Over many decades, the three roll mills have been utilized in multiple industries, from paint, food, and ink to industries like energy storage and electronics. In the industry of coatings, where small batches and different color changes are frequently required, a 3 roll mill becomes the perfect solution. For instance, coil coatings and bases for cans are often manufactured on three roll mills only. Moreover, it is the ideal solution for heat-sensitive systems such as UV-curable coatings as the mill has a big cooling surface and the best temperature control.
In the three roll mills, fine dispersing happen after pre-dispersion. The three roll mills require two or three passes to attain the needed coloristic properties or particle size. Its feeding is often done by the pumps or press-out systems. Cleanability is a major benefit of the three roll mills. On just one machine, it is possible to produce numerous small batches of various colors.
Advantageous features such as cleanability, defined stress, extremely small hold-ups, and no possible cross-contamination are still not repeated by other technologies. However, hydraulic systems, mechanical systems of roll pressing are not even comparable with the automated machines present these days.
The three roll mills are composed of basically three horizontally placed rolls that rotate in completely opposite directions at various speeds. The material which will be milled is then positioned between the center rolls and the feed. After that, the material is transferred from center rolls into the apron rolls, and this happens by adhesion.
Between the adjacent rolls, there are shear forces that produce dispersion. By reducing the distance present between the rolls, greater shear is produced. However, the distance reduction between rolls reduces the throughput. The gap settings with a range of nearly 0.001” are quite common.
Materials that are milled are taken out from an apron roll through the take-off knife. This cycle can also be repeated in order to enhance the dispersion or to reach the equilibrium of particle size. A three roll mill technology with low throughput generally needs skilled operators, but it is the best method to prepare a dispersion of fine particles in inks, cosmetics, paints, dental composites, ointments, and several viscous materials.
There are also many advantages of the 3 roll mills, and some of them are given below.
· It produces fine particles which show better product quality. The three roll mills guarantee that the product will pass in both the shear zones.
· The controlled energy input can increase precise processing.
· Powder clumps and agglomerates break up and completely homogenize.
· It generates less heat than most mills.
· A 3 roll mill has very less loss of moisture.
· It has a good work environment as the machine noise level is low.
· The three roll mills are energy-saving or energy-efficient.
Certain Finest Practices for Efficient and Safe 3 Roll Milling
1. Take Proper Care:
The three roll mills usually come fully assembled when normally supplied. While removing it from the container of shipping, do take proper care and handle gently in order to prevent any damage that may happen in the rolls’ working surfaces. The damage-free roll surfaces are very important for the mills to function properly.
2. A Good Installation is Necessary:
Before getting the mill to operate, it is important to make sure that it is bolted well in its place. Also, it requires a solid base, especially for the models of production size. When the 3 roll mill is properly leveled as well as bolted, installation of all electrical components then should be done. Moreover, ensure that it is done by a qualified electrician.
3. Take-off knife should be well handled:
The take-off knife of the apron has a sharp edge and needs to be handled carefully. When the knife is correctly positioned, it contacts the apron roll slightly above the line of center and remains parallel to it.
4. Never run the three roll mill dry:
It is essential to remember that one should not run a 3 roll mill dry. When all the product has run through, immediately open the roll and also disengage apron rolls.
5. Do testing to know the correct gap setting:
Test it for determining the best gap setting. It is important to have an ideal setting for a specific product to maximize the throughput while the dispersion quality is not compromised.
6. Avoid Loose Clothing Articles:
It is advised not to wear any loose clothing articles or accessories so that they will not get caught between the rolls.
7. Lubricate all the bearings:
Roll journals need to get equipped with roller bearing or ball. It is always better to lubricate all those bearings frequently or once a month.
A three roll mill remains as the finest method for preparing dispersions of fine particles in several elements like paint, cosmetics, pastes, and many more. Here are certain guidelines to determine whether your product fits as the three roll mills material.
· Flowable and viscous materials are perfect for a 3 roll mill. The majority of the applications are spilled in the region between the center rolls and feed. Very low viscosity can hamper the product from remaining on the surfaces of the roll.
· The materials need to be an element that has stickiness so that they can stick properly to the surfaces of the roll and transfer from a roll to another. Testing should be done to check the compatibility.
· Three roll mills cannot handle any solid or powder by themselves. Manufacturers add certain solvents to make the powder wet and ensure that it becomes suitable for milling.
The three roll mills are in higher demand due to their utilization in various industries as they have numerous advantages over others. New-generation and advanced three roll mills of Franli provide the greatest fineness that is necessary for several sectors. Moreover, the mills of the company have easy operation and safe cleaning. If you are looking for three roll mills, then it is the right place to go for.
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