Carsten Tille

Non‐toxic flexible photopolymers for medical stereolithography technology

Purpose – To describe the development of a novel polyether(meth)acrylate‐based resin material class for stereolithography with alterable material characteristics.Design/methodology/approach – A complete overview of details to composition parameters, the optimization and bandwidth of mechanical and processing parameters is given. Initial biological characterization experiments and future application fields are depicted. Process parameters are studied in a commercial 3D systems Viper stereolithography system, and a new method to determine these parameters is described herein.Findings – Initial biological characterizations show the non‐toxic behavior in a biological environment, caused mainly by the (meth)acrylate‐based core components. These photolithographic resins combine an adjustable low Youngs modulus with the advantages of a non‐toxic (meth)acrylate‐based process material. In contrast to the mostly rigid process materials used today in the rapid prototyping industry, these polymeric formulations are ...

Image-based analysis of the internal microstructure of bone replacement scaffolds fabricated by 3D printing

Rapid Prototyping and especially the 3D printing, allows generating complex porous ceramic scaffolds directly from powders. Furthermore, these technologies allow manufacturing patient-specific implants of centimeter size with an internal pore network to mimic bony structures including vascularization. Besides the biocompatibility properties of the base material, a high degree of open, interconnected porosity is crucial for the success of the synthetic bone graft. Pores with diameters between 100 and 500 μm are the prerequisite for vascularization to supply the cells with nutrients and oxygen, because simple diffusion transport is ineffective. The quantification of porosity on the macro-, micro-, and nanometer scale using well-established techniques such as Hg-porosimetry and electron microscopy is restricted. Alternatively, we have applied synchrotron-radiation-based micro computed tomography (SRμCT) to determine the porosity with high precision and to validate the macroscopic internal structure of the scaffold. We report on the difficulties in intensity-based segmentation for nanoporous materials but we also elucidate the power of SRμCT in the quantitative analysis of the pores at the different length scales.

Processing and mechanical properties of a new flexible acrylic stereolithographic resin family for engineering and medical device manufacturing

Stereolithography, as a well-known rapid prototyping process, has been used in a wide field of technical and also medical applications. Due to the stereolithography principle – the curing of a liquid photopolymer by a UV laser – the number of commercially available reaction mechanisms and related material characteristics is very limited. Our paper presents a novel class of non-toxic, biocompatible polyether(meth)acrylate-based resin formulations with outstanding flexible material characteristics. In contrast to the mostly rigid commercial engineering materials, these polymeric formulations are able to meet the demands for soft to stiff parts. Depending on the individual formulation, the cured resins can show a Youngs modulus from 25 MPa up to 1500 MPa. We give an overview over basic formulations and processing characteristics for this material class. Process parameters were studied in a commercial Viper Si² system (3D Systems); mechanical properties of different formulations were tested using standard tensile testing methods.

Novel, biocompatible polyether(meth)acrylate-based formulations for stereolithography – A new flexible material class for three-dimensional applications

Abstract Herein we present a novel polyether(meth)acrylate-based resin material for stereolithography and other photolithographic applications with outstanding flexible material characteristics. This group of photopolymeric resin products combines the advantages of a non-toxic (meth)acrylate-based process material with a broad spectrum of adjustable low Young’s modulus material characteristics. In contrast to the mostly rigid and non-flexible process materials used at the moment in the engineering world, these formulations are able to fulfil the extended need for a very flexible and also biocompatible engineering material, especially for threedimensional models or prototypes in the medical technology area. A short overview over the bandwidth of possible material characteristics is given in this publication.