Two Approaches to Inspection

The objective at Hexagon Metrology (hexagonmetrology.us) was quite simple: give customers a fast inline inspection system for body-in-white applications that enhances both quality assurance and process control. So Hexagon developed an integrated family of measurement solutions known as “360° SIMS” (Smart Inline Measurement Solutions). According to David Hill, senior account manager at Hexagon, 360° SIMS scans bodies-in-white (BIWs) inline, providing color mapping, trend charts and instantaneous feedback to the operator. This enables full surface inspection and measurement of up to 100% of the produced car bodies (it can also be used for parts and sub-assemblies) within production cycle times. A touchscreen interface allows operators to supervise the measurement process, visualize results and identify root cause for quality issues. 

The system will alert the operator if it detects a deviation on the object being inspected. If an issue comes up, 360° SIMS allows the operator to select the best course of action, such as stopping the line or simply sending an e-mail to a quality engineer explaining the problem. What’s more, the particular area where a problem is detected (e.g., a door) can undergo additional data collection for root-cause analysis.  

360° SIMS installations are configured for the application and typically include shop floor-proven white light area measurement sensors from Hexagon and point cloud-based software tools.  

Another recent development is the Leica Absolute Tracker AT960, an all-in-one portable laser tracker that provides hand-held probing, scanning and automated inspection.  It is particularly well suited for measuring both tooling and completed assemblies, up to entire vehicles.  When used with the Lecia T-Scan 5 unit, part features and surface contours can be scanned at up to 210,000 points per second.  The laser scanner can be used on carbon-fiber components.  The Leica T-Probe is used for wireless probing of hard dimensions with a wide range of styli of varying lengths (over 200 mm are available); it is Renishaw-compatible.  This system can output up to 1,000 points per second

In the past, these laser trackers were very large, according to Joel Martin, product manager at Hexagon Metrology. He says that moving them through an automotive facility or shipping them from one assembly facility to the next was difficult. “One automotive customer told us that the equipment wasn’t portable, it was transportable,” Martin says. “We wanted to create a truly portable piece of equipment for our customers.”  The equipment case for the AT960 weighs less than 50 lb. and the tracker itself weighs approximately 28 lb. Martin says it’s a single-case system that a customer can check on an airplane when traveling from facility to facility. 

The laser tracker system is water and dust protected (IP54-rated), so it can be used in some of the harshest production environments. Martin notes that in the past laser trackers were considered laboratory equipment. Hexagon wanted to provide factory-floor capability. Wi-Fi and battery operation give the AT960 more flexibility in an assembly plant, especially during line setup, when there is no available power.  

Another advantage of the AT960 is the addition of PowerLock vision technology, which prevents interruptions between the laser tracker and the target. PowerLock monitors the measurement area at all times and can determine where a target is without the need for the laser beam to be locked on. As soon as the beam interruption is detected, the camera relocks the laser beam on the reflector. This removes the operator from the tracker altogether, Martin says, so they can focus on measuring the part.