FingerMap: a new approach to predict soft material 3D objects printability

Abstract

Soft material 3D printing through Liquid Deposition Modelling (LDM) is a challenging manufacturing process where yield stress control is mandatory. Indeed, the higher the yield stress value, the more complex the 3D printed structure can be. In a bid to go one step further, this report proposes a new approach enabling the prediction of soft material 3D printability as a function of the material's properties and shape. The prediction consists in numerical simulation to anticipate, in silico, the collapse of a voxelized 3D design, called FingerMap. To do so, a calibration of the program using three silicone formulations (with increasing yield stress value) was first performed to define a printability domain according to mass/surface ratio, overhang angle and the zposition of each voxel. Then, two anatomical 3D models (ear and aortic valve) were used to demonstrate the capacity of the tool to predict printability. Good correlations between theoretical and experimental results were obtained. The proposed in silico simulation tool was then proven to be useful for LDM, even if some limitations were identified, particularly in the case of materials exhibiting complex rheological behaviours such as time-dependent rheological properties.

Computational Modeling and Experimental Characterization of Extrusion Printing into Suspension Baths

“…[2,[8][9][10][11][12][13] While many predictive models are available for extrusion printing, few models have been previously reported for suspension bath printing. [14][15][16][17][18] Most published approaches have relied on laborious and inefficient guess-and-check methods to determine optimal printing parameters, limiting overall progress and translation across research groups. [1,5,8] The extent of characterization of suspension baths in the literature also varies widely, from no characterization to varying levels of rheological analyses.…”

Enhancing the Yield Stress in Liquid Polydimethylsiloxane to Allow Its 3D Printing: Hydrogels as Removable Fillers

“…The first layers can be printed and withstand the weight of upper layers without collapsing. [ 41 ] Basically, the higher is the yield stress, the easier is the 3D printing process because it makes the under construction object stronger to support the successive added layers. In the present work, 3D printing tests have not been systematically carried out with different amounts of hydrogels so that it is difficult to determine the minimum yield stress needed for the printing (obviously this can depend on the printed object complexity).…”

3D Bioprinting in Microgravity: Opportunities, Challenges, and Possible Applications in Space

“…The capacity of the jetted material to generate large parts in the Z direction is then very limited since the material is collapsing under its own weight. [ 61,62 ] This can be partially solved on Earth by in situ reticulation of the jetted material during the printing process, either by using photochemistry [ 63 ] or soft chemistry. [ 64 ] In space, microgravity is expected to reduce the force applied by a layer due to its own weight, enabling the production of larger parts than on Earth while keeping the viscosity and static yield stress as low as possible. Surface Tension—The behavior of fluids in microgravity is driven by surface tension forces, and liquids can achieve sizes much larger than on Earth.…”