Sucking in the sides

Back to the vacuum table for a sec.  I’ve been cutting out a bunch of designs on the CNC, for a school fete in October – while the machine sits idle during the week, there is no reason for it to do the same on weekends.

The vacuum table makes a huge difference – designs can be cut out without tabs, which saves a phenomenal amount of effort.  Just the time saved between removing a sheet and securing down the next is enough to be significant.

I happened to glance over at the vac this evening, and more specifically to the Clearvue cyclone-like separator (I have the older version of the mini, where they had departed from a traditional cyclone design).  The collection bin on the separator had almost completely collapsed from the vacuum that was being generated.  Lucky it hadn’t caused the lid to spring a leak, otherwise I would have lost what was being cut, and probably the cutter as well.

It makes very evident that this is generating a pretty significant vacuum, and therefore there will not be a great deal of airflow.  Problem with that is the vacuum cleaner itself.  I expect it relies on the airflow for cooling, and without it, I’m probably slowly cooking the bearings.

While the bearings can survive some heat soak, they will be mounted in plastic, and that will not be enjoying the temperature at all.  When that fails, releasing the bearings and therefore the shaft of the motor, the failure will be catastrophic.  Something that is still on my mind.

Just as an aside, after testing out the new dust extractor yesterday, cleaning up around the CNC, I kept using it today after each job, and was easily able to keep the whole work area satisfyingly clean.  This is despite having had to temporarily reduce the 8″ opening to a measly 4″ (in hindsight I should have checked what the inlet was on the unit – I need to get a multi-inlet, or drive a whopping great cyclone unit with the thing).

Thought I would be alright – drop down to Bunnies and get some plumbing fittings to carry me over.  Except they don’t have fittings that run to 200mm!  Let alone tubing.

Based on cross section area of the inlet, I can connect 4x 4″ inlets simultaneously, as the cross section area of 4x 4″ is the same as 1x 8″.  Anything less than that is restricting the extractor’s performance.  Either way, I have some thinking to do to maximise the dust draw from around the workshop.  And where the extractor will permanently reside.

Addendum:

Had a thought, and took another look at the Oneida Super Dust Deputy.  Interesting – the version available in Oz is steel, but in the US there is also a couple of statically conductive resin versions.  One that is the equivalent of the steel version is a whole $US170.   Even if the libs go and dump us with paying GST on overseas purchases, $US170 equals $A267 at the current exchange rate.  There is an XL version, with 6″ inlets and outlets.  That is interesting, but as it is not available here, a bit academic.

The steel Super Dust Deputy has one problem for me (other than being $A500), it is only for 350-850 cfm.  I can now generate 2900cfm!  Hmm – wonder what a home-made Thein could handle?

Update 2 – fixed up my maths – the Sherwood has an 8″ inlet, not 6″!

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