Collecting 1.5 Million Points in 30 Minutes

Jerry Fain Models (Bedford, TX) has long been successful providing prototyping and modeling services to clients in a wide range of markets. The company uses a portable laser-based coordinate measuring machine (CMM) to measure dimensions of critical components, but the device is able to reverse engineer only simple geometries. Learning of a demand from its customers for more capabilities in this area, the company purchased a ModelMaker laser scanner that can generate surface models of the most complex geometries by creating a highly dense, highly accurate point cloud from which to construct digital surfaces.

Jerry Fain Models specializes in producing small quantities of complicated components. A prime business area is custom-made fittings for luxury jet manufacturers such as Gulfstream and Bombardier. One of the most critical aspects of the business is being able to accurately measure models that are provided by customers and to inspect parts produced by the company's machinists in order to ensure that they are dimensionally accurate.

The company has long used a portable laser-based CMM, and while this CMM continues to provide excellent service to Fain Models, a limitation of this device is that it captures points one at a time and the operator must manually move the steering system to track each point to be measured. The time involved in this process makes it impractical to completely reverse engineer anything outside of fairly simple components and assemblies.

For example, a year or so ago the company used the CMM to dimension a glass object that was to be duplicated for an aircraft interior. It took an operator about 12 hours to generate 650,000 points, which was enough to roughly but not fully describe its geometry.

A More Versatile Scanner

The major components of the ModelMaker system are a 3-D laser sensor, an articulated mechanical digitizer or portable CMM to which the sensor is attached, a PC, and software that extracts, displays and manipulates the data. To capture the shape of the part, the technician simply holds the laser sensor so that a line of laser light appears on it.

The ModelMaker's sensor is a single viewpoint laser stripe sensor, which is significantly faster than simple laser point sensors. These laser stripe sensors work by projecting a line of laser light onto the object while a small CCD camera views the line as it appears on the surface. The portable CMM moves freely about the body, allowing the technician to position the sensor easily and capture data rapidly and with a high degree of resolution. As the technician moves the sensor over the surface of the part, a dedicated PCI interface card translates the video image of the line into 3-D coordinates. This data is combined with the Cartesian and angular coordinates generated at each position of the mechanical arm. The result is a dense cloud of 3-D data describing the surface of the part.

Collecting More Points in Less Time

In addition, its accuracy is sufficient to perform highly accurate 3-D inspections. Fain operators simply import the point cloud produced by the scanner into Geomagic Studio. There they can compare the point cloud to a CAD model using a process called registration, which superimposes the point cloud from the scanned data onto the CAD surface model. Then a report is generated with the qualify part of the software. The resulting color-coded plot shows exactly how much the collected data points deviate from the CAD model. For example, points below the surface of the model might be shown in blue while those above the surface would be shown in red. Or the user might opt to show all of the points outside of the client's tolerance settings in a single color.

New Business

"We used the scanner to capture the complete geometry of the turbine blade. Then we used Geomagic Studio to convert the point cloud into a NURBS (non-uniform rational b-spline) surface model. This model can easily be read by our CAD/CAM software, which we use to generate a program that builds a perfect replica of the model. In a similar project, a toy company gave us a clay model that we scanned into a 3-D file that was later used to create an animation for a TV commercial. In the past, the company produced CAD files of similar products that could take weeks. We were able to provide them with a 3-D model in a couple of days," explains Runge.

While 3-D scanning has opened many new markets, custom interior plane fixtures have generated the most revenue to date for Fain Models. Typically, the aircraft manufacturers or companies involved in customizing planes come to Fain with a 2-D drawing and ask the company to build trim pieces and fixtures to match the contours of the plane or parts. The parts can include lights, chairs, countertops, shower doors and toilets.

Producing models or trim using the CAD/CAM software from scratch was a very time-consuming job and often required a major manual modeling effort after the part was generated to make it fit properly. Now, Runge says that the company can generate far more detailed point clouds of the most complex objects in an hour or less.

These point clouds are then turned into NURBS surfaces that require little or no touch-up in the CAD system. It allows the company to produce parts that fit the first time - lowering cost and increasing throughput. In some cases, the manufacturing process can be reduced down to a matter of hours by exporting cross-sections that can be used to loft surfaces through. Surfaces or point clouds also can be exported in several different formats including STL. This format can be imported directly into an SLA machine, bypassing the time and effort to create the model in a CAD/CAM software package.

"The capability to rapidly and accurately reverse engineer complicated 3-D components has allowed us to take on a whole new class of work," Runge says. "We have seen significant additional revenues already and expect our business to really take off as more potential customers become aware of our new capabilities."