Getting scanned complex parts.

Dume, Adrian ; Cosma, Cristian ; Stan, Daniel 等

1. INTRODUCTION

Rapid production is the use of methods of rapid prototyping (RP) to manufacture final end-use parts. Manufacturing companies are beginning to explore this idea as they seek methods and strategies of producing finished products more quickly than has been possible in the past.

Delays in tooling translate into lost market share when a company's competitors move swiftly, so rapid production can help reduce, or in some cases, eliminate these delays. Indeed, when only hundreds or a few thousands parts are needed, methods of rapid production may prove to be a viable replacement to injection molding.

The use of RP patterns for the production of metal castings for finished products is another important strategy that companies are now considering. Several factors will determine whether it makes sense to consider methods of RP for manufacturing. Companies that make parts that are relatively small and in relatively low quantities will be the first to embrace it.

Also, when the cost to produce parts is high, it may be less expensive to use methods of RP to manufacture the parts. Parts that do not require a high quality surface finish and are hidden from view are also good candidates.

In cases where tens or hundreds of thousands of parts are required, it may be feasible to produce and deliver finished parts using methods of rapid production in parallel with the creation of tooling.

This approach would permit the company to sell and gain valuable feedback on the product while waiting for the tooling and injection molded parts (Cosma et al., 2005).

2. METHODOLOGY FOR OBTAINIG A SOLID MODEL FROM A VIRTUAL MODEL

He took as example the of a realization complex humpback stamp die from the nest casts "mask". These extrapolation even if has one doubtful elements offers the entire sum the possibility of a realization notices with big degree of the generalization and utilization.

He directed to the possibility identification of the problems and the solutions of improve the procedures of scan, model and prototyping for which mark can be classified exhibitive of the study of a cavities casts in the case realization through inject.

He started from a mask from material ceramic represented the in figure 1. From this he passed to the scanning process for the realization of virtual model (Wang et al., 2008).

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After the process of began the software Dr. PICZA show us estimative the and the guy the total on which has it of realize the pick-up on the desirable surface were scanning and form which render it an in abaft scanning a such surface with shown the in figure 2.

After the whole realization of the process of scan ultimate form result is represented the in figure 3.

For the solid procurement surface scanning and therefore the realization of physical model, license the definiteness of specific which algorithm uses software's snowed and usual, but he reduces substantially number of necessary attempts.

3. CASE STUDY

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The size of the file of the result is stricken direct of the established methodology scanning, respectively for scan it of big fineness (that is from 0.10 mm) resulting a file of capacity 3.77 Mb.

After a check of a form results is can passed to next step scilicet to his rescue the export of the file of the result. In order to verified form obtained the in abaft the process of scan determined as this file is saved in the shape of cloud of points having the extension <points cloud> just as shown the in figure 4.

Former were the transformation of the cloud of points in Mesh. Such as do so to the utilization of the mode Mesh Prep Wizard from the framework of the software Solid Works 2008.

The importation mesh in Solid Works indicates what problem appears due to the process of scan through contact. In order to solve these problems arrived at the conclusion as the file output in trace of the process of scan is due to approach form of mesh. This mesh is imported then in CATIA below the extension of mesh rise from the software Solid Works.

For the verification of the form obtained the in abaft the process of scan he made ones choice for a software can be easy available from require a preparation previously, and the costs of his acquisitions is minimum. From these considerations he made ones choice for the utilization of the program of projection 3D Solid Works (Chang & Chung, 2009).

This mesh is imported then in CATIA below the extension of mesh rise from the software Solid Works (figure 4).

Using then the mode of mesh from framework of the software CATIA, he succeeded in mended this still more selected his discommodity can utilize this complex form farther in process.

After certified attentive but that he exists no surface of patched shall take again the method with help of the software Solid Works but starting this time from this mesh from the cloud of points output in trace scanning.

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Is noticed very clear he is the fact as the file the result from Solid Works in the shape of STL be used farther in processing, led to his importation in CATIA and the rescue from CATIA below the extension STL (Cosma et al., 2008).

This extension from CATIA can be used-up of any program of processing and the numerical control (figure 5, figure 6).

When choosing the pieces that we want to scan must know exactly what the result will be obtained (the virtual model).

Piece must fall within the limits of the machine MDX MODEL 15, meaning it can be easily scanned and not exceed the area of the machines scanned MODEL MDX 15.

If you wish to obtain a virtual 3D model and more precisely to the model should be scanned to keep account of the fact that it is influenced by the configuration of the part.

As part configuration is more complex with both the scanning time increases, and the size of the file scan result after doubles (this implies the use of superior hardware configurations. For these reasons you must keep in account the time of the CAM. In order to solve these drawbacks to trying to use more than one CAD programs.

File obtained after scanning and geometric modeling can be used for further processing, for CNC and rapid prototyping machines (Weinert et al., 2008).

4. CONCLUSION

Develop a study on the scanning and generation of virtual design for parts with complex surfaces that can create virtual models that define the cavity nests mould and algorithm research imperfections of digitizing using the software in combination: Dr. PICZA, Solid Works 2007, and CATIA.

This algorithm allows corrections "gaps" in training mesh highlighted the virtual model by successive passages in different formats and the software used to obtain a virtual model for a successful Prototyping.

The most important problem in the complex surfaces found in the impossibility of scanning hidden surfaces and glossy surfaces.

As future research we will try to create a methodology of obtaining solid models of scanning parts using the most common CAD software.

5. REFERENCES

Chang, M. & Chung, Y. C. (2009)--Efficiency of grid representation and its algorithms for areal 3D scan data, Journal of Mechanical Science and Technology Vol.23, No.5, (May 2009) page numbers (1234-1243), ISSN 17-38 494X (Print) 1976-3824 (Online)

Cosma, C.; Tulcan, A.; Dume, A.; Stan, D. & Iclanzan, T. (2008). A methodology for developing new products using reverse engineering and rapid prototyping techniques, 3rd International Conference on Manufacturing Engineering ICMEN and EUREKA Brokerage Event, Kallithea of Chalkidiki, Greece, 1-3 oct. 2008

Cosma, C.; Stan, D. & Iclanzan, T. (2005)--Reverse engineering and scanning techniques in plastic tools reconstruction, Academic Journal of Manufacturing Engineering, Vol. 3, No.2, (2005) page number (18-24), ISSN 1583-7904

Wang, J.; Oliveira, M.; Zhang, H. & Kaufman, A. (2008) Reconstructing regular meshes from points, The Visual Computer, Vol.24, No.5-10, (May 2008) page numbers (897-907), ISSN 0178-2789 (Print) 1432-2315 (Online)

Weinert, K.; Kersting, P.; Surmann, T. & Biermann, D. (2008) Modeling regenerative workpiece vibrations in five-axis milling, Production Engineering, Vol.2, No.3, (September 2008) page numbers (255-260), ISSN 0944-6524 (Print) 1863-7353 (Online)