Transcript Faber_GRaciti.ppt

IPD Technical Conference
February 19th 2008
GREG RACITI
30mm Projectile Inspection
 Project Objective
 Customer needed to inspect
integrity of machined copper rifling
band on 30mm projectiles
 Inspection was to be done on
existing eddy current test
equipment
 Existing equipment is spinning the
projectile under test head for
approximately 2 seconds
 When a defective band is detected,
a pulse is issued to existing PLC
controller for rejection at next
position in the rotary table
 Space for mounting hardware was
limited
Inspection Challenges



Illumination
 Inspection target is a shiny copper
band wrapped around a dull gray
cylindrical projectile body
 On-Axis Lighting was the only
solution – but only a small portion
of the band is illuminated properly
Triggering
 Due to the cylindrical shape and the
limited area of illumination, multiple
trigger pulses were needed to
inspect the entire part
Real Estate
 Area of interest is almost
underneath existing eddy current
test head
 NER DOAL had to have it’s
aluminum sidewall replaced with a
piece of shim stock to reduce its
overall width
Hardware Selection
Dalsa IPD VA41 with
single Teli TM1 640x480
camera
Fujinon 16mm standard
lens with a 2mm spacer ring
Siemens 50mm Diffuse On
Axis Light – red LED non
strobed
SICK Stegmann
programmable encoder for
camera trigger
Grayhill complete opto
breakout board for VA4X
All vision hardware was
mounted and wired into an
electrical enclosure
Sherlock Program
Final Installation
System Video
System Video
Conclusion & Observations
 Projectile was spinning faster
than anticipated – exposure was
set down to 150µs
 Lens aperture was set to full open
 DOAL had just enough light to
illuminate part sufficiently
 Original samples evaluated by
Faber were NOT typical
 Actual parts have been tumbled
and banged together leaving a
dulled and dented copper band
 Preprocessing filters were added
to eliminate excessive false
rejects
Conclusion & Observations
 Needed to acquire multiple times
around the circumference of the
projectile
 Programmable SICK Stegmann
encoder was used as trigger
 Allowed for easy encoder line
count change to acquire more or
less times
 Encoder yielded high trigger
frequency that was at 5V TTL
levels
 Needed to swap out the standard
Grayhill 70L-IDCNP opto module
for a Grayhill 70L-IDCB
 New input module has a 50µs turn
on time and accepts a 4.5 to 28
VDC input