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SMF - Just Installed!

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Messages - HanS

#1
Hello everybody,

I'm a long time lurker first time poster. First, a big thank you for sharing all of this information. This is a prime example of what is great about the net!

Here's my situation. I am the proud new owner of a cnc router. A 48"x48" Cnc Mogul to be exact. The CFO of my house, the missus, agreed to purchase of the machine if I built her a craft room. The one remaining space to be developed is the back half of the basement. So the machine is going to have to live in the basement in her craft room. This creates a couple of issues to overcome. First is that the boss is asthmatic and allergic to everything from grass to dust. Second is noise, as a test I flicked on a router and shop vac in the intended room then went upstairs, her eyes were drilling holes through me as I reached the landing.......then the baby was woken up. Oh my!!!

My solution is to build an enclosure for the machine. This enclosure will house the dc system which will  be comprised of a down draft/vacuum table as well as a dust-shoe at the spindle, flowing into a separator with suction created by one (or two) ridgid wd4522 vacuums.

Which leads me to my first question. Understanding that laminar flow entering the separator improves efficiency how long of a straight run for a given cross section prior to the inlet is required to ensure laminar flow? In other words, is there an ideal placement for the collector (Y)?

I will generally want to use both streams together as the down draft will also serve as cooling air for the router and other electronics, how can I ensure good suction from both as friction losses will be unequal and flow will take the easiest path? Would I be better off having  separate systems each with their own vac source and separator?

A final question related to my enclosure design is about the container for collecting chips. I envision a vacuum tight cabinet with the separator hung from the ceiling, with a hatch for clean out. This is where my brain gives out. Is there any difference between having a top hat sealed to the top of the container or sealed inside of the container? I'm inclined to believe that the "delta P" above vs below the baffle would be the same in both cases....but then I second guess myself.

This makes me think of one more question: what exactly is the physical process causing the chips to drop out? Is purely the pressure differential or is it impingement caused by centrifugal forces or a combination of both?

If your still reading thanks for hanging in there.

HanS