Part Reverse Engineering
Reverse Engineering—Why and How It is Done
Producing replacement parts for a variety of customers has become a sizable business and a valuable one. This has, in large part, been the result of a trend on the part of OEMs to focus more on assemblies than on making parts, and the subsequent challenge it places on other product manufacturing businesses to be able to adequately maintain their supply lines.
One of the challenges that both a parts replacement service and its customers has to contend with, is outdated engineering drawings, or a complete lack of them. This can be a relatively common situation with legacy equipment or systems.
Reverse Engineering to the Rescue
This is where reverse engineering (RE) enters the picture. There can be many reasons to reverse engineer a part, including replacing a worn part, replacing a lost part, creating spare parts, or upgrading or modifying a part when an assembly requires modification and the existing part can no longer serve its intended function
A solution to any of these problems would be tend to be straightforward, except for one thing – the lack of an up-to-date engineering drawing to work from. Therefore, to replicate the part in question it must first be measured, and a 3D model of the part must then be created from those measurements. Only then can the part be replicated.
RE does not in itself involve creating a copy of the original. It acts instead as a precursor. Reverse engineering is a purely analytical exercise. When done manually, it can be tedious and time-consuming, since it involves making multiple measurements, each of which must be precise and correctly accounted for.
Measuring the Part, and Building a Model
Existing technology has made the reverse engineering process a relatively rapid one for most applications. Hardware, typically laser trackers, laser scanners, or handheld scanners, is used to do the measurements instead of jigs and calipers.
The measured data, normally referred to as a point cloud, can literally involve millions of measurements; but it does not provide the necessary topological information from which a part can be constructed. A point cloud is simply an image. To create a new part requires the use of CAD/CAM software which, when fed the point cloud data, creates a precise virtual 3D model of the physical part. This would be extremely difficult, time consuming, and costly using manual measuring and modeling methods.
Drawings can be made from the 3D model, and its interactions with virtual models of other, typically adjacent, parts can be tested at the same time. In this respect, RE is a valuable tool for improving existing documentation for equipment operation, modification, or maintenance.
The costs of laser scanners, hand-held scanners, and other modern measuring tool has dropped significantly over the past few years, and continues to do so. The same is true with CAD/CAM software, which can be run on laptops or even smaller devices; allowing models to be created on-site.
The bottom line is that RE has become an extremely cost effective method for providing a working model of a part that requires replacement, and for which proper documentation of drawings does not exist.
Small manufacturing businesses can now rely on RE as opposed to having to rely on conducting a full-fledged system design process. Many businesses, both large and small, have found that even greater savings can be realized by contracting reverse engineering projects out to businesses that not only specialize in creating virtual models of parts, but can manufacture and supply the parts as well.
RE, whether done in house, or contracted out, can be used to effectively reduce design life-cycle times during product development, tool design, or mold making.
Summing Up the Benefits
RE can give extremely precise measurements over an extensive range of surfaces.
The turnaround time for the replication of a part can be significantly reduced.
RE offers a cost effective solution for the replication or reconstruction of machinery.
RE techniques can be applied to support the maintenance of legacy systems to extend their life cycle.
Reverse engineering practices have in the past, mostly been used by the military. Commercial enterprises however, are now finding it more and more challenging to adequately maintain their supply lines, and extend the useful life of their legacy systems. Consequently, RE techniques are now being applied as time-saving and cost-saving practices; not only for parts replication, but as a method of determining what the costs and benefits of manufacturing a copy of a part might be.