Raw materials, or feedstock, play a crucial role within the additive manufacturing process. 3D printing techniques, such as fused deposition modeling, stereolithography, and selective laser sintering, employ feedstocks which come in various forms. These include filaments, wires, pellets, liquids, slurries, gels and powders. These feedstock can range from plastic, elastomer, composite, metal alloy, and ceramic materials.
The majority of 3D printing feedstocks are comprised of multiple components, rather than single-ingredient materials. As such blending and mixing technologies play a vital role in the additive manufacturing process, with better mixing processes resulting in better end products.
Charles Ross & Son Company, also known as ROSS Mixers, offer a range of industrial mixing, blending, drying, and dispersion equipment that offers numerous benefits for the growing additive manufacturing industry.
Based in Hauppauge, New York, the 180-year-old company engineers and fabricates mixing systems that are designed to provide precise formulations, and consistent batch to batch repeatability.
“As the 3D printing industry evolves, ROSS Mixers remain at the forefront, delivering a diverse range of equipment and innovative mixing solutions for a wide range of applications,” states Erin Dillon, Media and Marketing Coordinator at ROSS Mixers.
ROSS Mixers’ industrial mixing portfolio
ROSS Tumble Blenders are optimized for handling metal and alloy powders used in 3D printing, which often possess extremely high bulk density.
Tumble blending is ideal for handling these materials as it is a very low-impact process, making it perfect for processing abrasive solids and friable ingredients. Indeed, out of all the dry blending technologies, tumble blenders are the best option when it comes to handling heavy batches, while limiting mechanical wear. Tumble blending is also commonly used in making precise blends containing trace ingredients or additives.
The ROSS Tumble Blender incorporates a rotating vessel that is usually formed in a double cone or V-shaped configuration, and turns at speeds of 5 to 25 revolutions per minute. One key advantage of these configurations is that they allow for the complete discharge of the blended material. This results in high yield, allowing for easy cleaning and limited contamination risks.
ROSS High Shear Mixers are designed for low-viscosity applications requiring high shear forces and intense turbulence. Available in batch or inline configurations, these mixers consist of a rotor that turns at high speeds with a stationary stator. As the blades rotate, material is continuously drawn into one end of the mixing head and expelled at high velocity through the openings in the stator.
Ensuring rapid mixing, these machines effectively break down aggregates and reduce droplet sizes. Thus, high shear mixers are ideal for 3D printing applications such as dispersion of pigments, additives and fillers into resins or waxes; polymer suspensions; ceramic slurries; lubricants; and binder solutions.
For applications that require the processing of viscous materials such as plastisols, thermoplastic inks, rubber blends, composites, and resins, ROSS manufacture an extensive line of Multi Shaft Mixers. These mixers can easily handle thick slurries, pastes, gels, and suspensions.
Thanks to their ability to mix under vacuum and provide temperature control, these mixers ensure superior dispersion, emulsification, and homogenization.
ROSS Triple Shaft Mixers typically incorporate a high shear rotor/stators to emulsify and homogenize material; a high-speed disperser to create a vortex and quickly wet out powders; and a three-wing anchor agitator to ensure constant motion and feed product to both the rotor/stator and disperser.
Similarly, Dual Shaft Mixers are usually composed of a high-speed disperser and a two-wing anchor agitator. A cost-effective system, Dual Shaft Mixers are ideal for straightforward applications that don’t require intense shearing of agglomerates or droplets.
ROSS Double Planetary Mixers, on the other hand, are optimized for handling thick pastes and putties. In fact, Double Planetary Mixers are well regarded for their ability to handle viscous formulations of up to 6 million cP or more. These systems are particularly well suited for 3D printer feedstocks and intermediate materials.
Double Planetary Mixers consist of two identical blades that rotate on their own axes, and orbit the mixing vessel on a common axis. The blades continuously advance along the periphery of the vessel, removing material from the vessel wall and transporting it to the interior. Moreover, the two blades move through every point of the product zone, physically contacting the entire batch in as little as 36 revolutions.
The blades of these machines run at relatively low speeds, making Double Planetary Mixers ideal for abrasive applications, including metal or ceramic dispersions in polymer, wax or resin binding agents.
ROSS Mixers’ patented PowerMix is a hybrid planetary disperser. Incorporating a planetary stirrer and high-speed disperser blade, this system combines high and low-speed agitation. Consisting of a disperser blade and planetary stirrer revolving around a central axis, the agitators in a PowerMix also rotate on their own axes at different speeds. The planetary stirrer sweeps material away from the sidewalls and bottom, carrying it to the sawtooth blade.
Both agitators are independently controlled. This allows flow patterns and shear rates to be easily fine-tuned as the product undergoes changes in rheology and other physical characteristics.
ROSS also offers the Planetary Dual Disperser (PDDM), a robust system combining two planetary blades and two high-speed dispersion blades. The two planetary stirrers and two dispersers rotate on their own axes while revolving around a central axis.
This allows material near the vessel walls and bottom to be efficiently carried towards the sawtooth plates. As such, agglomerates are disintegrated faster and turnover is extremely efficient, even when the material is particularly dense or sticky.
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Featured image shows ROSS Mixers’ mixing portfolio. Image via ROSS Mixers.
