hydrostatic linear bearings of granite - lareg mill
Posted by
hanermo 2
on 2006-05-10 07:50:09 UTC
jon, ballendo, others - thanks for your comments.
My rationale:
I wish to build a large (bridge design) mill with 1400 mm x 1400 mm work
area (approx 200 mm z).
Thats why I plan on granite ways. Im in spain, and can get local
granite, polished, ground for a decent price.
Industrial linear slides for this size would be over 3-4000 $ !
I managed to buy a bridgeport M-head thats now coming from the states,
and will use geckos and steppers to move the y axis head (on the bridge).
Using an H-frame on the bridge, with a granite baseplate on top of that,
that the z-axis rests on, I should have less than 0.01 mm deflection on
the z-axis due to head movement (weight).
Y-axle: the head plates and moving components will weight about 120 kg
(300 pounds),
and I plan to use pressurised oil through the head plate onto the ways,
using an electric motor, with integral reservoir.
X- axis: moving table, where I will build some kind of milling table,
and use a face mill to get it square with the machine itself.
The x-axis will be about 2800 mm wide, and the y-axis about 2200 mm.
Total weight should be about 600 kg, and is of no concern.
Uses:
to mill mild steel, 316L, and wood.
I believe that although my absolute precision may be 0.02-0.09 mm,
local precision (within, say 300x300 mm)and repeatability should be
around 0.01-0.02 mm,
thus giving good results within allowed error budget. By forcefeeding
(pumping) the oil
through the base plate onto the ways, a steady, controllable oil film
thickness can be achieved.
Why?
To build a steel yacht, 24 m long, 55 metric tons displacement.
I need 140 cm x-axle width to mill doorframes with just one offset (and
3 offsets for roof support arches).
The mill will be used to do all arches (wood interior), trim, corners,
support baseplates (mild steel) ,
portlights (windows), hatches ( doors), console supports, hinge bases etc.
It will save about 2000 hours work time on the project.
A further 3000 hours will be saved by CNC welding the steel flat sheets
together, and plasma cutting the frames to size.
Estimated time to build is 4-5000 hours ! (6 months, six people, 3 shifts)
I have been lurking on these lists for about 3 years, collecting pieces,
money and learning.
Any and all advice, support, comments are much appreciated.
I'll put up a website with pics over the weekend.
My rationale:
I wish to build a large (bridge design) mill with 1400 mm x 1400 mm work
area (approx 200 mm z).
Thats why I plan on granite ways. Im in spain, and can get local
granite, polished, ground for a decent price.
Industrial linear slides for this size would be over 3-4000 $ !
I managed to buy a bridgeport M-head thats now coming from the states,
and will use geckos and steppers to move the y axis head (on the bridge).
Using an H-frame on the bridge, with a granite baseplate on top of that,
that the z-axis rests on, I should have less than 0.01 mm deflection on
the z-axis due to head movement (weight).
Y-axle: the head plates and moving components will weight about 120 kg
(300 pounds),
and I plan to use pressurised oil through the head plate onto the ways,
using an electric motor, with integral reservoir.
X- axis: moving table, where I will build some kind of milling table,
and use a face mill to get it square with the machine itself.
The x-axis will be about 2800 mm wide, and the y-axis about 2200 mm.
Total weight should be about 600 kg, and is of no concern.
Uses:
to mill mild steel, 316L, and wood.
I believe that although my absolute precision may be 0.02-0.09 mm,
local precision (within, say 300x300 mm)and repeatability should be
around 0.01-0.02 mm,
thus giving good results within allowed error budget. By forcefeeding
(pumping) the oil
through the base plate onto the ways, a steady, controllable oil film
thickness can be achieved.
Why?
To build a steel yacht, 24 m long, 55 metric tons displacement.
I need 140 cm x-axle width to mill doorframes with just one offset (and
3 offsets for roof support arches).
The mill will be used to do all arches (wood interior), trim, corners,
support baseplates (mild steel) ,
portlights (windows), hatches ( doors), console supports, hinge bases etc.
It will save about 2000 hours work time on the project.
A further 3000 hours will be saved by CNC welding the steel flat sheets
together, and plasma cutting the frames to size.
Estimated time to build is 4-5000 hours ! (6 months, six people, 3 shifts)
I have been lurking on these lists for about 3 years, collecting pieces,
money and learning.
Any and all advice, support, comments are much appreciated.
I'll put up a website with pics over the weekend.