What is Quality Inspection?

Quality inspection is the process of comparing measurements from a real world part to the as-designed model. Inspections are utilized for a number of different reasons. New parts may be scanned to check for errors in the machining process, such as worn tooling equipment or machinist errors. By identifying errors early in a production run, massive amounts of time and money can be saved. Used parts can be checked for worn or deformed surface. By insuring a part is within specifications before returning it to service, you help to reduce the risk of unexpected break down, helping to protect against loss of time, further damage to equipment and even injury to personnel.
The traditional tools of inspection include micrometers, calibers and CMM machines. While these tools work great, their uses are somewhat limited and time consuming. Taking measurements to check for surface flatness, object thickness, hole size and hole location are all common practice for these types of tools. However, when measuring complex, freeform shapes, a 3D scan is the best solution. A typical hand held tool can take up to one point of data every 30 seconds or so, a CMM can measure up to one point per second, while a 3D scanner can record millions of points in under a second. It is this ability to quickly and accurately record millions of points of data that make 3D scanning excellent for complex free-form shapes. With traditional inspection tools, only a few key measurements are recorded. But with a 3D scan, the whole surface is recorded, giving the ability to check the entire object for deviations.

How Inspection Works

After being scanned, the “point cloud” is brought in to specialized software, along with either a second scan of a known quality part, or even better, an as-designed 3D model. From there the parts are aligned and can be compared in any number of ways. A color map deviation report allows a quick glance over the parts to ensure that everything is “in the green.” Maximum deviation amounts can be entered, so that only points that exceed that amount will be shown in varying colors, depending on if the part is above or below the accepted standard. Detailed 2D analysis can be given in a cross-section analysis reports. Geometric Dimensioning and Tolerancing (GD&T) reports are excellent at repeatedly checking for geometric shapes, angles, thickness and concentricity. Specialized custom reports can also be created to suit whatever is needed to ensure that the part is exactly as intended for its application. Whether it be just one part or every part on the production line, a quality inspection using 3D scans can be adapted to fit almost any need.