a mechanism and a method for framing a low - distortion flexible dielectric substrate during subsequent flex circuit processing . the processing method comprising the following steps : making a flexible dielectric substrate having an outer periphery ; joining a continuous portion of the flexible dielectric substrate near the outer periphery to a rigid open frame , the flexible dielectric substrate being in a state other than a state of substantially uniform tension as a result of the joinder ; causing the joined flexible dielectric substrate to undergo a change to the state of substantially uniform tension ; and printing an electrical conductor on the flexible dielectric substrate while the flexible dielectric substrate is joined to the frame and in the state of substantially uniform tension . the frame is in the shape of a polygon with rounded vertices .