Hi,
just to show how the calculation works I will demonstrate using the parameter of my mill, namely acceleration of 375mm/s2.
At 50mm/min approach:
V=50/60
  =0.8333 mm/s
ts=V/a
   =0.8333/375
   =2.22ms
d=0.5 * 375 * (0.002222)
  =0.925um
ie the overrun is les than 1 um, plenty good enough accuracy.
At 100 mm/min:
V=100/60
  =1.666mm/s
ts=1.6666 / 375
    =4.444ms
d=0.5 * 375* (0.004442)
  =3.7 um
ie at 100mm/min the overrun is about the same as the accuracy of my machine, ie its acceptable.
At 200mm/min:
V=200/60
  =3.33mm/s
ts=3.333/375
   =8.88 ms
d=0.5 * 375* (0.008332)
  =14.8 um
ie at 200 mm/min approach the overrun is nearly 15um and about three times the accuracy of my machine. If I am probing normal 1 oz board,
35um copper, then the probing overrun amounts to 43% of the thickness of the copper layer which is unacceptable.
Craig