Milling and grinding are crucial processes in material handling, each with unique roles in reducing raw bulk materials for various applications across industries. Understanding the nuanced differences between milling and grinding is essential for selecting the right equipment for specific applications.

Understanding the Difference Between Milling and Grinding 

Milling involves grinding into flour, meal, or powder, as seen in the process of milling corn into meal and barley into breakfast cereal. It can also include hulling, which removes the bran and husk of a seed. 

On the other hand, grinding specifically refers to reducing something to powder or small fragments through friction, like grinding coffee beans for espresso. 

While there is overlap between milling and grinding in particle size reduction, milling is a broader term that encompasses various processes, including grinding, which focuses on reducing particles to fine powder or small fragments. Learn more about particle size reduction for your application by downloading our Particle Size Chart.

Key Differences

Before understanding the key differences between milling and grinding within a material handling context, let’s look at one basic similarity. Both milling and grinding involve reducing raw bulk materials mechanically to make them more manageable, with both used in many of the same industries, though for different applications. These milling and grinding processes use powerful machines like crushers, grinders, and various types of mills for production in various industries, including agriculture, animal feed, chemical processing, food processing, mineral processing, and pharmaceutical manufacturing.

However, the milling process is more all-encompassing, involving shearing, grinding, cutting, or crushing, with the exact action dependent on the material, machine, and application. The agricultural, construction, mining, and many other industrial sectors rely on milling, which helps with processing, transporting, and conveying bulk materials more efficiently. 

Prater Case Studies: The Difference Between Milling and Grinding Equipment

Let’s look at the essential difference between milling and grinding equipment. We’ll consider two cases in which Prater Industries was approached to resolve production issues involving particle size reduction by two manufacturers. In the first case, we’ll look at a producer of grass seed; in the second anecdote, we’ll look at a pet food maker.

Grass Seed Production

The grass seed producer sought to fulfill orders for its specialty grass dust that augmented grass growing. With a solid reputation built over several decades, they reached out to Prater to find ways to improve their product, especially regarding its consistency. The solution included a system for unloading bulk bags, followed by a system for feeding and blending nutrient formulations. One of Prater’s fine grinders was used for grinding operations, with a control system that automated the process. The project included technical drawings of the various systems and how equipment fit into them. The result was a system that worked without trouble while saving both space and expense.

Pet Food Manufacturing

The second case involved a well-known branded pet food maker in the US retail market. They had been using Prater’s M-series Fine Grinder but found that the machine’s grinding jaws were wearing out in half the expected three-month period. Increased part wear and changes to the flow system and raw materials used were determined to be the causes of these issues. Approaching Prater’s engineering team, they looked at ways to increase the grinder’s jaw life. Prater’s engineers understood that a stronger material was needed to improve processing with the fine grinder. This involved finding a harder material that could be machined to the same precise tolerances without deforming. A new material was found for the grinder, which resulted in the grinder’s jaw lasting four months, a month longer than originally expected, while also lowering the annual cost of jaw replacement to the company by 17 percent.  

Conclusion

In summary, the initial case examines the grass production process holistically, whereas the latter delves into the intricacies of the grinder utilized by the pet food manufacturer. Both scenarios featured Prater fine grinders; however, the former focused on constructing a complete milling system, while the latter honed in on the grinding process. Despite these distinctions, Prater engineers adeptly resolved the issues in both instances. Having delineated the variances between milling and grinding operations, let's explore additional particle size reduction equipment beyond Prater's fine grinders.

Milling and Grinding Equipment from Prater

For companies who need assistance in choosing the best equipment for an application, Prater provides an easy-to-use recommendation tool that helps manufacturers choose the best machine for an application. While Prater makes many different types of equipment for operations requiring particle size reduction, let’s take a look at Prater’s hammer mills, a product that the company has been making for nearly a century, and Prater’s signature Rotormill, a long gap mill made by Prater’s subsidiary IPEC.

  • IPEC Rotormill: This machine’s capabilities reduce processing time, as it allows certain processes like surface coating and deagglomeration to be done simultaneously. Able to handle materials that are abrasive and less friable, unlike classifying mills or fine grinders, it offers manufacturers the ability to achieve higher throughputs while continuously producing finely milled materials that can handle an extensive range.  
  • Prater Full-Screen Hammer Mill: Used for operations requiring uniform particle size distribution, operating efficiency, and high throughputs, Prater’s full-screen hammer mill’s design augments product quality, as it also extends the unit’s lifespan. This hammer mill works well for recycling, granulating most material, and conditioning blended material that’s also agglomerated.  
  • Prater Mega Hammer Mill: The Mega Hammer Mill offers manufacturers a particle size reduction solution that falls between Prater’s more conventional full-screen hammer mill and fine grinders from the case studies above. As Prater’s Mega Mill performs with only minimal build-up of heat, it can run more efficiently and with the need for less airflow. With a unique grinding rotor, the machine works more quietly, while the Mega Mill can run continuously with less maintenance, nominal power requirements, and more uptime.  

In addition to these and other milling and grinding machines, Prater’s engineers can create customized solutions for a customer’s application. Contact one of Prater's knowledgeable representatives today to learn more about the difference between milling and grinding, along with the best equipment to use for specific applications.