When a bond joint needs more UV energy per cycle, the reflexive fix is a bigger lamp. Often the actual bottleneck is smaller than that — it’s the lightguide core collecting less light than the lamp is capable of delivering.
More Core Area, Same Lamp
Core diameter determines how much light a liquid lightguide collects from its source, and that relationship isn’t linear with diameter — it follows cross-sectional area. The Incure LLG-1P-5’s 5 mm core has a 19.6 mm² cross-section, against the 7.1 mm² of the 3 mm LLG-1P-3 — roughly 2.8× more collection area from the same lamp output. On wider or thicker bond joints that need a higher UV dose per trigger cycle, that difference shows up directly as more energy delivered to the adhesive, without touching the lamp head or extending exposure time. The guide itself is doing more of the work.
That distinction is worth spelling out because it’s counterintuitive to anyone used to thinking about lamp specifications first: two identical lamp heads driving different core-diameter lightguides will deliver meaningfully different dose at the bond point, purely as a function of how much of the lamp’s output each guide is physically able to collect and transmit.
That distinction matters when a process is under-curing on marginal cycles: before assuming the lamp needs replacing or upgrading, checking whether the current lightguide core is undersized for the joint is the cheaper diagnostic step, and often the actual fix.
Direct Terminator Compatibility, No Adapter
The LLG-1P-5 is built to pair directly with the Ø5mm LGT-Series terminators — the LGT-90-5 for perpendicular bond faces and the LGT-60-5 for oblique access into recessed or angled cavities. Both terminators mount straight onto the LLG-1P-5’s Ø5mm tip with no coupling loss at the joint, since the aperture is a direct match rather than a stepped-down interface. That means a facility standardizing on the LLG-1P-5 core size gets full terminator flexibility — perpendicular or oblique bond access — without adding an adapter component or accepting the energy loss an adapter interface introduces.
Email Us if a current bond process is under-curing and the lightguide core size, not the lamp itself, may be the actual bottleneck.
Reach Without Losing Transmission
Available in cable lengths from 1,000 mm to 3,000 mm, the LLG-1P-5 extends further than the LLG-1P-3’s 2,000 mm maximum — useful for stations where the lamp-to-part distance is simply longer, not just where a bigger spot is needed. Liquid lightguide construction maintains full UV transmission across that whole length range: the same 300 nm minimum wavelength and up to 5 W output at 1,000 mm as at 3,000 mm, since liquid waveguides don’t lose transmission per meter the way fiber optic bundles can on longer runs. Cable length becomes a fixture-layout decision rather than a performance trade-off.
Application Fit
The 5 mm core sits at the middle of the single-pole range — wide enough to raise dose meaningfully over the 3 mm option, without moving into the widest-flux territory the 8 mm core is built for. It suits wider or thicker bond joints that were previously marginal on a 3 mm core, along with any application where LGT-Series terminator compatibility at Ø5mm is a requirement rather than a nice-to-have. Mercury arc, xenon, and halogen spot curing lamps all drive it identically; it is not compatible with UV LED sources.
The 5 mm core’s popularity as the “default” single-pole size in mixed-fixture facilities often comes down to this terminator compatibility rather than the dose increase alone — a facility standardizing on the LLG-1P-5 keeps the option open to add perpendicular or oblique bond access later with an LGT-Series terminator, without having to swap the lightguide itself when the fixture geometry changes on a new project. Operating temperature is rated −5°C to +35°C, consistent across the single-pole family — worth confirming against ambient shop-floor conditions before final selection.
Choosing Core Size and Reach
Against its two single-pole siblings, the LLG-1P-5 sits in the middle on both dose and reach. The LLG-1P-3 offers a tighter, more contained spot and the only 500 mm cable option, better suited to compact fixtures and heat-sensitive adjacent components. The LLG-1P-8 goes further in both directions — the widest core in the single-pole range at 8 mm, and the longest reach at 6,200 mm, for the highest-flux, longest-run applications. Multi-point configurations — the bifurcated LLG-2P-3, trifurcated LLG-3P-3, and quad-pole LLG-4P-3 — solve a different problem entirely: simultaneous cure at multiple bond points from one lamp, rather than raising dose at a single point.
For UV LED spot curing rather than arc-based systems, the Incure L9000 lightguide series is the compatible platform, since LED sources require LED-specific fiber optic construction. See Incure’s full lightguide selection guide for the complete range comparison, the LGT-Series terminator lineup this guide pairs with directly, and the LS217 lightguide simulator for tracking transmittance over the guide’s service life. Contact Our Team to work through core size and reach for a specific bond process.
Visit www.incurelab.com for more information.