Numerical prediction of the printable density range of lattice structures for additive manufacturing

Abstract

Structured cellular structures are nowadays printed using additive manufacturing methods like powder bed fusion. The relative density of the cellular structures has a big role in the suitability of a lattice for printing due to the minimum printable radius constraint and powder being trapped inside an inclusion. In this work, the theoretical limits of the printable range of relative density of different lattice types are found based on the cell size using computer methods by leaving other process parameters for further research as the current parameters are the most basic ones. The results are approximated using simple polynomials to enable practical usage.

A performance metric for additively manufactured microlattice structures under different loading conditions

“…Thus, finding optimum stiffness values for different microlattice structures under loading conditions has its own scientific merit. The evaluation function that was developed in this study can be used both for the microlattices designed using topology optimization frameworks and any ordinary microlattice structure including unit cells. The proposed evaluation function can be improved by considering the effects of printability, 46 where it can include concepts such as maximum printable densities in a strut 47 or the need of support structures. 48 Performing experiments at the moment on different microlattice structures is time consuming, cumbersome, and expensive due to the cost of metal powder and running a DMLS or an SLM machine.…”

“…The evaluation function that was developed in this study can be used both for the microlattices designed using topology optimization frameworks and any ordinary microlattice structure including unit cells. The proposed evaluation function can be improved by considering the effects of printability, 46 where it can include concepts such as maximum printable densities in a strut 47 or the need of support structures. 48 .…”

Computer-Aided Prediction for Printable Density Limits of Additively-Manufactured Direction-Wise Stretch-Dominated Strut-Based Lattice Structures

“…In powder bed fusion methods, printability of a structured foam depends on unit-cell shape/topology [2][3][4][5][6][7][8][9], relative density of a lattice (i.e. volume fraction) [2][3][4][5]7,8,[10][11][12][13], strut inclination [14][15][16][17][18][19][20], cell size [5], powder particle size [5,[21][22][23], powder material [3,4,8,10,16,17,24], machine precision [2,5,10,11,25,26], laser power [3,4,10,23,[25][26][27][28]<...>…”

“…This implies that the lattice topologies which is defined, according to Maxwell criterion, as bendingdominated like BccZ and FccZ (See Figure 1) can exhibit stretch-dominated behavior based on the load's orientation with respect to the lattice [43]. Tanlak et al [5] investigated the printable limits of some wellknown strut-based lattice structures like Bcc, Fcc, and so on. However, the printability of direction-wise stretch-dominated strut-based lattice structures was an open question.…”

Elastic and elasto-plastic analysis of Ti6Al4V micro-lattice structures under compressive loads

“…Based on the designer’s requirements, the lattice structure can be fabricated as custom-made, whereby the required mechanical properties for specific applications can be achieved. The morphology and volume fraction of the lattice are subjected to adjustments to reach the desired properties [29]. The feature advantage offered by cellular solid materials is high strength accompanied by a relatively low mass.…”