Featured Research

from universities, journals, and other organizations

High-quality 3-D metal parts using additive manufacturing

Date:
June 16, 2014
Source:
DOE/Lawrence Livermore National Laboratory
Summary:
Researchers have developed a new and more efficient approach to a challenging problem in additive manufacturing -- using selective laser melting, namely, the selection of appropriate process parameters that result in parts with desired properties.

Direct metal laser melting (DMLM) machine in action: A laser fuses metal powder to form one of many successive layers that will form the final manufactured part.
Credit: Image courtesy of DOE/Lawrence Livermore National Laboratory

Lawrence Livermore National Laboratory researchers have developed a new and more efficient approach to a challenging problem in additive manufacturing -- using selective laser melting, namely, the selection of appropriate process parameters that result in parts with desired properties.

Selective laser melting (SLM) is a powder-based, additive manufacturing process where a 3D part is produced, layer by layer, using a high-energy laser beam to fuse the metal powder particles. Some SLM applications require parts that are very dense, with less than 1 percent porosity, as the pores or voids are the weakest part of the material and most likely would result in failure.

But building functional parts and components to specific standards and performance specifications can be challenging because a large number of parameters must be set appropriately. Some of the key parameters include laser power, laser speed, distance between laser scan lines, scanning strategy and powder layer thickness.As a result, there is a need for a reliable and cost-effective approach to determine the right parameters to develop parts with such desired properties as high density.

LLNL researchers have developed an efficient approach, based on simple simulations and experiments, to identify optimal parameters to print 3D high-density metal parts. Their work, titled "Density of additively-manufactured, 316L SS parts using laser powder-bed fusion at powers up to 400W" was recently published in the International Journal of Advanced Manufacturing Technology.

The paper explains how parameters for higher-power SLM machines can be selected by using simple, computational simulations to explore the process parameter space. These simulations are used to compute the dimensions of the melt pool, which is the pool of liquid formed when the laser melts the metal powder particles.

"We mine the simulation output to identify important SLM parameters and their values such that the resulting melt pools are just deep enough to melt through the powder into the substrate below," said Chandrika Kamath, an LLNL researcher who is the lead author of the article. "By using the simulations to guide a small number of single-track experiments, we can quickly arrive at parameter values that will likely result in high-density parts."

Kamath and her colleagues, who are part of LLNL's Accelerated Certification of Additively Manufactured Metals (ACAMM) Strategic Initiative, are using simulations at various scales to gain insight into the SLM process.

"We found that the metal density reduces if the speed is too low, due to voids created as a result of keyhole mode laser melting, where the laser drills into the material," Kamath wrote. "At the same time, too high a speed results in insufficient melting. The key is to find the right parameters where the melting is just enough."

The LLNL team found that the use of different powders affected densities at lower power, but not at higher power.

"Furthermore, for 316L stainless steel, at higher powers, the density is high over a wider range of scan speeds, unlike at lower powers," the article states. "This would indicate that higher powers could provide greater flexibility in choosing process parameters that optimize various properties of a manufactured part."

Although 316L stainless steel was used in this experiment, Kamath said the team's approach can be applied to other metal powders as well.

LLNL's findings will eventually be used to help certify properties of metal parts built using SLM. The paper is the first step in understanding how we can exploit computer simulations and a small number of carefully chosen experiments to efficiently determine the process parameters, Kamath said.


Story Source:

The above story is based on materials provided by DOE/Lawrence Livermore National Laboratory. Note: Materials may be edited for content and length.


Journal Reference:

  1. Chandrika Kamath, Bassem El-dasher, Gilbert F. Gallegos, Wayne E. King, Aaron Sisto. Density of additively-manufactured, 316L SS parts using laser powder-bed fusion at powers up to 400 W. The International Journal of Advanced Manufacturing Technology, 2014; DOI: 10.1007/s00170-014-5954-9

Cite This Page:

DOE/Lawrence Livermore National Laboratory. "High-quality 3-D metal parts using additive manufacturing." ScienceDaily. ScienceDaily, 16 June 2014. <www.sciencedaily.com/releases/2014/06/140616141547.htm>.
DOE/Lawrence Livermore National Laboratory. (2014, June 16). High-quality 3-D metal parts using additive manufacturing. ScienceDaily. Retrieved July 24, 2014 from www.sciencedaily.com/releases/2014/06/140616141547.htm
DOE/Lawrence Livermore National Laboratory. "High-quality 3-D metal parts using additive manufacturing." ScienceDaily. www.sciencedaily.com/releases/2014/06/140616141547.htm (accessed July 24, 2014).

Share This




More Matter & Energy News

Thursday, July 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

TSA Administrator on Politics and Flight Bans

TSA Administrator on Politics and Flight Bans

AP (July 24, 2014) TSA administrator, John Pistole's took part in the Aspen Security Forum 2014, where he answered questions on lifting of the ban on flights into Israel's Tel Aviv airport and whether politics played a role in lifting the ban. (July 24) Video provided by AP
Powered by NewsLook.com
Creative Makeovers for Ugly Cellphone Towers

Creative Makeovers for Ugly Cellphone Towers

AP (July 24, 2014) Mobile phone companies and communities across the country are going to new lengths to disguise those unsightly cellphone towers. From a church bell tower to a flagpole, even a pencil, some towers are trying to make a point. (July 24) Video provided by AP
Powered by NewsLook.com
Algonquin Power Goes Activist on Its Target Gas Natural

Algonquin Power Goes Activist on Its Target Gas Natural

TheStreet (July 23, 2014) When The Deal's Amanda Levin exclusively reported that Gas Natural had been talking to potential suitors, the Ohio company responded with a flat denial, claiming its board had not talked to anyone about a possible sale. Lo and behold, Canadian utility Algonquin Power and Utilities not only had approached the company, but it did it three times. Its last offer was for $13 per share as Gas Natural's was trading at a 60-day moving average of about $12.50 per share. Now Algonquin, which has a 4.9% stake in Gas Natural, has taken its case to shareholders, calling on them to back its proposals or, possibly, a change in the target's board. Video provided by TheStreet
Powered by NewsLook.com
Robot Parking Valet Creates Stress-Free Travel

Robot Parking Valet Creates Stress-Free Travel

AP (July 23, 2014) 'Ray' the robotic parking valet at Dusseldorf Airport in Germany lets travelers to avoid the hassle of finding a parking spot before heading to the check-in desk. (July 23) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins