The RepRap 3D printer development project is a fast growing, open-hardware initiative relying on the input of hobbyist designers. One of its key components is the printer nozzle. The performance and reliability deficiencies of currently available nozzle designs are common topics in the RepRap community, and our own experience with a RepRap 3D printer has identified a need for improvement in a few particular areas. We set out to eliminate melt leakage, improve thermal isolation, and develop a more effective method of nozzle assembly attachment. Here, we review the issues, describe design efforts, and report results.

Thermoplastic nanocomposites based on linear polymethacrylates as matrix materials and spherical silica particles as fillers have been synthesized using the in situ free radical polymerization technique of methacrylate monomers in presence of specially functionalized SiO2 nanoparticulate fillers. Uncoated monodisperse silica particles with particle sizes 100 nm and 10 nm were used as reference fillers. For surface modification, the alcoholic dispersions of the fillers were treated with appropriate amounts of methacryloxypropyltrimethoxysilane (MPTS) and acetoxypropyltrimethoxysilane (APTS). Transmission electron microscopy (TEM) was used to investigate dispersion behaviour in dependence on surface modification. Dynamic mechanical properties were measured by dynamic mechanical thermal analysis (DMTA).