Spectral Fiber Cladding and Prism
Printed parts:
- prism alignment jig
- fiber-cutting jig
- cladding mold top
- cladding mold bottom
COTS parts:
- M3 heat-set inserts
- M3 bolts
- [imperial] heat-set inserts (x2)
- 2.5mm acryilc PMMA fiber
- Luer lock connector (x2)
- luer lock connector cover (x1)
- 3mm coated prism (x1)
Materials:
- dp100 3M epoxy
- epoxy dispensing gun
- dispensing mixing tips
- DragonSkin 10 NV
- Silicone thinner
- Titanium dioxide powder
- Luer lock syringe
Equipment:
- Thinky mixer or similar centrifuge
- vacuum chamber (optional)
- Hand saw/bandsaw
Cladding Casting
Preliminary Steps:
Insert M3 heat-set inserts into all holes in the cladding mold bottom. Insert [imperial] heat-set inserts into the holes in the cladding mold top, and then screw in luer locks into both holes. Trim the syringe body using a saw until only ~2cm remains. Cut a [140mm] length of 2.5mm PMMA fiber and set aside.
Step 1:
Prepare the cladding mold by placing the fiber in the mold bottom and putting the mold top on. Screw in two screws at the bottom end [describe which end is which] so that the fiber is clamped in place. Now pull on the other end of the fiber until you feel that it is stretched taught, and screw in the bolts at that end. This ensures that the fiber is as straight as possible during while casting. Tighten all other bolts and set aside for now.
Step 2:
Combine 10 grams of DragonSkin 10 NV Part A with [0.5?] grams of silicone thinner. Mix slightly with popsicle stick. Now pour in 10 grams of Part B along with [1?] gram of titanium dioloxide powder. Before putting the powder in it is helpful to break up small clumps with a popsicle stick. Mix until roughly combined then put in centrifuge until the silicone is a uniform opaque white (1-1.5 minutes)
Step 3:
Screw on the cut syringe end into the top luer lock in the mold and then slowly pour the silicone mixture into the syringe, until the syringe body is filled around 3/4 of the way. Make sure you leave room for the syringe plunger to fit without trapping too much air. While holding the mold upright at a slight angle, gently press on the syringe plunger until silicone mixture comes out of the bottom luer lock. We have had luck with ensuring a lot of silicone mixture exits the bottom before putting on the luer lock cover. Once done, remove the syringe body from the top and leave it uncovered and prop the cladding mold at an angle. This will allow any trapped bubbles to leave through an air outlet. Allow to cure following the same instructions as the bladder casting.
Step 4:
Once curing is complete, unscrew the mold and carefully separate the halves. The cladding will likely delaminate more easily from the mold bottom and stay attached to the top. Unscrew the luer lock connections and remove. Carefully peel the cladded fiber starting at one end. It may be helpful to cut the connected silicone stems with a razor blade to prevent the cladding from tearing.
Step 5:
Once free, carefully remove all of the flashing along the molding seam of the fiber. This flashing should be very thin and should separate by gently pulling with a fingernail. Place the cladded fiber into the fiber-cutting jig and make two perpendicular cuts with a razor blade. There are two lengths of fibers needed per SCANS finger, so ensure you keep track of which cut you make each time.