Pump for small vacuum table on cnc router

[rjb]

Hi,

I have a small cnc router with a vacuum table (600mm x 400mm approx) and I need a vacuum pump for it. Until now I've been using an old vacuum cleaner, but it's just given up - burned out due to the lack of airflow I think. The vacuum cleaner was just about adequate, but I'd like to replace it with something more powerful. The problem is that I'm not sure what type of pump would be best or what pressure & volume would be required. Also the pumps I have seen are mainly rather expensive.

I'd be very grateful for any advice on what type of pump I need - I'm looking for the lowest cost option that will work. I did read an old post about using an old freezer compressor - would that work for this application?

Thanks,

Richard.

 

[9fingers]

Yes this should work but with a few extras and precautions.

1) Essential to have a filter to stop any dust etc entering the compressor.
2) Need a vacuum switch to switch off the compressor otherwise you might burn that out too.
3)Ideally need a vacuum tank off a truck or calor gas bottle (EMPTY!!!) to stop the compressor short cycling.
4) a vacuum tap to release the workpiece without the huge inrush as the tank tries to fill.
5) some provision to allow addition of oil to the compressor from time to time.

So yes easily done with some bits and pieces from the junk box but don't expect to pick them up as designed for your application.

Bob

 

[rjb]

Hi,

Thanks for the reply. I hadn't thought about the additional parts needed to make the freezer compressor setup work ...I'm now wondering if I'd be better off buying a purpose made pump. Do you know what type I would need and the cheapest source?

Thanks again,

Richard.

 

[TheTiddles]

For a small bed you could use a low voltage diaphragm pump which would run happily against a vacuum for non-continuous use, it wouldn't grab as fast as a vacuum cleaner but would be a higher vacuum and quieter too. I might have one kicking around you can have if you'll cut a couple of things for me....

Aidan

 

[dickm]

Remember that if you do use an old freezer compressor, they are only supposed to be removed by licenced operators because the refrigerant gases should not be released to atmosphere.
I'm not saying don't do it, but just in case......