A New Artificial Mouth using Linear Motor Technology

Methods: As a proof-of-concept design investigation, a hybrid system was first developed. A linear motor (Baldor) was coupled to a MTS Mini Bionix II to replace the original servo hydraulics that provided the horizontal motion. The vertical and horizontal motions were synchronized using a motion controller (Baldor) to produce chewing cycles at a maximum frequency of 4 Hz. At the same time, the output signal from the MTS load cell was used to achieve the required load-displacement profile.

Results: The wear patterns on an example composite material produced by the new hybrid artificial mouth after calibration were similar to those produced by existing servo hydraulics machines, the mean depth of wear after 300k cycles being 34.9±20.7 and 33.3±21.2 micron, respectively. The new machine appeared to be robust, having survived the millions of cycles of motions it has been subjected to without noticeable degradation to its mechanical performance. The digital signals also allowed a more comprehensive analysis of the wear data, linking explicitly the work done with the material loss parameters.

Conclusions: Linear motors can be used to manufacture cheaper, smaller and more efficient artificial mouths for dental biomaterials testing. Work is currently underway to build a chewing machine based on linear motors only.