Vol. 22
November Issue
Year 2021

Good Vibrations

in Vol. 22 - November Issue - Year 2021
Linear Force Finishing - The new benchmark in post-processing of additive manufactured components

3D printed parts for post-processing

3D part before and after post-processing


The rapid development of additive manufacturing processes makes it possible to use them in more and more new business fields and production areas. Today, series production in small- to- medium quantities is already becoming profitable and is expanding the field of additive manufacturing beyond prototype production.
Series production of sophisticated components requires an industrial process for post-processing of the printed workpieces. Manual smoothing or conventional vibratory tumbling, with sometimes very long processing times, are not economical enough to be used for series production in the future.
To meet customer needs, especially in the post-processing area of additive manufacturing, SPALECK Oberflächentechnik GmbH & Co. KG has developed a new process for smoothing and polishing of additive workpieces. As a manufacturer of vibratory finishing systems, SPALECK Oberflächentechnik has more than 100 years of experience in achieving the highest surface qualities. In addition to the right machine technology, customized process engineering is essential for every customer. Only the combination of vibratory finishing equipment, the right process media and the corresponding process technology guarantees the success of surface finishing.
The analysis of the industry-specific needs of additive manufacturing showed that the conventional vibratory finishing processes in this area have reached their limits in some cases. The reasons for this are various special characteristics that are not present in this way in other industries. First and foremost, these include the unusual, complex geometries that can often only be manufactured additively. In addition, the initial surfaces often have high roughness values and require strong surface smoothing while at the same, time edge rounding should be avoided as much as possible. In addition, very hard materials such as titanium are often used in metal 3D printing, which affects the post-processing time. 
In conventional vibratory finishing processes, complex geometries can lead to so-called shadowing effects. This means that undercuts and internal surfaces, for example, are not machined with the same intensity as surfaces that are easily accessible to the grinding media. The new Linear Force Finishing process is the solution. The new type of isolated, high-frequency movement of the workpiece reduces shadowing to a minimum. In addition, the process is characterized by the fact that edge rounding is significantly minimized and, at the same time, the total surface removal is maximized. This is not the case with conventional vibratory finishing processes. Here, primarily, the edge is machined, whereas long machining times are necessary to achieve noticeable surface removal. 
Extensive tests have shown that the LFF process almost reverses this "regularity". In addition to the low edge-rounding together with the intensive surface machining, it convinces by the very short processing times. Compared to a traditional round tub vibrator, the processing time with the LFF process is up to 15 times shorter, depending on the component. 
The first machine which carries out the LFF process, the PPL300, was also specifically designed for use in additive manufacturing. The aim of the development was to ensure that the system allows a high degree of automation and integrates well into the AM environment. This also includes the fact that, in addition to high flexibility, the system features gentle processing, is versatile, and operates particularly cleanly and quietly.
AMF Zero-Point clamping systems are used for easy use of different workpiece fixtures. These quick clamping systems are also used for fixing the removable processing tub. This allows grinding media to be changed within a very short time, thus increasing the efficiency and flexibility of the entire system.
Additive manufacturing processes are also used in the production of the PPL300 itself. For example, the bionically-optimized oscillating frame is manufactured using additive sand-casting moulds. The weight-saving of 60 kg achieved has made it possible to significantly increase the machining intensity and, at the same time, the payload.   
The PPL300 is thus one of the first systems for industrial post-processing of sophisticated additive manufactured components and is intended to support the transfer to series production in this area.
Visit SPALECK Oberflächentechnik at FORMNEXT 2021 in Frankfurt at booth 12.0-D128 and see for yourself.

Author: David Huls
Spaleck Oberflächentechnik
GmbH & Co. KG, Germany
Tel. +49.2871.9500 250
E-mail: D.Huls@spaleck.biz