A liquid light guide delivers UV or visible energy from a spot lamp to the work, but the bare tip sprays a diverging, partly stray beam that is hard to aim and exposes the operator to scattered UV. A lightguide terminator screws onto that tip and turns it into a controlled tool. What a Terminator Does A lightguide terminator is a machined fitting, usually aluminum, that attaches to the distal end of a 3, 5, or 8 mm liquid light guide. Depending on the model it performs three jobs: Blocks short-wavelength UV below roughly 340 nm before it leaves the tip, cutting operator exposure to the most hazardous part of the spectrum while passing the wavelengths the adhesive needs. Shapes the beam, either collimating it to a tighter, more uniform spot or projecting it at a fixed working distance so intensity at the bond line is repeatable. Redirects the beam through a 60 or 90 degree bend so the energy can reach a joint the straight guide cannot point at, such as a bond line facing sideways inside a fixture. Why It Matters in Production Repeatable dose: a fixed exit geometry and working distance mean each part sees the same irradiance, which tightens cure consistency. Less over-cure of neighbors: a defined spot keeps energy off adjacent adhesives and heat-sensitive components. Access: angled terminators reach recessed and shadowed joints without repositioning the whole part. Operator protection: integrated UV blocking reduces reliance on the operator keeping rated eyewear perfectly positioned. Email Us with your joint location, light guide size, and lamp wavelength, and our team will help select a terminator configuration. Selecting a Terminator Guide diameter: match the terminator bore to your 5 mm or 8 mm guide so no energy is lost at the coupling. Angle: straight for line-of-sight joints, 60 degrees for shallow access, 90 degrees for perpendicular bond faces. Spot size and working distance: a smaller collimated spot concentrates energy for fast cure of a tiny joint; a wider projection covers a larger fillet at lower intensity. Wavelength: confirm the terminator optics transmit your lamp's output, whether that is a broadband arc source or a single-wavelength LED. Beam Geometry and Dose Uniformity A bare guide tip emits a cone that diverges at roughly the guide's numerical aperture, so irradiance at the work drops sharply with distance and the spot has a bright center and dim edge. That makes cure time sensitive to how the operator holds the tip. A collimating terminator narrows the divergence, flattening the intensity profile and making irradiance far less dependent on the exact working distance, which is what tightens part-to-part cure consistency. A projection terminator instead images a defined spot at a fixed focal distance, useful when the same spot size must land on every part. When specifying, ask for the irradiance-versus-distance curve for the terminator on your guide and lamp. Set the fixture so the bond line sits in the flat part of that curve, then confirm the delivered dose with a radiometer at…