Diamond Drilling Systems. - Hilti

Diamond Systems
Diamond Core Drilling
Influencing factors
Water flow rate
too low:
Water flow rate
correct:
Water flow rate
too high:
Speed (r.p.m.)
too low:
Speed (r.p.m.)
correct:
Speed (r.p.m.)
too high:
Concrete of low
abrasiveness:
Concrete of med
abrasiveness:
Concrete of high
abrasiveness:
Drilling through
steel
reinforcement:
193
n The segments wear and power is lost due to increased friction
The segments can also overheat, which causes them to stop cutting
n The water cools the diamond, flushes slurry and fragments out of the hole and has a lubricating
effect; it thus ensures that factors such as segment temperature during drilling, core bit wear
and cutting performance remain in balance and that optimum drilling progress is achieved
n The self-sharpening effect on the segments is inhibited, core bit wear is lower and drilling
progress decreases. Excessively high water pressure opposes the pressure applied to the core
bit. This could cause polishing of the segment
n Excessive pressure on the core bit. Results in uneven wear of the diamond matrix,
erosion and loss of the diamonds (unsatisfactory core bit life)
n Optimum pressure on the core bit. Results in even wear of the diamond matrix and diamonds,
with optimum projection of the diamonds, optimum drilling progress and core bit life
n Insufficient pressure on the core bit. The diamond matrix does not wear, which means that the
diamonds do not project adequately, resulting in loss of cutting power
Drilling progress decreases and the core bit segments become polished
n The self-sharpening effect is inhibited and, as a result, segment wear is low.
If the diamond matrix is too hard the segments become polished. The most suitable
specification is with soft matrix
n The specification with medium-hard matrix provides the optimum balance between
segment wear and drilling progress
n The concrete causes the matrix to wear very quickly. Soft and medium-hard
segments wear extremely quickly. The appropriate specification for long life is
with reinforced matrix
n Reduce water flow rate in order to assist the self-sharpening process
n Increase pressure on the core bit so that the points of the diamonds are pressed into the steel
n Reduce speed (r.p.m.) in order to ensure that sufficient torque is available
n When several steel bars are to be cut through simultaneously, use of a special core bit is
recommended
n Rule of thuamb: Drilling through steel takes approx. 10 times longer than drilling through concrete
n Caution: Permission must be obtained from the site engineer or other authorised person before
drilling through steel reinforcement
Recommended drilling speeds, water flow rates and life expectancy guide for Hilti diamond core bits
Estimated, average water flow rate under ideal conditions (1.min.)
Diameter 8 - 50 mm 50 - 100 mm 100 - 250 mm
Water flow rate 1 - 3 l/min 3 - 4 l/min 4 - 5 l/min
Estimated, average drilling progress under ideal conditions (cm.min.)
Diameter 8 - 24 25 - 52 56 - 102 107 - 152 158 - 182 202 - 250 > 250
mm mm mm mm mm mm mm
Drilling 6 - 13 7 - 12 6 - 7 5 - 6 3 - 5 2 - 3 1 - 2
progress cm/min cm/min cm/min cm/min cm/min cm/min cm/min
Estimated, average core bit life under ideal conditions (m)
Diameter 8 - 24 25 - 52 56 - 102 107 - 152 158 - 182 202 - 250 > 250
Machine mm mm mm mm mm mm mm
DD-100 10 - 20 m 19 - 26 m 21 - 25 m
DD-80E 10 - 20 m 19 - 26 m 21 - 25 m
DD-160E 19 - 26 m 19 - 25 m 17 - 23 m
DD250E 19 - 26 m 19 - 25 m 17 - 23 m 15 20 m 12 - 18 m 4 - 10 m
The values listed were determined under laboratory conditions.
The actual figures obtained may vary by approx. ±20% under
differing conditions (e.g. high reinforcement content, etc.).
Hilti. Outperform. Outlast.
www.hilti.co.uk | 0800 886 100
www.hilti.ie | 1850 287 387