Concrete Testing Machines – Verifying the upper platen and machine components with 3D printed positioning mechanisms

A practical case of substituting the upper platen of a concrete compression testing machine will be presented, where original 3D printed positioning mechanisms are used in the verification of the machine according to Standard NP EN 12390-4:2021. Due to time constraints for this maintenance operation, the dimensions of these first prints were not properly verified and were later found to be out of the specified tolerances. However, machine verification results did, unexpectedly, turn out to be satisfactory and were validated by comparison to a later verification made by an ISO 17025-accredited laboratory. The dimensional inaccuracy was a consequence of the lack of calibration of the printer's axis and extruder motors, which has been successfully accomplished. In spite of the ongoing difficulties, these tools are worth it for their lightness, simplicity of usage and adaptive design, as well as the low costs and ease of production with a 3D printer.