Delta DLP 3-D printing of large models

Ran Yi, Chenming Wu, Yong-Jin Liu, Ying He, Charlie Wang

Research output: Contribution to journalArticleScientificpeer-review

15 Citations (Scopus)
90 Downloads (Pure)


This paper presents a 3-D printing system that uses a low-cost off-the-shelf consumer projector to fabricate large models. Compared with traditional digital light processing (DLP) 3-D printers using a single vertical carriage, the platform of our DLP 3-D printer using delta mechanism can also move horizontally in the plane. We show that this system can print 3-D models much larger than traditional DLP 3-D printers. The major challenge to realize 3-D printing of large models in our system comes from how to cover a planar polygonal domain by a minimum number of rectangles with fixed size, which is NP-hard. We propose a simple yet efficient approximation algorithm to solve this problem. The key idea is to segment a polygonal domain using its medial axis and afterward merge small parts in the segmentation. Given an arbitrary polygon Ω with n generators (i.e., line segments and reflex vertices in Ω), we show that the time complexity of our algorithm is O(n²log² n) and the number of output rectangles covering Ω is O(Kn), where K is an input-polygon-dependent constant. A physical prototype system is built and several large 3-D models with complex geometric structures have been printed as examples to demonstrate the effectiveness of our approach.
Original languageEnglish
Pages (from-to)1193-1204
Number of pages12
JournalIEEE Transactions on Automation Science and Engineering
Issue number3
Publication statusPublished - 2018

Bibliographical note

Accepted author manuscript


  • Manufacturing
  • mechanisms
  • primary topics
  • secondary topics


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