Not many of us would discuss the topic of humidity in our everyday lives unless we were living or planning to holiday near tropical seashores and coastal cities. However, if we consider a printing facility, the discussion and understanding of the topic of humidity would be of utmost importance. Getting it right could improve quality and increase machine speeds. But getting it wrong would stall production and damage machinery.
What is Humidity?
Humidity is the amount of water in a sample of air at a specific temperature, compared to the most amount of water the air can hold. Humidity is measured in Relative Humidity. It's expressed in a form of 0 to 100%.
The two primary ways in which humidity affects printing facilities are characterized by the following 2 factors:
Hygroscopic Nature of Textiles:
All textiles and paper are hygroscopic. It means they absorb or release moisture depending on the relative humidity of the surrounding air. The loss and gain of moisture occurs at every stage from the initial processing of the yarns to the final manufacture, distribution and use by the consumer and has a direct impact on the properties of textiles such as tensile strength, elasticity, etc. So by maintaining the right humidity levels, you can preserve the original integrity of the fabric and minimize imperfections.
Static is directly related to levels of relative humidity and its occurrence can be a major problem while processing textiles. Static electrification will occur depending on the moisture content of the air and fibers. If the fiber loses moisture, its electrical resistance increases, which means it can easily generate static electrical charge caused by frictional contact with the machinery. Textile production facilities with low humidity can cause static discharges of up to 4-5 inches. And all though they have a low current, it can build up several thousand volts. Apart from posing physical hazard to the staff, static electrical build-up will cause materials to stick together and make them less manageable. This will slow down machinery, affect production schedules and can also cause machine damage. One can eliminate static build up and all the associated problems it creates by simply maintaining humidity at around 50%rH. By controlling humidity in a processing facility one can also reduce air borne particles like lint, dust, etc. which also negative affect production. The simple use of humidifiers in your facility can create a less polluted, more productive, healthier and a more pleasant environment.
In the next blog post we will discuss, how to humidify and create an ideal environment for printing.