Order Number: 334785-002
Intel
®
Xeon
®
Phi™ Processor x200 Product Family TMSDG
33
Retention Assembly Mechanical Design
4.1.2
Bolster Plate with Spring
The bolster plate is an integrated subassembly that includes two corner guiding posts
placed at opposite corners, nuts to mate with the back plate, and two springs that
attach to the heatsink via captive screws. The corner posts guide the Processor
Heatsink Module (PHM) as it is lowered over the socket. The corner posts act as coarse
position constraints in the X-Y direction to prevent the PHM from moving and potentially
damaging the processor package or socket. The springs on either side of the bolster
plate are attached via small rivets. The springs attach to the heatsink via screws. The
bolster plate screws tighten in nuts on the center of the heatsink. The springs are
pulled upward as the heatsink is lowered and tightened in place, creating a
compressive force between socket and heatsink. The resulting socket-to-processor
contact force ensures maximum contact areas between socket pins and processor
package lands, as well as between package and heatsink. The springs provide 180-250
lbf. The springs include stoppers on their outer edges, to prevent movement of the
heatsink in the Z-direction due to forces parallel to the main board. The entire bolster
plate and spring assembly with nuts and bolts is expected to be supplied as a single
unit by vendors.
Note:
The PHLM heatsink nuts and bolster plate studs are rated to a durability specification of
12 installation and removal cycles, when using the reference designs with lubrication.
Lubrication is required on the bolster plate threaded studs and heatsink nut threads.
This is based on the visual inspection criteria of no observed dust/shavings greater
than 0.5 mm in length as seen from the naked eye from 24 inches away with direct
overhead lighting under cool white fluorescent light conditions [60-120 Ft-Candle (645-
1293 LUX)] or equivalent, and a viewing time of one visual pass of 5-7 seconds for
each surface. Refer to
Appendix E, “Retention Assembly Mechanical Drawings”
for
details on the hardware.
