Re: Vacuum pump for vacuum chuck?

The most reliable pump types are centrifugal and oil free diaphragm
pumps, you should look for one that will pull about 25" to 28" Hg
(Mercury) or 80 - 90% full vacuum.

Domestic vacuum cleaners, hoover, dyson, etc are no good, they are
designed to use the airflow through the cleaner to cool the motor,
block the air flow and you will burn out the motor.

High vacuum oil filled motors like Edwards speedivac, etc are designed
to pull full vacuum but with very low flow, unless you can get a good
seal on your clamp faces the pump will pull too much air and overheat,
blowing the oil as a vapour out of the exhaust. you should also filter
the air between the clamp plate and the pump.

Vane type pumps with graphite vanes need some air to flow through them
continuously or they get clogged with dust which jams the vanes, just
put a T in the pipe with a valve that can be set to allow a small leak
to keep the dust moving.

Hope this helps.

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "timgoldstein" <timg@...> wrote:
>
> Thinking that for a variety of my projects I need a vacuum chuck. Any
> suggestions on what type of pump I should be looking at? Do I want a
> real vacuum pump that can pull a relatively high vacuum, but the CFM is
> low or is there another style of pump that would work better. Most of
> the items I am expecting to clamp will be slightly to moderately air
> permiable.
>
> Thanks,
> Tim
> A2Z Corp
> A2Z CNC division
> 1530 W Tufts Ave Unit B
> Englewood CO 80110
> 720 833-9300
>
> www.A2ZCNC.com/store
> Upgrades and accessories for table top machinists
>