The mercury ban debate has been rife with speculation, confusion, strong accusations and well, a little bit of misleading information. So, together with Brendan Perring of Print Monthly I have been getting to the bottom of this tangled web of information. We have been in contact with the National Measurement and Regulations Office (NMRO) to seek clarification, and today I found myself meeting a Technical Enforcement Officer from the NMRO, who came armed with a copy of the regulations. We took a trip out to visit the very accommodating Neil Tarling of Berkshire Labels to see a UV lamp in action.
Upon arrival we were greeted with a netted hat and safety jacket before entering the facility. Berkshire labels have some 8 printing presses and finishing machines of which the majority employ the use of a GEW UV Mercury Vapour Lamp System, some to cure ink others to cure varnish. The team at Berkshire labels explained to us how integral the UV lamp is in the entire process, confirming that they would not be able to manufacture their goods without the use of a Mercury Vapour UV lamp. We looked at the heat and Ozone extraction systems, the compact lamp housings and took an up close look at a lamp.
We finished our visit by examining the regulations and my highlights are as follows:
Article 2 – The Scope
4.(d) Large- scale stationary industrial tools
4.(e) Large-scale fixed installations
Article 3 – Definitions
(3) ‘large-scale stationary industrial tools’ means a large-scale assembly of machines, equipment, and/or components, functioning together for a specific application, permanently installed and de-installed by professionals at a given place, and used and maintained by professionals in an industrial manufacturing facility or research and development facility;
(4) ‘large-scale fixed installation’ means a large-scale combination of several types of apparatus and, where applicable, other devices, which are assembled and installed by professionals, intended to be used permanently in a pre-defined and dedicated location, and de-installed by professionals;
Both of the above definitions cover printing machinery and as such rule them out of scope of the directive, in layman’s terms, none of the RoHS regulations document applies to printing presses.
Why is this information important? Print companies employ the use of UV to cure inks and varnishes. This has traditionally and continues to predominately use UV Mercury Vapour Lamps due to their efficiency, intensity and low relative cost. But it’s not only print, every drop of your drinking water is sterilised using UV, the soles of your shoes are bonded to the upper part with UV, your Ikea furniture is bonded and varnished with UV, even your TV screen is bonded to the shell with UV. UV is used in so many different processes that a ban on Mercury Vapour Lamps would see the quality of your drinking water drop to a dangerous level, money you buy goods with couldn’t be printed and other processes, like making shoes would take so long that prices would increase and more manufacturing would move abroad.
Why is it important that UV Mercury Vapour Lamps are still excluded from a potential Mercury ban? There are many reasons; the UK print industry alone relies on these lamps, it is the 5th largest printing industry in the World. It has a turnover of £14.6 billion, adding almost £1bn to the UK’s balance of trade, £7.5 billion GAV (50%) and has over 11,000 companies- employing over 153,000 people.
What about LED? I’ve read that it can replace Mercury Vapour Lamps?
You’ve probably also read about hover boards, for many, many years. Which should have been in use today and contrary to the claims of many are still some way off. Hover boards appear in various clever marketing ads, but you can’t go out and buy one that will do what they suggest. It’s a similar situation with LED, much hype and big claims yet the reality is something very different. Look at it like this, you hear there’s a great party next door with loud music, you can see the disco lights and it looks like a great place to be. You get dressed up and head on round only to find you’re the only person there and what was promised to be an incredible night has left you somewhat deflated.
LED’s require the development of exotic materials to produce short wavelengths. These are very expensive to produce. The transmission of shorter wavelengths is also increasingly difficult.
LED’s are great for use in your house, or for car head bulbs as their quantum efficiency is around 90% for visible light. However, for UVA (used for print curing) it’s between 8%-20% and for UVC (used for water treatment) its
Ink formulation for LED presents some issues too, as an LED curing system typically operates at 395nm, which means it is reactive to sunlight. There are a couple of other physical drawbacks that include:
- Low intensity- which means that they can require mounting very close to the substrate (1-3mm), opening them up to contamination
- If you double the distance between the substrate and LED, the intensity reduces to a quarter
- There is little forward heat from LED, but around 80% of the energy put is has to be removed as heat from the rear
- The chiller unit is very expensive to run and so energy savings at the LED lamp head can be offset by the energy costs of the chiller
We also ran some calculations on cost of ownership vs. a standard mercury vapour UV system, a high efficiency mercury vapour UV system and an LED system. The only way we could make the LED system financially viable was to spread the payment for the system over 15 years, work 120hrs/week (3 shifts), and increase energy costs 10 fold. All of which are unrealistic. These figures were based on data from a leading OEM. As a rule of thumb 16x volume reduces the price by half, this will take a considerably long time in the case of UV LED’s and it’s unlikely that these savings will be passed on.
We aren’t saying LED has no use, but that its use is limited. The areas we see potential are:
- Roll to roll press
- Full automated screen printing on pressure sensitive materials
- Some digital printing
- Analysis instruments
- But the viability is purely at a technical level; they still don’t make sense financially.
LED is most certainly not suitable for:
- Large format printing
- Water sterilisation
- And many, many more applications
ROHS info here: https://www.gov.uk/rohs-compliance-and-guidance