The Effect of Chemical Cleaning on Mechanical Properties of Three-Dimensional Printed Polylactic Acid

Abstract

Three-dimensional (3D) printing may be a solution to shortages of equipment and spare parts in the healthcare sector of low- and middle-income countries (LMICs). Polylactic acid (PLA) for 3D printing is widely available and biocompatible, but there is a gap in knowledge concerning its compatibility with chemical disinfectants. In this study, 3D-printed PLA tensile samples were created with six different printer settings. Each of these six batches consisted of five sets with five or six samples. The first set remained untreated, the others were soaked in Cidex OPA or in a chlorine solution. These were applied for seven consecutive days or in 25 short cycles. All samples were weighed before and after treatment and subjected to a tensile test. Results showed that a third of the treatments led to an increase of the median weight with a maximum of 8.3%, however, the samples with the best surface quality did not change. The median strength increase was 12.5% and the largest decrease was 8.8%. The median stiffness decreased 3.6% in one set and increased in three others up to 13.6%. When 3D printing PLA medical tools, surface porosity must be minimized to prevent transfer of disinfectants to people. The wide variability of mechanical properties due to 3D printing itself and as a consequence of disinfection must be considered when designing medical tools by selecting appropriate printer settings. If these conditions are met, reusing 3D-printed PLA medical tools seems safe from a mechanical point of view.