CM24 1 1 June 2009

ASPIRATIONAL SCHEDULE

Mechanics is reassembled; survived basic tests but more required – including positioning accuracy, bedding-in of gears….Electronics & Air Crates working; LabView controls starting (EPICS can wait)Developing ‘Disc transfer Mechanism’ – critical item – next slides

Done

Ongoing

Started

Starting

Done

Done

CM24 2 1 June 2009

DISC TRANSFER CONCERNS Simplified

Disc Holder Disc Carrier

Carousel rotation

D-H Rotation Carrier motion

Discs are transferred between Disc Holders and Carrier

Each disc has 4 pins to fit 4 holes on each side

Each disc has 2 SidesThere are 5 DiscsEach has (up to) 4 Orientations

160 pins & holes to align reliably & reproducibly – or something will bend / break / jam & it’s buggered

Pin – hole clearance is +/– 0.5mm

3 sigma positioning < 0.5mm

Position to < 0.15mm for varying loads on Carousel

CM24 3 1 June 2009

• Not easy to achieve required accuracy• Air motors overrun by several mm, depending....

• Now use piston to align Carousel arm• Measured misalignments are ~ 0.5 – 1mm

• Depend on loading (lead is heavy)

• Design is (was) not forgiving of any misalignments• Have incorporated ‘float’ + springs in carrier

• For L – R and U – D misalignment (1mm / 0.3mm)

• Designing & developing overrun & locking mechanisms for discs• To keep pins aligned in disc-holders & absorb overruns

• More springs / ‘Terry clips’ …. (? Lead times if custom items?)

• Shall build mock-up of Disc-Holder – Carrier arrangement• To test various ideas for locking the pins & overrun ‘buffers’• To develop transfer procedure – almost invisible on real device

• Have allowed 9 weeks in schedule for this (+ other tests)• May need more inspiration & imagination

• Transfer operation development on critical path