A spot lamp’s exposure time is rarely the whole story on a production line. Bond points, part handling, and lamp readiness all add seconds, and those seconds decide how many parts a station can actually deliver.
Q: How Do You Calculate the Cycle Time of a UV Spot Lamp Station?
A: Add Exposure Time Per Cure Event, Multiply by Cure Events Per Part, Then Add Handling
Start with the exposure time for one bond: the adhesive’s required dose divided by the irradiance measured at the bond. Multiply that by the number of separate cure events each part needs, then add load, unload, and index time. The total is the station’s cycle time, and parts per hour is 3,600 divided by it.
The number of cure events is not always the number of bond points. A controller that drives several lightguides at once can cure several points in one trigger, which is where large throughput gains in spot curing come from. For the basics of how the hardware works, Incure’s UV LED spot curing system overview is the starting point; this guide stays with the arithmetic.
Step 1: Exposure Time From Dose and Irradiance
Exposure time equals dose (mJ/cm²) divided by irradiance (mW/cm²). The dose comes from the adhesive data sheet or your own qualification work. The irradiance must be the value at the real working distance, because on a spot lamp it changes sharply with distance.
The Incure L9000™ illustrates how much this matters. Its irradiance is 2,300 mW/cm² at a 17 mm focal distance and 1,200 mW/cm² at 20 mm. Using a hypothetical dose of 3,000 mJ/cm²:
- At 17 mm: 3,000 ÷ 2,300 ≈ 1.3 seconds
- At 20 mm: 3,000 ÷ 1,200 = 2.5 seconds
Three millimeters of fixture clearance nearly doubles exposure time. Before any other throughput work, lock the lightguide position.
Step 2: Count Cure Events, Not Just Bond Points
Both of Incure’s spot platforms can feed more than one lightguide from a single controller. The L9000™ runs up to four independent lightguides, and the S20™ arc spot lamp is offered in 1-, 2-, 3-, and 4-pole configurations.
Cure events per part equal the bond points divided by the guides that can fire together, rounded up. Consider a hypothetical housing with six bond points:
- One guide: 6 cure events
- Two guides: 3 cure events
- Four guides: 2 cure events (four points, then the remaining two)
Rounding up is where poor fixture layouts lose time. Six points on a four-guide setup still needs two exposures, so a 3-guide or 2-guide arrangement can match its throughput if the points group evenly.
Step 3: Add Handling and Index Time
Handling time is usually measured, not calculated. Time an operator or robot loading, triggering, and unloading a part, and use the average across a full shift rather than one clean cycle.
Continuing the hypothetical example with 2.5 seconds of exposure per event and an assumed 8 seconds of handling:
| Configuration | Cure events | Exposure time | Cycle time | Parts per hour |
|---|---|---|---|---|
| 1 guide | 6 | 15.0 s | 23.0 s | about 156 |
| 2 guides | 3 | 7.5 s | 15.5 s | about 232 |
| 4 guides | 2 | 5.0 s | 13.0 s | about 277 |
These figures are illustrative only. The pattern is the useful part: once handling time dominates, adding guides produces smaller gains.
Email Us with your bond-point layout, adhesive dose, and handling time, and Incure’s engineers can check which lightguide configuration fits your target rate.
Step 4: Account for Lamp Readiness
An LED spot lamp and a mercury arc spot lamp behave differently across a shift. The L9000™ reaches full output from the first trigger, with no warm-up. The S20™ needs 1 to 2 minutes to reach full intensity and a cooldown before restart.
On a line that runs continuously, warm-up happens once per shift and barely registers. On a line that stops often for changeovers or breaks, it repeats. Ten restarts a shift at a 2-minute warm-up is 20 minutes of lost cure capacity, so count your restarts before comparing the two technologies on throughput alone.
Bulb changes also take time. Incure’s mercury arc replacement bulbs are commonly changed every 1,000 to 2,000 hours, and a hot lamp should cool for about 30 minutes before removal. Plan those changes into scheduled downtime rather than letting them interrupt a run.
Step 5: Check Timer Resolution Against Short Exposures
When exposure times drop to a few seconds, the controller’s timer step size becomes part of the dose. The L9000™ timer is programmable from 0.1 to 999.9 seconds, while the S20™ timer is programmable from 1 to 99 seconds. If a calculated exposure falls between the settings a controller allows, round up and confirm the cure; never round down to save time.
When Multi-Guide Setups Pay Off
Extra lightguides earn their place when exposure time is a large share of the cycle, bond points group evenly into the guide count, and the part can be fixtured so every guide sits at its qualified distance. They add less when handling dominates, when one bond needs a much longer dose than the others, or when guides would sit at different working distances and receive different irradiance. Each guide’s output should be checked individually, since a light guide degrades over time at its own rate.
Final Thoughts
Throughput on a spot lamp station comes down to four numbers: dose, irradiance at the bond, cure events per part, and handling time. Work them out on paper before buying lightguides or fixtures. Contact Our Team to model cycle time for your part on an Incure spot curing platform.
Visit www.incurelab.com for more information.