Rapid development of products using the technique of reverse engineering.

Cosma, Cristian ; Dume, Adrian ; Tulcan, Aurel 等

1. INTRODUCTION

Under the circumstances when the market competition becomes sharper and sharper, it is natural that the companies, when fighting for existence, use new concepts and engineering strategies. Finding the strategies that lead to ensuring the market success, must take into consideration the market characteristics and the way in which the goods are made.

Essentially, these characteristics are:

* A great variety of products;

* The rapidly changing market;

* A long product life cycle;

* Difficult and costly design changing.

Traditional engineering is not good anymore (as a consequence). This paper is meant to present new ways of improving the quality of plastics parts, focused on two major directions:

* to create a real replica of original object;

* redesign of the products.

Reverse engineering is the opposite of forward engineering. It takes an existing product, and creates a CAD model, for modification or reproduction to the design aspect of the product. It can also be defined as the process or duplicating an existing component by capturing the components physical dimensions (Zhang, 2003).

2. METHODOLOGY PROPOSED

Originally, the Japanese used reverse engineering to improve on competitors' products and, thus, avoid original design effort and expense (1). Japanese success in new product development has led to reverse engineering being considered as a design process. Many American engineering colleges have courses in reverse engineering, focusing on redesign instead of original design (2) as a problem-solving approach (Raja et al., 2006)

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3. CASE STUDY

There are several application areas of reverse engineering. It is often necessary to produce a copy of a part, when no original drawings or documentation are available.

3.1 Make a replica

Reverse engineering, the practice of studying an existing object to create a replica or a model of the part, is no longer a new concept. As the demand and popularity of Computer Aided Design (CAD) has increased, reverse engineering is becoming a feasible technique to generate 3D virtual replica or model of a presented physical part to bring into play in 3D CAD and CAM. Reverse engineering starts from scanning the original object by means of measuring devises to digitize the surface information

The part to be replicated after scanning is a hair clips (figure 2). As a result of scanning, two files will be obtained and saved in STL form.

The geometric model will be manufactured using reverse engineering software by overlapping and alignment up the two entities (translation and rotation) on all 6 axes. Once aligned the entities by using Booleans operations (cross section) the geometrical model of scanned part is obtained (figure 2).

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3.2 Product redesign

The design of a new product must meet functional, performance and aesthetical requirements. Once the design is approved, a geometrical model is created, using reverse engineering techniques, for redesign or manufacture.

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Reverse engineering initiates the redesign process, wherein a product is observed, disassembled, analyzed, tested, "experienced," and documented in terms of its functionality, form, physical principles, manufacturability, and assemblability. Product which has been study is a stapler made of elements such as metal and plastic (Otto & Wood, 1998). Figure 3 presents the existing product.

a). Redesigning tin stamped/folded components Figure 4 presents the original (metallic) system (left) and the virtual modified model (right).

b). Redesigning plastic components First, the two plastic components were scanned. These two parts were then imported to a CAD software, where were modified both esthetically and functionally, with the help of a module which allows operating STL files.

Note that the binding system for both plastic and tin components was totally redesigned. Finally we get a new product, the product presented in figure 5.

3.3 Reverse engineering for active mould parts

Reverse engineering, or digitizing a physical part, is a critical task for any mold and pattern shop.

Part of the following case is an application for an important company in automotive industry. For this case wanted a redesign of the part, and the achievement of mold inserts using reverse engineering techniques. After scanning the part and realization of finite element simulations we obtained the geometric model of the inserts mold (Yau et al., 2008). Initial geometric model was a STL file. We use STL importer software to transform the STL file in solid.

With the geometric model of the part can be obtained the insertions mould (figure 6).

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Finally, using rapid prototyping or traditional techniques (electrical discharge machining) we can make the physical insertion of the mould--figure 7 (Turc, 2003).

4. CONCLUSION

Integrating reverse engineering process together with rapid prototyping processes and generating and processing software leads to manufacturing something impossible little time ago: a physical model (or it's mould) for which no technical documentation is available. This paper presents three applications of the reverse engineering technique in order to reduce design time for a new product, with minimal production costs. The steps using in this combine conventional engineering methods with modern techniques like reverse engineering and rapid prototyping. Products with enhanced quality can be developed and produced in a shorter period of time. The limitations of reverse engineering is relatively high in the price of software, the user requires high knowledge regarding geometrical modeling. Another disadvantage is the STL format. This format was designed to give just the amount of data in the form of meshes to operate the Stereolithography machines, but not actual engineering data. This format is very difficult to utilize for reverse engineering. Future research plans are the development of a methodology as simple transformation STL file into a file of approved by traditional CAD software.

5. REFERENCES

Ferreira, J.C. & Alves, N.F. (2003). Integration of reverse engineering and rapid tooling in foundry technology, Journal of Materials Processing Technology Vol.142, No.2, (November 2003) page numbers (374-382), ISSN 0924-0136

Otto, K.N & Wood, K.L. (1998). Product Evolution: A Reverse Engineering and Redesign Methodology, Research in Engineering Design, Vol.10, No. 4, (December 1998) page numbers (226-243), ISSN 0934-9839 (Print) 1435-6066 (Online)

Raja, V.; Zhang, S.; Garside, J.; Ryall, C. & Wimpenny, D. (2006). Rapid and cost-effective manufacturing of high-integrity aerospace components, The International Journal of Advanced Manufacturing Technology, Vol.27, No.7-8, (January 2006) page numbers (759-773), ISSN 0268-3768 (Print) 1433-3015 (Online)

Turc, C (2003). The surveillance of the parameters of electrical discharge machining, Academic Journal of Manufacturing Engineering, Vol. 1, No.1, (February 2003) page number (43-46), ISSN 1583-7904

Zhang, Y. (2003). Research into the engineering application of reverse engineering technology, Journal of Materials Processing Technology, Vol.139, No.1-3, (August 2003) page numbers (472-475), ISSN 0924-0136

Yau, H. T. & Hsu, C. Y. (2008). Generating NC tool paths from random scanned data using point-based models, The International Journal of Advanced Manufacturing Technology, Vol.41, No.9-10, (April 2009) page numbers (897-907), ISSN 0268-3768 (Print) 1433-3015 (Online)