Page 26 - 3DMP Spring 2022

3D Automation Takes the Hurt Out of Post-Processing
processing—not only of surfaces but also of internal channels—and automated fin- ishing 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 abun- dance. But, automated post-processing provides wins in metal-AM applications, too, as the following example from Post- Process Technologies shows.
Less Manual Labor, No Deburring
Finding 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 proce- dures proved time-consuming and labor- intensive. The highly manual process con- sisted 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 vary- ing surface finishing/roughness results as well as breakage.
To overcome these challenges and bet- ter serve custom-tooling requests, Lill- backa employed Rador, which uses Post- Process’ Suspended Rotational Force (SRF) technology, to finish the company’s DMLS parts consistently to specifications. The Rador machine uses SRF—software-dri- ven agitation settings to suspend parts within an abrasive mix of media and deter- gent—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 pre- dictably 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 unpre- dictable, 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.
This crimping-tool component exits the printing process (left) and then undergoes automated finishing, courtesy of a Rador machine from PostProcess Technologies, to obtain the required surface finish (right). Testing found that the automated finishing machine 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 (previously employed in this application) tested as highly unpredictable, achieving final Ra values between 4 and 5 μm.
Time and Safety Advantages, Too
The automated finishing machine also delivered significant time savings. Previ- ous manual post-printing processes required about 1 hr. of hands-on techni- cian time, but the deburring process relied on one resource shared by the entire fac- tory. Depending on the factory’s workload, parts could take an additional 1 to 4 days to undergo deburring. The Rador effec- tively 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 elim- ination 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 fin- ishing on virtually every part it prints, including toolsets, crimping dies, inhouse tools and on-demand components. 3DMP
24 | 3D METAL PRINTING • SPRING 2022
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