Why might a degas unit be needed?
Dissolved gas and microbubbles in certain fluids and system set ups may significantly affect the speed and quality of printing. By interrupting droplet formation or pressurisation at the print head, dissolved gases can lead to improper jetting at the time of fluid ejection. This can lead to poor image quality and nozzle dropouts which can cause expensive shutdown of the equipment and the need for more frequent cleaning.
Degassing within recirculating systems can be desirable to counter the effects of any air that may have been absorbed by the fluid at start up or generated by the recirculation pump as the result of volatility of the solvent used in some fluids.
Note: It should be remembered that a certain amount of oxygen is necessary within a fluid. Too little, particularly with UV cured fluids, can result in premature curing within the system.
How does degassing work?
Degassing fluid with a membrane is a simple process. The fluid flows on one side of the membrane, while a vacuum is drawn on the other side. Gases dissolved in the fluid readily transfer through the membrane to the vacuum side, leaving the fluid degassed when it reaches the outlet.
Sourcing the degas matrix membrane
It is the customer’s responsibility to supply their own degas matrix membrane and ensure its suitability with regards to flow and compatibility with their fluids. Caution should be taken to ensure a matrix which is capable of the required flow rate is used, or ineffective degassing may take place. Megnajet is unable to recommend any particular degas matrix product due to specific details relating to different setups and fluid types. The following companies will be able to advise customers further.