Sintering Bronze Parts for Bearing and Bushings
Sintering is achieved by creating one solid product from powder. This process is based on atomic diffusion and occurs fastest at high temperatures. First, the power is placed into a mold or shape and is then heated. When the heat is applied to the powder in the mold the temperature remains under the materials melting point. From there the power particles diffuse across the boundaries and the particles, causing them to fuse together, thus, finally forming one solid piece or product. Sintering is advantageous to many products and parts, being able to be created in a highly controlled manner. Through this controlled environment uniform porosity can be created and maintained. In order for sintering to be successful high purity materials must be used. Sometimes powder will escape the mold in the process. If this happens the powder is collected to be used again. This helps with little wasted material.
Photo Courtesy of SMC Powder Metallurgy, Inc.
The process of sintering parts has been around for many years and as a result, a number of applications have become widely used to create products. A common alloy used in this process is bronze. Bronze is widely used because of its porosity allows lubricants to be impregnated into it making bronze ideal for bearings and bushings. Self lubricating or also called oil impregnated bearings and bushings have proved useful in a number of industries. By having self lubricating bearings and bushings minimal maintenance is required. This is beneficial for cheaper cost and will maximize the longevity of the products that have these bushing or bearing installed on the equipment.
Sintering bronze parts has saved many industries from the frustrations of constantly replacing hard to reach bearings and bushings. Furthermore, when the self lubricating bushings and bearings were created in the 1930s, this proved to be an even more ground breaking achievement. Without being able to control the porosity impregnating bronze parts would not only difficult, but also inconsistent. Bronze is able to hold a significant amount of its own weight in oil. In order for the bearing or bushing to release the oil for lubrication the piece must be under pressure. Then the oil is released to lubricate and when pressure decreases the bushings and bearings reabsorb the oil to be stored until the next workload commences.
Photos Courtesy of Proform Powdered Metals, Inc.
Although sintering bronze parts has been around for a long time, self lubricating bronze parts have only been in use for roughly 65 years. In the past 65 years or so these products have changed the way maintenance cycles and the duration of runs for many machines. What do you or your company use sintered bronze parts for? If you use sintered bronze bearing or bushings, how have they affected your business and machinery? In the meantime, keep the machines running because your sintered bronze parts are not stopping any time soon.