Development of Intertwined Infills to Improve Multi-Material Interfacial Bond Strength

Abstract

Recently the availability of various materials and ongoing research in developing advanced systems for multi-material additive manufacturing (MMAM) have opened doors for innovation in functional products. One major concern of MMAM is the strength at the interface between materials. This paper hypothesizes overlapping and interlacing materials to enhance the bonding strength. To test this hypothesis, we need a computer-aided manufacturing (CAM) tool that can process the overlapped material regions. However, existing computational tools lack key multi-material design processing features and have certain limitations in making full use of the material information, which restricts the testing of our hypothesis. Therefore, this research also develops a new MMAM slicing framework that efficiently identifies the boundaries for materials to develop different advanced features. By modifying a ray tracing technology, we develop layered depth material images (LDMI) to process the material information from computer-aided design (CAD) models for slicing and process planning. Each sample point in the LDMI has associated material and geometric properties that are used to identify the multi-material regions. Based on the material information in each slice, interlocking joint (T-Joint) and interlacing infill are generated in the regions with multiple materials. Tensile tests have been performed to verify the enhancement of mechanical properties by the use of overlapping and interlacing materials.

Interlacing Infills for Multi-Material Fused Filament Fabrication Using Layered Depth Material Images

“…After that, we can generate interlaced infills for the multi-material regions. This paper extends our previous works [ 10 , 11 ], which were the first step in testing the possibility of interlacing infills. Here, we present more in-depth implementation and experiments.…”

Three-Dimensional Printing of Liquid Crystals with Thermal Sensing Capability via Multimaterial Vat Photopolymerization

“…As illustrated in Figure a, the MVPP process was used to selectively cure a conventional acrylic-based UV resin and an LC-based photocurable material in a layer-by-layer manner to form high-resolution geometries and complex 3D shapes. The interface between two different photocurable materials is robust, and the bonding of two materials can be further improved by designing the intertwined infills in the interface . The viscosities of LC-based materials were evaluated through rheological measurements at different concentrations of 5CB and CE-RM257 (Figure S1 in the Supporting Information).…”

“…In terms of LCs in the isotropic phase, the randomly directed LCs scatter the 2D patterned light beam, leading to the reduction of the light penetration. Consequently, LCs in the nematic phase promote the photopolymerization process and subsequently affect the energy penetration depth of the projected UV light beam since the mean number of pathways in which photons can penetrate the photocurable material becomes significantly increased . For LCs in different phases and molecular orientations, the exposure time of the projected 2D patterned light beam must be adjusted in order to promote photopolymerization of the reactive mesogen to produce LCs with a desired geometry.…”

A Multi-Material Additive Manufacturing virtual prototyping method for design to improve part strength

“…Ribeiro et al's work showed that macroscopicbased interface geometries such as T-shape, U-shape, and Dovetail shape are shown to be able to strengthen the interface [15]. More recently, Mustafa and Kwok developed a new intertwined infill strategy to improve the multi-material interfacial bond strength and showed a 50% improvement compared to a 20% improvement from the T-shape interface [16]. It can be inferred that the mechanical behavior of a multi-material printed object can potentially be further improved by introducing a new boundary interlock geometry.…”