Every under-curing conveyor eventually faces the same fork: slow the belt, or add a second lamp head. Slowing costs throughput one-for-one. A second head costs equipment, ventilation, and maintenance discipline. Knowing which constraint you are really up against decides the right branch.
Q: When should a UV curing conveyor system use two lamp heads instead of one?
A: When total UV energy, not belt speed or geometry, is the limit — and the process is qualified for UVA-only exposure
Two heads in series along the belt expose each part twice in one pass, so dose doubles at the same speed. That is the right fix when the formulation needs more energy than a single head delivers at the required line rate. It is the wrong fix when the real limit is the spectrum, the working distance, the part width, or shadowing, because a second identical head repeats the same shortfall.
How Dual-Head Configurations Work on the CDM™
On the Incure CDM™ platform, the “x2A” arc configurations mount two UVA-only heads in series. Each part passes under both, accumulating energy from each consecutively. The “x2AC” configurations look similar on paper but are a single assembly holding one UVA tube and one 254 nm UVC tube — broadband exposure, not doubled UVA. The comparison at the nominal 6 ft/min belt speed shows the pattern:
| Lamp class | x2AC single assembly (UVA, mJ/cm²) | x2A two heads in series (UVA, mJ/cm²) |
|---|---|---|
| F100 | 1,050 | 2,100 |
| F200 | 2,250 | 4,500 |
| F400 | 2,630 | 5,260 |
| F500 | 1,480 | 2,960 |
In each class the x2A figure is exactly double the x2AC figure, and the relationship holds at every belt speed in the 1.5–12.0 ft/min range.
Two Heads or a Slower Belt?
Because dose scales inversely with speed, a second head and a halved belt speed reach the same energy. The difference is throughput. Consider a hypothetical formulation that needs 4,000 mJ/cm² UVA. An F200x2AC reaches that by slowing to about 3.4 ft/min (2,250 × 6 ÷ 4,000 ≈ 3.4). An F200x2A reaches it at about 6.75 ft/min (4,500 × 6 ÷ 4,000 = 6.75) — roughly twice the parts per hour on the same belt. If the line can live at the slower speed, the single head is the simpler system; if it cannot, the second head pays for itself in throughput.
Email Us with your required dose and target belt speed and Incure can show which single- or dual-head configuration reaches both.
The UVC Constraint Comes First
An x2A configuration has no UVC tube. A process qualified on broadband exposure that includes UVC cannot move to an x2A configuration simply because the UVA number is higher; it needs fresh qualification. Conversely, a UVA-only process gains the full doubled dose from x2A without any UVC ventilation or handling requirement. Check the qualification record before comparing dose tables.
Peak Intensity Versus Total Dose
More heads add dose, not peak intensity. The F500 heads run at 590 mW/cm² per head against 490 for the F400, yet the F500x2A delivers less total dose per pass than the F400x2A — 2,960 versus 5,260 mJ/cm² at 6 ft/min — because the F500 aperture is shorter in the belt-travel direction. A formulation with a minimum-irradiance threshold needs the higher per-head intensity; a dose-limited formulation is better served by the longer F400 aperture.
What a Second Head Adds to Upkeep
- Matched replacement. Both heads should be replaced on the same cycle, planned at the 1,000-hour threshold per head, so the two exposure zones stay equal. A fresh head paired with an aged one creates a gap a single combined reading may not reveal.
- Ventilation. Every arc head needs forced-air cooling and exhaust; two heads add a second thermal load to the facility.
- Control. Arc configurations have no external PLC or RS-232 port in either single or dual form; belt speed remains the only process control.
- Width. The second head adds dose, not belt footprint: maximum part width stays 8 inches on F100/F200 and 5 inches on F400/F500.
When Neither Fix Works
If a part needs F400-level dose and is wider than 5 inches, no single configuration on the platform covers both. The options are splitting the process into two stages sized separately, or revisiting whether F400-level dose is truly required for that part. Where a process needs external control integration, an LED head on the same chassis is the alternative to any arc configuration.
Full configuration data is in the Incure CDM™ UV conveyor guide, the arc chemistry is covered in the Incure F-Series™ flood lamp guide, and the general overview of curing conveyors is in the curing conveyor industrial guide.
Contact Our Team to compare single- and dual-head configurations for your process.
Visit www.incurelab.com for more information.