Lou Kren Lou Kren
Senior Editor

Automation Takes the Hurt Out of Post-Processing

March 29, 2022


This past November, a survey of additive manufacturing (AM) users revealed the three top pain points related to post-processing: length of time to finish parts, consistency of finished parts and throughput limitations. These findings, courtesy of the Annual Additive Post-Printing Survey: Trends Report 2021, from PostProcess Technologies, offer reasons why post-processing has been labeled the necessary evil of AM. Unquestionably of utmost importance in the production cycle, post-processing nonetheless can drop challenges and roadblocks galore in time, manpower and costs.

1-Post-Processing-Lillbacka-PostProcess“Post-printing as a portion of AM operational expenditure has trended up year over year,” the report, released each year since 2019, reads. “Respondents who say that they spend greater than 26 percent of their overall budget increased from 23 percent of all respondents in 2020 to 30 percent in 2021.” 

Automotive AM suppliers represent the highest spenders, with nearly 50 percent reporting that they spend 26 percent or more of their budget on post-processing. And, a fifth of respondents do not track expenses related to post-processing—surprising given the significant space it occupies in the full AM production chain, and the real opportunity that such knowledge offers for AM users to improve. 

Technology gains can ease post-processing bottlenecks and costs, with software, machine and quality-control advances allowing for more efficient designs and less need for the finishing speed bumps known as support structures. But the truth is, AM parts in nearly all cases require some amount of post-processing—not only of surfaces but also of internal channels—and automated finishing technology offers the opportunity to save time and money. Many in the AM industry recognize such technology as ideal for many nonmetal applications, with published case histories in abundance. But, automated post-processing provides wins in metal-AM applications, too, as the following example from PostProcess Technologies shows.

Less Manual Labor, No Deburring

2-BEFORE-Post-Processing-Lillbacka-PostProcessFinding traditional blasting procedures to be too time consuming, Finland-based Lillbacka Powerco Oy, a manufacturer of crimping technology, in 2020 selected a Rador automated surface-finishing machine from PostProcess Technologies to match post-processing of parts to the efficiencies of its AM production.

Lillbacka employs direct metal laser sintering (DMLS) to produce end-use crimping dies used in the machines it builds. Though AM productivity benefits had proved evident, post-printing procedures proved time-consuming and labor-intensive. The highly manual process consisted of multiple steps. Once depowdered, parts required treatment with a manually operated glass-ball bead blaster, then deburring to smooth out roughness. While hindering workflow, these processes also presented part-quality and -consistency challenges. Lillbacka struggled with varying surface finishing/roughness results as well as breakage. 

3-AFTER-Post-Processing-Lillbacka-PostProcessTo overcome these challenges and better serve custom-tooling requests, Lillbacka employed Rador, which uses PostProcess’ Suspended Rotational Force (SRF) technology, to finish the company’s DMLS parts consistently to specifications. The Rador machine uses SRF—software-driven agitation settings to suspend parts within an abrasive mix of media and detergent—to achieve desired surface-finish and dimen¬sional consistency.

Lillbacka, through rigorous testing to determine the efficacy of various finishing processes, found that the Rador predictably and repeatedly achieved final Ra values of 1.6 µm on a part with an original Ra of 6.5 µm. Conversely, manual bead-blasting results tested as highly unpredictable, achieving final Ra values between 4 and 5 µm. In fact, of five surface-finishing methods evaluated by Lillbacka, according to company officials, only the automated finishing method provided the ability to scale throughput with impressive surface-finishing consistency.

Time and Safety Advantages, Too

The automated finishing machine also delivered significant time savings. Previous manual post-printing processes required about 1 hr. of hands-on technician time, but the deburring process relied on one resource shared by the entire factory. Depending on the factory’s workload, parts could take an additional 1 to 4 days to undergo deburring. The Rador effectively eliminates the need for a deburring step altogether, according to PostProcess officials, making time spent manually post-printing parts almost negligible. 

Lillbacka also benefited from safety and environmental features enabled by the automated finishing solution, as elimination of deburring limits employee exposure to harmful powder particles.

“We needed a post-processing method that was just as versatile and adaptive as the tool designs and the AM process,” says Masi Tammela, Lillbacka AM manager. “Today we consistently and predictably can reach and exceed our surface-quality requirements for the working surfaces of our tooling.”

Lillbacka now employs automated finishing on virtually every part it prints, including toolsets, crimping dies, inhouse tools and on-demand components. 3DMP

Industry-Related Terms: Additive manufacturing, Direct metal laser sintering (DMLS), Post-processing, Sintering
View Glossary of 3D Metal Printing Terms

 

See also: PostProcess Technologies

Technologies: Post Processing

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