[gator9266]

Hi
Our CNC uses a 1 pump 4 zone system for hold down. Even with rear zones closed I am not getting enough vacuum to hold down 1/8" PVC, pieces being cut are 4.5" x 14". They seem to have less vacuum at end of piece. All edge channels are covered. What is the pressure I should be reading? Thanks. Greg

[Wrat]

You shouldn't be reading any pressure, because it's a vacuum. But approx. 30" of mercury (in/Hg) is the ideal. Seldom will you see over 26-27.

If it's different anywhere throughout the system, you have a leak.

Wrat

[inventor83]

You could have a leak or your filters are dirty. There could be more to this story tho.

[gfacer2]

OK, so yes 30" Hg is ideal. We generally could do that with way less. If this is solid pvc that's a bit tricky as its a bit slippery. If its foamed pvc, then 7" Hg should be OK. Even with solid, 10 or 11 I would think are fine. But they are smallish pieces and regardless of your vacuum, if you don't have the surface area, it doesn't help.

Add a layer or 2 of masking under it and then cut to that, keeps the vacuum and cuts the part.

Also,
What style of pump? What is the rated max pull? What are you pulling through (spoil board or?).






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