An Image-Based Three-Dimensional Digitizer for Pre-Decorating Thermoformed Parts

Thermoformed plastic parts are pervasive in modern products. Decorating these thermoformed parts is a critical step in their manufacture. For parts with significant relief, decorating the part after it is formed can be prohibitively expensive. Prior to thermoforming, the plastic which is in flat sheets or rolls can easily be fed through a printer. However, during thermoforming the plastic flows and stretches to conform to the shape of the mold distorting the original decoration. This paper describes a device called the Image-Based Three-Dimensional Digitizer (IB3D) which measures the plastic deformation using vision techniques. Knowing the deformation allows us to pre-distort the graphic printed on the flat sheets such that as the plastic flows into the thermoforming mold the decoration undistorts. 1