18Phone: 516-328-3970www.technocnc.comTechnical Sectionscanner, it is very similar to a fl at bed scanner scanning a sheet of paper in that both processes collect the data and under the best of circumstances; one should expect some noise in the data in both cases. This noise can come from a number of sources such as an imperfect surface, dirt on the surface and so on. Filtering and surface clean up is a crucial stage of reverse engineering and COPIOUS and RHINO are some of the best tools for accomplishing this. There are major software packages devoted exclusively to recreating surfaces from point cloud data. Some examplesof these software packages are Imageware, Rapidform and Geomagic. These packages are designed to fi lter the noise as well as recreate the features of the object from the point cloud, such as holes, cusps, edges and so on.The Grand FinaleOnce the surfaces have been created, edited and fi ltered they can be used for various applications. The results can be incorporated into other designs or transferred to a CAM program for machining or even projected onto existing parts as secondary machining on molds or models. Matching a System to Your ApplicationEach of the three systems has its own advantages and disadvantages in relation to an application. Although the laser scanner is the most expensive and is not typically used for 2D scanning, it also collects the most data in the most time-efficient manner. Laser scanning is an automated digitizer, which means you attach the laser module to the Z-axis of your CNC machine. X- and Y-axis data is collected via the CNC machines XY travel, while Z-axis data
is collectedby the laser. Through the software connected to the CNC machines controller, the laser creates a highly detailed point cloud from the XYZ data it collected. The point cloud, in turn, is saved to your computer hard drive in any number of standard formats. For example, over a 1x1 grid: By cutting the grid spacing in half, you wind up collecting approximately 4 times as many points. As you can see, collecting data to reproduce fi ne detail can quickly involve scanning millions of data points. This produces a calculation burden on the computer as well as a processing problem to get all the required detail from the data. Dealing with this large quantity of data can become burdensome.Cleaning Up the ActOnce the points are collected, the next stage is to
generatethe surface or the toolpath for the surface and this is where the software becomes critical. Think of the software as the word processor needed to edit the rough draft. Some software packages are available to reproduce the surface straight from the scanned data. Scanned surfaces can be projected onto existing surfaces or other G-Code programs with this software. The other approach is to create surfaces from the scanned data which will be integrated with other surfaces for an application or for reverse engineering. This approach is best done with a program like RHINO for the data collection and the surface manipulation. If the data collected is a point cloud, we would also recommend a program called COPIOUS. This is an add-on to RHINO and is specifically designed to convert a great number of data points into surfaces. It also performs critical tasks such as filtering and feature recognition, both of which are extremely important. When a sea of data points is collected with a 3D Number ofPoints Collected361214411681Grid spacing inInches.2.1.05.025