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发表于 2007-12-3 12:38
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[V] AutoCAD 实战讲座第七讲
4 {3 L0 q& H. U9 eAutoCAD 实战讲座第七讲
" J% w5 M0 R" w) d! {2 v0 @; cNew Maple AutoCAD (7)! |5 ]" }7 f8 Z+ F. |. ^
www.newmaple.com/video/autocad0007; j% n$ C+ x' n
4 Y1 k$ C9 j |" W- a1 y# WA real sample to review lecture 6; I& x" u& Q# M, T3 E+ E
9 V* P! B- H) S c$ m# H, ^Introduction Roughness9 e6 H$ L D h) L5 O4 d
Quick check hole size and position: m+ a# U9 n- j& w; `
Introduction O-ring groove
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- K2 I- F' a' u% t5 _7 }Surface roughness
) _5 e6 q8 z% w• Imperial Unit: micro-inch 10-6 inch- t3 i$ @ S3 z; b0 x/ w4 z: ]
• Metric Unit: micrometer 10-6 m y% r9 C8 h0 d. Y A5 }
• Sample 250 micro-inch = 6.3 micrometer
" q& c' u1 p5 R, a(250X25.4X10-3)4 W4 G% D8 R7 E. x7 W+ K) ~( y1 _. F
• 250 micro-inch – forging surface* t' k& F4 f# p T, _/ i; m5 Q3 _
• 125 rough machine, 32 fine machine: S) x F8 c+ Q
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Inch size O-ring' r9 z4 A @. g0 [
• O-ring number 232
2 a1 J4 v5 A) z& f" f, O6 V3 d• nominal size 2.75”x3”x1/8”
1 L; l1 J5 _. L" n) R• Actual size 2.734”x3.012”x0.139”
; J# Z$ j" w. @; u% O5 c4 |• Static surface seal groove depth 0.101~0.107 about 25% squeeze; _+ I5 t9 y# y6 e1 h3 Y/ o$ v
• One of OD or ID is close standard size
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