Machine leveling q.

[marker4x4]

Hiall,

this is a bit off topic, but I thought I asked anyway:

we've had a service guy in the shop yesterday to do some leveling on the VMC (we've had about .002 drop in one corner of the table). I watched him dancing around with his level-glass for a bit and I just can't see how the heck matters if the machine's table is perfectly horizontal or not.
In my opinion the whole idea is to ensure that all the "legs" are EVENLY supporting the machine, thus eliminating any unnecessary stress and bends.
Hypothetically, only three out of six, or eight, or whatever, legs are needed to make the table horizontal, correct?
What I'm thinking, perhaps going round 'n round the machine with the torque wrench to gradually tighten ALL legs to exact same value would be a better idea... am I missing something?

Any input will be appreciated, thanks



-mark
Edited by: marker4x4

 

[AHA-D]

I know nothing of the matter but with some common sense :


You need exactly 3 legs to have stability, not more not less. However supporting a large surface without local bending leads to more legs.


Making all legs support exactly their share of the load would indeed be a good criterium.


Getting a machine absolutely level is important when you consider that all movement of equipment is focused on precision first and force as a second. XY translation should only deal with friction and inertia, you don't want it to have to carry the attached equipment "uphill" or keep it from sliding down.


Alex

 

[dross]

Torquing would not work as not all legs have the same load on them. therefore, to get all legs at the same length would require different torque values dependant upon how much weight is on each.


Being level is important for coolant drainage and lubrication systems as well as having a flat work table.

 

[cncwhiz]

Mark,


The machine sits on leveling pads at the corners. They level the machine "close" with these leveling for lack of a better word, bolts. Now when the machine is close then they go to the next part of getting the table flat. If its a small table there are bolts in the center of the machine in line with the outside bolts. The machine will either "sag" in the middle of "bow". The machine can also have "twist". The center bolts are where they get the table flat either by screwing in or out the center bolts. This process is continued until the table is level and flat. This will get the machine close but at times the spindle ram is out of square as well and also needs to be adjusted. If your machine is just sitting on a floor without a pad of its own the machine will move again as the floor settles. I hope this helps.

 

[Zaki]

< = defer>


the best thing is to ask from the machine builder and\or seller from which you people purchased. normally they send a guy or two, whoinstall the machine and make it level,adjustingand makingmachine parallal from all angles, check slides etc. the company normally responsible for installation.