Chips and dust - suck or blow?

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tioJim
Posts: 135
Joined: Sun Apr 22, 2012 11:31 am

Chips and dust - suck or blow?

Post by tioJim » Sat Jan 26, 2013 12:27 am

Which is better for chip and dust extraction? I'd like an air compressor anyway for other uses (paint gun, sand blasting etc) but the chips (acrylic) get everywhere as it is even without a high speed jet of compressed air aimed at them! But vacuums are noisy (particularly if running for hours) and a vacuum hose is more cumbersome than an air pipe. But I'd quite like to get a vacuum table which I guess would need a vacuum ... unless you can get air compressors that suck and blow? Not that an air compressor has dust bag of course.

Thoughts?

levlandau2
Posts: 187
Joined: Tue Apr 17, 2012 1:52 am
Location: Minneapolis, MN, USA

Re: Chips and dust - suck or blow?

Post by levlandau2 » Sat Jan 26, 2013 12:37 am

I would not use an air compressor to blow dust/chips while cutting. This would create a giant mess in any workshop and coat everything in dust and garbage. Also, the dust from wood, MDF, fiberglass, and pretty much almost any material being cut is very unhealthy for the lungs.

So I would recommend the vacuum option for sure. I have a shop-vac connected to an Oneida cyclone system. This sucks most of the dust during a milling operation and avoids clogging of the shop vac filter. So your shop will be cleaner and dust-free.

That said running a shop vac adds a lot of extra noise to the already noisy spindle (DW660). REALLY noisy overall. I use earplugs to save my hearing.

tioJim
Posts: 135
Joined: Sun Apr 22, 2012 11:31 am

Re: Chips and dust - suck or blow?

Post by tioJim » Sat Jan 26, 2013 12:40 am

Yes good point. Acrylic chips are one thing but MDF dust is another. Noise is a big issue for me though as I'm in a domestic rather than workshop environment ...

Cwalster
Posts: 22
Joined: Wed Sep 26, 2012 8:12 pm

Re: Chips and dust - suck or blow?

Post by Cwalster » Sat Jan 26, 2013 3:09 am

The answer comes down to what your cutting and what your goals are. Are you more concerned with chip removal or cleaning up the mess? If your concerned with chip removal, such as removing the plastic chips before they reweld or form a blob, an air blast is going to be a god send. If your trying to clean up the mess that MDF makes, go with a vacuum. Ideally, you would have both available to you. You may want to look into a mist cooler too, though I haven't done any research into them. Might help if your after aluminum work.

As a side note, air blasts are common on high-production VMCs that run steel. They don't require coolant, but need something to help clear chips.

levlandau2
Posts: 187
Joined: Tue Apr 17, 2012 1:52 am
Location: Minneapolis, MN, USA

Re: Chips and dust - suck or blow?

Post by levlandau2 » Sat Jan 26, 2013 1:21 pm

Another option is an enclosure. Won't clear the chips but will keep the dust in one area.

As for the production tools, what amount of air flow do the air cooling nozzles put out to cool the endmill? Is this something that can be done by a hobbyist?

DanMc
Posts: 257
Joined: Fri Apr 13, 2012 3:34 am

Re: Chips and dust - suck or blow?

Post by DanMc » Sat Jan 26, 2013 1:37 pm

I'd go vacuum, to have a constant flow of air you need a serious compressor. Most small portable compressors are meant to power intermittent use tools such as nail guns. When you have a constant flow, even at a very low psi say 10 or less the tank will drain rapidly and the motor won't be able to keep up, result is you have the compressor motor running throughout your whole operation. To my ears a constant vacuum is a little less obnoxious than a pancake compressor. Plus there's the cleanup issue as mentioned above.

Cwalster
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Joined: Wed Sep 26, 2012 8:12 pm

Re: Chips and dust - suck or blow?

Post by Cwalster » Sat Jan 26, 2013 3:48 pm

I do not know the actual flow rates, as I do not work in a steel shop. However, you use coolant to 1. remove chips from your cutting area, 2. provide lubricant, and 3. cool your workpiece, in that order. Cooling your part is actually fairly low on your priority list. Therefore, you need just enough airflow to push chips out of a slot. I can't imagine it would take much. A few small orifices should suffice. I'd say that as long as you have a 20+ gallon tank you'd be ok, which is small workshop sized.

levlandau2
Posts: 187
Joined: Tue Apr 17, 2012 1:52 am
Location: Minneapolis, MN, USA

Re: Chips and dust - suck or blow?

Post by levlandau2 » Sat Jan 26, 2013 4:45 pm

That sounds good. Perhaps milling aluminum without any coolant (correctly) is in my near future.

Cwalster
Posts: 22
Joined: Wed Sep 26, 2012 8:12 pm

Re: Chips and dust - suck or blow?

Post by Cwalster » Sat Jan 26, 2013 5:01 pm

Aluminum LOVES coolant. It needs the lubrication from the coolant to prevent the aluminum from building up on the tool. Brass, steel, and high-temp alloys are what usually get run dry.

DanMc
Posts: 257
Joined: Fri Apr 13, 2012 3:34 am

Re: Chips and dust - suck or blow?

Post by DanMc » Sat Jan 26, 2013 5:30 pm

A pretty efficient blowgun at 20psi (20 at the nozzle will be way less than 10 at the work surface) will draw about 5cfm, one of those little 6 gal pancakes holds maybe 8cf of air at pressure, so after a minute the motor kicks on and at a refresh rate of around 4-5 cfm it will really never catch up, a 20gal tank will get you maybe 5 minutes of milling before it kicks on and with a 3hp+ motor can refill the tank but it will take a while. I just went through this trying to drive the air supply on a laser cutter off of shop air and even with a volume expander it used more air than I would have liked.

I'd just recommend trying this out on a borrowed machine before investing several hundred dollars in a compressor.

Edit: if one was interested in using a blowgun, possibly the aquarium air pumps people use for lasers would work at a fraction of the cost of a compressor

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