Most research and development (R&D) is done on a small scale to limit expense. Therefore, it’s not surprising that equipment for testing materials and processes has significantly lower throughputs than those used for largescale production. R&D testing often requires multiple trials to configure equipment properly within operational parameters and establish how much horsepower is needed to produce a certain material output. Yet the machinery also needs to suitably mimic real-world production, with small-scale milling and grinding machines reducing material in the same manner as those used on full-scale production lines.
Using Milling and Grinding Machines for R&D
Various equipment is used in research laboratories to develop and refine bulk powder products, with labs often needing to reduce this material via milling and grinding. Machines used in this process include various types of wet and dry mills, classifiers, and other apparatus to mix, disperse, classify and otherwise prepare material during small-scale test runs. Labs typically use both smaller machinery and less material to assess processes as well as to optimize product development and/or control quality.
Best R&D Milling and Grinding Machines
When choosing milling and grinding machines for research purposes, it’s important to employ those with characteristics that allow labs to reduce the material to its desired size effectively.
To achieve this, milling and grinding machines need to have the following properties:
- Cleanability: The easier a lab mill is to disassemble and clean, the more efficiently and quickly the lab can conduct product changeovers. For any lab experiment, it’s essential to maintain equipment cleanliness to prevent cross-contamination, especially between test runs involving different materials or processes. Implements like quick-release clamps, internal components that easily slide out, and proper sealing in zones where material is processed ensure greater efficiency and reduce downtime.
- Durability: Tougher and better-built milling and grinding machines will fail less often, resulting in less unplanned downtime due to breakdowns and decreased upkeep costs. Equipment should last years without requiring extensive maintenance, which requires that it be properly designed for the materials that it’s expected to process.
- Efficiency: For smaller scale lab processing, material may be expensive or difficult to produce, so ensuring recovery of sufficient amounts for evaluation makes sense. Ideally, lab mills should recover at least 95 percent of material after processing. Achieving these high yields for milling and grinding machines in laboratories entails minimizing the amount of material accumulating within equipment during processing. For this reason, special venting designs that prevent material from escaping should be incorporated into lab milling equipment.
- Flexibility and versatility: Reduction equipment used in labs should have capabilities beyond a single grinding or milling mechanism. Ideally, such lab equipment should combine technologies to enable impact, jet, or media milling, along with classification or mixing capabilities. For example, when testing the effects of impact milling, it’s necessary to use equipment that uses grinding principles like attrition, compression, impact, and shear to produce varied particle size distributions in the material being evaluated.
- Scalability: While generally used for smaller quantities, it’s important to examine how scaling up or down will affect particle size distribution and the rate of throughput. Therefore, labs need to assess how greater or lesser amounts of material affect milling and grinding machines and their output.
Milling and Grinding Machines for Food Processing
Scientists in the food processing industry often utilize milling and grinding machines to develop foods and ingredients for production. These must meet high standards to pass federal food safety inspections, while also giving manufacturers a means to explore different technologies and processes to commercialize food products.
One key area within the food industry that’s trending is a market for processed plant proteins, with food processors continuing to explore ways to incorporate plant proteins into a variety of foods. These products include foods like chickpeas (also known as garbanzo beans), dried peas, and lentils. Plants like these, known as pulses, have become particularly desirable, as they’re both vegetarian and gluten-free.
Determining Horsepower for Milling and Grinding Machines
Another piece of the R&D puzzle involves determining the amount of power necessary to reduce a certain amount of material over a specific time period. Say, for example, test results show that a 10-horsepower machine results in a production rate of 800 pounds of material per hour. By dividing 800 by 10, it’s determined that for each unit of horsepower, 80 pounds of material per hour are produced.
From this, it’s then possible to extrapolate the needed horsepower for milling and grinding machines when dealing with much larger amounts. For example, if the required capacity were 12 thousand pounds per hour, a machine would require 150 horsepower, whereas if the capacity required was 16 thousand pounds hourly, a 200-horsepower machine would be necessary.
Classifying, Milling, and Grinding Machines for Laboratories
Before putting in place milling and grinding machinery for production, it’s important to research the best processes and equipment to achieve material reduction with the desired particle size distribution and other properties. Choosing the right milling and grinding machines depends on the application, for which the needed particle sizes may vary considerably. Air classifying mills work best for materials that aren’t as friable and those that are difficult to grind or have narrow particle distribution requirements. One of the best pieces of equipment for lab work is a miniaturized air classifying mill, which can achieve tight particle size distribution of the processed material.
Features of these fine-grinding machines should include:
- Milling head uses two-stage reduction capabilities to ensure tight particle size in a bell-curved shape distribution.
- Product feeder provides a design for easy material flow, ensuring continuous feed of material of materials with varying properties.
- Control panel that’s user-friendly and incorporates a collection of features that make it simple to use, including a variable frequency drive (VFD) for adjusting various mill parameters; the control panel should also house many important components that can be removed easily to allow easy cleaning and maintenance.
- Product collector that’s easily cleaned and highly efficient with a system that filters out unwanted particulates.
The raw material is fed first into a chamber where particles are reduced by rotating blades that cause a vortex flow pattern to take place. In the chamber, particles are reduced via a method called impact attrition. The material then flows towards the classifying rotor, with larger particles returning to the grinding chamber. The machine uses centrifugal force throughout processing to direct material where it belongs and then discharge it from the grinding chamber into a collection bin.
Prater Mini-Split Air Classifier
Prater Industries makes a mini-split air classifier that’s primarily utilized for laboratory research and other small-scale applications. The classifier fits well in smaller workspaces, with a compact size that gives it portability and noise reduction capabilities. Prater’s mini-split air classifier features a robust design that allows it to be used for small production runs while also flexible enough for use in lab research.
Features of Prater’s mini-split air classifier include:
- An operating range for particle reduction from 1-75 microns
- Components made from stainless steel
- Easily disassembled
- Feed rate of 1-75 kg (about 2.2-165lbs.) per hour
- High throughput
- Narrow size distribution
- Versatile and robust design made to prevent vibrations
Prater’s mini-split classifier’s contact parts are made of easy-to-clean stainless steel, helping reduce downtime and prevent unplanned maintenance while also extending the machine’s operational life. The machine can easily convert to an opposed jet fluid energy micronizing system that includes an integral classifier. With suction capabilities, these machines promote an environment free of dust. Meanwhile, it can also adjust capacity to feed finished product into bins at different rates to meet specific R&D or production needs.
