metrology of the stave250 assembly jig (tim). what do we need to measure?
DESCRIPTION
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 = / CIRC=0.001 – Distance PH1-PH2 = Measure front edge of 14 Vee-blocks at 4 points along length (See plot) and reconstruct line of best fit – Y= x10 -4 X Measure Tooling ball – ( , ): DIA=8.207 / CIRC=0.011TRANSCRIPT
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