Choosing the Right Light Guide Diameter for Your Spot
The light guide diameter sets both your spot size and your intensity, and the two trade off. A small guide concentrates a lot of energy on a tiny joint; a large guide covers more area but spreads the same source over it. Sizing the guide to the actual joint is how you get a fast, even cure without wasting light.
A guide delivers the source’s output over its exit face, so a smaller diameter concentrates higher intensity on a smaller spot, while a larger diameter covers more area at lower intensity. Splitters divide one source into multiple legs, more joints per exposure, but each leg carries a fraction of the intensity. Matching diameter to the joint size gets the right intensity onto exactly the area that needs it.
The SunSpot 2 runs the full range of liquid light guides, a standard 5 mm for precise small joints, a high-flux 8 mm for larger spots or recesses, and two- or four-pole splitters for multi-point curing, so you can size the delivery to the job.
Step by Step
- 1 Measure the joint. Size the spot to the adhesive area you actually need to cure. Lighting far more area than the joint just wastes intensity.
- 2 Pick diameter for intensity vs. area. Choose a small guide (5 mm) to concentrate intensity on a tiny precise joint, or a larger guide (8 mm) to cover more area or drive flux into a recess.
- 3 Use a splitter for multiple points. To cure several joints at once, use a two- or four-pole splitter, but remember each leg carries a fraction of the source intensity, so per-joint time rises.
- 4 Verify intensity at the working distance. Measure the delivered intensity with a radiometer at your actual working distance, since it depends on both diameter and distance.
Common Pitfalls
- Oversizing the spot, lighting far more than the joint spreads intensity thin and slows the cure.
- Forgetting the splitter trade-off, dividing the source drops per-leg intensity, so balance and dose matter.
- Comparing guides without measuring, intensity depends on diameter and working distance; use a radiometer.
Questions
What size light guide should I use for UV curing?
Match the diameter to the joint. A small guide (5 mm) concentrates high intensity on a tiny precise spot; a larger guide (8 mm) covers more area or drives flux into a recess at lower intensity. Splitters cure multiple joints at once but divide the intensity between legs.
Does a bigger light guide cure faster?
Not necessarily, a bigger guide spreads the same source output over more area, so intensity per unit area is lower. A smaller guide concentrates higher intensity on a small joint and often cures a small spot faster.
How much does a splitter reduce intensity?
Dividing one source into two or four legs drops each leg to roughly its share of the total, so per-joint intensity falls and exposure time rises. Balance the legs and verify each with a radiometer.
