Most metal cutting operations – take punching, shearing and die cutting, for example – leave behind unrefined edges that often require finishing steps. And that’s why metalworkers are tasked with the job of deburring those sharp edges to spec. The goal is to leave behind smooth, safe edges and do so in a timely manner.
Deburring sheet metal is an essential step in improving product aesthetics, but it is also employed to increase shop safety. One way to reduce cuts and injuries while handling sheet metal is to break sharp edges before forming or welding. In doing so, final workpieces will not only look good, they will also be safe to handle for fabricators and customers alike. Understandably, kitchen equipment can’t be installed with sharp edges exposed.
What is the best way to complete this deburring operation? One way is to dull the edges in one pass using an abrasive mounted point tool designed for the operation.
Not all deburring tools are equal. There are many to choose from, but to properly remove sharp edges, a long-lasting, easy-to-control tool is required. Traditionally, deburring is done with a file, but files can leave inconsistent results and often require multiple passes. Abrasive discs are also used, but they are often too aggressive for sheet metal.
Abrasive mounted points are great for deburring because they come in many sizes and shapes, from small points used to finish punched holes in sheet metal to larger points for edge breaking on sheet metal. They are typically used on handheld die grinders, which provides easy control resulting in consistent metal removal and fewer imperfections. Mounted points can operate in one pass, deburring the top and bottom edge at once.
Abrasive mounted points are available in a variety of materials, including cotton fiber and rubber, like those offered from Rex-Cut Abrasives. Cotton fiber mounted points accurately deburr and improve edge quality with minimal effort on ferrous and non-ferrous metal. Basically, the cotton fiber features a cushioning action due to the cotton construction. This makes it deburr and grind well, but not too aggressively whereby the part geometry becomes altered. It provides the operator a lot of control while removing metal.
Benefits of cotton fiber include even material removal, chatter-free operation, long life, non-loading on soft metals, and deburring and finishing in a single operation. Cotton fiber mounted points create rounded edges as opposed to chamfered when finishing edges. This rounded edge helps distribute pressure more evenly and is useful for precision parts used in high-stress applications.
Rubber mounted points are made with a formula combining aluminum oxide grain and calendar synthetic rubber, which has high tensile strength and is tear resistant. Other benefits include smooth operation and less chatter.
It’s important to remember that deburring is a delicate process. Using too hard of an abrasive substrate and applying aggressive pressure removes too much material, which distorts part geometry. Deburring lightly with a wheel that is too soft risks never removing the burr or needing multiple passes, which can be too time-consuming mid-production. That’s why it’s important to remember to choose a tool wisely beforehand. Matching the size, shape, composition and hardness of the abrasive, along with the right type of bond, to the application to remove metal with control leads to quantifiable results in the work.
To suit the variety of operations that fabricators perform, Rex-Cut offers three main bonds in cotton fiber. The softest is GFX that has a soft yet strong quality making it the choice for blending and light deburring. JTX is a medium-bond product for light to medium deburring with a longer life. The hardest bond is MTX, which is used for light and medium stock removal.
Rubber mounted points, which are best for light grinding and blending soft non-ferrous metals and stainless steel alike, are made from a synthetic that is a softer bond than natural rubber. Typically, they are used for edge breaking to remove sharp edges on sheet metal, deburring machined parts, as well as polishing metals to improve performance, appearance and cleanliness.
Communication is always the key to achieve best results, and deburring sheet metal is no exception to that rule. When deburring sheet metal in production, properly relaying the deburring specifications to employees is imperative, and that includes explaining how much metal to remove and how best to do it.
Setting expectations for deburring with instructions is a great place to start. Use phrases like “deburring not required,” “remove all visible burrs” or “remove all burrs visible at
4X magnification.” Without guidance, there is often a possibility of removing too much or too little material leaving parts that are out of spec. It’s better to ensure the team has the tools and training to perform quality work.
With the right tools – abrasive mounted points – and clear instructions, the deburring process is simple:
Step 1. Secure the sheet metal to prevent slipping.
Step 2. Use a grinder with the mounted point and simply run the point over the edge of the sheet metal.
Step 3. Repeat. Run the point over the other edges of the sheet metal to break those sharp edges. As the groove in the point wears, just move down the point to create a new groove, and so on.
For safety and aesthetic benefits, it’s always recommended to understand the tools involved in deburring as well as the best practices when using those tools. In the end, employees and end customers alike will appreciate the care taken in this sometimes underappreciated manufacturing process.