Metrology of the Stave250 Assembly Jig (Tim). What do we need to measure?
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Transcript of Metrology of the Stave250 Assembly Jig (Tim). What do we need to measure?
Metrology of the Stave250 Assembly Jig
(Tim)
What do we need to measure?
Procedure• Measure PH2 and define as (0,0)
– 4 point: DIA=0.043 / CIRC=0.001
• Measure PH1 and define PH2-PH1 as primary axis– 4 point: DIA = 0.063 / CIRC=0.001– Distance PH1-PH2 = 1247.520
• Measure front edge of 14 Vee-blocks at 4 points along length (See plot) and reconstruct line of best fit– Y=-42.228 + 1.5738x10-4 X
• Measure Tooling ball – (1248.586,-119.685): DIA=8.207 / CIRC=0.011
Vee Blocks
-200 0 200 400 600 800 1000 1200 1400-43
-42.75
-42.5
-42.25
-42
-41.75
-41.5
-41.25
-41
f(x) = 0.000157382449975012 x − 42.2282247148167R² = 0.538518351391159
Position along jig (0 = PH2) (mm)
Dist
ance
from
(PH2
-PH
1)
CAD Analysis
CAD Analysis
Comparison with SmartScope• Procedure
– Mount jig on Smartscope & reconstruct lines along the edges of the Vee blocks (sub-stage illumination). Construct datum axis
– Measure tooling ball as a composite of 3 sub-circles• Diameter = 8.209 / CIRC = 0.0186
– Measure PH1 as a composite of 3 sub-circles• Diameter = 0.0287 / CIRC = 0.0015
– Measure distance from Tooling ball to PH1 parallel to Vee-block datum axis• 1.0765 – Diameter/2 = -3.028
– Measure PH1 offset to Vee-block axis• 42.040
Vee-blocks (CMM vs SmartScope)
-200 0 200 400 600 800 1000 1200 1400-0.5
-0.25
0
0.25
0.5
-0.5
-0.25
0
0.25
0.5
CMM (Corr)SmartScope
Position along jig (0 = PH2) (mm)
Dist
ance
from
(PH2
-PH1
)
Resid
ual (
Smar
tsco
pe)
CMM Survey with Back-lighting
• Pin-holes and tooling ball measured with back-lighting to try and improve measurement– Hi-tec torch (Wifi/3G enabled)
• Results– Pin-holes • 0.028 / 0.030 mm with 4-point circularity of 0.001mm
– Tooling ball• 8.205mm with 20-point circularity of 0.025mm
Comparison of CMM Vee-block alignments
-200 0 200 400 600 800 1000 1200 1400-42.5
-42.3
-42.1
-41.9
-41.7
-41.5
Back-lit SurveyFront-lit Survey
Position along jig (0 = PH2) (mm)
Dist
ance
from
(PH2
-PH1
)
Survey with 4mm dowels (CMM#3)• 4mm dowels
held into Vee blocks with tool-makers clamps.
• Inner edge of dowels reconstructed using back illumination via reflection from aluminium.
Comparison of Vee-block surveys
• NB 4mm dowel data offset by +3.40 mm
-200 0 200 400 600 800 1000 1200 1400-42.5
-42.3
-42.1
-41.9
-41.7
-41.5
Back-lit Survey
Front-lit Survey
4mm dowels
Position along jig (0 = PH2) (mm)
Dist
ance
from
(PH2
-PH1
)
SummaryParameter CMM CMM #2 CMM#3 SmartScope
Ref Offset Y1 42.032 42.036 45.472 42.040
Ref Offset Y2 42.228 42.229 45.649
Dim Y1 to Y2 1247.520 1247.522 1247.522
Ref Offset X1 3.053 3.057 3.055 3.028