When machined, parts are bound to have burrs, no matter how advanced and sophisticated equipment is used. A burr is a kind of excess metal shavings produced on the machined edge of the material being machined, mainly due to the plastic deformation of the material, especially the material with better ductility or toughness. Burrs not only affect the aesthetics of the part, but also reduce the function and safety of the part. Therefore, deburring is essential in CNC machining.
Metal parts processing goes through a series of steps in the manufacturing process, such as stamping, milling, etc. These processes are designed to form the machined part into the desired shape, but when machined, the surface is left with small metal bumps, known as burrs. Drilling, engraving, turning and other machining processes can also leave burrs on metal surfaces.
The main types of burrs
Flip burrs are the most common type of burrs and they look like small curled pieces of metal sticking out of the workpiece.
Poisson burrs occur when the edge of the workpiece is stretched too much laterally.
The separation burr is characterized by an upward protrusion and appears to be separated from the workpiece.
How to remove metal burrs?
Deburring is relatively easy with the right tools and techniques. Deburring can take several different forms, depending on the metal and application involved.
Manual deburring is the most common and economical method of deburring. In manual deburring, experienced technicians use simple tools to manually scrape and polish burrs on metal parts. Although this process is simple, it can be time-consuming and inefficient.
In addition, complex cross holes are difficult to remove manually. Manual deburring is suitable for products with few burrs, simple product structure, and low technical requirements for operators.
Use mechanical scraping to remove burrs. This method is more expensive, but more effective than manual deburring, and is currently the most popular deburring method. Common mechanical deburring methods include grinding and rolling.
Electrochemical deburring is often used when small metal parts with burrs are well deburred by other methods. In addition, after using other deburring methods, some unprocessable areas also have burrs, this method can also be selected.
Electrochemical deburring uses electrodes of similar shape to the edge to be deburred. As the name suggests, it uses electricity and chemicals to remove burrs. Therefore, current and electrolytes are required for electrochemical deburring. Sodium chloride (table salt) or sodium nitrate can be used as electrolytes. Combined with current solutions, burrs can be removed without stress. This method is fast and provides high accuracy in difficult areas.
The electrolyte is corrosive to a certain extent, so after deburring, clean the workpiece and carry out anti-corrosion treatment. Electrolytic deburring is suitable for deburring hidden parts and intersecting holes of precision machined parts. The production efficiency is high, and the deburring time is generally several seconds to tens of seconds. This method is commonly used for deburring gears, splines, connecting rods, valve bodies, crankshaft oil passages, and for rounding sharp corners. The disadvantage is that the parts on the parts close to the burrs will also be electrolyzed, causing the surface to lose its original luster and even affect the dimensional accuracy.
Also known as thermal blast deburring and blast deburring. The combustible gas passes through the furnace of the equipment. Due to the action of the medium and conditions, the gas explodes instantly, and the energy generated by the explosion is used to dissolve and remove the burrs. Thermal deburring uses flammable gases to generate heat, primarily burning burrs on metal. This process is often ideal for removing the most difficult-to-reach burrs, such as cracks and crevice burrs, and for treating burrs on multiple surfaces simultaneously.
It’s important to know which deburring method is right for your part so you don’t further damage the part and waste time and money. When done right, deburring helps provide the smooth, flawless surface that cnc machined parts require.