By Nel PreTech
We can provide scanned data as-is in an STL format. Models that are reverse engineered can be provided in a STEP, IGES, or Parasolid format. In some cases, we can also provide files in a native SolidWorks format. However, this is determined on a case-by-case basis. Dimensional accuracy depends on the method used to capture the data. Each measurement tool has its own accuracy. Generally speaking, our CMM's provide data that is accurate to ± 15 µm. Our structured light scanner provides an accuracy of ± 16 µm for parts up to 300 mm. For parts that are 300 - 900 mm, our structured light accuracy is ± 37 µm. For items CT scanned in our Zeiss Metrotom 800, our accuracy is ± 9.7 µm. For items CT scanned in our Zeiss Metrotom 1500, our accuracy is ± 11 µm. For items that are reverse-engineered and modeled using our scan data as a template, the results can be somewhat variable depending on the material of the original part and the condition of the original surfaces that we are interpolating. Typically, models that are created from steel parts usually have a surface accuracy of ±.001” or less to the original scanned surface. The accuracy of models that are produced from plastic injection molding usually has a surface accuracy of ±.001” to.005”. For large parts like auto body panels or bumpers, the surface deviation of the final model may be much larger, depending on part condition and customer needs. Yes. We have the ability to provide accurate external geometry for items like these. Yes. However, it is easiest to provide scan data on these types of objects if they can be brought in or sent to our laboratory. Our ability to blue light scan on location is somewhat limited due to our current restriction of scanning objects up to a maximum of 4 feet. Yes, we can provide CAD drawings in a 2D DXF format. We can usually quote most items from detailed photographs that have a size reference with them. For specialized parts like manifolds or assemblies, we may require that the parts be sent to us for evaluation prior to quoting the project. 3D files or drawings are also helpful if they are available. The more information, the better. An STL file is already sufficient to 3D print parts. If the customer requires a custom CAD model be produced from parts that have already been scanned by a 3rd party, we have the ability to do so. However, we cannot guarantee the accuracy of the original scan method. Our scanned files are exported as STL file formats. To produce a STEP file, further engineering of the data would be required. Once the part is scanned and an STL file is created, it can be imported into our specialized reverse engineering software, where a CAD model can be produced using the STL as a template. Two main workflows can be utilized during this stage - these methods are known as NURBS modeling or parametric modeling (depending on the needs of the customer). The NURBS workflow is a semi-automated process that produces a model of the part in an as-is condition. The surfaces consist of non-uniform patches, and there is no history-based design tree. However, the surfaces are highly accurate. If a parametric model is required, this can be achieved through the parametric modeling process. This produces a model that has perfect geometry (planes, cones, revolves, etc.) with imperfections from the scan data removed. This model can be exported in a STEP format, or a native SolidWorks model with an intact feature tree can be produced.
