Knowledge

Important application criteria for WTX drills

Axial offset
The axial offset between rotating workpiece and stationary tool may be max. 0.04 mm. A greater axial offset reduces the tool life and the hole quality and can lead to tool breakage.

Runout error
Should not exceed 0.015 mm for rotating tools.

Cooling lubricant
With internally cooled tools, the pressure should be min. 20 bar – see diagram bottom right. We recommend high-quality semi-synthetic or emulsion cooling lubricants with min. 10 % oil content and EP additives. This allows you to achieve better tool life, higher tolerance accuracy and better surface quality. A fine filter system is also recommended to prevent possible blockages of the coolant holes.

Drilling into solid
Due to the geometrical design, our solid carbide drills are ideal for drilling into solid. The solid carbide drills ≤ 12xD can be used to drill holes into solid without the need for centring and pre-drilling.

Slot exit
A safety distance of min. 1 to 1.5xD must be kept between the workpiece and slot exit in order to be able to ensure optimum chip removal and prevent a chip jam and tool breakage.

Evacuation process
To be avoided due to the risk of breakage caused by remaining chips or chips which have spilled into the hole.

Feed f in mm/rev
Drilling capacity relative to the diameter: vc = 80 m/min
Tensile strength of the material = 600 N/mm²

Follow-on tools 
For a smaller Ø in the same hole, follow-on tools need a point angle < previous tool to guarantee self-centring.

Interrupted cut
For angled entry and exit or transverse holes, the feed must be reduced.

Drill exit
To prevent significant burr formation, reduce vc and f.

Workpiece clamping
To prevent tool breakages, make sure that the workpiece clamping is correct and that there are no vibrations or workpiece deflection .

Tool clamping
Optimum clamping ensures high alignment and fit accuracy (IT7-8). The high surface quality frequently means there is no need for a reaming operation .

Machine dimensioning
Please see performance chart (bottom left).

Cutting speeds table
The lower limits of the feed rows should not be undercut in order to obtain controlled chip breakage (comma-shaped chip).