【转帖】aligment.txt

huangyhg

aligment
if i want to level to a cylinder, can i do that? say i don't have a flat surface to level to but i have a cylinder so i want to make it a datum a and orgin in the same time. do i have to level on it, or just rotate to it?
you choose it like you choose a lane to level to it. when you level to the cylinder it will become arallel to the axis chosen(ie +z, +x...)
you choose it like you choose a lane to level to it. when you level to the cylinder it will become arallel to the axis chosen(ie +z, +x...)
really, i thought make 2 circles and then rotate from one to another. would that be the same thing as make a cylinder and level it.
you need to level an object before doing a rotation.
1) measure the cylinder as a cylinder, to establish the centerline axis. leveling on the centerline axis of a cylinder is the same as leveling on the axis of a lane.
2) once leveled on the axis, then you will have to locate one end of the cylinder. i usually do this by measuring a lane on the zero end of the cylinder and then intersecting the lane with the centerline axis to get a oint. this becomes my origin.
3) now you have a leveled feature and a zero oint, but you still need to determine what to use to sto the rotation about the axis (tertiary datum). it should be called out on the rint, as to what feature to use for this. if the cylinder is symetrical all the way around, you may have to ick something like a art label, a stam number or something else that would rovide some sort of reeatability in your alignment.
really, i thought make 2 circles and then rotate from one to another. would that be the same thing as make a cylinder and level it.
ok, what if i'll do a bit different:
1. measure a cylinder (it's standing u) level the cylinder to lane z lus.
really, i thought make 2 circles and then rotate from one to another. would that be the same thing as make a cylinder and level it.
leveling is 3 dimensional while rotating is 2 dimensions about a third. if you are trying to rotate, what are you rotating about? an arbitrary third axis, h as a machine axis or something similar, isn't a measured feature and could lead to error.
actually you can rotate twice and get the same effect as leveling... but why would you do it?? when you go back to review the rogram later, it will be confusing to follow since it is not standard method.
if you measure the cylinder as two circles, then construct a 3d line between them and then level on that 3d line. and then, yes you can set xy zero on them
so if i measure 2 circled and then i construct a line b/n them then if my circles are standing u on the surface late i can level the line to say z lus?