Maker : Guhring

General notes

All the cutting rate recommendations specified in this catalogue are standard values valid exclusively for new tools or tools re-ground to Guhring specifications.
Pre-requisites are stable machines, optimal cooling, optimal tool clamping and maximum concentricity of the tool and the machine spindle.
Our recommended cutting rates must be reduced if the conditions deviate.
The values may also be adjusted to influence Surface finish quality, machining rate or tool life.

1. Workpiece clamping

Loss of tool life or tool breakage through unstable clamping
⇒ improve workpiece clamping

2. Tool clamping

Loss of tool life or tool breakage through unstable, worn or too small/long/thin tool holder
⇒ apply new or larger tool holder or holder with increased clamping force and increased concentricity

3. Surface finish quality

Excessive peak-to-valley height Ra/Rz at the tool Surface finish through excessive feed and feed rates or vibrations
⇒ improve workpiece clamping and tool clamping (see points 1 and 2)

4. Vibrations

High tool wear, insufficient workpiece Surface finish quality and insufficient dimensional accuracy through vibration
⇒ improve workpiece and tool clamping (see points 1 and 2)
⇒ increase tooth feed, because the chip centre thickness is too small
⇒ modify speed
⇒ modify milling strategy, i.e. select alternative cutting distribution
⇒ change tool selection, i.e. reduce no. of teeth or spiral

5. Chip congestion / cooling

Significant reduction in tool life, crumbling on cutting lips, edge build-up or conglutination of flutes through insufficient hip evacuation
⇒ select milling cutters with internal cooling

6. Pecking when drilling

Significant reduction in tool life as well as crumbling of cutting lips through insufficient chip evacuation and thermal stresses
⇒ select milling cutter with internal cooling with drilling depths>0.5 x D pecking in stages

7. Thermal influence on materials

Through welding or torch cutting, the material characteristics at the parting line do not correspond with the specified material class
⇒ reduce cutting rates
⇒ select tool for materials with a higher tensile strength

8. Entry in hardened materials

For entering materials over 44 HRC, reduce the feed rate vf (mm/min) in accordance with the illustration on the left

9. Loss in tool life with interrupted cutting

Significant loss in tool life through interrupted cutting (especially with milling angles of 90 ˚)
⇒ modify cutting distribution
⇒ reduce feed rate for entry and exit
⇒ reduce approach angle

10. Feed rate adjustment : Modifying the cutting width

⇒ when modifying the cutting width WOC, the feed rate must be reduced in accordance with the illustration on the left
⇒ cutting speed or revolutions remain unchanged
⇒ double reduction applies when also modifying the cutting depth DOC!

11. Feed rate adjustment: Modifying the cutting depth

⇒ when modifying the cutting depth DOC, the feed rate must be reduced in accordance with the illustration
⇒ cutting speed or revolutions remain unchanged up to cutting depths of 3 x D, must only be adapted over 3 x D
⇒ double reduction applies when also modifying the cutting width ae!

12. Plunging strategies

12.1for drilling:
⇒ reduce feed rate vf (mm/min.)
⇒ additional pecking for drilling depths>0.5 x D or transition to radial machining Attention: Danger of breakage through abrupt load increase!

12.2Oblique plunging up to 15˚ (preferred):
⇒ reduction in feed rate vf (mm/min.) not required

12.3Oblique plunging between 15˚ and 30˚:
⇒ reduce feed rate IPT in accordance with the illustration

12.4Helical plunging:
⇒ for helical plunging on a milling cycle, we recommend a feed of 0.1 to 0.2 per cycle
⇒ reduce feed rate vf (mm/min.) in accordance with the illustration
⇒ select preferred hole diameter 1.8 x D