Обший каталог Yamawa 2016 - 2017 - страница 839

3. Troubles on taper pipe thread tapping, and their solution

Taper pipe thread tapping such as for PT thread and for NPT thread is quite different from parallel thread tapping such as for metric thread. There, the trouble particularly special in taper thread tapping tends to happen. Following is the explanation about tapping troubles on taper pipe thread tapping and their solution:

• Materials and troubles

material tool steel, alloy steel, nickel base alloy,

high carbon steel, cast iron, tough cast aluminum alloy, zinc thermosetting resin, titanium alloy, heat

low carbon steel middle carbon steel stainless steel

heat treated steel of iron alloy, brass thermoplastic resin treated steel of lower

trouble lower than 35HRC than 35HRC

tap wear, cutting

performace ▲ ▲ ー

decreased

• Trouble occurs quite frequently ▲ Trouble occurs rather frequently ー Hard-to-macine material
• Trouble shooting

trouble tap wear, cutting Over-cutting of Shrinkage of internal Rough surface, Torn

Stop line performace welding on tap chipping on tap chip clogging

intenal threads threads threads

check point decreased Select machine Use machine with Use machine with Machine suitable for tapping more power more power size Use tap holder of floating type,

Jigs, Holders Fix workpiece Prevent vibrating

firmly of axis of tap, Prevent centeringoff with workpiece Adjust properly the stroke of tapping Cutting condition Reduce cutting Reduce cutting speed Reduce cutting speed speed, Adjust a feed Change to insoluble oil from water Change to insoluble oil from water

Lubricant soluble, Use other cutting oil which soluble, Use other cutting oil when Adjust oil volume, supply oil properly

prevents cold welding prevents cold welding Provide deeper Provide deeper tapping hole, tapping hole, Prevent slanting of Use taper reamer

On process Remove Check the viscosity,

hole for boring hole unnecessary chips Use taper reamer during tapping for boring hole Use carbide tap Use spiral fluted

Use thread mill (depending on Use interrupted Use spiral fluted tap, Use interrupted

Selection tap, Use interrupted

cutters materials being taps tap

tap cut)

Tap Provide oxide Select long shank

surface treatment, tap when ejecting Reconsider of

Design Change material of Provide TiN or chips interferes

number of flutes

tap TiCN on taps, with tap holder in

of tap Provide larger the case of SP cutting angle tapping

• Examples of trouble shooting

1) Torn thread trouble was solved by changing cutting speed 2) Stop line trouble was solved by using Thread milling cutter Tapping condition Cutting condition

• 08153X19G

machine Machining center cutter

• material
• Low carbon steel

holder fixed type

• machine
• Machining center

lubricant water soluble