IEMCA SIR 52 P, Manual For Use And Maintenance

Page: 90 / 174

EN
6 - USE AND OPERATION SIR-52-P/F
6 - Pag. 14 / 24
6.6.1 BAR STRAIGTHNESS - Measuration
The bar vibrations are partially caused by the condition of the bar itself: in case the bar is not
perfectly straight, this can cause vibrations.
Round bars
As stated also in the UNI-10233/2 regulation, the
bar straightness can be measured by positioning
the bar on two V-supports and control its
straightness. In that case, the measurement can
be carried out as shown in the figure.
It is necessary to rotate the bar on itself and
measure the three indicated sections. In this
case the S-max value (difference between
maximum and minimum reading on the comparator) should be interpreted as follows:
S max Quality
< 0,25 mm Good
0,25 < S max < 0,5 mm Mediocre
> 0,5 mm Problematic
In order to obtain a reliable value it is necessary to repeat measurements on the whole bar
length by positioning it on a series of supports at a distance of 500 mm from each other and
comparing the different values between prisms.
INFORMATION:
Obviously, bar straightness is proportional to the rigidity of the material and to
the number of revolutions (RPM) the lathe is operated at. highly The lack of bar
straightness highly influences the maximum number of revolutions reachable:
the bigger the diameter the greater the influence. The data concerning bar
straightness do not absolutely refer to local inflection and/or deformation that
the bar shall not absolutely show. Instead, they refer to the bar uniform
curvature.
INFORMATION:
For efficient operation of the feeder the use of rolled bar stock is not
recommended.