Manufacturer Uses NVision Laser To Get The Perfect Fit
Hensley Industries (Dallas, Texas), which builds ground engaging tools for the construction and mining industries, is saving a significant amount of time and money by using an NVision laser scanner to verify that its replacement parts will fit existing equipment just as well as do its original parts.
One of the greatest challenges for Hensley in building replacement parts for a wide range of equipment is the need to build teeth and adaptors that fit perfectly with the installed base of existing equipment. As they introduced a new product line recently, Hensley engineers wanted to verify that itâ€™s mating geometry was the same as that of its previous product line, which has been demonstrated over years to deliver a perfect fit with all the equipment that the company supports. But the earlier product line was designed without the benefit of solid modeling so the company did not have a definitive record of its geometry. The patterns for the molds used to cast the previous product line were made by hand by pattern makers and fine-tuned over the years.
Problems with the traditional approach to reverse engineering
Hensley engineers wanted to match the geometry of their new product perfectly to the old one in order to gain the benefit of the field experience that went into its development. In the past, the company would have addressed with type of measurement challenge with a touch probe coordinate measuring machine (CMM). They would have used the solid model of the new product to generate a surface model in the IGES neutral file format and created 12 to 15 datum points that represent particularly important areas of the geometry. Then they would have called up the IGES file in the laptop used to control the touch probe and measured the same datum points on the existing product. It would have taken several hours to move the touch probe around the part and capture the points.
Avoiding risk by engaging NVision’s service bureau
“Since this was our first project, it didn’t make sense for us to purchase laser scanning technology,” said Damian Castillo, CAD and Administration Manager for Hensley Industries. â€śWe weren’t sure if we have enough work to justify the investment and we were also concerned about the risk of technological obsolescence. We decided to look for a service rather than a machine. I went online and checked out various laser scanning service bureaus. I talked to several that appeared to have the greatest capabilities. NVision stood out because the people I talked to there made a major effort to understand what we needed and demonstrated a high degree of knowledge in helping us develop a solution. We originally planned to ship our castings to them but when NVision discovered how heavy they were decided to send a technician here instead with an NVision laser scanning system.”
It took about two days to scan the eight parts. The result was a point cloud consisting of tens of millions of points for each part that fully defined every aspect of its geometry. The NVision technician stayed on site for two days processing the data. He first converted the point clouds to surface models and then overlaid the two models of the old and new parts, creating error maps that highlighted differences in geometries that were supposed to be nominally the same. The error map showed that in defining the geometry of the new product, engineers had accurately duplicated the old part. Hensley engineers then used the CAD model as the master to produce the CNC patterns with total confidence that the new product would provide the same fit as the old product.
“This project demonstrated the viability of laser scanning both for reverse engineering our existing product line and for first article inspection,” Castillo said. “In both areas, laser scanning provides far more accuracy than a touch probe so it saves us a considerable amount of time that we previously had to spend tuning and modifying our product based on field test results. The benefits were so clear that soon after finishing this project we made the decision to purchase the NVision laser scanner and have begun using it as a regular part of our product development process.”
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