Computer-aided inspection

CAI or Computer-Aided Inspection can be used in a multitude of production settings and is used most commonly in quality assurance. Computer-Aided Inspection is the process of taking physically produced parts and comparing the geometry to the original CAD model to ensure the finished product matches up with the designed part. Traditionally, production lines would measure one part out of a large batch and use that information in the part quality check. This method allows for defective parts to slip through and pass as good parts when they are defective. The use of computer-aided inspection in turn ensures every part that passes through has the correct geometry and is within tolerance. Computer-aided inspection is much faster and more reliable than traditional measurement methods because CAI is inspecting every single part with an accurate computer.[1]

Types of CAI machines that can be used to inspect parts include laser scanners, structured light scanners, and industrial CT scanners. Laser scanners use point clouds from the 3D model to measure the production part with laser beams. The downside to laser scanners is that they are rather expensive and are less accurate than other options. Laser scanners also do not work well on parts that have reflective surfaces as it makes it difficult to read the measurements. Structured light scanners use light and reflection to record and make measurements on the shadow. Since they are not directly measuring the part, they can still measure reflective parts, unlike the laser scanners. Structured light scanners are generally preferred to laser scanners due to better accuracy and generally lower cost. While structured light scanners are the preferred method for external geometry, industrial CT scanners are preferred for checking geometry they may be internal to the part. Some CT scanners are accurate enough to be able to look at internal, external, and other small defects simultaneously. This system is a good choice if the application is one that has a very specific tolerance or cannot have any type of defects. On the downside, some materials do not scan well under the CT scanner.[2]