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Thread rollers are machines that are designed to form threads on a work piece by way of squeezing and flowing the metal in order to create a desired form. As a result of this process and the nature of the thread rollers, the original blank work piece is actually capable of growing following the rolling operation because material is not cut away, but rather rearranged to form the new shape. In other words, there is a difference in the result when you cut threads in comparison to rolling threads, making thread rollers a useful machine for a number of applications.
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The thread rolling process offers a number of benefits in comparison to other methods of creating threads in a work piece blank. F or example, thread rollers offer an additional level of tensile strength as well as an improvement in surface finish. The pressure of the rolling process is very high - high enough to make steel flow into the thread die. This pressure acts as a forging process; rearranging the molecules of metal to make the resulting part much stronger than if the threads were cut in a lathe.
Because the work piece blank is going to be deformed plastically by way of pressure during the thread rolling process, it should be expected to have a minimum elongation level of 5 percent as well as a maximum tensile strength level of 246,000 psi.
Thread rollers are machines that can be used for the purpose of creating a wide variety of different types of threads in blank work pieces, including but not limited to V type threads, Taper V type threads, Acme threads, Knuckle threads, Truncated Knuckle threads, Buttress Threads, Straight Wood-Screw Threads and Serrations.
There are different types of thread rolling and thread machining systems that can be used, including Axial thread rolling systems, tangential thread rollers and radial thread rolling systems. Thread cutting, by comparison, is done with the use of single point or form tool in a lathe machine. Threads can also be ground into a part with a special machine called a thread grinder. These are both processes that involve metal cutting and that are utilized in order to remove material, creating a desired geometry in threads. Thread rolling on the other hand is not actually a metal cutting process, but instead it involves forming the thread into the same shape or image as the roller die rather than removing metal in order to create a desired profile.
Thread rolling is primarily used when there are a large quantity of parts to be threaded - often millions - and the speed and the material savings (there is no waste) inherent in thread rolling are a tremendous advantage. Thread cutting is preferable when there are a limited number of parts being made or the parts are of a size that don't lend themselves to rolling (too big).Also, parts that are hollow can be crushed or deformed in a thread rolling machine - for example, a valve stem where gases or liquids need to flow through. Cutting generally does not create problems with this type of part.
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