An O-Ring or a toric joint is a gasket with round cross section suited to be placed in a groove and compressed during assembling of two or more parts creating a seal which can block pressure.
O-Ring Moulds are easily the most widely used seals because they are economic and reliable and most importantly easy to mount.
O-Rings are manufactured by varied methods and various material depending on lubrication requirements , sealing pressure and application temperature.
The typical processes for creating O-Rings molds are transfer molding,extrusion molding, compression molding and injection molding
Transfer molding is a process wherein the measurement and insertion of molding material takes place before the actual molding. The preheated material is loaded in a chamber. A plunger is then used to forcefully channel the material from the chamber to the runner system into the mold cavity. This process yields a good surface finish ,dimensional stability and high automation capability. Small tolerances and more intricate parts can be achieved using this process.
Extrusion molding is a process where in the melted material is forced through a die forming a long tube like shape. The extrusion is then cooled and allowed to form a solid shape. This is then cut at equal intervals to make the desired O-Rings. Its low cost manufacturing and ability to produce consistent cross section with considerable flexibility makes it a desired process.
Compression molding involves taking the rubber compound and creating a preform. This enables surplus of material to be channeled in the cavity ensuring total cavity fill. This mold is then closed and both heat and pressure is applied so the excess pre form material spills into the overflow grooves. The rubber is then demolded.
This process helps minimizing overflow and flash creation. Maximized cavity count and economical process for medium precision are the main benefits of this method.
Injection molding is easily one of the most efficient ways to create molded O-Rings. This process involves mixing the material in bulk and then stripping them continuously into strips. These strips are then fed into a screw which in turn fills a barrel with the appropriate quantity of rubber material. This process yields high volumes of medium to high precision tools and is capable of producing flashless rings with minimal material waste.