Additive Manufacturing Technologies
Quality testing using computed tomography of novel additive manufactured components can expose defects and process flaws. "The freedom in design for additive manufacturing is often a challenge for non-destructive testing, especially for highly-stressed AM-components with increased complexity." Integration of CT systems such as the diondo d5 and diondo d2 into different types of additive manufacturing provides highly productive inspection of critical components.
CT in Additive Manufacturing
Metal additive manufacturing and CT inspections are made to compliment each other. Due to the complexities of designing the component to function under stress and maintain a light weight and size, the quality science lab needs to view the internal structure to assure that it is made to design specifications. That is to check for out of specification porosity size, cracking during the manufacturing process, excess metal powder inside of parts, metrology, actual / nominal comparisons with CAD data. In line CT is the additive manufacturing process that can check all of the perimeters in a single scan. Automation of this process allows the operators to set the x-ray parameters and inspection criterion and gather the data while developing. First hand experience shows the possibility of providing detailed analysis and reports for each critical part that meets or fails the test criterion.
Metal Additive Manufacturing
Metallic additive manufacturing continues to develop with high dynamics. New processes and metal powders are being developed and tested daily. The figure on the right or below when using a cell phone, shows futures in printing to present day products being manufactured using 3D printing and additive manufacturing. Starting from an originally pure prototype production, the series production of metallic additive components has become more and more relevant in recent years. Additive manufactured parts differ from cast or forged components in particular in their surface finish, their metallic microstructure and their behavior under dynamic load. Quality testing procedures need to be able to quantify and qualify defects and the impact that they have on design criteria.
Characterization of Metal AM Powder
Metal AM powder should be characterized by different methods described in standards like e.g. DIN 65122, ISO ASTM 52925 or ASTM F3049 as part of the acceptance tests for:
grain size distribution,
contamination and / or foreign materials inside powder,
flowability and pourability of the powder.
The processes in which fusion of the metal is now widely held as secretive or patentable information. Most companies hold these AM processes tight to their breast. The typical energy requirements whether it be e-beam or laser is very critical and required to be repeatable. We have all experienced blowing a hole through a metal plate while cutting or using a welding torch. The same issues hold true with design for additive manufacturing.
AM Powder Aging
Surface analysis on AM powder is a critical to maintaining a high level of consistency in a repeatable AM process.
Chemical reactions during the AM process change the surface properties of the AM powder and have negative effects on subsequent production processes with recycled powder. These chemical changes can be characterized by using methods of surface analysis like TOF-SIMS, XPS and SEM.
Metal AM Testing Methods
According to DIN 65122 testing for the additive manufacturing powder will require several tests as outlined in the figure to the right or below for cell phone device users. effective analysis using 3D Computed Tomography can automate the determination of relevant powder parameters.
Special thanks to Dr. Olaf Günnewig and AM-Quality