When we look at 3D printing, the term “Reverse engineering“ inevitably comes up. Translated in a slightly simplistic way, it means “reverse development”. In this article, we want to take a closer look at this term and explain the special status of 3D printing technologies in the process of reverse engineering.
On the concept of reverse engineering
Basically, Reverse Engineering (RE) is the process of “transforming” an object into a design plan by examining its structure, conditions, and response to environmental change. So to turn the original construction process over.
For example, reverse engineering can be used to analyze wear and tear of heavily used components or to replicate parts where design data is no longer available, especially in older systems or vehicles.
The aim here is to represent the existing object as accurately as possible, usually in the form of a 3D model of the original object. For this purpose, a partial or almost complete disassembly of the object is usually necessary. For some objects, a professional 3D scan can be enough.
The contribution of 3D printing technologies to reverse engineering
The technologies that have developed (further) around 3D printing have once again pushed the possibilities of reverse engineering. The perspectives offered by the 3D scanning technologies not only reduce the disassembly effort, but also greatly speed up the process.
3D printing, in turn, makes it easy and inexpensive to make other models and compare them to the original or copy them. The former is often used to analyze the wear and tear of heavily used parts.
For example, Investigators look at where a mechanical component in a motor wears most. The resulting data can be used directly to produce reworked parts using additive manufacturing techniques.
The parts are either used for further testing or, in some cases, the optimized parts are also processed directly. 3D printing offers the possibility to create very complex geometries that can not be realized in other production processes or only with great effort.
The ‘copy’ is used when components are required for which no design data is available. These are often older systems, in particular in the field of special machine construction. Another increasingly popular application is the production of spare parts of vehicles or even airplanes. AutoCAD training center in Coimbatore will provide the additional training for SOLID MODEL, 3D array, 3D rotate, 3D move, 3D scale.
For reverse engineering, a particularly accurate measurement of the original is required. Two approaches have been established: the 3D scan and the direct physical (“tactile”) measurement. The choice of the method is dependent on the geometric complexity of the object and the planned use of the data obtained.
1. 3D SCAN
In 3D scanning, either a laser beam (“laser scan”) or a pattern (” structured light “) is projected onto the surface of the object. The resulting patterns on the object are recorded by cameras and assembled by software using an algorithm to form a 3D model.
The advantages of this method are:
- No direct contact with the object necessary.
- Very high speed of measurement (especially with structured light)
- Open spaces are easily measurable.
However, the fact that the cameras project light onto the surface of the object also has two disadvantages:
- Surface properties: Depending on the material, light is reflected differently, which can lead to inaccuracies. Therefore, all objects should be covered with a matt layer (eg chalk spray). For some objects, however, this is not possible due to the nature of the material.
- Undercuts: areas that can not be fully illuminated cannot be detected by the cameras and are missing in the final model.
2. COMPUTER TOMOGRAPHY (CT SCAN)
The CT scan scans the object using X-rays. The outer and the inner structure as well as the density of the object walls are measured. The object rotates 360 °. This creates a multitude of 2D images (“layers” or “slices”) that are converted into a 3D solid model using an algorithm. Advantages of this method are:
- Examination of surfaces and inaccessible areas (undercuts, cavities, etc.) possible.
- Disassembly of the object can often be dispensed with.
- Visibility of object parts in their function.
- Target-actual comparisons of original and replica possible.
- Material condition (or fatigue) can be analyzed.
However, the CT scanners are very costly and require a lot of space (shielding the X-ray radiation). In contrast, a 3D scanner often only has the dimensions of a kettle. For information about 3d modeling and AutoCAD courses visit FORT Education Training Center in Coimbatore.
Reverse engineering and 3D printing are often used in the same breath. Often, the RE’s techniques are used to obtain the data for creating an accurate 3D surface model.
This can be used to create a negative of the object, then compare it to the original and verify its accuracy. The manipulated variants of the original can be printed in 3D as quickly and inexpensively as possible in order to quickly test the effects of the manipulations.
Further fields of application arise for the production of casting molds. On the one hand, this can be the direct 3D printing of a casting mold. Or it will be tools that fit specifically for this object, manufactured.
If CT scanning is used for reverse engineering, it is also possible to measure complex internal structures of the objects (for example, to analyze material fatigue).
3D printing and related technologies can make a significant contribution to reverse engineering. In particular, the 3D scanning technologies simplify the digitization of objects. And with 3D printing, (manipulated) models can be made very quickly and with high accuracy to allow comparison with the original item.