Reverse Engineering of Mechanical Parts: Resolving Component Obsolescence

During one of the last lunar landing missions, astronauts broke the fender away from a lunar rover. Initially thinking that they didn’t really need the fender, the intrepid explorers drove the tiny vehicle around craters and rills—while becoming coated with lunar dust. Since the moon doesn’t have lunar rover parts stores and traveling back to earth to obtain a new part didn’t seem feasible, the astronauts made a new fender from a notebook and several random clips. The fix worked.

Today, the International Space Station includes an Additive Manufacturing Facility that features two commercial 3D printers and an extruder. During 2016, astronauts aboard the ISS printed a wrench—the first tool produced in space. Since then, the Additive Manufacturing Facility has developed hundreds of parts used both on the station and on earth. Capable of 3D printing in a zero-gravity environment, the printers can print polymers that have high mechanical and thermal properties, metals, composites, and carbon nanotube-doped materials. Astronauts have received digitized models of small satellites, printed electronic circuits for the satellites, 3D printed the satellites for launching into space.

Reverse Engineering Works on the Earth and in Space 

Reverse engineering process allows companies to duplicate or reconstruct a component, assembly, or product without having original drawings, documentation, or computer models. With reverse engineering, a team of engineers can:

• Design, develop, and manufacture new components or assemblies

• Build new digital models of a component or an assembly produced by Original Equipment Manufacturers (OEM)

• Rebuild and replace legacy components that no longer exist

• Reproduce artifacts

• Identify the components of an assembly

• Ensure that components comply with quality and tolerance standards, and

• Defend the patents of designs.

Some of the most important benefits of reverse engineering can come with finding solutions for problems that seemed like they were going to be unresolvable, costly errors or interminable supplier obsolescence. 

Reverse Engineering Works with Existing Mechanical Parts

Before moving to the actual reengineering of an existing mechanical part, establish a basic project management routine to determine the scope and parameters of the project. The routine considers the purpose of the project, the market, design objectives, constraints, and functional details. Design teams involved with a reengineering project study how products function and the interaction between components, sub-assemblies, and major assemblies through disassembly.

The functional study of a product also shows how the original manufacturer produced the product and leads to a detailed analysis of structural, mechanical, and electrical sub-systems. The analysis should include measurements, cover control systems, consider safety measures, and an overview of the overall system design. Any product testing should disclose how the product performs in different environments, durability issues, and how the original manufacturer viewed ergonomics.

The functional study and analysis of a product destined for reverse engineering should produce documentation that establishes design goals, provides a measurement system, and lists possible constraints. The design goals should cover form, function, and materials. Design teams reviewing a mechanical part for reverse engineering should produce lists of materials, components, assemblies along with any upgrade results.

Reverse Engineering Reverses the Design Process

The reverse engineering process flows in the opposite direction of the typical design process with the Product Design Specification serving as the endpoint of the process. Reverse engineering relies on the use of laser scanners or computer tomography (CT) scanners to capture data. The scanners output the 3D scanned data as a dense triangle point cloud that becomes a visual sketch containing the detailed dimensions of the part.

Reverse engineering software converts the dense triangle point cloud into a polygonal model that retains the shape and accuracy of the original part. 

You might not be using your phone camera for these types of data capture.

Other applications refine and convert the polygonal to a mathematical model called Non-uniform Rational B-spline (NURBS) that generates curves or surfaces. NURBS work with computer-aided design and engineering software and comply with the Initial Graphics Exchange Specification (IGES), Standard for the Exchange of Product model data (STEP), the 3D ACIS Modeler, and Programmer’s Hierarchical Interactive Graphical Standard (PHIGS). Each NURBS surface or curve represents simple geometrical shapes established by control points.

After refining and converting the shapes, the software export the images to Computer-aided Drafting (CAD) or Computer-aided Manufacturing (CAM) equipment. The combination of reverse engineering and CAD or CAM software produces the precise data needed for design for manufacturability. Detailed 3D solid or surface models and 2D vector-based drawings allow engineers to select the best conceptual design and to bypass the use of physical prototypes.

Capturing data from large items—such as aircraft or rocket booster--occurs through photogrammetry—or the capturing of data through photographs taken with a Digital Single-lens Reflex (DSLR) camera. Output of the photogrammetry data can take the form of a map, measurement, or 3D model. Photogrammetry uses reference points defined by multiple digital images. Precise 3D scanning systems use the reference points to enlarge the scanning area for the purpose of capturing and reverse engineering large items.

Capturing detailed information within the reverse engineering process establishes the foundation for testing. Deviation analysis of a reverse engineered mechanical part creates a precise point-by-point comparison of the original design and the new design. The analysis detects any deviation between the scan data of a component, assembly, or mechanical part and the CAD model. As a result, design teams can verify that the reverse engineered product will meet or surpass performance objectives while validating tooling.

Reverse Engineering Decreases Concept-to-Production Time

After completing the 3D model, a company can compare the model with the original component or assembly, make any adjustments, and mass produce the finished part. Because reverse engineering shortens product development times, manufacturers benefit by quickly moving products to the market. Rapid Product Development (RPD) allows manufacturers to use technologies and methods that reduce tool-and-die development times.

Working through an electronics production line. Editorial credit: humphery / Shutterstock.com

Capturing a dimensional product or model in a digital format decreases the time needed to refine the product by capturing physical dimensions, form factors, and material textures. Companies can use this information to conduct life-cycle and cost-benefit analyses. Generally, reverse engineering works as a cost-effective solution for high-cost components and assemblies, for units manufactured in large numbers, and mission-critical components.

Utilizing smart layout tools with excellent libraries of component models and incredibly synergistic constraint engines will enable any reverse engineering attempt. Thankfully, Cadence’s OrCAD PCB Editor is around for just about any design need you could run into. 

If you’re looking to learn more about how Cadence has the solution for you, talk to us and our team of experts.