LNS GT 326-E, Instruction Manual, Page: 66 / 218

Chapter 7 GENERAL DESCRIPTION
7 - 13
GT 326-E
7.7 BAR MEASURING DEVICE
The term TOP CUT presents both the action and the position of the bar front end machining
process for a newly loaded bar into the lathe. The purpose is to remove the unqualified surface at
the end of the newly loaded bar to start machining a good part and as a correct reference for
positioning the bar stock during machining. Generally this process will take place after a bar
change sub-program. Depending on the tooling layout of the lathe this position could be adjusted
to any position outside the lathe chuck. Generally 20 to 30 mm outside from the face of the
chuck.
The bar feeder is designed to allow the loading of random length bars without any adjustment.
The bar measuring device serves to receive the front end of the newly loaded bar. In automatic
operation via a mechanism and a sensor it will detect the presence of the bar and the servo
motor will automatically advance the front end of the bar to Top Cut position outside the face of
the chuck. When the bar end reaches the pre-adjusted TOP CUT position, a confirmation signal
(R2) is sent to the CNC lathe to resume the CNC program.
Since the bar measuring sensor is only activated by the front end of the newly loaded bar note
that the TOP CUT distance is not dictated by the bar stock length. Once the bar feeder position is
fixed (via parameter), the TOP CUT position is only related to the distance from the bar feeder to
the face of the lathe chuck.
Bar measuring flag