The latest printing technology for textile fabric/cloth is very rapidly penetrating the textile industrial sector in Pakistan. Its fine quality of fabric printing, substantial production with low production cost enable the manufacturers to compete with the competitors and serve the valued client with quality of product at very economical price . This digital printing technology machines needs temperature control environment. It’s each machine requires temperature 20°C to 24°C with 45% 50% Relative Humidification value.
In Pakistan HVAC Companies install 10 to 15 Tons of Air conditioners in one rooms for one Digital printing machines. But my question is why HVAC Companies cool the whole room instead of core required area like Printing Heads and its connected electronics system.
The printing Heads of Digital printing machines essentially require the 20°C to 24°C temperature to print the cloth /fabric finely without any printing error. So it mean if we can successfully maintain the Printing Heads temperature , we can get our ultimate required results of printing fabrics/ cloth. The heavy tonnage of air conditioning using for the whole digital printing cause to incur as a huge capital and operational energy cost in form of Air Conditioning machines, duct system, air devices, Air cool package air conditioner or substitute of it . The cooling we get from the air conditioning system cool the the volume of the room , then metal casing material of the digital machines, its glass covers and also its electronic accessories. The cooling reaches the printing heads after cooling the metal casing of the digital machine, glass covers that takes not only a lot of time for its penetration .
The cooling will secondly reach printing Heads where its temperature become more than earlier. If room temperature is 20°C the the temperature at heads may be 24°C because the temperature (20°C) has first cool the room air , then Metal /glass casing of machine . and lastly this temperature will touches the Heads of Printing machine. We should think that there is no use to cool down the glass / metal case body of the machine. The Companies install the HVAC system and duct work for the whole room which not only takes an huge operation energy cost but high labour cost, more production time and high cost of FOH (Factory overheads) . If we study the global scenario , the world is moving towards low energy consumption technology with high productivity level and economical cost effect. It is just like that we say “We need quarter inch hole not a quarter drill” . We need to cool the temperature of printing Heads and its associated electronics rather than its glass cases and metal casing of machine.
The dryer is the integral part of the digital printing machine where the printed fabric/cloth dry with heat of heaters built-in the dryer machine. The partition is necessary to make between dryer and digital printing machine in such a way that un necessary heat should not transferred into digital printing area. The heat of dryer area is blew out through ventilation with respect to the calculation of heat emission of dryers . The air changes of the area is being calculated as per requirement .
The temperature of dryer room should be in such a range where manpower can do work comfortably without effecting the dry function of fabric of machine. It is very common, successful and economical practice that a certain volume of cfm is entered in the room through electric water cooler from one side and same volume is thrown out of room through cabinet type centrifugal fan fixing just opposite side of the cooler .
Keeping in view the all above HVAC solution in vogue , we recommend another technical, economical and cost effective solution to maintain the required temperature level of digital printing machine without suffering the quality of printing:
We should fix the Heat Exchanger in the digital printing Machine with 02 Ton Air conditioner . The condenser should be fixed on the machine . The ink which is used in Printing Heads for the printing fabric/ cloth will be cool down upto 20°C which will keep cool the printing heads during printing the fabric. So when temperature of the printing heads will be maintained there will no error in its software . The fumes which generates from printing Head during printing process will be blown out from top exit points of the machine.
Another solution may also be possible . We can cool down the temperature of ink before entering in the printing heads . In this way the cool liquid of ink will cool down the temperature of printing Heads that will also meet our ultimate purpose essential for digital machine.
The solution for those textile Mills who have been printing the fabric/cloth with digital printing machine. They already installed HVAC system may be through duct layout or Free discharge floor standing cabinets. They can connect the cool supply air through flexible duct and put in one side of the digital printing Head section. Repeat the same process from second side of the printing section . The temperature of the Printing Head will reduce and maintain required temperature during its printing process. the four hundred cfm of cool air in each side having 18 to 20 C will be sufficient as per our estimation.
If we apply rational approach to analyse the productivity cost and productivity level we can easily understand the variance cost of 10 Ton and 2 ton of Air conditioner in addition to the heavy cost of the duct work. Following are the factors that affect :