Printed labels, coated cards, and decorated parts look finished when they come off the printer, but a UV ink or varnish that is only surface-dry will scuff, block when stacked, or smear in the next process. A UV conveyor turns the cure into a controlled step: every sheet or part passes under the lamp at the same speed and receives the same dose.
Q: Can a UV conveyor cure inks and varnishes on printed parts?
A: Yes. Flat printed items suit a conveyor well because they pass under a flood lamp in one layer. Choose a flood head wide enough for the sheet or part, match the lamp wavelength or spectrum to the ink’s photoinitiator, and set belt speed to deliver the ink’s required dose, then verify cure with the tests your print specification uses.
Why a Conveyor Fits Print Work
Incure’s documentation for its CDM™ conveyor names printing and packaging lines as users of belt-speed control to tune UV varnish gloss and cure depth across different substrate weights. That reflects how print work behaves: the same varnish on a light stock and a heavy board may need different exposure, and on a conveyor that difference is a speed setting rather than a new machine.
Flat items also make the geometry simple. There are no side walls or recesses to shadow, so a flood head’s full footprint reaches the whole printed surface.
Choosing the Head for Printed Items
On the CDM™ platform, two families suit print work:
- LED flood heads. The L88 covers an 8″ × 8″ area with up to 8 inches of part width; the L64 covers 6″ × 4″ with up to 4 inches. Both deliver 1,900 mW/cm² at 385/395/405 nm and 1,600 mW/cm² at 365 nm at a 2-inch working distance. Each head is factory-configured to one wavelength.
- Mercury-arc flood heads. The F100 and F200 allow up to 8 inches of part width and deliver broadband output; the x2AC versions include a UVC tube alongside UVA.
The deciding factor is the ink system. An ink formulated for a specific LED wavelength cures on a matching LED head. An ink or varnish developed for mercury-arc cure, particularly one that relies on UVC for surface properties, needs an arc head, and specifically the x2AC form if UVC is part of its qualification.
Email Us with the ink or varnish data sheet and your sheet size, and Incure can confirm whether an LED or arc head fits.
Setting Speed by Substrate
Belt speed on the CDM™ runs from 1.5 to 12.0 ft/min, and dose falls in proportion as speed rises. Treat each substrate as its own recipe:
- Start from the ink’s required dose.
- Use the head’s published figures to find a candidate speed. The F200x2AC, for example, delivers 2,250 mJ/cm² UVA at 6 ft/min and 1,130 at 12 ft/min; the L88 spans 6,325 to 50,600 mJ/cm² UVA across the speed range.
- Run samples on each stock at that speed and test cure.
- Record the passing speed per substrate and per ink.
As a hypothetical, if a varnish needs 2,000 mJ/cm² UVA on the F200x2AC, the published 2,250 at 6 ft/min gives a maximum speed of about 6.75 ft/min (2,250 × 6 ÷ 2,000), before allowing margin for lamp decay.
Testing Cure on Printed Work
The print specification should define what “cured” means for the product. Common checks include surface tack, scuff or rub resistance, adhesion of the ink to the substrate, and whether stacked items stick together. Perform them on parts taken from the conveyor at production speed, not on samples cured by hand.
Belt and Handling Considerations
The standard CDM™ uses a 9-inch polypropylene belt. Lightweight sheets need to stay flat and in position as they travel; plan how they are fed and supported so edges do not lift toward the lamp or drift toward the edge of the cure zone, where irradiance is lower. Published dynamic uniformity is 0.89 for the L88 and 0.82 for the F100/F200 arc heads at 2 inches, so center placement gives the most even result.
Lamp height on LED heads adjusts from 0.5 to 2.0 inches. For flat printed items, the height setting and working distance are nearly the same, which makes recipes easy to reproduce.
Lamp Decay and Color-Critical Work
Incure rates its LED heads past 20,000 hours with up to 20% decay, and its arc heads past 1,000 hours with up to 45% decay. Falling output means less dose at the same speed. Schedule radiometer checks and compare against the baseline taken when each recipe was qualified; if the reading drops, slow the belt in proportion.
Control on a Print Line
LED heads accept PLC, RS-232, and foot-switch inputs and switch between timer and continuous modes, which suits lines where the conveyor follows a printer’s start and stop. Arc heads have no external control port and rely on belt speed alone, and their warm-up and cool-down cycle favors leaving them on through short pauses.
For more on conveyors in general, see the curing conveyor industrial guide; the CDM™ lamp-head guide lists dose for every head, and the Incure F-Series™ flood lamp guide covers the arc lamps used for broadband ink cure.
Contact Our Team to set up ink or varnish curing on a CDM™ conveyor.
Visit www.incurelab.com for more information.