5 Tips for Choosing the Ideal Abrasive for Metal Fabrication

There are a few standard best practices that every welding or metal fabrication operator must be aware of while performing polishing and grinding operations. Even before an operator touches a workpiece, he or she must consider a few factors such as appropriate mounting of abrasives, usage of guards, safety gear, use of correct product for the job, spark control, correct speed (RPM), and ergonomics. Abrasives have been in great demand due to their applications.

Abrasives are an extremely important material that are used in grinding, deburring, and finishing of the product. The ideal selection of abrasives is highly imperative to attain a healthier appearance of the product.

In spite of abrasives being a critically important material for any machine workshop, they are usually overlooked. It is important that a welding or metal fabrication operator should select the right abrasive, as it can reduce the cost and give better outcome. Inappropriate weld knowledge, prolonged deburring operations, surface finishes that fail to meet drawing specifications—are the consequences of using the inappropriate abrasive.

However, as thousands of options are available in the market for choosing the best pad, belt, cloth or wheel for this highly important metal removal process, selecting an abrasive can be as extremely challenging. Also, as deburring and polishing are usually the last part of the whole process for various workpieces, using an incorrect abrasive can be a highly expensive mistake.

Here are 5 tips that can help you choose the best abrasive.

1. Work material that needs to be grounded

Abrasive should be chosen based on the type of material to be grounded. The most usually used abrasive is made up of aluminum oxide (Al203) or silicon carbide (SiC). Silicon carbide is ideally suitable for fragile and rigid materials such as hard steels, tungsten carbides, stones, and other porcelain materials.

Aluminum oxide is an ideal choice, if the object produced is built with hard materials and has better tensile strength like tough bronze, alloy steel, mild steel, annealed malleable iron, etc.

Hence, one should choose an abrasive as per the material of the workpiece.

2. Degree of stock removal

Quick removal of metal is essential to finish the workpiece in less time duration. The degree of stock removal completely depends on grade, grain size, and structure of abrasives.

GRADES: Rigid materials possess enhanced resistance to the wheel at the time of grinding. Such materials are tough for the wheel to grind, and thus weaken the wheel and results in inefficient grinding. In case of metals having greater strength, it is ideal to use an abrasive of which particles break easily, thus allowing the wheel to shape the workpiece efficiently.  

In case of softer materials, an abrasive having high-quality bond is suggested.

GRAIN SIZE: It is detected by the mesh number that is maintained even after passing through a vibrating strainer. Usually, in case of softer materials, an abrasive having coarse grain size is ideal; and in case of harder materials, fine grain is suggested.

STRUCTURE: It is the cavity between the abrasive and workpiece. For harder materials, an abrasive having dense structure is necessary. And in case of softer materials, an abrasive having open structure is optional as the degree of metal removal is high and the size of the chip is also large.

3. Area of contact between wheel & workpiece

If the area of contact is big, the whole grinding pressure is circulated across a huge area. The pressure per unit automatically reduces. Therefore, a softer wheel is required in cases where the curvature of contact is more. Moreover, a harder wheel is an ideal choice in case of external grinding.

4. Grinding machine’s condition

The abrasives used should be in a good condition; there must be no scratches or cuts on it. For a long-lasting grinding machine, purchase abrasives as per the machine. If the machine is heavyweight and tough, it is ideal to use a soft grade abrasive. On the other hand, in case of lightweight machines, it is ideal to use a hard grade abrasive.

5. Work Speed and Wheel Speed

In the process of grinding, 70% of the issues take place owing to the incorrect selection of work speed as well as wheel speed. If the surface of the workpiece is burnt, the speed of the wheel can get reduced. The speed of the wheel is dependent on the type of process such as internal grinding, external grinding or parting off operation. Work speed depends on the type of finish required for that particular workpiece. For greater work speed, a harder wheel is required.

Other aspects that are needed to be deliberated while choosing an ideal abrasive are revolutions per minute, the period it takes to finish the job, cost, user-friendliness, and others.

The Bottom Line

After going through all these tips for choosing an abrasive, one can easily figure out the ideal abrasive for any workpiece. So, if you are a welding or metal fabrication operator planning to purchase an abrasive you should take care of all these factors, and choose the best that suits your needs.

About the Author(s)

   

Aishwarya Korgaonkar

Aishwarya Korgaonkar holds a bachelor’s degree in Information Technology from the esteemed Mumbai University. Being creative and artistic, she leaped into the field of digital marketing and content writing. Her love for words makes her write creative, and her spellbinding content adds colors to the world.