There doesn't appear to be that much gummy stuff, and most of it is
at the end. When the machine is off, I can turn the motor and move
the quill quite easily by turning the position indicator (about 1.5"
diameter) mounted on the end of the motor shaft. It moves smoothly
and easily all the way up and down. Should the stickiness be
something I should be able to feel when doing this? It won't hurt
it to give it a good cleaning and it sounds like the cheapest
potential solution. Also are you saying that all motors for this
need about 2500 oz-in of torque? Or that servos need 3 times as
much as steppers? I think I had read about 900 oz-in for a stepper
replacement works good on these.
Thanks
Nathan Clymer
--- In CAD_CAM_EDM_DRO@..., Les Newell <lesnewell@...>
wrote:
Hi Nathan,
This a a fairly common problem. After a lot of use the slideway
oil
tends to leave a gummy deposit where the quill slides in the head.
I
found that taking the front cover off, cleaning out the oil then
pouring
in some cellulose (lacquer) thinners and running the quill up and
down a
few hundred times helped wash out the crap.
You can change to a servo on the Z without changing the other
axes. That
servo you are looking at hasn't really got enough torque to use as
drop-in replacement. Ideally you need one with 2.5 - 3x the
torque. You
can get around the problem by fitting a smaller pulley on the
motor but
this can be hard work. It is a big job to change the belt. If you
do
this be very careful to make sure the ball nut does not run off
the end
of the screw. According to Bridgeport if you do this you have to
replace
the nut and screw! You may also have to relocate the motor
mounting
holes if the belt does not line up perfectly.
Les
