THE PRINCIPLES

UNDERSTANDING THE TARGET

  • The first step of any attempt to develop a waveform is to clearly define the goal. Usually, the most important targets to identify are the desired drop size, drop velocity, and jetting frequency. If you already know the target specifications, then you can get started straight away. If not, then you will have to do some investigation.
  • If you are an ink company and have a specific machine to develop for, check with your customer what the usage conditions of the ink are. If your customer is an equipment manufacturer, they should be able to tell you all you need to know. If selling direct to user, then perhaps this information is not so easily available and you’ll have to work a bit harder to figure out what’s sensible. You can get an idea of the operating frequency from the carriage speed and the print resolution, remembering that if the print is multiple-pass this may be different from the final resolution.

THE STARTING POINT

  • The very first step in waveform optimization is to establish a sensible baseline for jetting so you can view it with the dropwatcher. If possible, an easy technique is to start with the printhead manufacturer-recommended, or default, single pulse waveform. As well as typical pulse timing, there will usually be some kind of calibration voltage (sometime called “label” voltage). Use this to start with as it should produce reasonable jetting. For the Dimatix Samba example in this video, a waveform from the printhead user manual was used.
  • The next step is to get the drops visible in the field of view of the drop watcher. It is important that you can see the faceplate if possible; it helps a lot when it comes to understanding failures if you get them. The video below gives you an ideal view on these topics and insights on waveform creation.