Evaluating the shape of plastic bottle drinking spouts

Micron-sized shape measurement using a laser microscope

Plastic bottle drinking spout

(1) Application

Plastic bottles are ubiquitous, and their quality is closely managed, including sanitation and ease of drinking. For example, the shape of the drinking spout varies slightly depending on the type of beverage that will be in the bottle. The edge that makes direct contact with the cap must be sealable to prevent liquid from leaking out of the bottle when it’s on its side as well as to eliminate contamination. Since the edge also makes direct contact with a person’s mouth, it must feel smooth. Therefore, correctly capturing the edge’s shape is essential to quality management.

(2) Olympus' solution

The LEXT OLS5000 3D scanning laser microscope combines multiple images with focused height information using its confocal optical system, enabling high-resolution, precise 3D profile measurements and clear images. The microscope uses three-dimensional roughness parameters that comply with ISO25178, the same roughness (two-dimensional) parameters used in contact-type roughness testers. Although conventional contact-type microscopes have difficulty handling a nonlinear shape, like a plastic water bottle’s drinking spout, and only enable you can to obtain a height profile over one line, the OLS5000 microscope is capable of contactless surface-area evaluation. The microscope’s stitching function is used to capture the profile of a wide area while maintaining a high resolution.

Images

(1) The difference between nondefective and defective products

(Nondefective)

(Defective)

(2) 3D image created using the image stitching function