Design, fabrication and characterization of porous structures produced by selective laser sintering
Figure2. Relationship of porosity and characteristic length. Figure2-H: porosity and wall thickness of honeycomb structure; Figure2-D: porosity and diameter of diamond lattice structure; Figure2-P: porosity and wall thickness of Primitive TPMS structure; Figure2-G: porosity and wall thickness of Gyroid TPMS structure. Figure4. Porosity measurement. The left one of two vertical axes is the relationship of designed porosity and measured porosity while the right one is the relative error. Figure5. Relationship of porosity and compressive properties of four porous structures.
Steps to reproduce
Four types of porous structures including honeycomb, lattice, Primitive TPMS and Gyroid TPMS porous structures have been presented. Computer aided design and implicit surface design are used to obtain four periodical models (50mm×50mm×50mm). The first two are designed by Solidworks while the last two are built by Rhino. For each one, firstly change the value of characteristic length in the appropriate range, measure its volume and calculate the porosity, fit the relationship of porosity and characteristic length. Then find the value of characteristic length with the target porosity on the curve. Finally carry out volume measurement again with the solved characteristic length to checkout the correctness of the fitted curve. All types of porous structures are manufactured by a selective laser sintering printer whose molding material is coated ceramsite. Compressive tests are performed on a universal material testing machine. The mechanical properties of porous structures with diverse porosities and shapes are evaluated from the perspective of compressive strength, compressive modulus, specific strength and specific stiffness.