Twin Shaft vs. Planetary Mixers: A Precaster’s Choice

When it comes to producing the highest-quality precast concrete for infrastructure or building projects, one of the most important choices a producer can make, begins before the process even begins:

“What kind of mixing technology will I rely on to get the job done?”

These days, precast producers and concrete producers as a whole can choose from a wide array of mixing technologies. There are many mixing options available and each offer different features and benefits. Understanding your mixing options to match the right technology early in the selection process, saves time, saves money, safeguards operational reliability, and ensures quality results.

Many of our precast producer clients gravitate toward two mixing technology solutions: twin shaft mixers and planetary mixers. The better choice for your project requires thought, from what properties you value most in your finished concrete product, to where you can maximize operational efficiencies, and ultimately what quality standards you desire for your poured and placed precast concrete.

Here’s a look at the benefits and strengths of both twin shaft and planetary mixers, and how a producer can determine which technology is best for their particular project.

Twin Shaft vs. Planetary Mixers: A Comparison

Critical to making the proper choice between planetary and twin shaft mixing technology for your next project is understanding the key differences and similarities between the two.

Twin Shaft – Horizontal Mixing At Its Most Powerful

Horizontal precast mixers have long been utilized as the standard mixer choice for precasters looking to maximize output while minimizing the total cost of ownership.

Often described as the “workhorse of concrete production,” twin-shaft horizontal mixers are highly regarded for their ability to handle low- to very-high volume concrete. Even with relatively complex structural designs, twin shaft mixers like the Simem MSO or MDC are able to produce a large output capacity range (1 yd3 – 12 yd3) at a low operational cost per cubic yard produced.

In addition, the relatively straightforward design of our twin shaft mixers allow for customizable configurations to accommodate specific recipe applications, producing optimized mixing results even for highly-specific production needs.

Many twin-shaft mixers are also designed to withstand consistent heavy use, often utilizing hydro-dynamic engineering and integrated oil cooling systems within the gearbox to keep the mixer running at optimal temperatures, helping to reduce wear and extend longevity. This, in addition to a relatively low up-front ownership cost, makes twin-shaft mixers the ideal choice for precasters focused on high-volume production for major precast projects.

Planetary Mixers – Precise and Efficient Production

Experienced precast producers know that every project brings its own unique needs and requirements. At times, a variety of precast products are needed for a job. When a variety of products are needed, product requirements will vary. When it comes to maximizing precision and versatility, there may be no mixing technology more suited than planetary mixers.

A departure from the standard race track rotation pattern utilized in the standard pan mixer, a planetary mixer instead moves a paddle through material in a rotating star pattern. By pairing this highly-efficient star-pattern motion with an optimized rotational speed, a planetary mixer can create a counter-current mixing action that is optimal for achieving a true homogeneous mix in a short mixing time.

The mixing shear achieved through this counter-current action is well suited for elegant mix designs. Additionally, the mixing action assists moisture control or the measuring of moisture, because the characteristics of a fully homogenized mix, allows for a truer moisture measurement. Additionally, the flat mixer tank bottom coupled with this counter-current paddle rotation, allows fresh mix material to pass over a measuring probe. Low mixing shear values in a short mixing time impacts mix consistency. This low shear mixing, may leave recipe materials not fully coated by water and cementitious material, which impacts moisture measurements.

While most planetary mixers do bring a higher up-front cost of ownership compared to twin shaft mixers, their durability and versatility (ease of mixing elegant mix designs-architectural colors/finishes) – often afford planetary mixers a lower total cost of ownership due to a planetary’s mixing efficiency. This makes a planetary mixer an ideal option for precasters focused specifically on consistency, precision, and mix design versatility for low to medium/high volume concrete output.

Our Experts Help Make The Choice Simple

When selecting the proper mixing technology for precast production, “walk in reverse.” Producers need to consider multiple variables and know their market opportunity. Aside from products and process, mixer and plant upgrade decisions should align with a business vision. Upgrading and selecting the right mixing technology improves competitive advantage and opens new opportunities to gain market share.

Our team of precast concrete production experts in North America are ready to help. Bringing a heritage of over 50 years of precast production experience to each customer, regardless of project size or complexity. Our team at Simem America specializes in creating the right solutions for precasters. If you’re looking to move your precast production forward on the best path possible, get in touch with our team and see how we can help guide you to the twin shaft, planetary, or other mixing technology that best suits your needs today, and tomorrow.