An enclosure that's rated IP67 on paper can still let moisture in at exactly one point — the seam where two housing halves meet — and that seam is almost always sealed with a bead of adhesive, not a molded gasket, once volume and geometry get complicated. Q: Why use a dispensed adhesive seal instead of a cut gasket at all? A cut or molded gasket only seals as well as the flatness of the two surfaces pressing against it, and it adds a discrete part that has to be sourced, inventoried, and placed correctly on every unit. A dispensed UV-curable seal follows any groove or irregular seam geometry exactly, fills machining and molding variance that a rigid gasket would bridge and potentially leak past, and removes a line item from the bill of materials entirely. For high-volume enclosure lines, that combination of geometric flexibility and reduced part count is usually the deciding factor. Q: Does the seal go on before or after the housing closes? Both approaches are used, and the choice depends on whether the enclosure needs to be reopened. Curing the bead before the housing closes leaves a resilient, compressible gasket that the closing housing squeezes into place — this suits battery doors, access panels, and anything with a defined service interval, since the housing stays serviceable. Curing after the housing is fully assembled bonds both surfaces into one sealed unit with higher pull-apart resistance and a better overall ingress rating, at the cost of making the enclosure effectively non-serviceable without cutting the seal open. Q: What actually determines whether a bead-and-groove seal holds up outdoors? Surface preparation determines whether the bead anchors at all — the housing surface has to be clean and dry, and low-surface-energy plastics often need plasma treatment before the bead will properly wet out and bond rather than just sitting on top of the surface. Bead volume control matters just as much: a starved bead leaves gaps, and a flooded one squeezes excess material into the enclosure interior or blocks a nearby feature, so volumetric or time-pressure dispensing control is standard on any line producing this seal at scale rather than a hand-triggered syringe. Q: How does groove geometry affect seal performance? A shallow rectangular or trapezoidal groove — roughly one and a half times as wide as it is deep — gives the bead a defined space to sit in, controls how much it compresses when the housing closes, and gives the cured seal a shoulder to react against under internal or external pressure. A flat land with no groove works adequately for low-pressure ingress protection but lets the bead spread unpredictably once the housing is closed, which is a common cause of inconsistent seal performance across a production run that otherwise looks identical unit to unit. Q: What has to be verified before this seal design goes to production? A qualification program for this kind of seal typically covers leak rate at the enclosure's rated ingress-protection pressure, leak rate again…