Fiducialisation and shims dimensioning Sylvain GRIFFET 24012011 Measurements performed on the 3 rd week of January 2011 1 5 Measurement objectives Unfortunately neither the girders or cradles but to a lesser extent ID: 251259
Download Presentation The PPT/PDF document "Boostec girders and cradles measurements" is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
Slide1
Boostec girders and cradles measurementsFiducialisation and shims dimensioning
Sylvain GRIFFET,
24/01/2011
Measurements performed on the 3rd week of January 2011
1
/5Slide2
Measurement objectives
Unfortunately
neither the girders or cradles (but to a lesser extent) have a perfect
geometry. It is therefore necessary to determine the defects of these elements to allow us to dimension shims. During the assembly of the girders with the cradles, these shims will allow correcting a large part of machining defects and to position the girders, and so the beam axis,
as close to their theoretical locations.
Boostec
, Fiducialisation and shims dimensioning
Sylvain GRIFFET,
24/01/2011
2
/5
The girder-cradles assembly is
difficult to measure at one time in metrology,
yet it is necessary to know where are located the pin holes on the cradle with respect to the beam axis. Measurements of cradles were performed last week included the fiducials, the sensor plates and the pin holes. So during the next measurements of the girder-cradles assembly by the CMM, the measurement of the fiducials will link the inaccessible pin holes to the coordinate system of the girder and therefore to the beam axis. Slide3
Cradles
measurements
The 5 cradles have been measured by Lilian REMANDET with the help of the Ferranti CMM, with an accuracy of ±3 µm
. These measurements should have been performed with the more accurate Leitz CMM but unfortunately it
currently doesn’t work.
Sylvain GRIFFET
,
24/01/2011
3
/5
What was measured on cradles:
Boostec
, Fiducialisation and shims dimensioningSlide4
Girders measurements
The 2 Boostec girders have been measured by Dominique PUGNAT with the help of
the Olivetti CMM, with an accuracy of ±6 µm. As for cradles, these measurements should have been performed with the Leitz
CMM.
Sylvain GRIFFET, 24/01/2011
4
/5
What was
measured on
girders:
Boostec
, Fiducialisation and shims dimensioningSlide5
Results
According to
the preliminary results, which we will validate together with
Nicolas CHRITIN, it seems possible to compensate all defects: that is to say that the calculation doesn’t provide negative shims. So we will be able to machine shims before reassembling of DB girders in building 169.
Fiducials measurements allowed us to determine their locations in
two different
coordinates systems: cradle and girder.
The next
measurements of
all these fiducials will
allow us to link the pin holes to
the beam axis, using a simple change of coordinates system .
Sylvain GRIFFET, 24/01/2011
5/5Boostec, Fiducialisation and shims dimensioning