N Carolina State improves finishing of 3D-printed metal parts

16 May 2024

Method based on integrated 3D printing, automated machining, and laser scanning.

Researchers at North Carolina State University have demonstrated a technique that allows manufacturers of metal machine parts using 3D printing technologies to conduct automated quality control of parts during finishing. The technique allows users to identify potential flaws without having to remove the parts from the manufacturing equipment.

“One of the reasons people are attracted to 3D printing and other additive manufacturing technologies is that these technologies allow users to quickly replace critical machine components that are otherwise difficult to make outside of a factory,” said Brandon McConnell, co-corresponding author of a paper on the work.

“Additive manufacturing tools can do this as needed, rather than dealing with supply chains that can have long wait times. That usually means using 3D printing to create small batches of machine parts on demand,” said McConnell, who is an assistant research professor in NC State’s Edward P. Fitts Department of Industrial and Systems Engineering.

After a metal machine part is printed, it requires additional finishing and has to be measured to ensure the part meets critical tolerances. In other words, every aspect of the part must be the right size. Currently, that involves taking a part out of the relevant manufacturing equipment, measuring it, and then putting it back into the manufacturing equipment to make modest adjustments.

“This may need to be done repeatedly, and can take a significant amount of time,” McConnell said. “Our work here expedites that process.”

Specifically, the researchers have integrated 3D printing, automated machining, laser scanning and touch-sensitive measurement technologies with related software to create a largely automated system that produces metal machine components that meet critical tolerances.

The development is described in Automatic Feature Based Inspection and Qualification for Additively Manufactured Parts with Critical Tolerances published in the International Journal of Manufacturing Technology and Management. The work was done with support from the U.S. Army Research Office.

How it works

When end users need a specific part, they pull up a software file that includes the measurements of the desired part. A 3D printer uses this file to print the part, which includes metal support structures. Users then take the printed piece and mount it in a finishing device using the support structure. At this point, lasers scan the mounted part to establish its dimensions.

A software program then uses these dimensions and the desired critical tolerances to guide the finishing device, which effectively polishes out any irregularities in the part. As this process moves forward, the finishing device manipulates the orientation of the printed part so that it can be measured by a touch-sensitive robotic probe that ensures the part’s dimensions are within the necessary parameters.

To test the performance of the new approach, researchers manufactured a machine part using conventional 3D printing and finishing techniques, and then manufactured the same part using their new process.

“We were able to finish the part in 200 minutes using conventional techniques; the same part was finished in 133 minutes using our new technique,” said McConnell. “Depending on the situation, saving 67 minutes could be incredibly important. Time is money in most professional settings. And in emergency response contexts, for example, it could be the difference between life and death.”

Ricoh opens Center of Excellence at NC State

In related news, Ricoh, a provider of integrated digital services and print and imaging solutions, has opened its Center of Excellence on NC State’s Centennial Campus.

The university stated that “proximity to leading talent and research were drivers for choosing the location”. NC State is home to a notable U.S. program in additive manufacturing.

“Ricoh’s new office on Centennial and the partnership with NC State will help manufacturers accelerate innovation and product development,” said Gary Turner, managing director of additive manufacturing at Ricoh. “As the applications for additive manufacturing grow, 3D printing will drive efficiencies for a range of industries.”