The plastic is melted in an extrusion tool and forced through a nozzle to obtain a flowing bead of molten plastic. A computer-guided manipulator directs the flow of plastic to correspond to sectional profiles of the socket at varying intervals. Software translators were written to convert CAD data files for the fabricating device. Due to the novel method of socket production mechanical tests have been, and are being performed to evaluate the acceptability of the method in comparison to established techniques of socket provision. Standard ASTM methods are used in the testing.
Clinical tests are also underway to gage the performance of the sockets in real-world application.
Results - Standardized tensile testing has been performed on specimens prepared from polypropylene homopolymer and copolymer. Examination of the failed specimens and the tensile strength data indicates that the tensile strength of the experimental specimens is equivalent to the tensile strength of the material in general. The fabricating device and technique, in and of themselves, do not compromise the mechanical strength of the material, nor do they result in structural characteristics which facilitate tensile failure. Standardized fatigue testing is underway to evaluate the endurance of the fabrications. Preliminary results for polypropylene homopolymer suggest that fabrications made using the experimental system will have high resistance to fatigue and be appropriate for long term use without failure.