The printhead in the printer ‘shoots’ millions of tiny drops of the ink which constitute the texts and pictures. It is essentially the same concept when we talk about inkjet printing in AM. Imagine we use a much ‘thicker’ fluid material rather than a normal printing ink, we can create a pattern in either 2D or 3D dimension, depending on how many drops we put in there. Clearly, the quality of the pattern is dependent on the drops: How is the size of drops going to have impacts on printing? How reliable are the drops over the printing period? At what frequency we can get nice drops?
The answers to those questions above lie in a ‘drop watcher’ which we frequently use as a camera system bundled with the drop firing system to visualize the drops before they set down on the substrate. The secret of optimizing drops is to tune a specific waveform which actuates the formation of drops, and this is often an iterative process. With the assistance of a drop watcher, every single attempt on tinkering the waveform will immediately reflect on the ‘movie’ of drops travel in flight, and then we can easily determine how the shape and velocity of drops respond to the change of waveforms.
At ASL, we constantly establish the know-how of making each drop nice and pretty by using a drop watcher for a wide range of applications. For example, one of our recent research translations of inkjet printing for oral dosage forms requires a high precision of controlling the drop volume. By introducing several pulses on the waveform, we could vary drop sizes which could be directly measured with the high-resolution JetXpert drop watcher system. In this way, a personalized pill with a controllable drug dose could be tailored to a patient’s need. In some other cases, the waveform-editor would focus on having drops without satellites (i.e. small secondary drops split from the main one) such as in printing electronics. The satellites will normally be detrimental to the electronics if they land on the undesired position, which may cause short circuit.
If we can’t see what drops look like, we won’t know what we are printing. There is no doubt that a drop watcher is a powerful tool to facilitate inkjet printing research, and we are committed to stand in the frontier of inkjet printing for AM.