Got Questions? UV LED Curing FAQs

How do you know the wavelength of LED that reacts well with UV-curable resin and gaskets? Is it 365nm, 385nm, 395nm, or 405nm? Is it a mixture of two wavelengths?

The easy answer is check with your material manufacturer, or have a specialist experiment for you (this is one of the services we offer our clients).

But since that’s a bit bland, here are a few rules of thumb.

Generally for thick adhesives, long wavelengths are effective in deep areas.

But there are also methods of irradiating with multiple, staggered wavelengths. For example, go with 405 nm first to penetrate the surface, and then follow with 365 nm.

UV LEDs with wavelengths shorter than 365 nm have also been developed, but due to the price and illuminance, they are not common in general use yet.

How much integrated light is needed to cure?

Well, the easy answer is ask your manufacturer, or experiment.
But for an in-depth breakdown on how cumulative light works, check out our guide here!

What sort of production setup should I use, and which irradiator shape? Area (aka flood or surface)? Line? Spot?

This all depends on your application. Roughly - area irradiators are for stationary objects, line irradiators are best for conveyor setups, and spot irradiators are used for detailed or small applications.

But the reality is the lines between these categories are blurred - our solutions are very flexible and can configured in many ways. We recommend you contact us with your application specifications, so we can get you in touch with the right engineers.

How close can the illuminator be to the curing material?

UV LED light usually spreads at an angle of approximately 120 degrees. Therefore, UV LED light is stronger (more concentrated) when installed closer, and becomes weaker the farther away it is.

The distance between the irradiator and the sample is called the working distance, abbreviated as WD. Exactly how many millimeters your working distance it is important to establish and calculate when you choose an illuminator and will be different by application. Contact us to get in touch with our engineers.

How do you decide how to illuminate?

For a comprehensive answer, see our full-fledged guide on how to pick a UV LED irradiator here.

But for the short and less-elegant version:

First we need to figure out if both the light and material you’re irradiating are stationary, or if either is moving.

If it’s stationary, we’ll be looking at spot and area (A.K.A. flood or surface) solutions. There are many applications here.
But just to give an example, if you have a stationary 20mm diameter sample with a 6,000 mJ energy need, maybe we’d recommend you use our 300 mW/cm2 UVT20 light for 20 seconds.

If the light or sample is moving, things get more complicated. You’ll probably start looking at our line irradiators (unless you mean moving as in you need something portable - if that’s the case, check out our general-purpose area irradiators!). You’ll need to calculate time spent in the irradiation area in along with all of your curing energy needs. This means factoring in the motion of your system.

Every application is different - you need to factor in unit time, production cost, how much work-area space is available and more. It’s why Micro Square & OCIR TECh, tailored more than 500 designs to fit customer needs.

What are the reasons for converting from UV lamps to UV LED illuminators?

Reduced price, smaller space requirements, less heat shed onto the samples, environmental friendliness, and more! Check out our dedicated list of LED advantages here.