This article was published in the
March/April Reverse Engineering supplement of Time-Compression Technologies. For more great articles,
visit the "Time-Compression Technologies'"
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A Guide to Reverse Engineering

Todd Grimm

Welcome to the first ever selection guide for reverse engineering. Time-Compression Technologies has compiled this supplement to provide information and guidance on the selection and application of reverse engineering.

The selection guide (page S30) and supporting resource grid (page S34) are designed to assist both those who are considering the purchase of a reverse engineering system and those who are investigating service bureaus for upcoming projects. Due to the state of the reverse engineering industry, it is impractical to present a decision-making matrix. Therefore, the goal of the selection guide is to lead you through a logical sequence of considerations that are important to the selection process.

The technology is powerful, the benefits are huge, and the applications are endless. Reverse engineering is a technology that should be considered. With this supplement and its selection guide, Time-Compression Technologies hopes to build your understanding, fuel your interest , and jump-start your investigation of the technology.

Many Options

Reverse engineering can be daunting. You will find yourself deluged with systems, technologies, and vendors. While choice is always good, too many choices can cause confusion and hesitation. There are more than 50 vendors of reverse engineering hardware, and this number does not include the numerous vendors of CMMs (coordinate measuring machines). From these vendors, there are systems that range from $9,995 to well over $250,000. There are technologies that use triangulation, photogrammetry, and interferometry. There are scanners that use lasers, white light, and x-ray. The challenge is gaining an understanding of the advantages of each because there is so little information available.

Opinions abound and claims are prevalent. But, what are the facts? They do not appear in magazines, white papers, or benchmarks. Even the experienced professionals find it difficult to obtain a factual understanding of all the technologies. While these long-time users may have vast knowledge of a class of technology or of a handful of systems, it is likely that questions about technologies outside of their primary scope will go unanswered.

While the selection guide does not completely fill this information void, it will help you to understand the key criteria in selecting a system for purchase or a service bureau for a project.

Selection Guide

The selection guide will lead you through a logical, but not necessarily obvious, series of considerations that apply to hardware (e.g., scanners) and software. Since the technology is very different from other measurement devices, there are new considerations, constraints, and advantages that need to be discussed. As you progress from the first consideration to the last, you will be clearly defining your needs, which will allow you to communicate these to a system vendor or service bureau. The structure of the selection guide will also introduce you to the advantages, limitations, and constraints that may exist.

Your path to an appropriate solution begins with a basic definition of what you are trying to do. The intended application has tremendous impact on many variables in the decision making process. Equally important is the consideration of the state that you desire for your output. Specifying "as-built" (reflecting attributes including those created by the manufacturing process) or "as-designed" (reflecting the original design intent) will have a significant effect on the technology selected, software tools needed, and more importantly, the time and money required to complete the project.

While all of the considerations presented are important, it is appropriate to also single out consideration of the file format and desired accuracy.Without reflection on the impact of the decisions, new users are likely to state that they need a CAD solid model with the highest degree of accuracy. These requirements are easy to state, but they are also the most costly and time-consuming to deliver. Easing these demands will open the door to more opportunities and decrease time and labor. Those experienced in reverse engineering find that in a high percentage of applications a polygonal mesh (STL file) with moderate tolerance will suffice.

When using the selection guide, it is important to define reasonable and realistic demands. Granted, it does take more thought and effort to define reasonable goals than to specify the ideal situation. However, it is worth the time and effort because a suitable, cost-effective, and time-efficient process is more likely to be identified.

Hybrid Solutions-Blending Technology

Complicating the selection process is the practical concept of hybrid solutions. Many companies employ multiple technologies, both in terms of hardware and software. Those that use reverse engineering have discovered that one device and one software application are not likely to address all of the needs. Reverse engineering operations around the globe commonly have multiple hardware technologies and even multiple software applications at their disposal. They have found that a hybrid approach is necessary.

Companies may combine a CMM and laser scanner on the same project, or they may use both laser and white light scanners. What is equally interesting is that they may have two or three different reverse engineering software applications. The demand for a hybrid approach is best evidenced by the laser scanning heads for articulated arms. It is now common for the laser head to have an integrated touch probe. The laser captures the bulk of the object's geometry, and the touch probe is used to capture deep, narrow channels or shadowed features.

For those who intend to purchase a reverse engineering solution, the need for a hybrid approach means that the plan should include adding a variety of technology or establishing relationships with service bureaus. For those that plan to use only service bureaus, you will find that you need more than one supplier, a supplier with multiple technologies, or a supplier who will subcontract work to other organizations.

Augment and Complement

When we need to measure something, we have many options: yardstick, engineering scale (AKA ruler), calipers, micrometers, and CMMs. The tool of choice is the one that delivers the quality of data that we need in the most efficient fashion. We make this decision based on past experience and current knowledge. Since it is much different in process and capability, you will need to expand this experience and knowledge when reverse engineering is included in your list of options.

Reverse engineering is powerful , and it can do some pretty amazing things, but it will not replace other tools and established technologies. It will become one of many options. Reverse engineering expands the possibilities, yet it is merely a complement to other measurement and capture tools. It augments; it does not replace.

You will need to develop an understanding of how reverse engineering works, what the capabilities of the hardware are, and what is required to complete the process. This will take effort. This information will take time to acquire. But the effort and time are well worth it because the benefits are numerous. Hopefully, the selection guide makes the learning process a bit easier.

Moving Forward

Time-Compression Technologies' team has worked hard to assist you in evaluating reverse engineering. We believe that the technology is poised for growth and that the major hurdle is a lack of information. It is the magazine's goal to fill some of the information gap to assist you in adopting reverse engineering in your day-to-day operations.

Use the selection guide-and all the content in the supplement-as a learning tool. Use the information to assist in selection and decision making. Use it as the starting point for your journey into reverse engineering.

With the aid of the selection guide, press on and discover the advantages of reverse engineering. Move forward towards adoption of the technology in your engineering, manufacturing, and quality control processes.

TCT

For more information, please contact Todd Grimm, Grimm and Associates, Inc. (Edgewood, KY) at (859) 331-5340 or email at tgrimm@tagrimm.com, or email at tgrimm@tagrimm.com.

Contact information:
Todd Grimm
T. A. Grimm & Associates, Inc.
3028 Beth Court, Edgewood, Kentucky 41017
Phone: (859) 331-5340      Fax: (859) 514-9721
tgrimm@tagrimm.com      www.tagrimm.com

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