Effect of Manufacturing Conditions on Structural and Handling Properties of Braided Polyamide Suture
Suture performances include handling characteristics and knot mechanical properties. These performances depend mainly on frictional, flexural, and compressive forces. The interaction between these forces developed inside the suture knot governs the displacement mode and the deformability of the suture yarn inside the knot. In the present work, we studied the effect of manufacturing conditions on structural properties and handling characteristics. Obtained results show that manufacturing parameters have significant impact on slipperiness, flexibility, and compressibility. Consequently, suture performances widely depend on manufacturing parameters. We show that after a hot stretch step, suture structure becomes more uniform and compact. Furthermore, after this treatment, lateral deformation, friction force, and bending rigidity are reduced and knot performances are improved.
Simultaneous optimization of mechanical properties of braided polyethylene terephthalate suture subjected to hot-stretching treatment
Braided polyethylene terephthalate sutures are the first used braided suture. They have to undergo several manufacturing steps including hot stretching. However, there is a lack of literature describing precisely braided suture manufacturing process. Hot-stretching treatment was reported to have positive impact on suture mechanical properties. The main objective of this work is the simultaneous improvement of different mechanical properties related to this treatment. Obtained results show that polyethylene terephthalate suture hot stretching leads to a uniform compact suture with high ultimate tensile strength and low friction coefficient. However, during this treatment suture becomes stiff. By increasing temperature and drawing ratio, suture becomes flexible. Below 200℃, polyethylene terephthalate braided suture shows low friction coefficients difference and low Young’s modulus. Performing overlaid contours plot permitted to determine optimal values for significant manufacturing parameters in order to manufacture polyethylene terephthalate braided suture having at the same time high ultimate tensile strength, low friction coefficient, low extension at break, low rigidity, and high yield point values. In this study, optimal conditions for hot-stretching suture in main heat zone are defined. Reported results show also optimized conditions of suture preliminary hot stretching in order to obtain further best mechanical properties. Results approve that suture hot stretching in main heat zone after preliminary heat without tension involved the best suture mechanical properties.
"Flying Triangulation" - a new optical 3D sensor enabling the acquisition of surfaces by freehand motion
In order to obtain complete 3D surface information of an object it is often necessary to acquire many partial 3D views. For this purpose, the sensor has to be moved (e.g. for the acquisition of sculptures or rooms). Further, in many cases a motion of the object relative to the sensor is unintended but inevitable (e.g. for medical applications such as intraoral measurements of teeth). Nearly all existing optical 3D sensors either lack an easy handling or require a standstill during the acquisition of a single partial 3D view, since usually multiple camera shots have to be taken for this purpose. This makes such measurements elaborate or even impossible.