Reverse engineering, as defined by the Merriam-Webster dictionary, is ‘the activity of studying the parts of something to see how it was made and how it works so something like it can be made.’ But what does that mean from an engineering perspective?
Applications of reverse engineering
The main application of reverse engineering is to recreate mechanical components or spare parts that are no longer commercially available. The need for reverse engineering normally arises when there has been some mechanical failure or machine functioning problems. Sometimes, excessive wear to a component means that bad product features may need to be designed out in the process.
Often the original manufacturer is no longer trading, or they can’t provide mechanical designs or support. In these cases, reverse engineering the components is the only viable option.
Some other situations that may require reverse engineering are:
- to gain a better understanding of a competitor’s product.
- the original suppliers or manufacturers are unwilling to share parts or designs.
- when updating antiquated manufacturing processes.
The basic process of reverse engineering
Reverse engineering differs considerably from the normal mechanical design process. When designing a new component, an engineer will write up a design specification and use CAD software to sketch and draw the item.
When it comes to reverse engineering, the engineer starts with an existing item and works backward through the design process, i.e. creating a CAD visualisation, then writing up a design specification from it.
The first step in reverse engineering is to capture all of the relevant geometric data. This is accomplished by process of 3-D scanning or photogrammetry. 3D laser scanning gives a highly accurate point cloud that is better for highly intricate components, whereas photogrammetry uses digital photography from many angles to create a less accurate point cloud, which is more appropriate for systems where tolerances are not so important.
The next stage is to build a 3D model or visualisation using CAD software. We will discuss the types of software used later on in this article. The point cloud is uploaded into the software and mapped into polygons which are then rendered into a 3D model. The model is then digitally inspected and compared with the original object to ensure that the shape and dimensions are accurate or within tolerance.
If a rough prototype is to be created, this will often be made on a 3D printer. Again, inspections will take place to validate accuracy at this stage. Then a final prototype will be made from the material that will be used in the final product. Final checks will be done in comparison to the original component and testing will take place. If the component is to be used in machinery that is safety critical, rigorous destruction testing may take place.
Reverse engineering software
Before the days of scanning and CAD software, reverse engineering was a long drawn out process. It involved using manual measuring tools such as calipers to get the dimensions, then drawing it out by hand.
Thankfully, CAD software and dedicated reverse engineering software have revolutionised the process, making it far more time and cost-effective. Sophisticated software is now available that will analyse how the components will perform in a real-life mechanical environment. This allows an iterative design improvement process to take place.
Autodesk makes the benchmark CAD product, Autocad which is probably the most common piece of software used in the reverse engineering process.
Companies that specialise in reverse engineering or have a high demand for it will often invest in more expensive dedicated software. Here are some examples:
- Rapidform XOR Redesign is a simple and quick system that creates parametric CAD models, allowing for efficient reverse engineering of mechanical parts.
- Geomagic Studio is a highly accurate system for creating 3-D models from point clouds and polygon meshes. It is optimised for reverse engineering, quick prototyping, and product analysis.
- Rhinoceros NURBS Modeling is a piece of software that specifically deals with NURBS (Non-uniform rational basis spline) solids, the preferred mathematical model of some 3D digitizers.
There are also software packages available that perform metrology (measurement) inspections. Here are a few examples:
- PowerINSPECT from Delcam provides a full inspection process linked directly into CAD software.
- Geomagic Qualify specialises in first article and production inspections and quality control.
- MobiGage is the first fully mobile metrology application. Installed on an iOS system it uses wireless technology to receive and share inspection data.