Quote Originally Posted by andy_con View Post
yeah I'm machining ally and all the way through
Well there's your problem doubled then.!! Soon as you cut thru you release vacuum. So even more vacuum is required. IF the remaining area is small you'll need high vacuum to hold onto it.

Really with small parts then vacuum is only any good if you have dedicated jig that will hold full high vacuum in areas of the parts that don't cut thru.

End of the day it's logical if you think about it. Surface area is the key, so if the part is small there's much less area to hold onto so higher vacuum pressure is required to hold it but less volume needed. Large parts have more surface area so a lower vacuum pressure can hold it because there's more to hold onto. Start cutting thru and large area then volume of vacuum required is more but cut too much and at some point the pressure will drop and you'll loose grip.