Case Studies: Measurement in a Hostile Environment
Wyman Gordon (Houston) supplies forgings to both military and commercial aerospace manufacturers. The company’s need to generate critical high-accuracy measurement data in a hostile forging environment presented unique challenges. The requirements included an ability to measure large components up to 23 feet, measure hot dies and a need for both discreet point probing and high-density point cloud acquisition. All of which takes place in a setting where thermal extremes and particulate contamination are guaranteed. In addition, there was a frequent need to reverse-engineer patterns and tooling that may be up to 50 years old.
Wyman Gordon decided to invest in a measuring solution consisting of a structured light scanner navigated by a Metronor (Nesbru, Norway) DUO electro-optical, large-volume coordinate measurement system-the NaviScan3D. The NaviScan3D is portable, allowing the operator to take the measurement system to the workpiece on the shop floor. The system can probe deep into hidden areas, and generates high-accuracy scans of large surfaces quickly. This is particularly important in the die shop where worn dies are repaired in a process that entails heating, welding and machining.
Because of the high temperatures involved, a scanning solution that requires targets was simply not viable. A laser line scanner also was out of the question, because prolonged exposure to the intense heat would damage both the line scanner and the operator. The solution overcame these obstacles because the standoff distance of the NaviScan3D is large enough to position the scanner away from the effects of the hot die.
In the die repair process, dies are heated to around 450 F before welding to minimize distortion. Traditionally, the die must cool before the process of machining welded material can begin. However, several days can be lost if the machining process reveals that inadequate material was added during weld-up. The die must then be reheated, and the process repeated. The NaviScan3D system is used to scan the dies while still hot. The scan data is then compared to a computer-aided design (CAD) model of the die, and areas that still need material are identified through a color-coded map. These areas are then welded while the die is still hot, saving significant time.