Exploring Print Resolution of 3D Color Printers with Siemens Star Targets

Erin Clark, Clemson University

Due to its vast material and color selection, low cost, and high-resolution capabilities, inkjet printing has become a leading technology within the print industry. As a result of this and the speedily advancing 3D print industry, developers have begun incorporating inkjet’s material jetting technology with their own 3D printing machinery. DragonFly LDM’s 3D electronic circuitry printers, Stratasys’s 3D PolyJet printers, and Mimaki’s 3DUJ-553 Photo-realistic Full Color 3D Printer are a few examples of these developers who are working to create more precise and high-resolution prints. Although inkjet printers are known for their high-quality prints, this technology may have resolution limits when applied to a three-dimensional printing space. 3D printers equipped with inkjet technology need a way to analyze their print resolution against their innovative inkjet printer counterparts.

The objective of this research is to develop a method for testing the resolution of printed graphics from any 3D printer. For this project, the Mimaki 3DUJ-553 Photo-realistic Full Color3D Printer will be used for resolution analysis against one of Mimaki’s standard inkjet printers. The Mimaki UJF-6042 Tabletop Type LED-UV Curing Flatbed Inkjet Printer was used as the comparative inkjet printer for this specific project. Although Mimaki has implemented the inkjet technology in its 3D printer, the hypothesis is that the resolutions of the two printers will differ due to interference from the materials required for third dimensional printing. The Mimaki 3D printer will be printing a model and design whereas the Mimaki inkjet printer will only be printing the design.

In the research process, Siemens Star resolution targets were used as the print design by which the resolutions of the individual Mimaki printers were visually analyzed. The Siemens Stars are designed to test and compare the resolution of printers via the star’s radiating black and white spokes that become thinner as they head towards the center of the star. The spokes are to only touch at the very center; however, a printer may not be able to print at such a refined resolution, causing the individual spokes to eventually merge together. For analyzing the resolution of both printers, three Siemens Star were used with each star having a differing number of spokes but with equal diameters.

Figure1: Siemens Stars (from left to right), Siemens Star with 72 spokes at 5°,
Siemens Star with 90 spokes at 4°, Siemens Star with 128 spokes at 2.8°

The 3D printed Siemens Stars rectangular plane was visually analyzed against the rectangular plane and cylinder that had Siemens Stars printed via the Mimaki inkjet. The results illustrated the visual print resolution of each star from data obtained by three separate participants to obtain reasonable repeatability and reproducibility. Moving towards the center, the diameter of where the black and white spokes began to blend, and where individual spokes can no longer be seen were measured and assessed against one another is considered as the point of resolution limit. These findings showed the visual resolution variation between the Mimaki3DUJ-553 printer and the Mimaki UJF-6042 inkjet printer merely from their appearance to the naked eye. This research project provides a useful method for testing the resolution of 3D printers in order to retermine where improvements can be made for the benefit of future three-dimensional printing machinery as the industry continues to develop and expand.