Общий каталог Widia 2017 - страница 1808

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Technical Information Tapping Speeds Factors when trying to determine the best tapping speeds: The method of feeding the tap, and the type of equipment • Material to be tapped for driving, also influences the permissible speeds. If taps are mechanically fed at the proper rate of advance, they can be • Length of chamfer on tap operated at higher speeds than if they are required to feed • Percentage of full thread to be cut themselves and pull some part of the machine along with them. • Length of hole (depth of thread) Speeds may be modified to take into account any or all of • Pitch of thread these factors: • Cutting fluids • Speeds must be lowered as length of thread increases • Machine equipment because, in deep thread holes, the accumulated chipsincrease friction and interfere with lubrication. • Horizontal or vertical tapping • Bottoming taps must be run slower than plug taps. The best and most efficient operating speeds for taps cannot be • Tapping full height of thread calls for slower speed than if calculated with the same certainty, as for many other metalcutting the commercial 75% height only is required. tools. • Coarse-thread taps in the larger diameters should be run With other tools, the feed per revolution can be set at any desired more slowly than fine-thread taps of the same diameters. point and can be varied as conditions demand. Taps, on the other • The quantity and quality of cutting fluid may affect the hand, must always be advanced at a rate equal to one pitch for permissible speeds as much as 100%. every revolution. The style of tap may vary the conditions. • Taper threaded taps, such as pipe taps, should be For example, with a bottoming tap, the first thread on each land operated from 1/2–3/4 the speed of a straight thread tap cuts the full height of thread, while, with a taper or starting tap, a of comparable major diameter. number of threads do their share of the cutting before the full height of thread is reached. The depth of thread also varies, depending on the pitch. The coarser the thread, the greater the advance of the tap per revolution and the greater the amount of material removed. „RPM Formulas SFM = Surface Feet per Minute S m/m = Surface Metres per Minute RPM = Revolutions per Minute / = 3.1416 IPM = Inches per Minute mm/min = millimetres per minute TPI = Threads per Inch P = Pitch (1/number of threads per inch) Inch Sizes SFM = RPM x tool diameter or 0.26 x RPM x tool diameter 3.82 RPM = 3.82 x SFM tool diameter IPM = RPM or *P x RPM TPI* Metric Sizes S m/m = / x tool diameter x RPM 1000 RPM = mm/m x 1000 / x tool diameter mm/min = mm P x RPM Y104 widia.com Technical Information