9
The stretched and shaped 2A12-O aluminum board with thickness of
δ
=2mm is used as
individual sector plate after quenching, stretching and shaping. Z type aluminum casting
material is used as back rib after quenching, stretching and shaping in order to perform
positioning with rivet the die table for riveting rib and reflector. Each sector plate is
supported at backups via 6 stretching bolts. In order to ensure the process precision, such
process technology as first bonding and second riveting is adopted to improve the
strength of individual plate and reduce the number of rivets and thus decrease the local
deformation of plate caused by riveting points. The high precision mould and tool set up
process are used for all procedures, such as stretching, stretch bending, riveting. The
accuracy of the individual plate is
≤
0.15mm (R.M.S). The reassembly precision of
whole main reflector is
≤
0.45mm (R.M.S).
3.1.1.3 Subreflector and Its Supporting Mechanism Design
The subreflector is made of aluminum casting material and adopts the integral structure. It
is manufactured with the numerically controlled machine tool to ensure its precision,
which is not more than 0.15mm (R.M.S). The subreflector supporting mechanism is
composed of four support rods and one adjustment mechanism. In order to reduce its
shadow to the main reflector and ensure the supporting rigidity, the subreflector support
rod adopts the flat oval steel tube, of which one end is supported at the main backups and
the other is connected with the subreflector through adjusting mechanism. The four
adjusting bolts of adjusting mechanism are used to implement the adjustment of
subreflector axial movement, lateral movement and drift angle. The three-dimensional
forming diagram of subreflector and its supporting mechanism is shown in Fig.3.1-6.
