An apparatus and method for detecting whether platens in a mold clamp remain parallel throughout an entire molding process. The apparatus includes a frame, a first platen having a surface orthogonal to a predetermined axis, a second platen having a surface opposing the first platen, the second platen being reciprocatable along the predetermined axis, actuating cylinders for reciprocating the second platen along the predetermined axis, and positions transducers for electromagnetically detecting the positions of a plurality of points on the surface of the second platen. The method includes the steps of emitting first and second electromagnetic interrogation pulses from a controller, transmitting the first pulse to a first transducer rod fixed relative to the first platen, and transmitting the second pulse to a second transducer rod fixed relative to the first platen and parallel to the first transducer rod, generating a first return signal when the first pulse reaches a magnet disposed adjacent to the first transducer rod and fixed relative to one end of the second platen, and generating a second return signal when the second pulse reaches a magnet disposed adjacent to the second transducer and fixed relative to an opposite end of the second platen, transmitting each of the first and second return signals to the controller, measuring the time elapsed between the emission of each pulse and the arrival of the corresponding return signal at the controller, and determining, based on the times elapsed, whether the opposing surfaces of the second platen and the first platen are substantially parallel.