Page 16 - Industrial Technology EXTRA 24th May 2021

from the typical automation benefits such as leave them running all day, with the increased
improved repeatability and precision, and the fact power consumption. The 20,000 hour life of an
that robots do not get tired or need breaks. LED curing lamp therefore represents 20,000 hours
of curing time (in practice many years), whereas the
Two different UV technologies lifespan of a mercury arc lamp refers to running
Part of the ROI calculation will be the cost of a UV time.
curing lamp. For optimal results and to get the full LED UV curing lamps are attractive because of
benefits of the technology, an industrial unit with better process control and low running costs.
the correct output is required. It is always a false However, if you are looking to switch from a
economy to use UV sources which do not meet a mercury arc lamp to an LED UV lamp, it may not be
minimum recommended intensity or output non- as simple as a straight swap. It is important to
optimal wavelengths — incomplete cure being the ensure that your adhesive cures effectively with the
most obvious result. A good supplier will work with narrow spectrum output; some, especially those
you to choose and evaluate appropriate curing designed for broad spectrum cure, will cure with
equipment. unexpected characteristics.
There are two types of UV curing lamp, based If you are already operating a mercury arc
on fundamentally different technologies. The process, you may need to consider how often you
traditional light source used during UV curing is a are changing your bulb, the price of the bulbs, the
mercury-based arc lamp, which emits broad downtime for bulb changes, and the cost of
spectrum light. The alternative is an LED UV curing monitoring the output of the bulb, and calculate
lamp, which differs by emitting narrow spectrum whether upgrading to an LED curing lamp will
UV light. deliver an appropriate ROI.
For manufacturers establishing new processes, For manufacturers who can change their
LED UV curing is usually the recommended option. adhesive, consider whether you are trying to reduce
The range of adhesives suitable for curing with costs, solve a technical problem, or both. Because
narrow spectrum LED UV light is increasing all the switching adhesives may require revalidation, it is
time. typically done by businesses with a strong
Process control is much easier with LED UV commercial or technical drive for the change. Some
lamps, as they offer more consistent output — up to examples may be supply issues, a change in the
or exceeding 20,000 hours. On the other hand, regulatory environment, or a product update
mercury arc lamps have a typical life of 2,000 involving new substrates or bondline design.
hours, degrading throughout this period. LED curing A UV curing adhesive can deliver good return on
lamps have no bulbs to change, which removes the investment. It is important to take a holistic view,
need to pay for replacements. They run at lower considering productivity, quality, yield, throughput,
temperatures, helping to avoid thermal rise and energy, H&S and similar factors in the calculation;
substrate damage. material and equipment costs are often offset by
LED lamps have no warm-up or cool-down time, these other benefits and the resultant savings. The
so the manufacturer can turn them on, as and when materials offer fast, on demand curing, and can be
needed, using them immediately. In contrast, the easily combined with automation to further improve
warm-up and cool down time associated with a throughput and yield.
broad spectrum lamp means that manufacturers www.intertronics.co.uk

May 2021 • INDUSTRIAL TECHNOLOGY EXTRA • p16