Case study

EN - Measurement drilling force evolution with full nib pcd micro-drill Ø1.78mm into CFRP.

Machining parameters on CNC Hurco BM30 at Diamoutils testing tools R&D center.

  • Spindle velocity : 8000 RPM
  • Feed: 480mm/mn
  • VC: 45m/mn                                                                   
  • f: 0,06mm/U
  • ap: 4mm

1st-test-o1-78-into-cfrp

Drilling force measured  with a sensory tool holder equipment set up on CNC milling centre Hurco BM30, drilling into curved CFRP 2.6mm thickness with a soft plastic skin on the exit side of the panel:

 

Signal- mean/slope 1st hole 100 hole 350 hole – 650  hole 850 hole 1050 hole
Tension [N] 20.2        -7,8 30.2        8,2 36.2         5,8 44.5         -20,1 48,7           -3,7 52.8        0,9
Torsion [Nm] -0.1           – 0,3 -0,1         -0,1 -0.0         -0,1 -0.1           -0,4 0.0            -0,0 -0,0         0,2

electro-scan-500%c2%b5-new-foret-1-78

SEEM drill new with 3.2µ of preliminary edge radius.               

Tension at  1st hole :        20.2 N

Tension at 1050 hole :    52,8 N

 

 

Tension evolution from 1st drilling operation and 1050 operation : + 161.3% due to preliminary wear edge cutting evolution.
electro-scan-100%c2%b5-foret-1-78-after-1050electro-scan-50%c2%b5-foret-1-78-after-1050electro-scan-20%c2%b5-foret-1-78-after-1050

SEEM of cutting edge after 1051 drilling operations.

SEEM realise at UNOTT on Hitachi S2600 N.

img_0243

Pictures of the diameter and circularity of holes in CFRP, measured with the Bruker interferometer.

circularite-1er-trou

First hole, entrance side : value of diameter measured: Ø1.775 mm, value of circularity measured: 0.024 mm.

detail-1000-trouscircularite-1000-trous

After 1000 holes entrance side : value of diameter measured: Ø1.759 mm, value of circularity measured: 0.011 mm.