MICE Target Mechanical Design

Contents» Status of modelling and drawing» Work being undertaken at RAL on shaft and bearing

prototypes» Procedure for shaft manufacture to ensure straightness» QA» Procedure for alignment of bearings in core» Manufacturing ‘database’» Cut-off date» Assembly location (discussion)» Stator

MICE Target Mechanical Design Status of drawings

» All modelling complete bar few last minute changes (prototyping) see later

» Shaft piece parts and assemblies finished, ready for checking

– Engineering check (N Sage provisional)– Tecvac OK for coating– W/S OK for manufacturing– Weld contractor OK for joining (also for jigging)

MICE Target Mechanical Design Status of drawings

» Bearings almost ready for checking– Engineering check (N Sage provisional)– Tecvac OK for coating– W/S OK for manufacturing

» Core drawings to be finished (AL)» Overall assembly drawing (JT)

– Parts list

» Peripheral parts to be drawn (TJ)

MICE Target Mechanical Design Prototype work at RAL

» Shaft– Conventionally turned top section accurate

size but not straight Use centreless grinding technique (size,

geometry, finish) shaft design changed

– Cutting 1 flat bends shaft (as expected!) Use very small cuts (stress zone ~ depth of cut) Flat on both sides – 3 stage production

– Socket prototype Taper socket with shallow angle to centre and

align top and bottom sections (preferred by weld contractor)

MICE Target Mechanical Design Prototype work at RAL

» Bearings– Can be bored accurately but best with pre-

ream– Polishing showing ‘bell-mouthing’– Location in housing using taper or close fit

About 1mm square

MICE Target Mechanical Design Recent changes

» Shaft– Double flat– Taper joint

» Bearings– Thickened base bearing– ‘Start part’ with features for machining– Taper OD for location (parallel option too)

» Core Assembly– Decreased vacuum tube length to allow

taper location of bearings

MICE Target Mechanical Design Shaft Procedure – (up to 4 shafts)

» Rough m/c & straighten stock materials– Rough turned as necessary

» Stress relieve heat treatment– vacuum oven– 650degC 30 minutes– Max rate heat & cool to minimise grain growth– Review oven cycle from print-out

» Final machine upper shaft– Centreless grind to size– Return to RAL for Metrology– Machine on features on upper shaft– Polish bearing regions(?) then Metrology to determine Ra Rz

etc

MICE Target Mechanical Design Shaft Procedure...

» Pre-weld assembly– Upper shaft press on rough machined socket– Lower shaft fit stop

» Weld on socket & stop– Undertaken in chuck in EB (Electron Beam) welder– Rapid weld in precise location minimises heat (added to low

thermal conductivity of Ti = minimal HAZ)– Procedure variables and QA schedule agreed with

contractor

» Final machine socket ends of upper and lower shaft

– Machine to fit on taper– Partner pieces identified

MICE Target Mechanical Design Shaft Procedure...

» Press fit (with T)– Involve metrology to ensure geometric location between

bearing sections

» Weld both together– Requires jig with bearings and compliant couple to

powered chuck in EB welder

» 2nd Stress relieve heat treatment– Vertical orientation (under tension?)

» Metrology– Relative location of 2x bearing sections

MICE Target Mechanical Design Shaft Procedure...

» DLC Coating– Clean– Coat– Tecvac to advise on QA

» Metrology– Final check on dimensions and geometry of bearing sections– Where manufactured outside CofC required

» Transportation– Transportation boxes required (2 off with capacity for 4

shafts each (= despatch flexibility)

MICE Target Mechanical Design QA

» Materials– Certificates– Element analysis (Bodycote)

» Size & geometry– Dimensional measurements (RAL Metrology)

» Surface Finish– Surface trace (RAL Metrology)

» DLC coating (Tecvac to advise)– Adhesion test– Wear test on swatch– Print out of cycle

MICE Target Mechanical Design QA...

» Welding– NDT method on shaft (e.g. X-ray)– Tests on pre- & post-production samples undertaken

immediately before/after shaft weld Section & micrograph Tensile test (qualification of procedure?)

– Request definition of ‘quality weld’

» Heat Treatment– Cycle data from vacuum oven– Copy of certificate of calibration of vacuum oven– Swatch testing

MICE Target Mechanical Design QA

» Recording information– Traveller document linked to specific shafts– Method of identifying particular shaft– Sign off at each stage with sign off criteria

» Prototyping– Enables definition of what is achievable on drawing,

quicker sign off

MICE Target Mechanical Design Bearing - Core Procedure

» Bearing production– Machine ‘start part’– Send off for wire cutting of wedge (Di-Spark or

ICL?)– Inspect fit upon return– Add features to clamp wedge– Add dowels– Add bores (incl. polish) and turn taper and part

off (all in one) Highly accurate location of bore to OD

– Metrology– Add reverse features– DLC coat

MICE Target Mechanical Design Bearing - Core Procedure

» Core production– Produce core cap part (1130) with precision fit but not

bearing recess - Metrology– m/c features of main core (1128) on general lathe &

part off - Metrology– Add fixing holes to flange– Fit precision lathe with drilled flange and face off– Fit m/c core and clock concentric– Machine fit for cap– Add cap and machine bearing recess (use molyslip or

similar!)– Remove, dowel on mill remove cap– Turn around and clock concentric– Add bearing recess

MICE Target Mechanical Design Bearing - Core Procedure

» Core production – Alignment features– Best alignment

Precision lathe for fine tolerance work (sole operator Eamonn Capocci)

Bearing ID / OD machined w/o changing position in chuck

Bearing holes machined in assembled parts on same dedicated jig using same reference datums

Taper fits on bearings & dowels to give consistent repeatable alignment

Dowelled cap on core body for accurate reassembly

MICE Target Mechanical Design Manufacturing ‘database’

» General assembly of MICE Target– Parts list used as BOM

» Decide responsibility for:– Manufacture– QA– Sign off etc

» Individual item (critical) or batch log– Logs...materials certs, processes, when, where/who,

inspection, sign off– Held by responsible

Schedule – for cut-off date

(V2)No contingency