Manufacturing Case Study: From 3D Scanning to CAD
Posted by Thomas Tong on Tue, Feb 19, 2013 @ 11:00 AM
This week’s blog post is contributed by 3D3 Solutions’ distributor in India, Aman Bir Singh, from Rasco Automotive Systems Private Limited
PHOTO: Digital 3D model of a physical prototype produced using a white-light 3D scanner (also known as structured-light 3D scanner)
Designers need an efficient workflow to convert their design prototype into a mold for mass production. Rasco Automotive Systems recently collaborated with a commercial automotive manufacturer to achieve this goal using a process called Scan to CAD.
In this project, the design prototype is a seat that was designed by hand. The Scan to CAD process involves using a 3D scanner to capture digital 3D scans of the prototype. The 3D scans have the prototype measurements which are used to create a Computer-Aided Design (CAD) model. The CAD model is then used to create a mold of the prototype for final production. In this project, Rasco Automotive Systems scanned the prototype using the HDI Advance R1 scanning system.
In this project, Rasco Automotive Systems encountered three challenges they were able to solve successfully:
Challenge #1: How to Scan a Large Object
The prototype must be scanned at all angles to create a full digital 3D model. The team was able to achieve this goal with relative ease since the HDI Advance R1 3D Scanner is a portable and light weight system that can be moved around. The 3D scanner captures the prototype in sections. Once a 3D scan captured one area of the prototype, the scanner is moved to a different section of the seat for 3D scanning. The scans are then merged together to form a complete digital 3D model.
PHOTO: The HDI Advance R1 is mounted on a tripod for maximum portability
Challenge #2: Aligning 3D Scans of a Large Object
PHOTO: Preparing the prototype for scanning
Preplanning was necessary before starting the 3D scanning process. Since the seat is a large object that measured 21” (W) x 30” (D) x 44” (H), Rasco Automotive Systems’ plan was to use a combination of marker alignment and geometry based alignment for scan processing. Scanning with markers is a faster and more convenient way of aligning multiple scans. The alignment algorithm is greatly sped up by having far fewer reference points to search for and to match up for alignment. Geometry-based alignment uses specific features of an object as a point of reference to align 3D scans together. As a result, the technical specialist needed to make sure he captured geometry features of the seat in the 3D scans for easy scan alignment.
Challenge #3: Managing 3D Scan Data with Large Volume of Points
For this project, the 3D scanner captured approximately 60 million points of scan data in total which is difficult to manage even on high performance PCs! Rasco Automotive Systems tackle this challenge by decimating the scan data often. They also combined sets of scans and applied fine alignment regularly so the data is more manageable.
After 3D scanning is complete, the scan data was imported in Solid Works as STL polygon file. A 3D CAD was generated from the 3D scans using Solid Works.
PHOTO: Digital 3D model from scan data (Left), CAD Model (Right)
The HDI Advance R1 3D scanning system offers great resolution and an accuracy of +/-0.075mm for the digital 3D model! This is an incredible achievement for scanning a large object. The scan data was invaluable in order to produce high accuracy CAD models of the prototype for manufacturing.
Have questions about 3D scanning to CAD? Please comment and share your thoughts.