| abstract |
An additive elastomeric manufactured part with an improved surface finish is produced by repeatedly extruding through a nozzle to build up layers of a material consisting of a prepolymer and a filler, the prepolymer consisting of an isocyanate terminated prepolymer The amount of material is such that the material has a shear storage modulus G' of 100,000 to 300,000 Pa measured at an oscillation rate of 1 Hz and a relaxation time of 20 to 360 seconds. The particular material with these rheological properties has been found to improve the surface finish of the additively manufactured part without collapse, and is believed to be due to ingress between the extrudates as they stack caused by the surface flow of the material in the valley. |