Processing of 3D printed parts, manufactured via Selective Laser Sintering (SLS), to improve the surface appearance and smoothing can be challenging. These parts tend to have a textured surface and require improvement of surface roughness. We are proud to announce that ActOn Finishing can now assist companies from the additive manufacturing industry to surface finish 3D printed polymer parts, through Vibratory Finishing technology.
The implementation of this mass finishing solution offers a reduced cost per part, consistent results and a short ROI often 6-12 months as compared to other solutions available in the market. More importantly, we have proved that we can improve, through vibratory finishing, the Ra value to 3 Micron, leaving the surface of the parts smooth.
Project Background
Recently we have been contacted by Ricoh UK Products, who we have met at Made in the Midlands Exhibition 2018, to develop a Vibratory Finishing solution to smooth 3D printed polypropylene parts they manufactured, via Selective Laser Sintering. Ricoh is a global provider of technology that transforms business processes and information management to help organisations be more agile, productive and profitable. Amongst other business services and products, Ricoh also manufactures 3D Printers and offers additive manufacturing services.
As they manufacture Selective Laser Sintering parts in different shapes and sizes, they were interested in purchasing a Vibratory Finishing system that can accommodate these parts and which would help them achieve a smooth surface finish to offer added value to their customers.
“We were aware that the technology was already being used in the industry to smooth 3D printed parts manufactured in Nylon, however, we did not want to simply accept that the established method would be suitable for our polypropylene material,” commented Richard Minifie, Senior AM Engineer, Ricoh UK Products Ltd. “We began to look for a technical partner who would conduct tests across a range of technologies and various media types to provide conclusive data that would allow us to identify the most suitable smoothing process before purchasing the technology. ActOn Finishing were open and honest with us at every stage, stating that they had not previously investigated the smoothing process for 3D Printed Polymer parts, but that it was an area that they were keen to explore and gain knowledge in.”
Processing Trials
Ricoh didn’t have a specific Ra value requirement, but chose the preferred finish and time frame based on the requirements of its customers. The parts provided by Ricoh included VW bumper components, wing mirrors, and rotary atomiser parts, the initial roughness surfaces of which ranged between 3.6 and 13 microns.
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We initially processed the components in its Centrifugal High Energy (CHE) machine for an hour. The trial was carried using a highly abrasive ceramic media and a concentrated liquid compound, which acts like a cleaner and polisher. We achieved a surface roughness between 1 and 3 microns, but parts were slightly damaged.
Thus, a medium abrasive plastic was used instead of a highly abrasive one. Again, there was damage, so we ruled out the use of CHE technology. At this point, we decided to turn to the Vibratory Finishing machines. Harnessing the same ceramic media and liquid compound as the first trial, the 3D printed components were processed in ActOn’s Vibratory Bowl machine for 20 hours, and finally achieved parts that showed no damage, and with a Ra value of between 0.5 and 3 microns, looked good. Larger parts were then also tested on ActOn’s Trough Vibratory Finishing machine, which also proved successful. The rotary atomiser head, for example, started at 7.2 microns, and after 4 hours in the Trough machine was reduced to 5.9 microns, and a further four hours, down again to 3.7 microns, with no visible drawbacks.
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Damaging on thinner wall sections of parts was noticed during finishing processes between 8 and 20 hours, so Ricoh was advised not to exceed 8 hours and use a mix of sizes of the abrasive ceramic media, the concentrated liquid compound for cleaning and polishing, and water. We also advised Ricoh to use divider plates to separate larger pars and smaller parts into two different chambers.
Benefits of the Vibratory Finishing Process
- In a 4 hour Vibratory Finishing process most of the Selective Laser Sintering parts are smoothly finished
- The process reduces the faceting caused by the printing process and could also be a method for reducing the orange peel
- The mass finishing solution we have developed helps our customer to achieve an Ra value of approx. 3 Micron. This is visually a good result, parts being smooth to touch
- The solution offered by ActOn is cost effective as client can use only one finishing machine to process 3D printed parts of different shapes and sizes.
- The ROI for this project was 34 weeks
In Richard Minifie’s (senior AM engineer, at Ricoh UK Product Limited) statement, he concluded that:
"We worked together to devise a series of tests and these were conducted by ActOn Finishing using a range of technologies employing different media types and a range of run times, to establish the optimised equipment and process to support our application. This was done quickly and professionally with regular updates along the way.
ActOn Finishing’s openness and willingness to conduct trials to establish the most suitable technology and process, was exactly what Ricoh required from a technical partner. As engineers, we like to capture lots of data to prove processes and learn through experimentation. During this collaborative project, we were able to share knowledge with ActOn Finishing to quickly establish a smoothing process for SLS printed parts. This open style learning approach is really important to Ricoh, because the knowledge developed provides value on both sides, which in turn increases the chances of future collaborative projects."
To learn more about ActOn’s finishing technology for Additive Manufacturing industry please visit the Industries page. To discuss your mass finishing project contact our technical team at [email protected]