1.4 Applications of Reverse Engineering
1.4.2 Applications of Reverse Engineering in the Life
The physiological characteristics of living cells, human organs, and the inter- actions among them form the baseline requirements for reverse engineering in life science and medical devices. Some success has been reported from
time to time in identifying the biological components of the control systems and their interactions. However, a fully comprehensive understanding of the complex network of the interacting human body is still beyond today’s sci- ence and modern technology. In fact, engineers and scientists often work in the reverse direction with the belief that between the observed body behav- iors and the biological elements there must underlie the mechanisms that can reproduce these biological functions. This is the typical reverse engi- neering approach, similar to trying to figure out how a complex piece of electromechanical equipment works without having access to the original design documentation.
To reverse engineer a medical device, engineers first have to identify the materials that are used for this part and their characteristics, then the part geometric form has to be precisely measured, and the manufacturing pro- cess has to be verified. Also, more frequently than most other industries, a medical device is operated with sophisticated software for proper function.
The operating software has to be fully decoded. For example, the software compatibility of a reverse engineered implantable cardiac pacemaker is one of the most critical elements of the device. In another example, to reverse engineer a blood glucose monitoring device that can be used to measure the glucose level of a diabetes patient, compatible software is a mandatory requirement for the proper transfer of the test results to a computer, and any communication between this meter and the host computer.
Reverse engineering is used in several medical fields: dentistry, hearing aids, artificial knees, and heart (Fu, 2008). Two medical models produced by prototyping are shown in Figure 1.7, including a dental model that illus- trates a detailed teeth configuration. The different and unique shape of each individual’s teeth configuration provides an excellent application opportu- nity of reverse engineering in orthodontics. The three-dimensional high- resolution scanner used in reverse engineering can be utilized to accurately measure and model the dental impression of a patient’s upper and lower arches. Based on the input digital data, advanced computer-aided manufac- turing processes can build customized orthodontic devices for individual patients. Modern computer graphics technology also allows the close exami- nation of teeth movement during follow-ups and the necessary adjustment, if required. Traditional braces with wires and brackets are no longer needed.
The application of reverse engineering offers a less expensive and more com- fortable treatment in orthodontics. It is worth noting that this new treatment is possible only because of the recent advancement of the modern digital process and computer technology.
High-tech computer hardware, sophisticated software, feature-rich laser scanners, advanced digital processes, and rapid prototype manufacturing have also made more effective applications of reverse engineering to other medical devices, such as the hearing aid, possible since the early 2000s. The digital technology processes sound mathematically, bit by bit, in binary code, and provides a much cleaner, crisper, and more stable sound than that from
analog processing. It offers better overall performance and is relatively easy to update, modify, and revise, thereby providing superior consumer satisfac- tion in hearing aids. The further growth of reverse engineering applications in this field is mostly dependent on technology evolution to make the wire- less hearing aid smaller, more sophisticated, and more efficient, while easier to manufacture and at lower cost.
The applications of reverse engineering to orthopedics, such as the knee, hip, or spine implantation, are very challenging, partially due to the complex motions of the knees, hips, or spine. A proper function of these implants man- ufactured by reverse engineering requires them to sustain multiaxial statis- tic stresses and various modes of dynamic loads. They are also expected to have sufficient wear and impact resistance. Several institutes, such as ASTM International, originally known as American Society for Testing and Materials, have published various standards on the testing of these implants. For
FIgurE 1.7 (See color insert following p. 142.) Prototype models in the medical field.
instance, ASTM F1717-04 provides guidance on the standard test methods for spinal implant constructs in a vertebrectomy model (ASTM, 2004). The ASTM standards are issued under an established designation system, such as F1717, and are frequently updated. The numerical suffix immediately following the designation, such as 04, indicates the year of adoption or last revision. It is criti- cal to understand the purpose of these standard tests and correctly interpret the test results. The complex loading condition of a spine is difficult to mimic with the limitations of a laboratory testing environment. The test conducted in a dry laboratory environment at ambient temperature might follow all the guidelines of ASTM F1717 and still not accurately predict the fatigue strength of a spinal assembly exposed in the body fluid. The biological environment effects can be significant. The body fluid may lubricate the interconnections of various components in a spinal assembly; it can also have serious adverse effects, such as fretting and corrosion. Therefore, the test results are primar- ily aimed at a comparison among different spinal implant assembly designs, instead of providing direct evaluation of the performance of a spinal implant.
A simulated fatigue test applied with real-life walking and running profiles is often desirable to ensure the high quality of these orthopedic implants.
Medical devices, biomedical materials, and orthopedic implants are usually thoroughly tested to satisfy the rigorous regulatory requirements. U.S. Food and Drug Administration (FDA) regulations require them to get premarket approval (PMA) before they can be put on the market, no matter whether they are brand-name products produced by the original inventors or gen- uine products produced by reverse engineering. The European Union and many other countries often accept FDA test data and approval in accordance with specific agreements. In an interesting coincidence, the acronym PMA is also used in the aviation industry, where it stands for Parts Manufacturer Approval. U.S. Federal Aviation Administration regulations require all the parts approved under PMA procedures to satisfy the relevant airworthiness requirements before they can be put on the market as well. However, most aviation PMA parts are either produced through licensee agreement with the OEM or reinvented by reverse engineering. The European Union and many other countries also accept FAA PMA approvals with discretion in accordance with specific bilateral agreements.
References
ASTM. 2004. Standard test methods for spinal implant constructs in a vertebretomy model.
ASTM F1717-04. West Conshohocken, PA: ASTM International.
Boehm, B. W. 1979. Guidelines for verifying and validating software requirements and design specifications. In Euro IFIP 79, ed. P. A. Samet, 711–719. Amsterdam:
North-Holland Publishing Company.
Chikofsky, E. J., and Cross, J. H., II. 1990, January. Reverse engineering and design recovery: A taxonomy. IEEE software. Washington, DC: IEEE Computer Society, 7:13–17.
Francis, P. H. 1988. Project Management. In Tool and Manufacturing Engineers Handbook volume 5–Manufacturing Management, ed. R. F. Veilleux and L. W. Petro, 17–20.
Dearborn: SME.
Freerisks, C. 2004. GD250: Lifecycle process mode “V-model” in the World Wide Web. http://www.informatik.uni-bremen.de/uniform/gdpa/part3/p3re.htm (accessed September 25, 2009).
Fu, P. 2008. Reverse engineering in the medical device industry. In Reverse engineering:
An industry perspective, ed. V. Raja and K. J. Fernandes, 177–93. Berlin: Springer.
MIL-HDBK-115A. 2006. US Army Reverse Engineering Handbook (Guidelines and Procedures). 6. Redstone Arsenal: US Army Aviation and Missle Command.
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2
Geometrical Form
In recent years the part geometric form has been very accurately measured and replicated by the advanced technology of metrology. The precision hardware and sophisticated software allow engineers to visualize, meter, and analyze the part geometric details. They also allow the transformation of raw data to be intelligently reconstructed into computer modeling. The revolutionary advancement in software algorithm and hardware infrastruc- ture offers a set of new tools for rapid prototype in reverse engineering. All the miniature geometrical details of a part can be captured and retained. The development and deployment of the interchangeable operating systems and data transformability further accelerate today’s reverse engineering capabil- ity in geometric form analysis and reproduction. These new technologies have a huge impact on modern reverse engineering and have been ubiqui- tously deployed in this field. This chapter will discuss these technologies and their applications in reverse engineering.