If developing a sustainable graphics-printing process is a goal for your business, consider how the latest generation of UV-curable screen inks can help. This discussion looks at the history of UV inks, recent ink-formulation developments, and ways you can increase productivity while helping to reduce carbon dioxide emissions.
Note: Each printing press outputs varying degrees of mJ and mW. Each UV cure station on a multicolor press should be measured and compared to the recommended cure levels of inks used. UV cure settings should be fined tuned to produce the desired level of cure before calculating the savings.
1 lamp x 200 W x 60 in. = 12 kWh x 8 hours x 20 days = 1920 kWh / month
1 lamp x 300 W x 60 in. = 18 kWh x 8 hours x 20 days = 2880 kWh / month
2 lamps x 200 W x 60 in. = 24 kWh x 8 hours x 20 days = 3840 kWh / month
2 lamps x 300 W x 60 in. = 36 kWh x 8 hours x 20 days = 5760 kWh / month
Significant savings will be realized if you can switch from one 300-watt bulb to one 200-watt bulb or if you can switch from two 200-watt bulbs to one 200-watt bulb. Making changes in belt speeds will not impact electrical use significantly. Also, use the above calculated information to determine the energy cost per your area.
The kWh can be used to calculate the CO2 emissions. An estimated value of 1.55 lbs of CO2 per kWh when the electricity is derived from combustion of coal was used for the example. (Calculation from www.energystar.gov.)
1 lamp x 200 W x 60 in. = 1920 kWh x 1.55 lb CO2 per kWh = 2976 lbs CO2/mo (35,712 lbs CO2/yr)
1 lamp x 300 W x 60 in. = 2880 kWh x 1.55 lb CO2 per kWh = 4464 lbs CO2/mo (53,568 lbs CO2/yr)
2 lamps x 200 W x 60 in. = 3840 kWh x 1.55 lb CO2 per kWh = 5952 lbs CO2/mo (71,424 lbs CO2/yr)
2 lamps x 300 W x 60 in. = 5760 kWh x 1.55 lb CO2 per kWh = 8928 lbs CO2/mo (107,136 lbs CO2/yr)
The amount of lbs of CO2 emissions has been further calculated for a 12-month period and converted to CO2 tons; the savings per setting is outlined below. This savings is represented per UV cure station. A typical inline screen-printing machine will have five to six cure stations. The use of a fast curing UV screen ink on a properly maintained inline printing press allows most shops to use a 200-watt setting with only one bulb.
When changing from two lamps to one lamp, you can also figure the environmental impact of replacing only one lamp. 1000 hours as an average lamp life.
To calculate your own settings, use the following factors and equations:
C kWh = average kWh per lamp at current settings
N kWh = average kWh per lamp at new settings
C lamps = number of lamps per UV-curing station for current settings
N lamps = number of lamps per UV cure station for new settings
UV stations = number of UV cure stations
hrs/day = number of hours running the machine
day/mo = number of days running the machine
kWh cost = cost of energy for location per kWh
lbs CO2/kWh = estimated lbs CO2 per kWh
Energy user per printing press (current and new UV-cure settings):
C kWh x C lamps x UV stations x hrs/day x day/mo = Current kWh/mo
N kWh x N lamps x UV stations x hrs/day x day/mo = New kWh/mo
Energy cost and lbs CO2 comparison
Current kWh/mo – New kWh/mo = Energy savings/mo
Energy savings/mo x kWh cost = $ savings/mo x 12 mo = $ savings/yr
Energy savings/mo x lbs CO2/kWh = lbs CO2/kWh savings mo x 12 mo = lbs CO2/kWh savings/yr
Laura Maybaum is the point-of-purchase market segment manager for Nazdar. Involved in the industry for more than a decade, she has served in screen-printing technical and marketing positions with Nazdar, KIWO, and Sefar America. Maybaum holds a Master’s degree from Bowling Green State University.
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