Общий каталог Tungaloy 2020 - 2021 - страница 1665

Drilling Tools B

• Chip shape produced with peripheral insert
• Chip problems such as entangling are mainly caused by chips produced with the peripheral insert. These problems are dependent on the types of Workpiece material and the cutting conditions.
• As shown below, when the feed is extremely low, the chips jump C over the chipbreaker groove and the continuously long chips may wrap around the drill body.
• When the feed is too high, the chips increase in thickness and can not be curled. D
• Therefore, it is important to select proper cutting conditions to suit the machining so that well controlled chips will be formed. Medium to high carbon steels, alloy steels, etc. E

As shown below, several turns of coil are an ideal shape. As the feed increases, the curl radius and the number of turns tend to decrease.

• Typical chip shapes of general steels
• Variation of chip shapes relating to feeds F

G

f = 0.07 mm/rev f = 0.1 mm/rev f = 0.13 mm/rev

Stainless steels, low-carbon steels, low-alloy steels, etc.

• When machining long-chip materials such as stainless steels and mild steels, the wrong selection of cutting conditions re- H sults in chip entangling and tool breakage at worst. Therefore, cutting conditions should be carefully selected.
• “C” shaped, continuous coils of several to ten turns having adequately divided lengths are the ideal shape.
• Ideal chip shapes I

Stainless steel (JIS SUS 304) Mild steel (JIS SS400) For machining stainless steels or low carbon steels,

( ø22, Vc = 100 m/min, f = 0.1 mm/rev ) ( ø22, Vc = 160 m/min, f = 0.08 mm/rev ) DS chipbreaker is recommended. When using a TDX drill in tool-rotating condition, DS J chipbreaker produces compact chips and allows more

stable machining than DJ chipbreaker. When using it in work-rotating condition, DS chipbreaker provides outstanding affect on chip control. K

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