Counter balancing

Carey,
I noticed your post on the CAD_CAM group about counter balancing.
Some one else also mentioned using air cylinders to support the weight.
I used the same method a few years ago to fully support the head on a laser
cutting machine.
The Z motor was having to do a lot of work to retract the head and this
caused a lot of burnt out motors.
I fitted an air cylinder at the side of the slide and ran a bowden cable
from the slide, then over a pulley mounted on the air cylinder and secured
the end at the bottom of the air cylinder.
This reduces the stroke needed to half that of the slide and so saves a bit
more room.
I just took a feed of the normal shop air supply and ran it through a
normal regulator.
With the ball screw disconnected by adjusting the regulator I was able to
fully counter balance the slide so that you could literally move it up and
down with one finger and it stayed where it was left.
Since this time I have modified the other 4 lasers and they have had no
more motor problems.
--

Regards,
John Stevenson
Special Purpose Machines
Nottingham, England