In this direct-to-shape printing DTS project, a robot-based print platform with a moving printhead was set up and put into operation, including a fluid supply system and a printing system control.
The robot controller was programmed accordingly, with a dedicated software that calculates the trajectory and allows communication between the robot and the printing system control. In order to analyze the behavior of the printhead and the robot, various test patterns with different printhead orientations were printed and subsequently analyzed.
It became apparent that the trajectory’s accuracy by the robot ex-factory is insufficient for high resolution graphic printing.
Patterns emerge that are unrecognizable by the human eye, due to imprecise positioning of the pixels.
The repeat accuracy of the robot, on the other hand, can be located in the micrometer range and is thus better than or equal to that of an inkjet printhead.
Based on the printing tests, various solutions have been proposed in order to be able to print medium-term low-resolution and longer-term high-resolution free form objects.
Printing strategies were discussed as well as the improvement of the path curve accuracy and measuring systems for absolute or relative determination of position with corresponding correction of the printing data.
Furthermore, the required algorithms for image distortion as well as initial approaches to color density compensation were investigated and specified.
Based on the results now available, a major research project with several industrial partners is being sponsored by the national research funding agency Innosuisse.