Общий каталог Yamawa 2022 - 2023 - страница 1212

Carbide Taps 20. Carbide Taps

Technological advances in CNC machines and machining centers, and machining automation have helped improve the overall tapping process. YAMAWA was quick to respond to evolving customer needs resulting from technological innovations. We can now recommend carbide taps, which provide tremendous improvements in mass-production and in reducing costs. It is estimated that carbide taps have 50 times more durability than HSS taps in tapping, when used properly. YAMAWA engineering believes the best carbide materials suitable for taps are ultramicro grain tungsten carbide, or ultrafine grain carbide made of high cobalt.

■Features of Carbide Taps

(1)Excellent durability with high toughness is obtainable. (2)High anti-friction features are provided by the material's high hardness and comparatively high toughness, which ultimately results in a longer tool life. (3)Specially designed cutting angle and other dimensional features produce the internal threads with high tolerance accuracy and consistency. (4)Under certain tapping condition, YAMAWA carbide taps can be used even for tapping hard-to-machine materials. ■Points to note during tapping with Carbide taps: (1) Machine vibration, or run-out, can lead to Carbide tap chipping and premature failure. Tapping vibrations need to be kept to a minimum. (2) Tap holder should be a rigid type for a Carbide tap. A holder attachment with axial float, or radial float tends to promote Carbide tap breakage and chipping. (3) The hole to be tapped must be located correctly and on center ; any centering off or non-straight drilled hole tends to cause Carbide tap breakage due to deflection. Select correct hole depth with respect to tapping length (for blind hole only). It is especially important to prevent tap damage from chip packing and bottom thrusting in blind hole tapping. (4) Cutting lubricants - select grade of lubricant. Improper flow of coolant, or lack of sufficient amount of lubricant, or cooling can increase the likelihood of Carbide tap chipping due to work material welding. Caution must be taken during dry machining to prevent chip welding to the tap. (5) Work pieces - we provide Carbide taps with increased toughness, but Carbide taps are inferior to High Speed Steel (HSS) in the area of toughness. As a matter of fact Carbide taps have limited application due to this difference in toughness to HSS.

■Commonly used materials and cutting conditions.

■Toughness and Hardness of Cemented Carbide and HSS

Deflective Strength (MPa) (HRA) Hardness

P50 UF・A UF・B SKH51 SKH58

(SKH9) (AISI M7) Cemented Carbide HSS

■Carbide Tap examples and comparison of tool life

Size M2×0.4 M8×1.25

■Chamfer wear and number of holes of Carbide taps and HSS taps

Cutting ConditionCutting Condition Tap : M5×0.8P4 Tap : M5×0.8P4 Chamfer : 3 pitches Chamfer : 3 pitches Machine : Machine with multi spindles Machine : Machine with multi spindles Hole Size : Hole Size : φφ4.2mm4.2mm Thread Length : 10mm Through Thread Length : 10mm Through Fluid : water soluble Fluid : water soluble Workpiece : FC250 Workpiece : FC250 HSS taps Carbide taps

Number of holes

M6×1 M8×1.25 M10×1.25

Tapping Hole.

Note : The table shows only general conditions. As for actual cutting operation, please consider the following points : (1) Machine Capacity, (2) Work piece(s), (3) Work Shape, (4) Setup (5) other factors. Number HSS Tap of Holes Comparison of Life Note : In all situations, HSS taps being used are standard ones. Carbide taps, when used properly, bring out a long tool life. These datum have come from end users of carbide taps. Technical Inf