3D scanner speeds roof rack production

Utilizing laser scanning technology to rapidly capture millions of points of data, a Texas job shop was able to design three new roof rack product lines in just one-third the usual time.

To accomplish this feat, Hamar Industries Inc. in Fort Worth engaged the engineering services of NVision Inc. in Southlake, Texas, to make highly precise roof profiles with the NVision 3D HandHeld laser scanner. The profiles were incorporated into CAD files used to create the custom-fit racks.

“Without the scans we would have extended our R&D and production time by 300%,” said Chris Pelley, vice president of operations and engineering.

Hamar Industries is a job shop for aftermarket vehicle accessories and custom metal fabrication services, including laser-cutting, bending, and welding. One of the company's most in-demand services is custom-fitted roof racks. 

Roof racks are designed to support a large amount of weight with a minimal number of contact points. They must be engineered to minimize wind noise, reduce drag, and withstand high speeds, sudden stops and turns.

To get the right fit it is necessary to determine the precise geometry of the vehicle’s roof and that of any possible interferences. “The contour of the roof is important for a great overall fitment,” said Pelley. “Location of all mounting locations is also very important to making the roof rack install easily for our customers. We are also looking to avoid conflict with any factory accessories or features like sun roofs, windshield wipers, rear hatches and doors.”

Hamar Industries first used 3D scanning to develop custom roof racks for three Toyota pickup and SUV models; the Tacoma, the Tundra and the 4Runner. To best fit the rack to the roof, Hamar needed an accurate roof profile in about 12 spots and the company determined that 3D laser scanning would provide the most geometrically correct representation of the roofs.

NVision technicians performed scanning onsite at Hamar Industries, focusing on the vehicles' roofs down to the tops of the windows. Over the course of roughly four business days, NVision engineers scanned the roofs of the three vehicles.

The HandHeld scanner captures 3D geometry from objects of almost any size or shape. It is attached to a mechanical arm that moves about the object, allowing the user to capture data rapidly with a high degree of resolution and accuracy. As the object is inspected, the scanner generates a point cloud consisting of millions of data points, each with x,y,z coordinates and i,j,k vectors. These points comprise an exact duplicate of the object’s surface that is converted to an STL polygon. Intuitive software allows real-time rendering, full model editing, polygon reduction, and data output to all standard 3D packages.

NVision technicians performed four scans per roof with each scan comprising a quarter of its surface (driver’s side front, passenger’s side front, driver’s side rear, and passenger’s side rear). They then did a basic post-processing clean-up to remove “noise,” and then stitched the different roof scans to produce a composite point cloud of each roof, using reference spheres.

After scanning, NVision polygonated the raw point cloud data into an STL file. The STL file was used as a template to create design intent CAD models. The models were delivered in IGES and STEP format, which is a generic CAD file, importable into any CAD software. Hamar imported the IGES/STEP models into their in-house CAD software to interface with models of final roof racks to check for form, fit and function.

The ability of 3D laser scanning to quickly capture complex geometries resulted in optimally designed roof racks and greatly accelerated completion times for this project, allowing Hamar to begin selling the racks that much sooner.

“NVision provided us with the 3D CAD models we needed to launch three product lines,” said Pelley. “Having the quality scans import seamlessly into our in-house CAD software made design and testing very easy and very fast.”

NVision Inc. produces non-contact optical measurement systems and offers reverse engineering and inspection services for its customers. For more information, phone 817-416-8006 or visit the company’s website at www.nvision3d.com