1. Status Brussels GANTRY
O.Bouhali, J.D’Hondt, C.Vandervelde, L.Van Lancker, J.Wickens
TEC meeting Lyon – January 2004
Try to assemble modules with good precision
different calibration plates (Karlsruhe and Bari)
determination of pin positions relative to markers on plate
Control methods for precision
compare measurements in Brussels and Aachen
compare measurements in 3 different positions of the plate
Plans for the near future
Test to glue stiffeners is OK

2. Comparison of different calibration plates
We have 2 calibration plates :
Karlsruhe plate (measured in Karlsruhe)
Bari plate (measured in Bari and Dusseldorf)
Bari the plate was only partially measured (500 of 625 points)
At Dusseldorf we measured the complete Bari plate at the
temperature equal to that in the GANTRY clean room (21.5 oC)
The measurements were performed by a Mitutoyo high precision machine (resolution ~2mm) and with some pattern recognition
Two measurements :
fit with circle
fit with cross
no difference
(~1-2 mm)

3. Comparison of different calibration plates
Before calibration
After calibration Y X
operator

4. Comparison of different calibration plates
Karlsruhe on GANTRY
Bari on GANTRY Y X
operator

5. Comparison of different calibration plates
Karlsruhe calibration
defined as perfect
Bari calibration Y X
operator

6. Comparison of different calibration plates
Karlsruhe calibration
defined as perfect
Dusseldorf calibration Y X
operator

7. Comparison of different calibration plates
Dusseldorf calibration
defined as perfect
Bari calibration Y X
operator

8. Comparison of different calibration plates
Y axis
Dusseldorf calibration
defined as perfect
Bari calibration
X axis
X axis
Y axis Y X
operator

9. Comparison of different calibration plates
DY(Bari – Dusseldorf) Y
Line 1
Line 10 X
Line 20
operator

10. Comparison of different calibration plates
DY(Bari – Dusseldorf) Y
Line 1
Line 10 X
Line 20
operator

11. Comparison of different calibration plates
DY(Bari – Dusseldorf) Y
Column 25
Column 10
Column 1 X
operator

12. Comparison of different calibration plates
DX(Bari – Dusseldorf) Y
Line 1
Line 10 X
Line 20
operator

13. Comparison of different calibration plates
DX(Bari – Dusseldorf) Y
Column 25
Column 10
Column 1 X
operator

14. Comparison of different calibration plates
Differences up to ~20 mm
For all the rest we will use the Dusseldorf calibration file
Pins have been re-measured
Pin positions are determined relative to the fiducial markers on the plate
Once determined they can be calculated everytime with a translation and
rotation of the reference system (should be simple procedure) + +

15. Procedure to determine the pin positions
Pin positions are determined relative to the fiducial markers on the plate + +
Measure both fiducial markers on the plate
Take ~8 points around the circle of each pin hole
Fit a circle through them
Repeat the above at least 10 times
Look if the fits are stable (small residuals)

16. Fits to determine the pin positions

17. Comparison modules measured in Aachen and Brussels
We assembled 3 real modules on our GANTRY and re-measured them in Aachen
DY( [measured – nominal]GANTRY – [measured – nominal]Aachen )
verified that nominal positions are identical !! 60 55 34 37 54 57 49 42 23 30 37 28 44 44 23 22 37 41 32 30 17 19 24 18 +
Pos.1 +
Pos.2
Pos.3
All can be explained by a rotation and a translation of the module between
GANTRY position and Aachen position  measured shape of module is the same
Assuming that the sensors didn’t move on the frame during transportation,
we have to conclude that the pin positions are not the same in both cases

18. Comparison modules measured in 3 different positions on the GANTRY
A dummy module has been measured in the 3 GANTRY positions
DY( [measured – nominal]Pos.X – [measured – nominal]Pos.X’ )
assuming position 1 is perfect : [meas – nom] = 0
-22
-17 17 20
-20 -8 8 12
-17
-13 10 11
-14 -9 4 + +
Pos.1
Pos.2
Pos.3
smaller residuals than one month ago
All can be explained by a rotation and a translation of the module between
GANTRY positions  measured shape of module is the same
Same conclusion (transportation issue excluded),
the pin positions used by the GANTRY are not the true ones…

19. Conclusion and outlook for the future
Precision of modules is good according to GANTRY
Large disagreements with Aachen
Large disagreements in different positions (smaller than before)
The problem can probably be allocated to the position of the pins
Outlook : go back to the ‘old’ procedure of assembling modules
Revise the soft-ware which uses the calculated pin positions
Some delay for R5 and R3 due to above problems
R5N : pick-up tool for sensors should be ‘aligned’
R5S and R3 : soft-ware in development
R5 plates are ready and successfully tested for vacuum