Page 5 - Industrial Technology EXTRA 25th January 2021

curing materials lend themselves to automated gains. The spectral output of the curing lamp should
processes, because the dispensing and cure is be correctly matched with the material that is being
readily controlled and repeatable. Inspection can be cured for best results.
facilitated by using a fluorescing or colour-change- Metering and mixing can also cause
on-cure material. In addition to structural inefficiencies, waste or added process time. There
adhesives, these benefits can be gained with UV has been progress in the design of meter, mix and
light curing encapsulants, coatings and temporary dispensing equipment, providing better capability
masking materials. for challenging materials (those with very different
viscosities or which are highly filled), as well as
LED UV curing greater accuracy for smaller quantities.
There are two types of UV curing equipment, The manufacturer may consider switching from
mercury arc and LED, which are based on two a two-part to a single-part material, so that mixing
different types of technology. For manufacturers is no longer required. The latest adhesives based on
using mercury arc lamps, there are some light curing acrylics or cyanoacrylate technology
productivity drawbacks — a limited operational provide fast, single-part cures and excellent
bulb life which requires regular bulb change, and an performance.
output intensity that degrades over time and which
adds a process variable to be monitored and A big change
managed. These lamps require a warm-up/cool Changing materials is a complex approach and is
down time, mandating the use of mechanical not a decision that should be taken lightly. For
shutters for exposure control. regulatory reasons, it is particularly difficult for
Compared to traditional mercury arc lamps, businesses working in medical or military
there are productivity advantages to UV curing applications to change a validated material in an
lamps based on the latest LED technology. Because established process. It may be simpler to identify
LED lamps are instant on/off, they are activated only how you can improve the process with equipment,
when needed, and do not need to be left running all such as automation or process control.
day, saving energy consumption. Their intensity While Intertronics is here to support customers
output has very little degradation over time, so that want to change material and will provide
process monitoring is simpler. guidance on what to look for and how to evaluate
While they work in functionally similar ways, candidates, the best approach is to design a process
mercury arc lamps emit broad spectrum UV light, with productivity in mind from the get go. An
whereas LED systems emit narrow spectrum UV adhesives supplier can consult with you on which
light. For an existing UV curing process, materials will provide the required performance,
manufacturers wanting to take advantage of the balanced with an efficient, robust, repeatable
productivity enhancement of LED technology should process which suits your production volumes, not
ensure that this different spectral output still cures only now but in the future.
their material to acceptable levels, meeting their Your chosen material should be able to be
functional tests. scaled, be suitable for future automation, and work
For a new project, it is recommended to trial within the process times available as numbers
adhesives which are formulated to be cured with increase.
UV LED lamps in order to reap all the productivity www.intertronics.co.uk/productivity

January 2021 • INDUSTRIAL TECHNOLOGY EXTRA • p5