Planetary Centrifugal Mixer Applications

Another Dimension to Planetary Centrifugal Mixers: 3D Printing

Blending materials for 3D printing processes can require a delicate balance between precision and automation. Depending on how the materials are blended together, the mixture can run the risk of being low quality or difficult to use, or it might just require additional processing steps. Luckily, an efficient machine called a planetary centrifugal mixer was designed to help with this exact requirement. Planetary centrifugal mixers are also known as paste mixers. They operate without blades or propellers, using a no-touch process to blend materials using simultaneous rotation and revolution. This technique allows for fast and thorough mixing, as the 3D printing ink materials are deaerated and blended at the same time.

For instance, electronics paste is commonly used in manufacturing solar cells. Silver rear contacts are made out of silver or silver-aluminum electronics paste, which are printed and fired onto silicon to allow the electrical connection between different cells in a module. In one laboratory procedure, researchers used a Mazerustar planetary centrifugal mixer to blend batches of TiP and Ta-P dielectric paste. Their goal was to electrically isolate electrodes of opposite polarity types on the same side of a silicon-based solar cell. Achieving faultlessly blended electronic pastes was crucial to their purpose.

A study exploring the fabrication of 3D printed capacitive sensors was published in Sensors, an international peer-reviewed journal by MDPI. These types of sensors have typically been manufactured using carbon nanotubes (CNTs), due to their high electrical conductivity. However, CNTs can carry health risks, especially when used in a healthcare environment with sensitive individuals. In the study, several scientists experimented with different techniques to create flexible, thin, and elastic wearable sensors using carbon black (CB)/Ecoflex conductive ink instead. They used a Mazerustar KK-50S model planetary centrifugal mixer to homogenously disperse barium titanate (BaTiO3) particles into the conductive ink, with the goal of increasing the dielectric constant and sensitivity of the sensor. The scientists also added silicone oil to the blend, in order to thin the highly viscous mixture. The KK-50S model used in the study is not a vacuum model, but still produced well-blended and degassed 3D printing inks. To go a step further, a vacuum planetary centrifugal mixer eliminates bubbles at a submicron level, and can further refine the ink mixture when nanoparticles need to be blended into 3D printing ink.

Selective laser sintering is another additive manufacturing technique. With this type of 3D printing, a material (commonly powder polymer, resin or metal) is exposed to a laser. The heat of the laser fuses material together, creating a solid object based on a 3D model. Micropowders for laser sintering are typically blended with carbon nanopowder, and if the mixture is not homogenously blended then the final strength of the sintered product may not be acceptable. If the blend of the sintered powder is not optimal, the final 3D print will contain structural weaknesses. Using a planetary centrifugal mixer helps to produce optimal mixing results for 3D printing materials. Torrey Hills Technologies offers two lines of planetary centrifugal mixers: their own advanced SI-PM series, as well as Mazerustar paste mixer models.

Sources

  • https://www.mdpi.com/1424-8220/19/1/42/pdf
  • https://link.springer.com/article/10.1007/s11015-016-0183-0