Description
Non-circular bore geometry is the reason this is a separate product from round capillary — a square or triangular internal bore holds a component against multiple flat faces for rotational alignment, which a round bore can’t do.
Bore Geometry
| Profile | Detail |
|---|---|
| Square bore | Inner diameter accuracy to ±0.001 mm on precision optical-grade product |
| Triangular bore | Per drawing |
| D-shape | Per drawing — flat reference face plus curved wall |
| Eccentric | Off-center bore, per drawing |
| Corner geometry | Sharp or radiused corner, per drawing |
Outer Dimensions
Standard capillary OD/wall range applies (see Precision Round Capillaries) — the outer profile can be round or match the inner bore shape (outer-square, outer-circle with square hole, outer-hexagon, all available per drawing).
Application
- Precision fiber alignment — square-bore capillary can position up to 4 optical fibers against its flat internal walls
- Optical connectors, fiber joints, and couplers where rotational/angular alignment against a flat reference matters, not just centering
Production Method
CNC wire-drawing tower process — same dimensional accuracy and positioning precision approach as round precision capillary, applied to the non-round bore profile.
Material
High-purity fused quartz, SiO₂ >99.99%, superior UV transmission for optical-path applications.
FAQ
How tight can the bore tolerance be held on a square-bore capillary?
±0.001 mm (inner diameter accuracy) is cited for precision optical-grade square-bore product — confirm against your fiber-positioning requirement.
Can the outer profile differ from the inner bore shape?
Yes — outer-round with square bore, outer-square with round bore, and outer-hexagon variants are all available per drawing.
How many fibers can a square-bore capillary position?
Up to 4 fibers is cited for standard square-bore capillary positioning against the flat internal walls; confirm against your specific fiber count and diameter.