AIA: Machine Vision Checks Truck Frames
Magna International's Canadian chassis plant in Milton, Ontario, uses advanced hydroforming presses, tube bending machines and robotic welding cells to manufacture truck frames and chassis for DaimlerChrysler and other customers. The frames have dozens of studs and holes-often more than 100-that are critical to their function in the completed vehicle. When holes or studs are missing or located in the wrong position on the frame, final assembly line productivity decreases and line cycle time increases-costing thousands of dollars in downtime and repairs.
To ensure that it ships only defect-free components, Magna International uses an Inspection.IQ machine vision system installed by Siempelkamp Canada Inc. (Cambridge, Ontario). The system is located at its own station at the end of the highly automated robotic welding line. It employs more than 50 machine vision cameras and 80 light sources for quick, noncontact frame inspection.
As part of the process, the system logs each truck frame inspection into a database, complete with a unique identification number. These files create an inspection history where, if required, inspection results and a bitmap image for every frame can be retrieved and viewed. This allows Magna and its customers to meet the requirements of the U.S. government's Transportation Recall Enhancement, Accountability and Documentation (TREAD) act. The legislation requires motor vehicle equipment manufacturers to submit information that will help the government identify defects related to automotive safety.
In implementing the system, Magna had to ensure that the cameras would not be affected by the harsh plant floor environment. Specific problems included airborne dirt, oil and dust particles, along with vibration and electrical interference from nearby heavy welding equipment. Siempelkamp used specialized optics to compensate for ambient light interference and custom-designed lighting to reduce optical noise.
Another challenge was configuring the many cameras and lights within the workcell's tight dimensions. Magna solved this problem by using Inspection.IQ 1-inch tubing, which allowed for both floor and ceiling mounting without interfering with the automated frame transfer equipment.
Finally, there was the challenge of the complexity of the truck frames being inspected. Part shape, reflectivity, color, size, location, station layout, part transfer speed and cycle time all influence a vision inspection system. Because Inspection.IQ allows for up to 64 cameras with a host of configurable parameters, Magna was able to fine-tune the system to allow for the size and complex geometries of the frames.
Looking toward the future, Magna has the option of adding more cameras and lights to the existing configuration, should new holes or features be added to the product line.
For more on vision inspection, visit www.siempelkamp-na.com, call 877-246-7832 or eInquiry 8.