-UV curable resin is a common material used for adjusting the position of two aligned components. (Fig.1 and Fig.2)

-Adopting the UV curable resign is beneficial in terms of the following:
1) The time required for resin curing can be shortened.
2) Thermal deformation during resin curing can be avoided.
3) When using a UV permeable material (such as a glass substrate),
       the resin can be cured on the backside.

-However, Inappropriate positioning process may cause a dislocation of the components after the resin has been cured.

-The most common causes for dislocation using UV curable resin include the following:
a) Inconsistent application amount of UV curable resin (Fig.3)
(Too little: Lack of strength. Too much: Dislocation caused by variations
       in cure shrinkage)
b) Varying UV curing conditions (lighting intensity X irradiation time) for
       respective application areas
c) Inconsistent adhesiveness of the adhesion sureface inconsisent
       adhesiveness of the adhesion surface

-Variations in the resin application amount are generally resulting from uneven spraying from the resin dispenser. This phenomenon occurs due to the following: i) Inconsistent viscosity of the resin; ii) Varying conditions of the resin being applied (such as viscosity, resin conditions at the dispenser head, and so on) due to changes in application pitches; iii) Changes in the properties of the resin itself.

-Variations in the UV curing conditions occur due to the reduction in illumination intensity caused by the shortened life of the UV lamp and the misaligned spray position resulting in uneven hardening.

-Variations in the adhesiveness of the bonded surface are usually caused by inconsistencies of the wet & dry cleaning quality in the previous process.

-The following table summarizes the common causes and solutions.

Precautions

-It is recommended to prepare a black cover to prevent the UV curable resin inside of the dispenser from being exposed to fluorescent light.

-Unstable spraying positions are generally attributable to the positioning accuracy of the workpiece being sprayed and the direction of resin released from the dispenser.