‘Computer vision-based auto-calibration system for Direct Light Processing printers’
By: Mikkel Hansen and Aqqaluk Hans Sydel Møller, Mechanical Engineering, Technical University of Denmark (DTU)
Using methods inspired by photography, a system for automatic calibration of Direct light processing (DLP) printer is proposed. Using this method, parts requiring tight tolerances like injection molds can be printed.
The focus of the project was to increase the usability of Direct Light Processing (DLP) printers by automating the calibration process. Previously, calibration relied on hand and eye, but using the proposed method, the only manual operation required is moving a camera from one position in a jig to another.
The increase in precision offered by calibrated machines allows for the production of complex geometries with tight tolerances, such as those found in injection molds. The project challenges the notion that injection molds are expensive and only produced by highly skilled toolmakers using exotic processes like electric discharge machining, by offering alternative production methods able to meet the same requirements.
The key innovation is clearly the entire toolchain allowing for low cost, low run molds, and this project is only a modest link in this chain. That being acknowledged, autofocusing is a plain improvement in the DLP space.
In short, this project and the toolchain is a part of, accomplices three key innovations: Automatic calibration, reducing operating cost and increasing the life of DLP printers. Increasing precision, thus making, low run, low cost, printed injection molds a reality. Expanding the commercial scope of injection molding, by lowering the barrier of entry.