PDR Vacuum Spool Clearances Check. T. Brown September 1, 2003. VV spool assembly clearance space allocation goal. 1.00 VV insulation 0.25 minimum gap at final position (also makes up part of the space needed for final assembly in the area of the VV spool piece)
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September 1, 2003
1.00 VV insulation
0.25 minimum gap at final position (also makes up part of the space needed for final assembly in the area of the VV spool piece)
0.188 VV fabrication tolerance (3/16”)
0.06 MC fabrication tolerance (1/16”)
0.25” Additional assembly tolerance for final assembly (this value is 0.75” for the assembly of the MC over the VV).
1.75” Target clearance set for the MC to VV spacing in spool region
Reverence VV-06 vessel spool had 1.50 clearance to MC during assembly. With weld prep added to basic VV-06 spool the clearance degraded to 1.32”
Ref VV-06 basic spool
Note: We accepted the 1.5” clearance because we were expecting a .25” build reduction in the Type C MC.
Spool altered to eliminate crease
PDR baseline spool
New PDR spool shape exceeds original boundary in some areas
1/8 VPI layer
0.375 (9.5 mm)
2.175 (55.2 mm)
Component Build Dimension Comparison
VPI layer ?
1.50 (1.0 insulation + 0.25 gap + 0.188 VV tol + 0.06 MC tol)
The clamp is .125” thicker but a large corner radii HELPS the spool assembly
(this took a 2 hr run!)
1.060” low side
The two servos driving the spool are not properly adjusted to arrive at a maximum clearance value (see next slide).
Servo’s can be adjusted to obtain an average minimum clearance of 1.56 inches between the MC and new PDR VV spool piece.
1.060” low side
2.068” high side
0.5 Jim C needs 0.5” assembly gap at spool for final assembly
0.00 change VV spool tolerance to +0 / -.060
0.06 MC fabrication tolerance
1.56” This will work!
Per discussion with Brad, the VPI layer is under the clamps
1.75” Target clearance that initially was set for the MC to VV spacing in the spool region can be reduced if the spool tolerance is changed to +0 / -.06;
or we can increase the clearance by going back to a 3/8” thick clamp.