UBC Theses and Dissertations
Automated manufacturing of orthodontic appliances Roberts, Scott Cameron
This thesis presents a computer controlled system that partially automates the production of upper-mouth orthodontic appliances. The machine performs the deposition and curing required to manufacture the acrylic portion of the appliance. Under this new process, the operator places the orthodontic wires and expansion screws on the surface of the dental cast, secures the cast onto the machine and describes the desired shape of the appliance through a graphical user interface. The machine then applies and cures the acrylic to form the finished appliance. Only minimal grinding and buffing is required. The system consists of a robotic device that includes a two-axis platform for manipulating dental casts; and a two-axis gantry for positioning an acrylic pump, ultraviolet lamp, laser and rotating mirror system, and a camera. The laser and camera are part of a range vision system for mapping the surface of the dental cast to obtain elevation and surface normal data. The pump and lamp are used to deposit and cure light activated liquid acrylic. The rotary table system provides orientation for the dental cast to permit surface mapping and acrylic deposition and curing. The table is able to orient the dental cast to avoid movement of the liquid acrylic on the surface of the cast before curing takes place. The machine software provides tool-workpiece collision avoidance, process planning, and machine function and motion control. Several tests, including the complete production of orthodontic appliances, have been performed with the system. The average time for surface mapping of a dental cast is 11.5 minutes and the average time for acrylic deposition and curing is 54.3 minutes.
Item Citations and Data