In-situ Evaluation of Component Fidelity During Additive Manufacturing Processing
Many manufacturers have been striving for a single system that can produce a true final product using one processing tool. Additive manufacturing (AM) is a rapidly growing field that is finding applications in a wide range of communities including aerospace, civilian, military space, manufacturing, automotive, and biomed. The vast majority of AM built components require additional processing after the AM build is complete; at a minimum, some surface machining is required. Current AM technologies are essentially set-it-and-forget-it. For complex components, more involved subtractive machining steps, such as drilling or reaming holes, are required. Each of these steps requires fixturing the component in a new machine, significantly adding to the overall cost and build time for the part. The ideal solution for this problem would be to use an AM tool that was also capable of subtractive machining.
Researchers at The Johns Hopkins University Applied Physics Laboratory proposed a system of cameras, scanners, or other source/detector combinations to interrogate features of a component during an AM build process and compare the as-built part to the original drawing file. The goal is to reconstruct a 3D-image of an as built component by imaging each layer during the AM build process.
This system could also incorporate a wide variety of inspection processes beyond simple bright field imaging, providing a wide array of interrogation modalities; laser scanning, thermal, magnetic or acoustic imaging, and x-ray inspection could all be incorporated into the basic framework of this idea. The proposed system could be applied to any AM tool, regardless of manufacturer, build material (metals, ceramics, or polymers), or processing technology (laser, electron beam, UV cure, etc.).
The proposed system provides closed-loop system, known as scope, which actively monitors AM builds. The system will inherently know if the part it is building matches the design file. By automatically inspecting the part during the build process, it will be possible to detect internal and external defects such as voids, bad build lines, warping, or shrinkage. In addition, the system can be programmed to take steps to repair the detected anomalies, creating a self-correcting AM tool.
Novel features of this technology include the ability to detect internal and external defects during the build process, to correct detected anomalies with subsequent steps in the build process by modifying the build instructions during processing, to provide accurate measurement of both internal and external features, and to accurately assess the degree to which the as-built part matches the design file, providing valuable information regarding part tolerances and set a design tolerance window.
This system would be of interest to any of the additive manufacturing vendors across all industries. The software and user interface can similarly be adjusted and targeted to a specific AM application.
This machine agnostic 3D printer can be adapted to be a third-party add-on system for any current AM tool; this would allow it to be marketed to current users of AM systems.
The ultimate goal of this in-processing monitoring of AM builds is to create a Stereo Lithography file of the component during the build from individual images captured in each layer, as well as a self-correcting AM machine that monitors the part of dimensional accuracy both internal and external defects during the build, and applies the necessary corrective actions to yield a successful componentCONTACT:
Mr. K. Chao
Phone: (443) 778-7927