How to Choose a UV Light Guide
The light guide is the part of a spot-curing system that actually touches your process: it sets the spot size, the irradiance at the bond line, and how far and how flexibly the light reaches into a fixture. Choosing well comes down to five decisions, system family, construction, core diameter, length, and single versus multi-pole, plus a little care once it's on the bench. Here is how to work through each one.
Start with the system: the two guide families don't cross over
Guides for the arc-lamp SunSpot 2, the UV0570 and UV0571 single-pole guides, the UV0774 high-flux guide, and the multi-pole splitters, couple to the lamp's front-panel receptacle and interchange freely with each other. The SkyBeam LED controller instead takes the dedicated UV4053 LED light guide, one per channel, built at the channel's wavelength (365, 385, 395, or 405 nm) with interchangeable 6 and 12 mm focusing lenses. The two families are not interchangeable, so settle the system question first, everything below applies to picking within a family, and the full lineup is on our light guides page.
Liquid-filled or fused fiber?
Liquid-filled guides carry the UV through a sealed liquid core; fused-fiber guides bundle many individual glass fibers. Liquid-filled construction transmits more UVA for the money, which is why it is the standard across our catalog. Fused-fiber bundles tolerate tighter routing and autoclaving, and they are available made-to-order when a process demands them. Fiber construction also matters for splitters: fiber multi-pole guides randomize individual fibers from the input bundle to distribute light evenly between legs, while liquid multi-pole guides rely on a balancing procedure instead (more on that below).
Core diameter: intensity versus coverage
The same lamp energy pushed through a smaller core produces a hotter spot: a 5 mm guide delivers roughly 2.5× the irradiance of an 8 mm guide at the same setting. The rule is to pick the smallest diameter that still covers the bond line, excess diameter spreads energy over area you don't need and stretches cure times. The 1 m × 5 mm UV0570 is the standard guide shipped with every SunSpot 2 for exactly this reason, while the 8 mm UV0774 trades intensity for coverage on wide bond lines and small flood cures. If one guide must serve several spot sizes, a focusing lens assembly on a 5 mm tip adjusts the spot from 2 to 12 mm; on the SkyBeam side, spot size is set by swapping the lens at the guide's output end.
Length: order the shortest guide that reaches
Every meter of guide costs output, expect roughly 10–15% loss per meter in the UVA band. The stock 1 m guides suit most benches; the 1.5 m UV0571 buys reach into enclosed fixtures and robot end-of-arm tooling at a modest transmission penalty. Single-pole guides are also available made-to-order from 0.5 m to 3 m in 3, 5, and 8 mm cores. Whatever length you choose, verify the dose at the tip with a radiometer before locking in exposure times, and re-verify after any length change.
Routing and bend radius
A light guide is an optical component, not a cable. Kinking or tight bending permanently damages the core and cuts both output and life expectancy, so hold a 100 mm (4 in) minimum bend radius on liquid-filled guides and route them so nothing pulls or crushes the sheath in service. (On the SkyBeam, the LED guide's cable has a 50 mm minimum bend radius, and the head should be fixtured so no strong external force acts on it.) In automated cells, plan the guide path at design time, a guide that flexes with every machine cycle wears out early.
Single-pole or multi-pole splitter?
A single-pole guide delivers one spot. A multi-pole splitter divides one SunSpot 2 lamp into several legs so a multi-joint assembly cures in a single timed exposure: the UV2168 dual-pole splitter feeds two cure points, and the UV2587 4-pole splitter feeds four, with legs you balance to within about 10% using the manual’s rotation procedure, so every joint sees a comparable dose. Splitting divides the lamp's output between legs, so confirm each leg still meets the adhesive's irradiance requirement, the SunSpot 2's high output is what makes it a strong host for split guides. If leg readings ever diverge, the manual's balancing procedure applies: measure each leg with a radiometer, rotate the guide handle in the receptacle in 30-degree increments until the legs read even, then lock the handle thumbscrew.
Default pick: the UV0570 1 m × 5 mm liquid-filled guide, the highest-intensity, most flexible starting point for a SunSpot 2, and the guide every system ships with. Go 8 mm for wide bond lines, 1.5 m for deep fixtures, or a splitter for multi-point cures. Request a quote with your spot size and reach and we'll confirm the fit.
Care and cleaning: protect the end faces
- Cap the ends whenever the guide is disconnected, every guide ships with protective end caps for a reason.
- Clean with alcohol on a lint-free wipe. Wipe the quartz end faces with 99% isopropyl alcohol; a scratched or contaminated input face absorbs energy instead of transmitting it and can heat-crack the guide.
- Inspect with room light, never the lamp. Hold the input end up to an overhead light and view the output tip. Never look at the tip of a guide plugged into an operating source, with or without UV glasses.
- Close the shutter between cures. Prolonged UV and heat exposure age the guide; minimizing exposure time significantly extends its life. Under normal use a liquid guide typically lasts one to two years.
- Keep the tip out of wet adhesive. Adhesive cures onto the quartz window and must then be cleaned off, carefully, since scratches are permanent.
Baseline the tip output with a radiometer when the guide is new, and log readings alongside lamp hours. A drop of about 20% with a known-good lamp means the guide (or the lamp, see replacement lamps) is due for service.
Common questions
Can I use a SunSpot 2 guide on a SkyBeam, or vice versa?
No. SunSpot 2 guides couple to the arc lamp's receptacle; SkyBeam channels take the UV4053 LED guide matched to the channel wavelength. Within the SunSpot 2 family, though, single-pole guides and splitters interchange freely.
How often does a light guide need replacing?
There is no fixed interval. Guides degrade through end-face wear and gradual solarization, typically one to two years in normal service, and a well-handled guide often outlasts two to three lamp changes. Replace when tip readings drop about 20% against your baseline with a known-good lamp, or when the core shows visible discoloration.
Do splitters slow the cure down?
Each leg carries a share of the lamp's output, so per-leg irradiance is lower than a single-pole guide's. In practice the SunSpot 2 has output headroom to keep split legs above most adhesives' requirements, verify per-leg dose with a radiometer during setup and size exposure time accordingly.
Can I get a custom length or core size?
Yes, single-pole guides come made-to-order from 0.5 m to 3 m in 3, 5, and 8 mm cores, typically shipping in 2–3 weeks. Longer runs trade away intensity, so plan a radiometer check at the tip before committing exposure times.
