Powder mixing is common in companies across many industries, including pharmaceuticals, advanced materials, and chemical engineering. The powder mixing machine 's mixing step is crucial to many processes, with its primary goal being the achievement of uniform distribution of all components. While powder mixing may seem simple, it is usually complex.

Challenges in Powder

The main challenges in powder mixing machine are segregation and agglomeration, which are directly related to the flow properties and particle size of the powders in the mixture. Before delving into these issues, it is helpful to have a basic understanding of the flow properties of powders.

Characteristics of Powder Mixing

Based on flow properties, powders can be divided into two main categories:

(1) Free-flowing powders: Powders that do not stick together.

(2) Cohesive powders: Powders that stick to each other and form agglomerates, which cannot be well dispersed during the mixing process.

Several factors can affect the formation of agglomerates, such as moisture, static charge, and interparticle forces.

Furthermore, as the particle size decreases, the tendency of powders to bond increases; in other words, smaller particles tend to be more cohesive, while larger particles flow more freely.

How Dose Powder Segregation Occur?

Powder segregation (or demixing) is one of the biggest challenges in the powder mixing machine. Free-flowing powders are at a significantly higher risk of segregation compared to cohesive mixtures. Segregation typically occurs through one of three mechanisms: percolation, vibration, or conveyance.

Percolation happens when gravity pulls smaller particles into void spaces. This form of separation usually occurs when the powder mixture has a wide range of particle sizes.

Vibration occurs over time as smaller particles vibrate and move beneath larger ones. Similar to percolation, vibration primarily takes place when the powder mixing machine occurs and the mixed powder contains both large and small particles.

Conveyance arises from the collision of powder particles with each other during transportation. In many cases, larger particles tend to migrate toward the outside of the container, while smaller particles move closer to the center.

These scenarios can occur at any point during the mixing step, as well as during the transportation and storage of powder materials.

To prevent segregation, companies typically aim to minimize the time between the powder mixing machine 's mixing step and the next process, and implement special material handling procedures.

How Dose Powder Agglomeration Occur?

Agglomeration is another issue that frequently arises when mixing powders into cohesive mixtures. In cohesive powders, agglomerates are clumps of the powder mixture that, if not properly dispersed, can lead to uneven mixing within the container. In many cases, cohesive powder mixtures require grinding or sieving to break up these agglomerates. Additionally, larger powder particles can be dry-coated with smaller particles to reduce interparticle forces and the tendency for agglomeration to form.

Due to mixing intensity and mechanisms, traditional powder mixing methods used in powder mixing machine such as shear, diffusion, and convection are only effective for mixing certain types of powder mixtures. They are often very slow and inefficient, failing to achieve complete uniformity.

Moreover, these traditional methods generally cannot mix both free-flowing and cohesive powder mixtures simultaneously. Therefore, historically, the selection of mixing technology in the powder mixing machine has depended on the specific powder properties of the particular mixture, including flow characteristics and particle size.

How to Achieve Uniform Powder Mixing?

Resonant mixing systems have revolutionized the landscape of powder mixing. They can mix powders more uniformly and rapidly than any other mixers, earning them the reputation as the most exceptional powder mixing systems to date.

Typically, Resonant Mixing Technology (RAM for short) can thoroughly mix powders of almost any size, material property, or morphology—including both free-flowing and cohesive powders—in just 30 seconds. RAM high-viscosity powder mixing machine can easily handle cohesive materials and pastes that are beyond the capability of other mixers. Viscosity, a measure of a fluid's resistance to flow, is expressed in centipoise (cP) and is one of the properties that influence the difficulty of achieving uniformity in a mixture.

Low-viscosity substances (such as water and other liquids) have lower resistance and flow more quickly. The viscosity of water is 1 centipoise (cP).

High-viscosity substances (such as honey or tar) are less deformable and flow more slowly. The viscosity of honey ranges from 2,000 to 10,000 cP. Some high-viscosity substances can even reach viscosities as high as hundreds of millions of centipoise.

Pastes and high-viscosity mixtures consist of solids in a liquid matrix. The less liquid in the matrix, the higher the viscosity—up to hundreds of millions of centipoise—resulting in an appearance and behavior that are closer to solids.

Finding a high-viscosity powder mixing machine that operates quickly and achieves uniform mixing was once nearly impossible... until now.

Resonant Mixing

Resonant mixing can easily blend high-viscosity materials with a speed and uniformity that traditional powder mixing machine cannot match. RAM high-viscosity mixers utilize acoustic energy to rapidly and uniformly achieve wetting, incorporation, and extensive mixing throughout the entire matrix. RAM accelerates these processes by inducing Faraday instability—a phenomenon where invasive "fingers" form at the boundaries of materials with different densities, combined with encapsulating "cavities". Through rapid wetting, incorporation, and mixing, RAM is capable of achieving highly uniform, higher-viscosity results at a much faster rate than traditional technologies.