98:2 systems are available in different variants:
Open - means that the sprayed plastic (98 %) is also mixed with the hardener (2 %) jet in jet. The liquid hardener is sprayed into the sprayed plastic by means of a low-pressure system. The advantage of this is that you can stop the machine at any time without the hardening of anything in the system. The disadvantage is that it is difficult to visually check whether hardener is also being injected.
In the closed system, ink and hardener are combined in a mixing chamber. The advantage lies in the electronic monitoring of whether sufficient spray plastic and hardener are actually mixed. The disadvantage becomes obvious when the machine is stopped for longer and more frequent periods. In this case, the mixing chamber, hoses and nozzles may have to be freed (rinsed) from the activated material more often.