“Cut tapping can cause ‘birdnesting,’ which means the operator has to stop the machine, clean out the chips and start again-repeatedly-throughout the day. “In a lot of cases, depending on the material, form tapping is better for high-volume production,” OSG’s Gennuso said. The biggest benefit of roll tapping is that no chips are created, eliminating chip handling and all the cleaning, maintenance and equipment it encompasses. As long as the thread profile is 10 tpi or greater, you should be able to form it.” The limit is about 10 tpi, or 2.5 pitch in metric. “A fine pitch thread is easier to form because there is less material to displace. “There is also a limit on the pitch,” said Pat Nehls, product manager for Walter USA LLC, Waukesha, Wis., which offers the Protodyn CAP and Protodyn S Synchrospeed thread formers. Larger tools produce more friction and require more machine horsepower. When form tapping titanium, a lot of that heat penetrates the tool and causes premature failure.įorm taps are typically less than 3⁄4 ", or an M20, in diameter. Because forming doesn’t create chips, the heat must go into the tap or the material. During a tapping operation, heat enters the workpiece, tap and chips, he explained. “In addition to its high tensile strength and low ductility, titanium has very low thermal conductivity, meaning that it doesn’t absorb heat very well,” Gennuso said. Brittle materials, such as cast iron, do not flow well and cannot be form tapped. Material with a tensile strength of 160,000 psi and a maximum hardness of 36 HRC is about the limit for form tapping, although form taps for some materials up to 40 HRC are available.Ī range of metals can be form threaded, including aluminum, stainless steel, carbon steel, titanium and nickel. He estimates the ratio of cut taps to form taps used is about 100:1.įorm tapping requires a workpiece material that can actually flow to create the thread profile. But whether they call it form tapping, cold form tapping, thread forming, cold roll forming, roll forming, thread rolling, roll tapping or cold roll tapping, many metalworking professionals are unfamiliar with, according to Peter Gennuso, applications engineering supervisor for OSG Tap & Die Inc., Glendale Heights, Ill.Īl Zaitoon, marketing manager for YG-1 Tool Co., Vernon Hills, Ill., agreed that cut taps are more accepted and better understood. The process of displacing metal instead of cutting it is called many things. At REMINC/CONTI we primarily use “high-performance thread-rolling” when referring to TAPTITE ® designs and “thread-forming” when referring to PLASTITE ® and REMFORM ® products.When the application is right, form tapping provides real production benefits. For example, we would refer to a Type AB screw used in sheet metal or a light metal alloy as a thread-forming screw, not a thread-rolling screw like TAPTITE ® that creates more clearly defined and cleaner internal threads.Īfter stating all this, we conclude that there is no “right” or “wrong” here. These definitions are not universal therefore, they are often used interchangeably and can cause confusion. Thread-rolling screws create an internal thread, like how a thread-rolling tap would function. (commonly called self-tapping screws) that create an internal thread by displacing material but typically are driven into thin sheet metal where the metal simply changes shape. Thread-forming screws can be Type AB, Type B, etc. Thread-cutting screws remove material and create real metal chips in the process. In fastener parlance, screws that create their own internal threads are often called thread-forming screws however, that class is made up of thread-cutting, thread-forming and thread-rolling. Both thread-rolling and thread-forming designations are used interchangeably in our industry, but what’s the difference? Thread-forming describes the process of creating a thread both internally and externally. The introduction of the original TAPTITE ® fastener elevated the application of thread-forming screws, resulting in the term “high-performance thread-rolling screws” and what can be some confusing nomenclature.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |