Today we will introduce our readers to the technology and tell about the rules of choosing 3D scanners. We will consider paid and free reverse engineering programs.
Definition of Reverse Engineering
It is easiest to rely on the developer’s technical documentation or drawings to create a design for a complex object. However, in most cases, access to such information is closed. In this case, reverse engineering (reverse engineering) is used. The technology is designed to create a model of a physical object based on the study of its parameters.
The CAD-model formed with the help of 3D-scanning can be modified in order to improve its characteristics, for example, to increase productivity, increase service life. Reverse engineering is in demand in many areas: from large industrial and repair enterprises to medium and small service workshops, restyling and other areas.
Reverse engineering is becoming more and more popular due to the active use of 3D printing. Creating a model of an object with a 3D scanner and printing it on a 3D printer can even be done by a user who is just beginning to get acquainted with digital technology.
ICON restores vintage cars. It uses different models of 3D scanners to reverse engineer the desired parts.
The process consists of three steps:
- scanning produces a point cloud to create a digital copy of the object;
- from the information obtained, create a 3D model;
- prepare the model for production: adjust the image, transform it into the desired format.
It is important to choose the right equipment for the user’s needs. For example, it doesn’t make sense to use a time-of-flight scanner for scanning small museum artifacts for large objects, or to digitize an airplane fuselage with a high-precision handheld 3D scanner.
With the Creaform HandySCAN 700, NeoMetrix technologies conducts metrological control activities and creates designs using reverse engineering technology.
How to fabricate a new make with reverse engineering
- examine the object. Recall that to work with light-reflective surfaces, you must first apply a matting agent, otherwise it will not be possible to digitize them. If necessary, apply marker-stickers.
- digitize the part with a 3D scanner. Hard-to-reach areas, deep holes for example, may require additional scanning.
- Process the data obtained: remove unnecessary elements, optimize the size, check the accuracy of the stitching of the surfaces.
- Transfer the mesh to the appropriate software.
- Transform polygonal surfaces into solid surfaces. More information about creating 3D models can be found in this article.
- If necessary, make changes to the finished model.
- Make a new part based on the design using a numerically controlled machine or print it out on a 3D printer.
Creaform creates auto parts using the Creaform 3D scanner, and Autodesk Inventor software.
Cases
Reverse engineering an impeller
The challenge for the manufacturer was to eliminate part defects and improve the manufacturing process. The complex geometry of the impeller, with its many dead angles and cavities and narrow slots, prevented measurements from being taken with a CMM stylus or other traditional methods. To solve the problem, we used a 3D laser scanner and reverse-engineering technology.
Digitization was performed using ScanTech PRINCE – a high precision 3D scanner with 20 µm resolution, powered by blue and red lasers. The device quickly switches from one mode to another, works with objects of complex geometry, and does not depend on an external light source.
As a result, they created an accurate model of the part.
Based on the finished design, the object can be analyzed and adjusted.
Top 3D Shop case: Reconstructing a part with reverse engineering
The job set by the client to the specialists of the Top 3D Shop was to recreate a damaged part from plastic.
RangeVision Pro 3D scanner, reverse engineering and 3D printing were used in the process.
Stage 1. The size of the part determined the choice of equipment. The 300 mm length did not allow the object to fit in the camera of a desktop instrument with a multi-axis platform. Medium-precision 3D scanners to work with large-sized objects were also unsuitable for the task. The only remaining options were high-accuracy handheld scanners or optical tabletop models.
Stage 2. We assessed the geometry of the object. The level of difficulty was medium, requiring a scanner with 0.04-0.06mm accuracy.
On the photo: models after restoration work.
Step 3. It is common knowledge that the price depends directly on the functionality of the 3D scanner. The task required the use of models from various manufacturers, such as Scantech, Solutionix, and ZGOM. Within the framework of the customer’s budget we used the RangeVision Pro scanner, which has proved itself for small objects with an accuracy of up to 0.04 mm.
After digitizing the part, we processed the model and prepared it for 3D printing.
Recommendations for Choosing a 3D Scanner for Reverse Engineering
First of all, the size of objects influences the choice. Depending on this parameter, you should decide on the type of device and scanning technology.
- Time-of-flight scanners are suitable for working with large-sized objects that exceed 10,000 mm on any side. Manual scanners based on structured illumination or laser scanners will not do the job. Also in this case, photogrammetry can be used to improve the accuracy of the data.
- For digitizing objects between 500 and 3000 mm, portable scanners are best suited: laser or optical.
- For scanning objects from 100 mm to 500 mm, floor-mounted (on a stand) or desktop laser and optical units are the best option. Laser models are more expensive than their optical counterparts. Some mobile 3D laser scanners are suitable for quick scanning.
- Small objects are better scanned with stationary optical devices. They come in two varieties: universal and dental.
Universal ones are usually equipped with a multi-axis rotating platform, or the devices themselves are loosely mounted on axes. This type of devices copes well with relief surfaces.
Dental scanners are equipped with pivoting platforms on which stands for impressions and occluders are attached. The devices are distinguished by high resolution and accuracy.
Mobile 3D laser scanners can be used to digitize small objects (from 100 mm to 500 mm):
- regular scanning;
- it is not possible to bring the object to the location of a stationary device;
- the workplace is too small to install a desktop or floor device;
- The surface of the object is black or with strong light-reflecting properties that make it difficult for optical devices to grasp.
After selecting equipment based on the size of the objects, it is important to decide on the accuracy, allowable errors, and the need for a metrology device.
A video shows an example of using the Faro Quantum ScanArm HD laser 3D scanner and a Stratasys Dimension 1200es 3D printer for reverse-engineering automotive parts.
