum modified epoxy
  MP5405bk-Mod
• Additional carbon black

9
Original Material

• The orginal material was Alumilite, but we had
  problems
• It is more fluid than we want
• We tried to make it less fluid but this didnt
  work well
• Will require a chemical hood, restricts how we do
  production
• 4,4 diphenylmethanediisocynate MDI, require ppb vapor
• Not fire resistant
• We tried to make it fire resistant by putting in
  ATH
• If you put in enough ATH to make it fire
  retardant, it expands
• If you put in less its worse than if you put in
  no ATH.
• The ATH makes a gun mixing system difficult to
  use
• When painted, it did worse than the Heigl.
• Some other materials worked but set in 1.5
  hours
• One fire retardant material - ESH problems no
  mixing system

10
Making and Verifying Boots

• We have put boots on 10 cables which have been
  tested
• In addition, we boots on 4 other cables, in which
  we learned we had to add a step to make them
  light tight
• As of today, 27 cables have boots put on, but
  only whats in this talk has been tested.
• Verify the cables satisfy the following
  requirements
• Cables should be fire resistant
• The epoxy should not damage the fibers
• Cables should be light tight
• Note at this point there is no evidence of
  physical changes in the epoxy or the epoxy making
  physical changes in the boots
• Note, if bent, an RTV boot can move a fiber glued
  fiber in the connector
• We have had Heigl boots for 3 months and boots
  still seem OK

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Tasks to Making Light Tight Cables Beyond ODUs

• Have been producing ODUs since beginning of the
  year
• Cables like ODUs (Optical Decoder Units) only
  cables are light tight.
• Before gluing fibers in ferrules
• Put on black tube of correct length
• Region from ferrule to black tube was made longer
  so that putting on the clip is easy
• Insert fiber order is correct in connector
• After gluing
• Put ferrules in gluing fixture and inject Heigl
  epoxy into the ferrules to close a hole
• Need to do this due to viscous nature of the
  epoxy
• Can do as many as 40 cables at once

12
Tasks to Making Boots Beyond ODUs

• Mold release on mold
• Put ferrule cable in mold
• Inject epoxy into mold, let harden 10 minutes
• Will be doing anywhere between 3-8 cables at once
  so this 10 minutes is not a wasted time
• Clean up mold release on boot
• File two of the edges so they are not sharp
• 1 coat of fire retardant paint
• Test cable for light tightness
• Test order of fibers with Fiber Order Tester
• Box with multi colored LEDs

13
Fire Tests

• Jim Priest suggestion is to paint boots with fire
  retardant paint
• Old can of black paint
• Sent initial set of Heigl boots painted sample
  to for fire test
• They ignited at the edges
• These edges were sharp, paint flows off edges?
• Jim suggested getting some new paint and painting
  the samples
• Filed the sharp edges and painted with green paint

14
Fire Tests

• Heigl Orig 1 coat of paint, 3 samples
• Passed, Good Slight ignition and self
  extinguished after 1 min of 10 sec applications
  of flame
• Heigl Orig 2 coats of paint, 2 samples
• Passed, ignition after 45 sec of 10 sec flame
  application was able to ignite and burn till he
  extinguished
• Heigl Carbon 1 coat (2 samples) 2 coats (1
  sample)
• Good news all the tests went well. They exceeded
  the UL 94 V-0 requirement.
• Looking at video, 2 samples no flame, one sample
  slight flame

15
Transmission QC Device

• LED on Calibration Pin Diode and WLS pigtail
• Calibration Pin Diode just in front of LED
• WLS fiber - jumper- cable-jumper-pigtail-pin
  diode
• Cable Measurement
• Measure without cable
• Direct Measurement
• Transmission (Cable Measurement / Direct
  Measurement)

Pin Diodes
LED
Tested Cable
Jumper
Jumper
WLS Pigtail
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2d ODU shipment, last 180

• Attenuation length of the clear fiber removed
• 1st transmission
• 2d each channel normalized to 1
• Divided each fiber by cable average
• Cable average

17
Fiber average over ODU number

• These are the ODUs which from the previous page
• We QC the prototype cables, but with 5 lengths
  the data is more difficult to understand at this
  point. Some of the cables were polished at the
  very end of a diamond change when were still
  trying to understand diamond changes.

18
Heigl Effect on fibers, Boot/no Boot

• Measured cables before putting on boot
• Measured after and take the ratio

19
After Boot/Before Boot

• Left plot has a damaged jumper for fiber 8, this
  makes fiber 8 measurement unreliable
• No indication the epoxy is damaging the fibers

20
Light Tests

• The Light Leak Checker
• Use R580 -17 (1½ in green extended tube) and
  picoammeter
• Ped is 0.80 na, HV1200
• Use room light of Lab G, have all lights on
• 2 configurations
• Interchange connectors on box
• The lower connector on box is not completely
  light tight for this test
• Decided to proceed with light tight test anyway

21
Light Tightness

• Current ped
• One cable in this set had a light leak in mold
  and this leak was covered
• For gain of 106, 0.2na corresponds to about 1
  g/ms
• Later, test 1 cable
• Shinned bright LED flashlight directly on boot
• Current ped 0.00 na
• Boots appears to be light tight

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3 out of 28 problem boots

• 3 of the boots had light leaks, 2 of these boots
  were not in the final production technique, but
  for these leaks it wouldnt have mattered
• 3 problems boots
• Pin hole leak near strap used to pull out cable
• Tape used to plug holes, stuck up slightly
  thinning the mold slightly
• Air bubble came out of tube while epoxy was
  hardening
• Problem due to the viscous nature of the epoxy
  and the thinning of the boot
• Do not want to modify epoxy 3 to 4 month
  process
• Although, these are easy to touch up we might
  tweak the mold
• Might make mold 1-1.5 mm thicker

23
Tasks to Production

• Finish prototype cable production
• Molds ordered except inserts
• Test insert and order 3 more inserts
• Original mold release didnt work with the new
  formulation of Heigl
• Switched mold release This one has 2 on health
  of MSDS
• Although not required by ESH, we will get a hood
  to spray the molds with release if we dont find
  a new mold release
• Possible use of existing spare hood.
• Will try other mold releases to get around this
  ESH problem
• PAM works well, but we have to clean all the oil
  off the cables
• Fire tests
• Another fire test with new mold release
• Jim Priest want to do a full fire test to
  complete burning

24
Schedule

• Expect to start tracking prototype cable
  production 1st of year
• It will go for about 5 months
• Start production cables, we are 2 months of
  critical path