More effective screening of challenging metal powders

Metal powder particle sizes have to meet increasingly higher demands in regards to the further processing of metal powders. A newly developed screening machine technology helps to meet these demands.

Additive manufacturing, such as SLM printing of parts of all kinds, plays an important and increasingly greater role in many industries.
It is due to new manufacturing methods and technologies that the demands on the processed material are higher than ever.

That is why e.g. the qualitative character of the metal powder used for laser melting processes are a prerequisite for the economic efficiency of following processes and the quality of the final product.

The titanium, steel, stainless steel and alloy metal powders, which are usually a result of spraying processes, have to be conditioned before they can be processed further. The separation from oversized grains (bigger than 40,63, 80 µm) is an essential and necessary part of the conditioning process. Also small particles may want to be removed.

The target particle size depends on the type of application. In order to provide a solution for the particular problem, the Sonic Speed Screen technology was developed by assonic. It can be used in different screening machine configurations.

The patented technology is based on the excitation of ultrasonic frequencies (30.000-38.000 Hz) into the screening chamber and a simultaneous medium-frequency excitation (80-1000 Hz) of the screening surface. The fine metal mesh screens with firmly bonded laminated supporting fabric used by Assonic enables an optimal transfer of the ultrasonic energy.

The result is reduced static friction and therefore an increased process effectiveness. Moreover, due to the use of a robust laminate, the screening surface is protected against screen breakage, even at very high loads.

Different stages of the metal powder process cycle require differing screening performances. Assonic has developed different systems using Sonic Speed Screen technology to meets these needs.

RoSM 700

(image: Assonic)

The RoSM 700 is an extraordinarily high-performing rotary machine that reliably processes higher volumes of powder and impresses with its small footprint.

It is successfully used by metal powder producers to eliminate oversize grains or to recondition larger quantities of used powder. It is equipped with a cylindrical sintered metal mesh laminate screening basket. This, in combination with the use of ultrasonic energy, is the bases for higher performance. It also has proven to be very durable in high volume separation.

Especially designed rotating paddles move the metal powder continuously across the screening surface. The surface is additionally stimulated with a medium frequency vibration to avoid surface clogging and to enhance flow.

(image: Assonic)

Its superior performance/ surface area ratio leads to the very small footprint of the RoSM compared to round screen separators. It is prepared to be ATEX (zone 20) certified.

The KSM 300 is a efficient compact screening machine for medium to small powder volumes driven by Sonic Speed Screen technology. It can continuously separate up to 4 fractions of fine powder. For higher performance usually sintered laminate screens are being used. The machine can process under explosion proof inert gas situations.
The machine can be used in a mobile version or incorporated into automated process lines.

The KS 200 and KS 300 compact sieve models are used in laboratories or as stand alone small lot screeners. Due to the use of the Sonic Speed Screen principles and sintered laminate as screening media like their bigger brothers they sift finest and difficult materials where other vibratory screeners have to give up.
The units are available as table screeners, but also on a little trolley to easily locate it where it is needed.

(image: Assonic)

A very convenient version of the efficient small screener is USEL 200 or USEL 300. The flexible use of already existing standard laboratory sieves is cost effective and practical.




(image: Assonic)


Screening trials of all kinds can be performed with machines equipped with Sonic Speed Screen technology in the laboratory of assonic Dorstener Siebtechnik GmbH in Radevormwald, Germany.