IPC-TM-650 EN 2022 试验方法1.pdf - 第297页

Figure 5 Measurem ent of T wist R A C D B R = Highest P oint of Boar d Shim under raised corner of A. B, C, and D touc hing Datum Surface. Only one corner may be ph ysically restrained. Figure 6 Sample Placement R2 Lowes…

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Note:
Note:
Figure 4 Bow Measurement
Touching Datum
Surface
HIGHEST POINT
measured as R or R
L
W
Touching Datum
Surface
IPC-TM-650
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Figure 5 Measurement of Twist
R
A
C
D
B
R = Highest
Point of Board
Shim under raised
corner of A.
B, C, and D touching
Datum Surface. Only
one corner may be
physically restrained.
Figure 6 Sample Placement
R2 Lowest
Corners
R2 R2
R1
Raised Parallel
Surfaces
IPC-TM-650
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Figure 7 Corners Supports
R1 R1
R2
Supporting Jacks or Blocks
Figure 8 Highest Point Measurement
Measure at
This Point
Measure at
This Point
R2
R2
R1
IPC-TM-650
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