Grinding grit are a measurement of the size of abrasive particle on the grinding wheel. The size of the grinding grit will determine the amount of material that the grinding wheel will remove from the workpieces. If you use grinding grit that is coarse, it will remove a large amount of material quick.
However, it will also leave deep scratch on the workpiece. If you use grinding grit that is fine, it will remove very little material. However, it will leave a smooth surface on the workpiece.
How to Choose the Right Grinding Grit
Grinding use a sequence of grit sizes to go from rough to smooth finish on the workpiece. Low grit number mean that the particles are large. Coarse grinding use large particles to remove metal quick.
High grit numbers mean that the particles are small. Fine grinding use small particles to create a smooth finish on the workpiece. It is important to not skip any grit numbers in the sequence.
If you skip grit numbers, then the fine grinding will not be able to remove the deep scratches that the coarse grinding created. Coarse grinding is used for removing large amount of metal from workpieces. It is often used for welding and removing scale from metal forgings.
The downside of using coarse grinding is that it create a great amount of friction. This heat can be damaging to heat sensitive metals such as titanium. Medium grinding is used for general work on metal part.
For instance, medium grinding will allow you to shape your steel parts without overheating them. The correct grit for your workpiece will depend on the size of the grit, the metal you are working with, and the type of grinding operation you will perform. The correct abrasive will also extend the life of your grinding wheel.
For example, if you are working with steel parts, use aluminum oxide rather than silicon carbide. The size of the grit particle will determine the rate at which your grinding wheel will remove the metal from your workpiece. For example, grit 8 is a very large grit size and will carve into your metal.
Grit 400 is a very fine grit size and will slice into the metal very smooth. The higher the grit number, the less the grinding wheel will remove. Coarse grinding grits should of be use at the beginning of your grinding process and fine grits should be used at the end.
If you use the wrong type of grit for the grinding operation, the grinding wheel will either experience glazing or loading. The different types of grinding operations requires different types of grit sizes for the best results. Rough grinding operations will use coarse grits to remove the metal from the cast iron billets.
Finish grinding operations will use finer grits to polish the metal parts. Precision grinding operations will use the finest grits to remove metal from parts that must have very precise measurement. For example, if you are grinding gear, you will need precision grinding.
You can follow a sequence of grinding grit sizes to ensure good results. For example, follow a sequence of 36 grit to 60 grit to 80 grit to 220 grit for a superfinish. If you do not follow the correct grit size sequence, you may have to spend more time fixing the error than if you followed the sequence properly.
The type of abrasive material that you use will depend on the metal part you are grinding. For example, silicon carbide grinding wheel are used on non-ferrous metals and ceramics. The crystals that make up the silicon carbide is brittle and will snap to create new edge to cut the metal.
Aluminum oxide grinding wheels are used on metals like steel. Aluminum oxide is a very tough material. For the hardest metals, you can use superabrasives like diamond or cubic boron nitride.
However, do not use diamond grinding wheels on ferrous metals because the diamond will chemically react with the iron in the metal parts. Different grit size use different number standards. For example, the FEPA and ANSI grit standards is similar to each other but not to the JIS standard.
You can find a conversion table of these different grit standards so that you can order the correct grinding wheel for your metal parts operations. When using the correct grit sizes and abrasive material, you can expect good results from your grinding operations and efficient production processes.
