Cross-sectional analysis of tubular polymer semi-finished products using ultrasound in comparison with other measuring methods

Olga Sahmel,Stefan Siewert,Klaus-Peter Schmitz,Niels Grabow,Wolfram Schmidt

doi:10.1515/cdbme-2020-3039

Abstract

Abstract In the sector of biomedical engineering and implant technology, high-precision geometry is often decisive for successful end product functionalization. Especially in the production of tubular polymer semi-finished products, e.g. for stent fabrication, it is important to assure the desired parameters, such as inner and outer diameter and wall thickness. Within the current study we analyzed semifinished products for manufacturing of polymeric stents using three different methods. Biodegradable poly-L-lactide (PLLA) tubes were examined by means of micro computed tomography, ultrasonic scanning and scanning electron microscopy. The final evaluation presents clear advantages of the ultrasonic measuring method for the measurement of outer and inner diameter and wall thickness.

Highlights

Tubes, cannulae, catheters as well as tubular implants made of polymers are of great importance in modern medicine
An ultrasonic measuring method is evaluated as an alternative to micro computed tomography and scanning electron microscopy for the analysis of polymer microtubes [1, 2]
The extrusion process resulted in tubular polymer semifinished products with an outer diameter in the range of 0.6 2.3 mm within a short period of time and without extensive preparation and post-processing

Summary

Introduction

Cannulae, catheters as well as tubular implants made of polymers are of great importance in modern medicine. Regardless of whether they are invasive or non-invasive, tubular medical devices contribute to life-saving measures. In addition to basic requirements, such as biocompatibility, there are high demands with regard to geometry and mechanical properties. The morphological investigations of the cross-sectional geometry are often only carried out selectively and not always non-destructively. Measurement of outer and inner diameter, as well as wall thickness, requires additional work steps, respectively. An ultrasonic measuring method is evaluated as an alternative to micro computed tomography and scanning electron microscopy for the analysis of polymer microtubes [1, 2]

Extrusion

Micro computed tomography

Scanning electron microscopy

Results and Discussion

Conclusion