When deciding on the right industrial brake for your application, it’s important to know the advantages and disadvantages of drum brakes vs disc brakes. However, the answer can be a bit complicated because you can often find both types of brakes being used in the same application! In this article, we take a deep dive into the major differences between the two so you can choose the brake best-suited to your application.
Maximum Brake Torque and Clamping Forces
A major difference between drum brakes vs disc brakes is that disc brakes have a significantly higher maximum brake torque. Due to drum size limitations and the mass moment of inertia for heavier drums, drum brakes are generally better-suited to lower torque applications.
Another major point to consider when deciding between industrial disc brakes vs drum brakes is the higher clamping force offered by disc brakes. It’s this clamping ability that makes industrial disc brakes ideal for grinding mills in mining operations or projects with overland conveyors that require long stops. In fact, for large scale mining operations, Johnson Industries manufactures a range of massive disc brakes with 800,000 lbf clamping force for grinding mills —a level of force that an industrial drum brake can’t match.
Ease of Burnishing
Burnishing a brake lining surface to a drum or disc surface is crucial to ensure the maximum coefficient of friction is achieved. On a microscopic level, there are peaks and valleys between materials which, when burnished correctly, are virtually smoothed off thus creating a higher contact area and overall higher coefficient of friction. In this regard, disc brakes once again have a distinct advantage thanks to being able to clamp to a flat surface which provides better lining contact. By comparison, the lining curvature of an industrial drum brake can make burnishing a bit more challenging as the surfaces take much longer to achieve the smoothness and overall mutual contact resulting in the best possible coefficient of friction.
A unique advantage that industrial drum brakes have compared to disc brakes is that their design facilitates a ‘balanced load’ by having equal pressure applied to each side of the drum mounted on a drive shaft. This is in contrast to disc brakes where one side of the disc can cause a slight torsional pull on the shaft and offset the load on the bearings. This can be rectified by using two disc brakes or certain specialty brakes—but a single drum brake can provide a more affordable option.
Industrial disc brakes are often mounted directly to the low speed / higher torque side of the gearbox in applications such as the discs bolted to a conveyor pulley or hoist drum flange. This mounting location is perfect for the higher maximum torque offered by disc brakes.
As for drum brakes, you can often find them mounted on the high-speed, lower torque side of the motor output shaft. Drum brakes excel in high-speed applications and are a great, cost-effective option for lower torque applications. Crane travel drives for portal cranes and hot ladle cranes in the steel industry use drums brakes and Variable Frequency Drives (VFD’s) to ensure an excellent level of control.
Finding the Right Brakes With Johnson Industries
If you need help deciding between drum brakes vs disc brakes for your application, don’t hesitate to reach out to Johnson Industries. With over 100 years of combined experience manufacturing brakes for the mining, ports, bridge, steel, crane, and oil industry, Johnson Industries would be happy to help you find the ideal industrial brake for your application.
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