Metal additive manufacturing (AM) offers many benefits over traditional subtractive manufacturing processes, including cost and time savings, as well as design flexibility. However, one deficit of additive manufacturing, also known as 3D printing, that is impossible to ignore is reduced quality and repeatability when compared to traditional subtractive manufacturing processes like CNC machining.
The properties and performance of end products are determined by the 3D printer and printing process, which most notably includes laser-beam accuracy and powder-bed control. To address these concerns and take full advantage of the benefits additive manufacturing offers, many recent developments in quality control focus on the manufacturing process.
In the past, quality assurance methods took repeatability for granted. Manufactured parts were considered acceptable after a sample of parts from a specific production run were deemed to be quality. Additive manufacturing does not offer the same tight tolerances and therefore lacks repeatability. One of its unique advantages is the ability to quickly prototype new products or print customized devices, especially in healthcare. These two features make it hard to use traditional quality control processes.
It is no longer enough to identify defective products. One way researchers are adapting common quality assurance practices to additive manufacturing is by considering the entire process. An interdisciplinary team at Penn State University is examining 3D printed parts using ultrasonic nondestructive evaluation (NDE) to identify flaws and tie them back to defective raw materials and/or manufacturing processes.
In addition to this type of hybrid approach to quality assurance, 3D printing industry leaders are designing equipment and processes for real time updates on printer activity. Rather than just examining finished products or calibrating machines every 90 days (NASA’s current standards for optical systems), real time prebuild calibration eliminates downtime caused by manual calibration and identifies potential issues sooner.
These types of complex monitoring systems offer many benefits, including improved yield and performance. However, they are often cost prohibitive for smaller facilities. Making real time quality control more accessible is essential, as additive manufacturing inherently “allows for the decentralized manufacturing of highly customized products.” Another way industry leaders are making their quality assurance tools more accessible is the ability to retrofit machines that are older or produced by another company with updated monitoring systems.