Define the function of each layer
Document which layer provides the compliant interface around the glass and which provides external protection. Set separate material and finished-fiber criteria for those roles.
Map the wet-on-wet process
Record application order, material temperature, concentricity control, layer dimensions and the time between coating and cure. Evaluate the actual sequence used on the draw line.
Characterize the cure sequence
Document UV source conditions, line speed, atmosphere and how the primary and secondary layers receive exposure. A nominal lamp setting alone does not establish cure compatibility.
Check the coating interface
Inspect layer continuity, adhesion, surface condition and dimensional stability using agreed methods. Include aging or conditioning when it is relevant to the finished construction.
Qualify the finished fiber
Use optical, mechanical, environmental and handling tests on fiber made with the intended glass, dimensions and line process rather than relying on bulk material data alone.
INFORMATION CHECKLIST
Prepare these details for a productive material discussion.
- Primary and secondary layer functions
- Wet-on-wet application sequence
- Layer dimensions and concentricity
- UV and line-process conditions
- Finished-fiber qualification tests
TECHNICAL FAQ
Questions to clarify before evaluation
Can primary and secondary coatings be selected independently?
Their individual properties matter, but the interface, cure sequence and finished-fiber performance should also be evaluated as one system.
Why is the draw-line sequence part of compatibility?
Application timing, geometry, UV exposure and atmosphere can affect the interface and the cure state of both layers.
What should be compared between coating systems?
Compare materials under matched test conditions and then qualify the complete coated fiber using the intended process and acceptance tests.