Общий каталог Yamawa 2022 - 2023 - страница 1171

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Description of productsTechnical Information 12. Guide to Thread Forming Taps (Roll Taps) Thread Forming Taps are the tools used for producing internal threads by a thread forming process. Currently, YAMAWA's Thread Forming Taps have a good reputation by being used in large area. They are widely used along with the diversity of workpieces and with the change into miniaturization of workpieces. Followings are the characteristics and features of Thread Forming Taps (Roll Tap) which cutting type taps do not have. ○Tapping without producing chips. They are suitable for blind hole tapping. In producing internal threads with no chips, they save you a time for chip disposal. ○Roll taps are stronger than cutting taps due to their design. The e ect of uteless design gives a large cross-section area to the tap, and there is no worry of chip jamming, which makes Roll taps very tough against breakage. ○Roll taps produce excellent pitch diameter well within pitch diameter tolerances. Material deformation process produces the internal threads with good surface nish as well as precise pitch diameter. ○High e ciency and tool life The con guration of the lobes at the crests of the tap threads makes high speed tapping possible and extends tool life compared with cutting type taps. The addition of a supplemental tap surface treatment, such as Oxidizing, Nitriding, TiN, and TiCN can extend tool life 2 to 20 times over an uncoated (bright) tap performance. ○Tapping torque is 2 to 3 times larger than that of cutting type taps. ○Roll tapping is only applicable to stringy materials. ○The deviation of hole size before tapping should be about 5% of pitch. The control of hole size before tapping should be more severe than that of cutting type taps. ○The selection of lubricants is important to prevent sticking or welding. ○Burrs at the face of an internal thread are larger than those produced by cutting type taps. In some cases it is necessary to take additional counter- sink processing at the top of hole. ○In the minor diameter of internal thread, U-shape form (Tine form) at the hole entrance can be seen. U-shape form is never seen when using cutting type taps. ○Types of Roll Taps YAMAWA produces various types of Roll Taps which include General purpose taps, Special purpose taps for non-ferrous and steel, as well as special purpose taps with surface treatment for the speci ed applications. To provide for longer tool life, specially developed premium materials are also used together with physical vapor deposition (PVD) such as TiN and TiCN. In particular, OL-RZ is superior product developed for dry machining with good regards to tapping environment and performance. ○Tap Materials YAMAWA's standard tap material is SKH58 designed for improving torque, superior anti-friction properties as well as toughness. To extend tool life, we use SKH56, or SKH10(Powder HSS) which is the best tap material for antifriction. ○Tolerance Class Using the datum 12.7μm in a step form, in accordance with ANSI standard GH class, we made up YAMAWA's G class system. The di erences in materials being Roll tapped, as well as hole size, contribute to di erences in thread forming. YAMAWA o ers 2 to 3 oversized tap tolerance classes in order to achieve the most suitable internal thread pitch diameter size. ○Chamfer length Chamfer lengths : 2 pitches for blind hole use and 4 pitches for through hole use. Basically 4 pitches have longer tool life than 2 pitches because force applied on one blade at 4 pitch chamfer is smaller than that at 2 pitch chamfer. However, it is di cult to say about tool life in a few words because each di erent tapping condition in uences the tool life. Compared with the basic height of thread engagement, the actual height of the thread engagement is called "thread engagement ratio" in percentage. Depending on the bored hole diameter, internal threads and thread engagement ratio will change. In tapping, the tapping condition must be chosen by referring to the thread engagement ratio. In tapping, it can reduce cutting space and forming space to make bored hole diameters as large as possible. This, through reducing the load on taps, can restrict tap's wear and damage. S50C, minor diameter of threads cut Aluminum, minor diameter of threads formed M24x3 M25x2 minor dia. tolerance of internal threads minor dia. tolerance of internal threads φ20.752~φ21.252 φ22.835~φ23.210 【S50C internal threads cut ①】 InternalM24x3threadsbored hole size :φ20.652minor dia. tolerance of internal threads NGthread engagement ratio : 103.1%External【Aluminum, internal threads formed ①】InternalthreadsM25x2threadsbored hole size :φ23.903minor diameter of nished internal threads : 22.723mmminor dia. tolerance of internal threads NGthread engagement ratio : 105.2%Externalthreadside 【S50C internal threads cut ③】M24x3bored hole size :φ21.000minor dia. tolerance of internal threads: Middlethread engagement ratio : 92.4%【Aluminum, internal threads formed ③】M25x2bored hole size :φ24.042mmminor diameter of nished internal threads : 23.067mmminor dia. tolerance of internal threads : Middlethread engagement ratio : 89.3% 【S50C internal threads cut ⑤】M24x3bored hole size :φ21.352minor dia. tolerance of internal threads NGthread engagement ratio : 81.5%【Aluminum, internal threads formed ⑤】M25x2bored hole size :φ24.240mmminor diameter of nished internal threads : 23.462mmminor dia. tolerance of internal threads NGthread engagement ratio : 71.0% Technical-20