Manufacturing Presentation

The process started with a 3d dataset that is sliced

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Unformatted text preview: inhomogeneiHes of pore distribuHon [1]. SCAFFOLD BASED RP TECHNOLOGIES cont’d The salt leaching scaffold has quite an irregular distribuHon of pores in the scaffold [1]. This procedure cannot guarantee interconnecHvity of pores, because this depends on whether the adjacent salt parHcles are in contact [8]. SCAFFOLD BASED RP TECHNOLOGIES cont’d Other general limitaHons to the convenHonal techniques include [8]: The heavy reliance on user skills and experiences ofen results in nonuniformity. They are associated with poor reproducibility, irregularity of pore shape, and insufficient pore interconnecHvity. They involve mulHstage manual processes that are labor- intensive and Hme consuming. SCAFFOLD BASED RP TECHNOLOGIES cont’d They require extensive use of toxic organic solvents to dissolve the raw stocks (granules, pellets, or powders) and convert into the final scaffold. It is also difficult to remove the toxic solvents completely from the fabricated scaffolds especially, in thicker constructs. The residual toxic solvents cause adverse effects on adherent cells, incorporated biological acHve agents, or nearby Hssues. SCAFFOLD BASED RP TECHNOLOGIES cont’d Some techniques use salts or waxes as porogens to create porosiHes in the scaffolds. These techniques that use porogens, it is difficult to prevent the agglomeraHon of porogen parHcles and thus to achieve uniform porogen dispersion. Some of the techniques use moulds or containers to manufacture scaffolds as thin membranes or 3D constructs. These techniques are confined to create certain simple shapes and cannot produce scaffolds with complex and/or desired structural architectures. Some of the techniques produce scaffolds mostly in the form of foams. Cells are seeded and expected to grow into scaffold. Probably due to the diffusion constraint of the foam, there is a scarcity of nutrients and oxygen supply, and insufficient removal of waste products. 3- DIMENSIONAL PRINTING a RP TECHNIQUE 3DP was invented and patented by Michal J. Cima and co- workers in 1993 and is based on the convenHonal inkjet prinHng technology [2,14]. An advantage of 3DP is the wide range of materials that can be used, from syntheHc and natural polymers to ceramics, as well as composites of the aforemenHoned [2]. Three- dimensional prinHng method requires the use of organic solvents as binder for powder- based aliphaHc polyesters such as poly(lacHc acid) and poly(lacHc- co- glycolic acid) [3]....
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