apa frame inspection - indico-fnal (indico)
Post on 28-Oct-2021
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APA frame inspection
David Payne
24/10/20
Procedure
● Basicly as defined in PSL TN-2016-03
● Some slight alterations● Frame was in wire
winding frame not free● Survey tool was FARO
Vantage laser tracker
Point location tools
● Workshop at Liverpool made us some custom tools to precisely locate reflector at measurement points
Cross corner deviation
● Tolerance: 2.0mm (1mm target)● On table measurement not possible
– Best alternative was using edging tool, constructing edge lines and corner points, taking distance between points:
Measurements and co-ord system
● 6 points along each beam, 5 along head and foot.– P20 unreachable
due to winding frame- moved to next available point
● Co-ord system defined by plane of P1,P6,P12,P17, origin P20
Flatness and twist
(all mm)
● Overall flatness tolerance: 11.0mm
● Overall twist tolerance 1.0 mm/m (?)
● Split into 5 twist zones (same tolerance)
● Zone 5 shows worst twist, but all within tolerance
Comparison to PSL survey
Daresbury PSL
Bowing (beam by beam)
● Deviation from line between head and foot in z (all mm)
● Tolerance 11.0mm
“right”
“left”“middle”
Straightness
● Straightness of board mounting surfaces
● Deviation in y● Tolerance: 1.5 (1.0 target) ● (all mm)
“middle” (no defined tolerance)
“left”Max y dev. -1.5
“right”Max y dev.-1.2
Comparison to PSL: Straightness
Daresbury
PSL
“Right” “Middle” “Left”
Comparison to PSL
Daresbury PSL
Fold
● Displacement in z of side beams relative to centre beam and z of head and foot
● Tolerance 1.2 mm
z
Fold 1.7 mm
Foot tube Rib 1 Rib 2 Rib 3 Rib 4 Head tube
Fold -0.8 mm
Fold -0.1 mm
Fold -0.6 mm
Fold 1.3 mm
Fold 1.3 mm
Where is “folding” coming from?
● Have measurements along edge of head tube (used in slide 3)
● Suggests deviation is not in frame, but in reference points, or in method used to locate them
● Point location tools lift reflector some distance away from frame– Could be picking up and
amplifying surface shape
De v
iatio
n in
z fr
o m s
t ra
i gh t
y
Summary
● APA surveyed in wire winding frame– Not according to original survey
conditions– Twist and bowing within tolerance– Straightness worse than target
but within tolerance– 3 fold measurements outside
tolerance
Fold: rib 3
Fold 1.3 mm
Fold: rib 4
Fold 1.7 mm
Fold: Head tube
Fold 1.3 mm
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