by Blake SandnesRMS builds and services quality roller mills for many different applications. For those just learning about roller mill grinders, we want to remove the fear of making the wrong decision. We are committed to educating and working with our customers to help them find the right solution.
Some commonly asked questions are about the differences between a roller mill vs. a hammer mill. Specifically, people regularly ask us questions about hammer mill advantages and disadvantages in operations, energy efficiency, and maintenance.
To help those who are actively researching this topic, we’d like to provide a brief overview of some of these four frequently asked questions:
- What’s the difference between a roller mill vs. a hammer mill?
- What are some common roller mill uses and benefits?
- Which industries and applications typically use roller mills?
- What’s the maintenance like for a roller mill vs. a hammer mill?
1. What’s the difference between a Roller Mill vs. a Hammer Mill?
A hammer mill acts like the name implies by milling grain in a smashing motion. So if you took a kernel of corn and smashed it, you will have pieces with a variation in size.
A roller mill acts more like a cutting knife. As a roller spins, it creates a shearing effect. Roller mill particle size generally sees lower variance than from hammer mills, which results in a more consistent grind.
Hammer mills also use different screen sizes to adjust the particle size for either a coarser or finer grain. Often, they have to shut down their entire mill to change a screen.
Roller mills can alter the grind by changing the roll position. So if you want to achieve a finer grind, you can simply move the rolls in. If you’re looking for a coarser grind, you’ll do the exact opposite and back the rolls out.
Which one is better?
Target particle size is a leading factor in determining if a roller mill vs. a hammer mill is better for your application. Also, if the material has high moisture, then a roller mill is better. With a hammer mill, you run the risk of the temperature of the product rising as it runs through the machine, which can lead to plugging and an increased risk of fires.
If a coarser particle size is desired (which can positively affect animal health), a roller mill can generate coarser particle sizes at a much higher consistency. Especially now that the cost of corn is going up, it is essential to have consistency. The pulverizing motion of a hammer mill often leads to more waste in the form of “fines” than grinding with a roller mill.
2. What are some common roller mill uses and benefits?
The function of a roller mill
Simply put, roller mills are used for particle size reduction. They take raw material, and reduce it into a finished, final product size. More specifically, they are used to execute quality and consistent particle reduction in non-fibrous materials such as grains, fertilizers, coffee beans, and other biomasses.
The consistency of a roller mill
One key benefit of a roller mill is its ability to produce a more consistent grind profile. Due to how it grinds, all the particles are ground up with greater consistency. Another main benefit to a roller mill vs. a hammer mill is that it uses substantially less energy. The roller milling process does not produce excess heat and other energy-consuming effects like hammer milling does.
The energy efficiency of a roller mill
Energy efficiency is becoming a top priority for many mill owners, and roller mills are typically around 25 to 30% more energy efficient than their hammer mill counterparts. Unlike a hammer mill, a roller mill doesn’t require an air assist system to pull material through the filtering screens. With a hammer mill, a lot of extra electricity is needed to help pull that material through. That electricity usage translates into increased expenses.
3. Which industries and applications typically use roller mills?
Agriculture– This industry is the main user of roller mills. Integrators and toll mills who feed cows, chickens, and hogs are implementing roller mills because roller mills are an efficient way to achieve different sized grain particles for the different animals’ needs.
Breweries & Distilleries – These industries depend on a consistent grind profile for the different grains they use to create their products. Because of their reputation for a consistent grind, roller mills are becoming increasingly popular for breweries and distilleries in the United States and overseas.
Fertilizers – Many companies and farms on the west coast are looking to reduce the amount of unabsorbed materials in their products to create a more even application. They need a consistent, fine grind to increase absorption rate into the water because they’re looking to spray the liquid through a fertilizing unit. A better grind not only allows for better coverage, it also prevents blocking in the application units.
Coffee – Some businesses in the coffee industry have been employing roller mills to grind up coffee beans for larger companies. For those businesses, the coffee grounds must be a consistent grind, and the roller mill is an optimal way for them to do that.
Biomass – This is a newer industry integrating roller mills. One example is biochar. This is used as a fertilizer and as a filter to clean out contaminants in water sources and other applications. Biochar comes from wood that’s been burned in a vacuum chamber. Often, this wood has to be sized at a consistent output before it can be utilized.
4. What’s the maintenance like for a roller mill vs. a hammer mill?
Both roller mills and hammer mills use tooling to reduce the particle size. Like most tools over time, the hammers used in a hammer mill will wear out and will need to be replaced. Roller mills use corrugated rollers to reduce the particle size. Those also will become dull over time. How often the rollers will need to be replaced depends on the target particle size, how often the machines are running, and the cleanliness of the grain or product.
Obviously, foreign materials such as rocks, cobs, and stalks will tend to reduce the life expectancy of the rollers. But when the rolls become dull, they can be easily taken out and replaced with sharp ones.
In recent years, to help alleviate some of those costs with replacing and sharpening, RMS has been offering a comprehensive service program to qualified customers.
Are you interested in learning more about roller mills?
We have an experienced sales and research and development team that are always ready to help you in any way we can. We are here to answer your questions about a roller mill vs. a hammer mill. Or, if you’re just curious about what your day-to-day process with a roller mill might look like, we can give you insight into that.
If you would like to learn more about the advantages of a roller mill vs. a hammer mill, please contact us.
