How to achieve higher volumetric positioning
accuracy and cut more accurate parts with your existing machine tools
I. Introduction For lean manufacture, it
is import to improve
the volumetric positioning accuracy of the existing
machine tools and to cut more
accurate parts without the purchase of new
machine tools. The key to achieve
that is the new
revolutionary laser vector
measurement technique
developed by Optodyne.
With this
laser vector measurement technique, the volumetric positioning errors,
including 3 displacement errors, 6
straightness errors and 3 squareness errors, can be measured in a few hours instead of a few days by a
conventional laser interferometer.
The measured volumetric errors can be used to generate lookup tables or compensation
files to correct the machine positioning errors in 3 D. For the
existing machine tools, as long as
they are repeatable, the volumetric positioning accuracy
can be improved up
to the positioning
repeatability of the machine. There are 3 types of existing
machine tools, namely, 1. manual machines
with or without numerical display
of 3-axis positions, 2.
CNC machines with pitch
error compensation
capability only, and 3. advanced CNC
machines with volumetric
compensation capability such as Fanuc 15, 16, and 18 with straightness compensation capability and Siemens
840 and 810 with sag compensation
capability. II. Laser vector measurement technique (patent
pending) The laser
vector measurement technique is developed by
Optodyne for the
calibration of volumetric positioning accuracy
of a machine tool.
It uses a single-aperture laser head and a flat-mirror as target.
Similar to the ASME
B5.54 standard body diagonal displacement
measurement, the
laser beam is pointing
in the body diagonal
direction. However, instead of
move x, y, and z-axis together along the
body diagonal direction, stop and collect date, now move x only,
stop and collect data,
then move y only, stop and collect
data, then move z only, stop
and collect data, and so on until the opposite corner is reached. Hence, 3 times more data can be collected.
For 4 body diagonal measurement, a
total of 12 sets of data can be collected and the volumetric positioning errors determined. The
measurement time 1
