IS 3D SCANNING RIGHT FOR YOUR PROJECT?
3D scanning in its basic form is the process of scanning a part to create 3D data of that part. It can create a surface alone or a full blown part. At first blush, it seems like this would put us out of a job. Thankfully for us, it doesn’t. However, it is very useful for some projects that use existing surfaces or critical data points that would be difficult to measure.
WHY DO YOU SCAN SOMETHING IN THE FIRST PLACE?
Take for example, a computer mouse. Let’s say you have created the ultimate mouse, it fits perfectly in your hand and moves effortlessly across the table. The problem is, you made the shape out of clay because that’s what worked best for you. So, to accurately measure that part, we will need to scan that outside surface and get it into CAD data. To do this, we will need a 3D scan of that part. From there, we would rebuild that outside surface and begin creating all of the internal detail so the part can be molded and manufactured. Rebuilding that surface is important for several reasons, but in a nutshell, we need a clean surface to work from in our CAD data. There are programs that can convert point cloud data or STL data to surfaces, however, in most cases, this will not give the result that will be needed for a clean product design.
SCANNING TECHNOLOGY
There are a few scanning technologies available, the most common are LASER or Light scanning, Medium and Long Range Scanning, and CT scanning.
Medium and long range is for scanning buildings and very large objects. Examples of this type of scanning would be in the construction industry to scan a plot of land to get exact measurements prior to building. Or Scanning bridges and buildings from year to year to show settling or change over time.
CT scanning or Computed Tomography scanning uses X-Rays to see inside an object without cutting it open This is also known as CAT Scan or Computed Axial Tomography. This is a very expensive process and is rarely used for product development.
For our purposes, we will focus on the the LASER and Light scanning. LASER scanning as one can guess from the name uses a LASER beam that will shoot a beam onto an object and a camera will analyze how that beam changes shape and recreates the surface in 3D space. Light scanning will basically do the same thing except it uses dots of light projected onto the surface. We will then use that scan as a 3D guide so we can take the important data points and surface contours and recreate them in CAD. The result will be clean CAD data that can be used for tooling and allow us to create the other important features that will be needed for a complete product design.
WORKING WITH A CAKE PAN
In the example of the Mickey pan above, our customer had an existing pan that was created from a sculpted pattern. The pattern was made from clay by hand, and the features were not very precise. The lines and surface changes had 3-4mm radii on them and the scan data added more imperfections. This did not make for clean delineation between the features. You can get scans with very high resolution to minimize the scan imperfections but often times the file size is so large it becomes cumbersome or impossible to work with. In the example below, you can see how soft and inconsistent the features are around the eyes. In the CAD image, you see the surfaces, radii and lines are very clean and crisp.
KNOWING WHEN TO USE THE TECHNOLOGY IS IMPORTANT
We have used 3D Scanning for many projects, but not necessary for all. For most projects, we can measure mating parts and create 3D CAD data from those measurements. We can download existing components and build our data to fit them. However, If the customer has parts that have surfaces or geometry that is difficult to recreate in CAD, 3D scanning is the answer. In the case of the Mickey pan and the other pans in that product line, 3D scanning allowed us to save time for the customer rather than creating the shape from scratch.
3D scanning is just one of the many tools that we use to create the best product we can. Sometimes it will save time in the development cycle, but more often it is used to give us an accurate 3D underlay so we can create our CAD models quickly and precisely the customers required specifications.