Hyd-Mech PH 211, Use And Maintenance Manual

Page: 88 / 98

10--2 80
Use and maintenance manual PH211
SOLUTION PROBABLE CAUSE PROBLEM
Rapid tooth wear
'
Teeth pointing in the wrong
direction
.
Set teeth in correct direction
'
Blade worn in wrongly
.
With a new blade cutting
should be done at half--spe-
ed and with downstroke spe-
ed also at half normal speed.
After the blade has been
worn in (about 300 cm 2 of
work for hard cutting ma-
terials and about 1000 cm 2
for soft cutting materials) the
cutting and downstroke
speeds can be brought up to
rated levels
'
Material too hard
.
Check cutting speed, down-
stroke speed and blade pres-
sure, as well as type of band
saw being used
'
Material defective
.
Surface defects: oxides,
sand, surface hardening.
Hardened inclusions in sec-
tion.
Reduce cutting and down-
stroke speeds or clean surfa-
ce.
'
Cutting speed too high
.
The teeth slide on the mate-
rial without cutting: reduce
cutting speed
'
Head downstroke speed too
slow
.
The band saw runs over the
material without removing it:
increase downstroke speed
'
Insufficient coolant
.
Check coolant level and
clean pipes and jets
'
Incorrect fluid concentration
.
Check and use the correct
concentration
'
New blade inserted into a
partially--made cut
.
The cutting surface might ha-
ve been subject to a locali-
sed heat--induced alteration,
making it harder: recommen-
ce cut using a slower cutting
and downstroke speed. The-
re may be a broken tooth
from the old blade lodged in
the cut: check and remove
before recommencing work
'
Flutter
.
Blade tension too low:
tighten.
Tooth shape or pitch unac-
ceptable: change type of bla-
de used.
Widia blade steady buttons
too far from the blade back:
adjust guide heads, rotating
them slightly to bring them
closer to the blade back.