Description

The Princeton Scientific Instruments Condom Testing Machine has advanced the state of the art in condom defect detection. The optical technology used in this machine offers significant advantages in information gathering capability over the presently used electrical techniques. The Condom Testing Machine, built on a rugged, factory-ready mechanical platform, offers ease of mounting, high test capacity and automatic rollup and dismounting of condoms which are sorted into accepted and rejected bins.

Condoms are mounted on transparent mandrels and moved to two optical test positions. At the first position, visible light illuminates a narrow line parallel to the axis of the condom. A detector system mounted outside the mandrel scans the illuminated line as the mandrel is rotated. In this way, the entire side wall of the condom is inspected, with high spatial resolution. The light intensities are digitized in the camera. They are processed first in the test station's electronics, and later in the associated control computer. Measurements at this station serve two purposes - to determine if a condom has been mounted on the mandrel, and if it has no gross defect, such as a large rip or tear. Undesirable material variations or embedded particles are also detected and quantitatively described.

At the second test position shown in Figure 1 below, ultraviolet light is used to illuminate a narrow line along the condom as it rotates. At the optical wavelength chosen, latex and other condom materials transmit very little of the incident light. A pinhole defect appears as a bright point of light moving against a dark background. Extremely small pinholes are easily detected.

The computer may call for any given condom to be rejected on the basis of visible-light defects, pinholes, or thin spots. Since the pass/fail decision is made in the computer, rejection criteria may be changed easily and at will. After the pass/fail decision has been made, the condoms are rolled up and stripped at the appropriate machine location. Accepted condoms are placed in one bin, unacceptable condoms in another.

Figure 1: Pinhole Detector

With experienced operators, the machine can be operated at rates as high as 40 pieces per minute. Optical tests are convenient, dry and totally non-destructive. When a defect is found, its location on the condom can be precisely determined. As a result, this machine lends itself not only to production screening, but also to studies focusing on the nature and the causes of defects. This testing machine can support many functions in production and in research, including: production screening tests, factory quality assurance and process control, manufacturer or other defect analysis studies, and efficacy testing.