In this blog post we are going to explore 3D Scanning as technology and it’s advantages.
What is a 3D Scan?
A 3D scan is a three dimensional model of a real world object, it is the collection of many small points in 3D space. These points represent the volume of an object or scanned area and are called point cloud. After the initial 3D scan these data are converted in a 3D mesh model (polygon mesh). The number of the mesh and it's size characterize the overall file’s size and resolution.
On the left picture you can see the point cloud data, a series of many points in 3D space. A point cloud is the first data extrapolated from the scan.
Next step is the conversion of the model to polygon mesh, a series of triangles the famous STL file extension format.
Where 3D scanners are used?
The list of applications 3D scanners are used for, is long and more and more business utilize the benefits of this technology. Some examples on where you could use 3D scanning:
Feasibility studies.
Utilizing 3D scanning CAD engineers have access to the space they can design on. This is very helpful when you have an existed assembly and you need to change some parts, retrofit or relocate them.
Medical industry
3D scanning allows dentists to plan and construct implants or procedures such as bone grafts.
Forensics.
From crash accidents to murder scenes 3D scanning provides more information compare to photos or videos. Main benefit is that the scene can be digitized and explored after a long time from when the event took place.
Archaeology and heritage preservation.
3D scanning does not damage the object during the scan, thus this is a big advantage of archaeological subjects.
Art and design.
3D scanning can be used to create digital data and render a scene or video. It is a fast way for media creators to visualize or create very realistic scenes. Additionally you can even capture the colours of an object in order to have a realistic 3D model.
Reverse engineering
Sometimes we do not have manufacturing drawings in order to produce an old component. By reverse engineering that component we create all the necessary engineering information in order to produce it again. Additionally reverse engineering is used in feasibility studies and engineering assemblies like the picture you see below. Thus CAD engineers have a clear picture of the design space they can work with.
Product development.
A big part of product development is 3D scanning, mainly for verification reasons. It reduces the amount of prototypes needed and as you will see below, sometimes we can even skip prototyping completely.
Quality Control.
Verification of a product to each engineering design and specifications. You will read more details on that later on the article.
Clay modelling
Automotive companies use clay modelling to verify in scale or real size models surface reflations, propositions or packaging. Designers use clay as it allows them to do fast visual changes on the clay model. By 3D scanning the final model engineers have a digital format of the clay model and can work on the manufacturing.
Below you can check a very informative video of the development of Porsche 911. At around 1:00 minute you will see the process of 3D scanning a clay model.
Milling from scan data
CNC machines can read scanned files (polygon mesh) and produce a part based in that information.
Scan data for CFD
In the automotive industry, the design of a vehicle goes hand by hand with CFD aerodynamic simulations. These simulations has to be done early in the design stage before the final design is signed off, as any change after that point cost a lot of money and takes time. By 3D Scanning a clay scaled model engineers can easily see if designers are heading the correct direction or changes need to be made.
Fit and finish validation
You can use 3D scanning to validate assemblies and product finish. Engineers can use scanned files into their assemblies mixed with CAD files.
Types of 3D Scanners:
Of course there is not one only type of 3d scanner and you should choose depending the application. Below is a list with the different scanning technologies and a small description of each one.
3D Scanners are classified in following categories:
(We will not go to deep into each technology, as this blog post is mainly a first introduction on 3D scanning).
1. Laser triangulation 3D scanning
In this technology the camera and the laser are targeting the object we want to scan. There is a known angle offset between the camera and the laser which helps determine depth variations. This technology is very famous in DIY applications as it is pretty affordable and an easy way for someone to start experimenting with 3d scanning.
2. Structured light 3D scanning.
This technology allows for very fast scanning. They are very accurate and depending the scanner the data are in high resolution as well. This method uses trigonometric triangulation as the above example but instead of a laser it uses a pattern of light.
A projector provides the light and cameras that are offset compare to the projector are used to calculate the distance of each point. This technology is a bit more sensitive at lighting conditions and reflective surfaces.
3. Photogrammetry
With this technology a series of photos are utilized from different angles. It is a time consuming process as some times you need to take many close photos to each other as an overlap must be made. Of course there are systems that uses many cameras all around the object in order to reduce the process time. All these photos are inserted in a software that does the alignment in order to create a point cloud.
4. Contact-based 3D scanning
This scanners use a probe and scan the object through physical touch. Usually the resolution of these scanners is by far superior. Maybe the most well know example of such scanner is a CMM or coordinate measuring machine, which are mainly used in industrial application and manufacturing.
On the left is a CMM (although these can measure without a prope as well) let’s say a CMM is the king of Scanners! And below is 3D scanner with a probe arm configuration, it is portable and for sure the way to go if you need increased resolution on the go.
Benefits of 3D scanning:
-Reverse engineer an object to a CAD model ready for manufacturing or do any change you might need. From the scanned data we can complete recreate (design) an object in digital form and manufacture it.
-Saves time in design stage. CAD engineers can use scanned files in their CAD assemblies without really redesign everything. That means they can focus only in specific components they have to design.
Especially for feasibility studies, where you need to check clearance and available space that can save a lot of time and bring down the design cost.
-No need for physical object on sight. Which is not a big deal for a small component but imagine when you have a whole engine or engine bay of a car. See for example one of the many engine bay scans we have done:
This an engine bay from an EVO 8. The customer needed some custom work to be done but the vehicle was available only for a short period. With that said we 3D scanned the engine bay in a matter of couple hours and that’s it. Is it an exhaust manifold, mounts for various components or an intake system? It doesn’t matter you have the 3d space available in your computer ready to be inserted into your CAD system and start the feasibility study. Check for clearance, overall available space, service provision as well as installation easy.
-Makes prototyping process faster. A good scan file can help speed up prototyping phase, as it reduce the risk of errors. There many instances where we manage to have final product
without prototyping. One example is our charge pipe that we designed in the past.
First we 3D scanned the original part, took all the mounting points and maintain the same clearance in specific areas.
The model you see in our example was our first try. The result where exactly what we expected, plug and play fitment and enough clearance. So in one go we had a working product, and we were able to start real work testing in just 13 days form the day the project started.
-Quality control:
Quality control in manufacturing is crucial as products have to meet quality standards against design specifications. For example in an injection molding production line we can 3d Scan the produced product and verify if it meets design requirements by checking the deviation between the scanned and CAD model.
-Re-manufacture parts without CAD:
Although it is not that easy as it sounds, it is possible assuming the 3D scan quality is very good. You can 3D scan an object and without reverse it to a CAD model you can produce the scanned file. A small fiddling here and there with the 3D mesh is unavoidable but for fast changes or prototyping is a good option.
Does 3D scanning damage the scanned object?
Absolutely not, that is the main reason why we use this technology in expensive objects, artifact restoration, jewelers, humans, even crime scenes.
How to prepare an object for 3D Scanning?
Depending the scanner we are using. There are scanners that require not preparation of the object at all, although shinny-reflecting or transparent surfaces are a bit harder to scan without any preparation. In big flat surfaces we use some targets (stickers) and in reflecting surfaces we use a specific powder spray in order to give a mat white finish in that surface. None of these will damage for example a car body panel, a soft or hard surface.
In the picture you see small targets required in order the scanner not to lose it’s position. On the other hand scanning an object with many features will not require these target, like an engine bay.
We hope this post has helped you to understand how this technology works, the benefits it has and the applications you could use it on. Of course if you have questions you can comment below, sent us an email at info@tpepresicion.com or if you see the chat room available just chat with us in real time!
