Ανάπτυξη ψηφιακών εργαλείων για το σχεδιασμό και την κατασκευή κομματιών μεταβλητής πυκνότητας με τη μέθοδο της εξώθησης υλικού της προσθετικής κατασκευής

Βασιλάκος, Αγγελος

Doctoral Thesis

Author

Βασιλάκος, Αγγελος

Date

2024

Abstract

Additive Manufacturing is a relatively new class of manufacturing methods that were developed at the end of the 20th century. What, in practice, differentiates Additive Manufacturing methods from standard/conventional manufacturing methods, is their ability to efficiently handle morphological and structural complexity. In the context of the present thesis, the issues concerning the design and fabrication of the manufacturing of heterogeneous structures/objects, i.e. objects with locally defined density and composition, by thermoplastic material extrusion are examined. Three main research questions were identified: a) the fabrication of a heterogeneous structure at the layer level by a single deposition path without interruptions, b) the fabrication of a heterogeneous structure at the object level without the use of internal supporting structures, and c) the fabrication of heterogeneous structures using two materials. To address the above issues, two methodological approaches were developed, the point cloud approach and the grid approach. In the first approach, a cloud of points is aptly distributed at the layer level based on the corresponding bitmap image, and the deposition path is subsequently designed, by defining the visiting sequence of the points through Traveling Salesman Problem optimization techniques. In the grid approach, heterogeneous objects are represented by voxels, which are assigned specific density and/or composition values. The voxels are broken down into sub-elements (laminae, cells and tiles), which are then used to design layer-by-layer deposition paths by joining elementary paths of standard or semi-random shape. Computational and fabrication tests of the developed methodological approaches and algorithms showed that the computational burden is not particularly high, and that it is possible to design and manufacture complex heterogeneous structures/objects satisfying the basic constraints of a single and uninterrupted path per layer and the absence of internal supporting structures. According to the results of the study, it is also possible to extend the specific methodology to two materials, following the appropriate adjustments. Achieving, however, uninterrupted paths for both materials faces more constraints and can only be achieved under conditions. Interesting topics for further research, identified during the study, are the development of methods to smooth the deposition path by reducing the number of turning points and the application of the developed methodological techniques employing various material combinations and different Additive Manufacturing technologies

Department

Σχολή Ναυτιλίας και Βιομηχανίας. Tμήμα Βιομηχανικής Διοίκησης και Tεχνολογίας

Number of pages

100

Language

Greek

URI

https://dione.lib.unipi.gr/xmlui/handle/unipi/16397
http://dx.doi.org/10.26267/unipi_dione/3819

Collections

Τμήμα Βιομηχανικής Διοίκησης και Τεχνολογίας

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Except where otherwise noted, this item's license is described as
Αναφορά Δημιουργού-Μη Εμπορική Χρήση-Όχι Παράγωγα Έργα 3.0 Ελλάδα