Application of Reverse Engineering in Furniture Segments by Traditional Technique
In the current scenario, technology-based companies are continuously on the leading edge by considering unconventional and innovative ways to meet the demands of the customer requirements. When it comes to the furniture industry, their usual workflow for product development is by the master wood pattern approach. This mold is considered as a master to develop final products. However, this manufacturing method might not be more accurate when compared to products manufactured by a CNC machine (which is fully automated). To improve the existing process to a fully automated one, we need 3D CAD data of existing physical products. So, we are in need to use some reverse engineering techniques & develop 3D CAD model from the available physical product line. In this study, a traditional technique of reverse engineering with customized approach has been discussed.
A one-line history, reverse engineering was often used during the Second World War and the Cold War. It was often used by the military in order to copy other nation’s technology, devices, information or parts of which had been obtained by regular troops in the field of intelligence operations. In the recent year, the impact of reverse engineering in the manufacturing industry is increasing day per day and it also plays a significant role in promoting industrial evolution by introducing expensive products and stimulating additional competition.
Reverse engineering, also called as back engineering, is the process of extracting the knowledge or design information from anything man-made and reproducing it either partially or completely based on the extr acted information. The process often involves disassembling the products as a component, analyzing & capturing its functionality & design details.
Figure 1.1 illustrates the process of reverse engineering.
Fig. 1.1 RE process
The unprecedented speed of technology changes is having a major impact on what we are doing & how we are producing and sustaining in the market. To accommodate the rapid rate of reinvention of modern machinery and instruments, reverse engineering provides a high-tech tool to speed up the reinvention process for future industrial evolution.
Existing techniques for RE: As computer-aided design (CAD) has become more popular, reverse engineering has become a viable method to create a 3D virtual model of an existing physical part to use in 3D CAD, CAM, CAE or other software. The physical object can be measured using 3D scanning technologies like CMMs, laser scanners, structured light digitizers, or Industrial CT Scanning (computed tomography). These conversion processes are expensive and the cost is directly proportional to the product or part’s complexity.
Fig.2.2 a. CMMs, b. Laser scanners, c. Structured light digitizers & d. Industrial CT scanning
On the other hand, the average life cycle of the modern inventions is much shorter, so most of the cases the project may not able to fund for the above said RE technologies. Hence, there is a need to find out the cost effective RE process to obtain the quality dimensions.
Proposed Methodology and Experiments
Reverse engineering can be applied to re-create either high-value commercial parts for the business profits or the valueless legacy parts for the historical restoration. In this article, we are trying to propose the detailed procedure on, how to extract the dimensions of an existing wooden part with traditional measurement techniques, either for business profits or for historical restoration. Results, the same quality of the high-tech techniques can be obtained through the traditional technique.
In this study, we were going to take the wooden guest chair (refer fig 3.0) as an experimental process for doing traditional RE technique.
Fig. 3.0 Wooden Guest Chair (Physical Product)
Figure 3.1 is showing one of the guest chair product taken for this study. In traditional techniques, first, we need to understand the overall product & its component functionality. Critical dimensions for the manufacturing and also for the CAD modeling need to be understood carefully before capturing the data. Based on the study, we propose to capture the maximum data as a whole product rather than the component dimensions. It will help to retain the overall shape of the CAD model closer to the physical part.
Fig. 3.1 Manual outlining of the chair
Fig. 3.2 Top of chair at corner
For this study, the rear post of the chair is taken for the detailed experimentation (refer fig 3.2). The complete chair was moved closer to the wall as shown in the picture and their extreme edges are hitting the wall, herein, the chair should move neither towards the back nor to the right side. The walls were kept at a right angle to each other and right angle to the floor as well. The back wall was taken as OD (Overall Depth) plane and the right side wall was taken as OW (Overall Width) plane for capturing the dimensions. The OD & OW planes were considered for measuring the Y & X dimensions respectively. The floor was taken as a TOP plane and all the height dimensions (i.e. Z dimensions) were captured from the floor.
As figure 3.3 shows, the dimensions were taken and filled as per the tabulation given below. While taking the measurements, the chair should not be disturbed. So it is necessary to cross check the correct placement of the chair during the entire course of the measurements, if not the dimensional accuracy may vary.
Fig.3.3 Manual dimension of Rear post
Creating CAD Model:
After taking all the dimensions of the part (i.e. the rear post), the data were moved to create the geometric CAD model. In this study, CREO 3.0 was taken for the modeling purpose. As shown in fig 3.4, the corner face of the part was created first. The corner face profiles were inclined from (or depends on) both OW & OD planes, so we have created two sketches from the OW & OD planes. After extracting X & Y dimensions for the 7 segments, two extruded surfaces were created from the sketches and they were then merged to create the corner face curvature profile. The entire height of the post or the corner face curvature was divided into 7 segments (or points) to simplify the measurements.
Fig.3.4 Corner face of the part
Fig.3.5 OW plane & OD plane
As shown in the figures 3.5, the first surface of the corner face was created from the OW plane and the second surface was created from the OD plane. The intersection of these two surfaces was considered as corner face curvature profile.
As discussed before, the post or the corner face curvature was divided into 7 segments (or points) and we have to measure the post’s cross section (on both X & Y direction) on each segment. The imperative reasons for taking the cross-sectional dimensions will be explained in the upcoming procedures.
Now the cross-sectional dimensions were applied on each segment of the corner face to create the profiles from OW and OD planes. The newly created sketches were extruded to form the four faces of the post. If the cross-section of the post is taken properly, then the shape of the post will be replicated exactly.
The four surfaces were merged (by using MERGE feature) to form the final shape of the post. Later the top and bottom of the post were created as blank surfaces and they were merged with the surfaces of the figure, to solidify the part.
Finally, the top of the post was created through Radius feature. Now the 3D CAD model is ready with its final shape, which needs to again be cross verified with a physical component (using random checking method) to conform the shape, size & profile of the 3D model.
Conclusion and Future Scope
In this study, the traditional technique of the reverse engineering has been suggested as a suitable methodology for any complex design or profile with the customized approach. The RE approaches gaining popularity in today’s competitive market because the current global environment is evolving at a rapid rate and seeking new ways to improve their existing products and to include the current trending technologies in their products to sustain in the market. The coin has two sides, likewise, even though the traditional RE techniques have some pros on the cost aspects, it has cons on the measurement time & product accuracy. The traditional technique might be suitable for consumer industries like furniture or any consumer products, but it may not be suitable for the automotive industries where the accuracy level is expected to be high. Hence, when it comes to complex design in any type of product, traditional techniques (RE) require further refinement so that one can apply it to any sector.
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- Reversing: Secrets of Reverse Engineering, Textbook by Eldad Eilam