The O ring basically is a technical name for a seal in the shape of a ring (so the name O-Ring) having a round cross-section, that appears to be a donut. They are simply rubber rings that work as seals. O-rings in fact are some of the very extensively used seals in equipment since they are inexpensive, reliable, easy to put in place, and have an easy production process.
The material from which the basic O-Ring is produced is primarily an elastomer. That’s why the O-Ring is also dubbed the rubber O-Ring or rubber rings. O-rings furthermore are manufactured in LSR, other thermoplastic materials, FKM (Viton O-rings) not to mention metal both solid and hollow.
O-Rings Find Most Use In Machine Design
The reason that O-rings are so extensively employed in machine design is that they are affordable, and don’t need much to manufacture. And on top of it have simple mounting requirements regardless of whether they are, static or dynamic mounting applications.
Thomas Edison several centuries ago utilized a round rubber ring within his light bulb patent. A Sweden national patented an O-ring way back on 12, May 1896. It was many decades later that Niels Christensen, an inventor, developed an advanced form of O-rings while working on automobile brakes. His O-ring was patented in 1937, but there were not many takers of the product, until the aircraft boom of World War II.
Christensen during the war became a popular Metric O-ring supplier to the military; after experiments concluded that the simple, but critical O-ring allowed for a complex technology to advance.
Size Standards of O-Rings
O-rings have several size standards, like British, and Japanese among others. However, the one that is accepted worldwide is the ‘dash’ number which is the Aerospace Standard that commissions a dash number & tolerances to each size.
Tolerance of O-Rings
O-Rings tend to be complicated when one needs to design exact dimensions every time. Varied rubber compounds, the manufacturing process, and additional factors that bring about variations and shrinkage while curing will influence the exact size of the final product. Remember that tolerance is a vital component in seal design, and the tolerances of varied O-Ring materials need to be determined.
Elastomers and O-Rings
The rubber-based Viton O-Rings are used the most, while plastic and metal are available as well. In the market are available 36 unique rubber compounds for varying temperatures, chemical exposure, and aggressive compounds to name a few. When shopping for O-Rings it is crucial to give your supplier the full details of where and how the O-Ring would be used. For example, Nitrile is best suitable to oil and grease but wears out in sunlight. So, the temperature is the most important factor when choosing the right material. For instance, Nitrile functions optimally at minus temperatures; however, Silicone is found suitable for very high temperatures.
This is one other point to keep in mind when picking the right product from a reputed Viton O-Rings. Applications entail the perfect shore hardness in every case. This might be trial and error in the testing stage of a new application. However, the right shore hardness makes all the difference when it comes to productivity.
The durometer reading is typically raised at 5 durometer points, from extremely soft to hard. The hardness of rubber is nearly impossible to control at the time of manufacturing, even for the most high-tech plants. Manufacturers of O-Rings need to maintain a tolerance of +/- 5 durometer points. The most utilized O-Ring in a wide range of applications is the 70-shore Nitrile O-Ring.
The Bottom Line
It is most important that you buy your sealing requirements, including O-Rings. From a professional Metric O-Ring supplier who can advise and recommend the best-fit product for the application. Even if O rings can be produced by using metal, elastomer rubbers are the most popularly used material. The fact that an elastomer’s dimensions can be modified and restored by the application, makes them the best fit for use in a range of applications. The leading names when it comes to elastomers include FKM, FFKM, EPDM, Nitrile, and Silicone. Picking the right material is important. If the material of the O ring is a misfit, it can give rise to an increase in cross-link density. This will usually degrade the material and make the O ring turn hard and brittle.