Due to the complex and detailed shape of these organic models, a mathematical description of the shape is possible only in theory. Creating the CAD data would be very time consuming and the resulting file would exceed by far the maximum file size that can be handled. Therefore modern prototyping and production processes based on CAD data could not be used for this kind of parts.

The ATOS scanner now allows the use of modern 3D CAD/CAM technology for tooling in applications where a mathematical description of the part is not feasible and only master or design parts are available.

• ATOS can digitize models, parts or tools accurately and with high density data. The resulting polygonized data set describes the form of the object and can be exported as a standard STL file.
• The STL file can be edited by many CAD / CAM tools which have a module to treat this data format. Using these tools, modifications can be applied to the data set without the need to modify the master part.
• Rapid Prototyping systems (e.g. stereolithography system or wax printer) can produce copies of the master model which can be used as the master in a conventional production. Using this technique, scaling of master parts is simple and cost efficient.
• The STL file generated by the ATOS scanner can be imported into CAM systems and be supplemented with CAD data. Using this technique, an efficient production/milling of very complex forms is possible.

First the three hand made wax master model parts of the stomach are digitized, using the high end ATOS scanner (figure 2). Instead of a master part, a scaled model, a tooling set or a part can be digitized. A complete, accurate, and high resolution digitizing is needed. Due to the complexity of the object, different views have to be taken, which have to be automatically and accurately transformed into one set of data.
ATOS is a second generation system, with two cameras, which allows digitizing with high accuracy and verification of the data integrity and an automated and very accurate integration of additional views into an existing set of data.

ATOS converts the 3D data cloud consisting of different individual clouds into a high quality polygon mesh. This data set can then be exported in the STL file format. Basic operations, such as transformations, combining, splitting and displaying the data, calculating the deviations to additional data sets, filtering, thinning and the filling of holes by NURBS surface patches can be done in an efficient manner with ATOS (figure 3).

The data set produced by ATOS is ready to be integrated into standard RP systems. Figure 4 shows a copy made by the Thermojet wax printer from 3D systems. The scanned data can easily be scaled and the resulting copies can be used as master models. Using this scaling functionality, conventional production techniques can compensate shrinkage or produce a product "family" in an easy way.

Based on the requested high production volumes and the requested delivery date, a steel mold has to be produced. As no CAD data is available, the above mentioned hybrid production process is selected to get the tooling done. The tooling has to be designed and milled based on the digitized data. First the STL data from the ATOS scanner is imported into the TEBIS CAM system. TEBIS allows a hybrid modeling, using STL data and CAD surfaces. After the import of the data, the position of the individual elements is defined virtually to allow the production of a simple tool with only few inserts and a simple party line. The party line is defined and the functional surfaces are constructed using standard CAD functionality as shown in figure 5. Then the milling strategy and the passes are defined.
The milling of the complete two tooling parts into steel was made on a 3 axis HSC milling system.

After the milling, the fine details are reworked on the steel tooling by a specialist, in one week hand work (figure 6).

Using the combination of modern technology, 3B Scientific could realize an "impossible" order in an efficient and lucrative manner. In a short period, a high quality tool was produced. This tooling is now used to produce the high volume of complex parts needed, without any need of rework on the tooling or the parts.

We would like to thank 3B Scientific for the good cooperation and the approval to share this production experience.