What’s the difference between Shredding, Grinding, and Granulating?
Often, the terms grinder, shredder, and granulator are used interchangeably. So what is the difference and why does it matter? Perhaps the best way to approach this is to answer the “why does it matter?” question first. Buying a shredder when you really needed a grinder, or visa-versa, size reduction machines could cost you lacs in the purchase of a machine that just will not work for your application, or will not provide the production rates that your processing requires. There’s no room for mistakes. An expert analysis of your application can save you lots of money on equipment purchases. With that in mind, let’s help you determine what you really need.
The full answer to this question is a bit more annalytical, basically depending on three basic factors;
1) What is the material ?
2) How much do you want to reduce per hour
3) What kind (size) do you want it reduced to?
These three factors will determine whether your money is best invested in a shredder, a grinder, or a granulator – or perhaps even a combination of two or more machines.
Thus it ia always prudent to do some research maybe contact multiple vendors, manufacturers surf on the net or speak with an experienced user to begin the decision making process.
Let’s start with your material… Is it plastic, paper, rubber, PVC, MSW, C&D, medical waste, or something else? Next, determine what you want to do with it. Do you need it reduced to larger pieces, say 2” in size or do you need it reduced to something smaller; lets say – 3/8” or smaller. Those are the primary questions you will need to answer to determine the machine you will need. However; with a few simple guidelines, you should be able to determine it from the following:
So, you think you may need a “shredder” – but what does shredding actually do. Shredding is normally carried out in a machine that is “low speed and high torque”. A shredder is designed to take large components and shred them down to random, smaller components – normally in the range of 1” – 2” and larger. Most often, a shredder is selected if you want to do any of the following:
Reduce a product down for compacting to save on expensive Indian real estate!
Reduction of items such as tires to larger chips for fuel, recycling, etc…
The reduction of paper or confidential documents to pieces unrecognizable in regard to their former condition.
Reduction of plastics for washing
Destruction of product containing proprietory literature thus negating of liability issues
Or the preparation of the product for another application.
The above is not all inclusive of course, but it does comprise the most common applications for shredding.
While we often interchange the terms “shredding” and “grinding“, the actual process and the end product yielded, could not be further apart. Grinding, most simplistically stated, is the shaving, chipping or “grinding” of small pieces off of a larger piece. Or in the case of size reduction, grinding off small pieces until the original part is in thousands of smaller consistent chips, usually less than 1/4? to 1/2”.
So, what applications are best for grinding? There are many…
Grinding large rejected parts back to smaller chips that can then be recycled into making more parts.
Reducing larger raw materials to chips that can be mixed with other compounds to make new components.
Reducing organic materials for bio-fuels production.
Grinding carpet and other textiles for fiber reclamation.
Essentially, grinding is an application used to take any larger raw or rejected material and process it in the grinder to obtain a small enough particle, chip or fiber suitable for the manufacturing of other components parts. The best example being to grind a raw or rejected piece of rubber or plastic so it can be used to make things like bottles, tires, or those hundreds of recycled plastic products that we see commonly all around. To get a better idea of how a grinder works, you can check out some grinder videos on you tube to see a rubber grinder and plastic grinder in action.
Granulators are perhaps the most commonly confused machines with grinders, as they essentially do the same thing; they take larger components and make them smaller. Perhaps the best way to know if you need a granulator is to determine how small you want your discharged component to be. Granulators have the ability to reduce certain materials to a much smaller particle size than a grinder. The reason for this is that a granulator differs in design significantly from a grinder in the following ways:
Most all granulators have an “open rotor” design. This means that there is a great deal of air space around the rotor for product agitation and cooling. The open rotor allows for better processing of lighter materials that would not be well suited for a closed rotor design.
Many Grinders on the other hand, especially the type of grinders that have closed rotor designs, meaning the rotor is closed have high speeds and very tight tolerances. These type rotors leave little room for the product being process to go anywhere other than across the cutting edges.
There are advantages to both designs mentioned above, but simply put; each design is more applicable to specific products.
A granulator, with an open rotor type design, is normally more applicable in taking small components in the ½” to 6” or 8” sizes and reducing them to much smaller chips than a grinder would be used to do. Often in the range of producing 8mm flake to even powders.
Granulators are often used as an after process for materials that have been size reduced previously.
Granulators are well suited for lighter materials such as plastic bottles which do not grind well in a closed rotor design unit.
All of this is a large amount of information to consider when selecting the proper machine for your size reduction needs. And often, so many products can cross over from one machine to the next. In considering your needs, the best way to determine your needs is to answer the following questions:
What material am I trying to reduce?
What is the size of the material that will be fed into the size reduction unit?
How much per hour will I need to do?
How small do I want the final product to be?
So i hope I've given you a fair idea of these machines, to help you choose for a start, grinder vs shredder vs granulator?
please feel free to call - 91-22-23775521 / 2375 5521 if you want to discuss your requirement or email - firstname.lastname@example.org Once you have answered these questions, i shall be glad to assist and maybe colaborate on your project and help you determine the machinery for your project.
I am Shabbir...
Hi , I am trying to help you understand industrial shredders, their applications and help you to make a proper choice of machine to give you maximum value from this costly capital expenditure.