Taking necessary safety measures in the printing process
Welcome to my second blog about safety in the printing process when using solvent inks. As highlighted in my first blog, safety on the job is a primary concern in every company.
Possible risks with solvent-based inks
Usage of solvent-based inks inside a complex machine such as a flexo press doesn’t come without risks. Solvent ink usually consists of 70% solvents, 12% pigments and 18% of binders and other additives. Most of the time ethanol or ethyl acetate is used as the main solvent.
When a solvent evaporates it mixes with the air around it, when the solvent/air mixture is just right, a potential explosive atmosphere can form inside the print unit. Just a little spark is all it requires to cause detrimental effects to you and your company.
After investing in a long period of research and development, MPS designed a press that is capable of processing solvent inks in a safe manner. As you will learn below, there are several ways to prevent an explosion from happening. Measures that MPS took involve two of the three below listed factors.
Powerful ventilation is key
The effect of the air/fuel ratio and prevention of other possible sources of sparks and heat was one key measure MPS implemented with their press design. The first thing MPS did was to locate where potential solvents can freely leak into the surrounding air. These points were then precisely ventilated to transport potentially explosive fumes outside the machine as quickly as possible.
Actual airspeed of the ventilation is constantly monitored and compared to the required calculated airspeed. If for whatever reason the ventilator is not providing enough ventilation, a second ventilator will automatically engage to ensure the air/solvent mixture is getting refreshed at all times. This redundant system, which increases overall reliability, is of course fully in line with EN-IEC 60079-10.
Next step: encapsulation
Very precise and powerful ventilation is not the only measure that MPS is taking within their presses to prevent an explosion. We also encapsulate the areas where possible solvent can leak into surrounding areas. Inside these encapsulated zones, special care is taken for the selection of electronic and mechanical components to ensure they are non-sparking devices.
As a result of these encapsulation and ventilation measures, MPS presses are well-suited and safe for use in normal non-ATEX environments. A significant advantage for you as our customer is that modules for solvent inks can be used in a normal production hall, as outside the encapsulated area a non- dangerous area is formed. Therefore, no special ATEX equipped area is required to operate the press.
MPS puts safety first — so you can focus on your printing productivity!
Koen Posthouwer was R&D Engineer at MPS until 2019.