Small bonded assemblies — lens holders, sensor caps, plastic housings, glass-to-metal joints — are often cured one at a time under a spot lamp. Moving them to a UV curing conveyor can raise output, but only if each tiny bond line ends up where the light is and stays put while it cures.
Q: How do you use a UV curing conveyor for small adhesive-bonded parts?
A: Hold the parts in fixtures or carriers that fix the bond-line position and stop parts shifting, choose a lamp head whose width matches the bond pattern, select an adhesive grade that cures at the head’s wavelength, and set belt speed to deliver the adhesive’s required dose. Verify with bond tests on parts taken from the conveyor at production speed.
Fixture First
On a conveyor, small parts move, and a joint that shifts before the adhesive sets ends up misaligned. A carrier or fixture plate does three jobs:
- Holds alignment until the adhesive cures in the lamp zone.
- Positions the bond line consistently relative to the lamp, so every part sees the same irradiance.
- Sets pitch, the spacing of parts along the belt, which determines throughput.
Fixtures also add height. On Incure’s CDM™ conveyor, LED heads work at a 0.5–2.0 inch curing height, so include fixture height when setting the lamp and when deciding which head fits.
Matching the Head to the Bond Pattern
Small parts give two quite different options on the CDM™ platform:
- Focused-beam heads for single seams or narrow joints. The M51 exposes a 5″ × 1″ strip at 6,150 mW/cm² at 365 nm; the M62 a 6″ × 2″ strip at 3,100 mW/cm² at 365 nm. Components outside the strip receive no UV, which protects pre-cured joints or sensitive neighbors.
- Flood heads for parts with adhesive spread over the surface, or for many small parts in a carrier. The L64 covers 6″ × 4″ and the L88 8″ × 8″, both at 1,900 mW/cm² at 385/395/405 nm.
A carrier holding a grid of small parts usually suits a flood head; a row of parts each with one bond seam aligned to the belt direction can suit a focused beam.
Email Us with your part size, bond pattern, and adhesive, and Incure can recommend a CDM™ head and fixture approach.
Choosing an Adhesive Grade for the Substrate
The adhesive must suit both the substrates and the lamp. Incure’s UV adhesive lines include:
- Uni-Weld™ Plastic Bonder grades — 1054, 1072, 1417, 1435, 1444, 1453, 1462, 1483, and 3271 — for PC, ABS, and PMMA assemblies.
- Uni-Weld™ UV Glass & Metal Bonder grades — including 1910, 1931, 2204VT, 2463G, 2813, and 8260 — for glass and metal joints.
- Optik™ UV optical adhesives for optical assemblies where clarity matters.
Whatever grade is chosen, confirm its cure wavelength. CDM™ LED heads are factory-configured to one wavelength (365, 385, 395, or 405 nm) at order, and high irradiance does not make up for a mismatch. The Uni-Weld™ Plastic Bonder guide explains how those grades differ by substrate and mechanical demand.
Setting Speed for a Small Bond
Belt speed on the CDM™ adjusts from 1.5 to 12.0 ft/min, and dose falls as speed rises. Published dose at 6 ft/min is 25,630 mJ/cm² UVA for the M51 and 15,500 for the M62. Start from the adhesive’s required dose, pick the fastest speed that meets it with margin, and confirm with a radiometer at bond-line height.
As a hypothetical, a carrier of small parts on a 3-inch pitch at 6 ft/min (72 in/min) moves 24 carriers per minute past the lamp. If each carrier holds four parts, that is 96 parts per minute, or 5,760 per hour, assuming the head’s width covers all four.
Shadows and Opaque Parts
UV adhesives cure where light reaches them. A bond line hidden under an opaque cap, or between two opaque parts, may not see the lamp at all. Check whether at least one substrate transmits the cure wavelength, or whether the joint is designed so the adhesive fillet is exposed. If neither is true, the conveyor will not cure the joint no matter how slowly the belt runs.
Verifying Bonds
Take parts from the conveyor at production speed and test them per your specification: alignment, fixture-free handling strength, and the bond strength test the product requires. Repeat at a slightly faster speed to see where bonds start to fail; the gap is the process margin against lamp decay. Incure rates its LED heads past 20,000 hours with up to 20% decay over that life.
Control for Small-Part Lines
LED heads on the CDM™ accept PLC, RS-232, and foot-switch inputs with timer or continuous modes. On a line fed by a robot or a dispenser, the conveyor can follow the upstream cycle, and lamp output can be tied to carrier-present sensing.
For the general role of conveyors, see the curing conveyor industrial guide, and for every head’s dose and width, the CDM™ lamp-head guide.
Contact Our Team to set up small-part bonding on a CDM™ conveyor.
Visit www.incurelab.com for more information.