# Chapter 11 : Surface Finish¶

## Exa 11.1 : Page 436¶

In [2]:
from __future__ import division
v = 15000 # vertical magnification
h = 100 # horizontal magnification
l = 0.8 # sampling length in mm
a1 = 160 # area above datum line in mm**2
a2 = 90 # area above datum line in mm**2
a3 = 180 # area above datum line in mm**2
a4 = 50 # area above datum line in mm**2
a5 = 95 # area below datum line in mm**2
a6 = 65 # area below datum line in mm**2
a7 = 170 # area below datum line in mm**2
a8 = 150 # area below datum line in mm**2
a = (a1+a2+a3+a4+a5+a6+a7+a8)/(v*h)
CLA= a/l
print "C.L.A value = %0.2f*10**-6 m " %(CLA*1000)

C.L.A value = 0.80*10**-6 m


## Exa 11.2 : Page 436¶

In [4]:
from math import sqrt
# #from figure 11.23
y1 = 0.15 # mu_m
y2 = 0.25 # mu_m
y3 = 0.35 # mu_m
y4 = 0.25 # mu_m
y5 = 0.30 # mu_m
y6 = 0.15 # mu_m
y7 = 0.10 # mu_m
y8 = 0.30 # mu_m
y9 = 0.35 # mu_m
y10 = 0.10 # mu_m
y1sqr = y1**2 # mu_m
y2sqr = y2**2# mu_m
y3sqr = y3**2 # mu_m
y4sqr = y4**2 # mu_m
y5sqr = y5**2 # mu_m
y6sqr = y6**2 # mu_m
y7sqr = y7**2 # mu_m
y8sqr = y8**2 # mu_m
y9sqr = y9**2 # mu_m
y10sqr = y10**2 # mu_m
n = 10
yn = (y1+y2+y3+y4+y5+y6+y7+y8+y9+y10)/n # arithmetic average in mu_m
rms = sqrt((y1sqr+y2sqr+y3sqr+y4sqr+y5sqr+y6sqr+y7sqr+y8sqr+y9sqr+y10sqr)/n) # r.m.s value in mu_m
print " The arithmetic average = %0.2f*10**-6 m \n The r.m.s. value = %0.3f*10**-6 m"%(yn,rms)

 The arithmetic average = 0.23*10**-6 m
The r.m.s. value = 0.248*10**-6 m