Sandvik Coromant Machining carbon fibre materials - Manual (Page 25)

Hole requirements
Stacked materials
Common demands •
- Cpk>1,33
- Ra<3,2 in carbon fibre
- Ra<1,6 for Aluminium and titanium
- Hole tolerance: +/- 20 µm to +/- 40 µm
- No delamination or chipping in the hole exit
- No chip erosion on the carbon fibre from the metallic stacked material
Criteria •
- Chips evacuation
- Lubrification through the center
Dimension control •
- Holes are commonly pre-drilled
- Finish hole size produced with one shot solution if possible
- Reamer to be used when high demands on finish and size control
Holes are usually measured as diagram shows above every 90 degree
Material 1
Material 2
2 mm in from Entrance
Middle of material
2 mm from Exit
2 mm in from Entrance
Middle of material
2 mm from Exit
SANDVIK COROMANT USER’S GUIDE - COMPOSITE SOLUTIONS 25