Smoothing out Pulsing Air Assist

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Smoothing out Pulsing Air Assist

Postby andrewblanejr » Fri Oct 07, 2011 11:40 pm

Anybody doing anything to smooth out the pulsing of their air assist compressor?

I got this one: http://www.amazon.com/gp/product/B002JPPFJ0

its just like the one that came with my FSE 40W, but bigger (110lpm vs 82lpm). But they do have quite a pulse to them. Would a cheap inline air regulator reduce this pulsing?

/Andrew
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Re: Smoothing out Pulsing Air Assist

Postby BenJackson » Fri Oct 07, 2011 11:42 pm

The ball valve with mine does not help, but I have heard that if you hang a bigger inline volume in there first it might. I've been meaning to make a PVC reservoir to put inline.
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Re: Smoothing out Pulsing Air Assist

Postby bdring » Sat Oct 08, 2011 12:19 am

It is like the air equivalent of an RC filter.

R = resistance from a valve
C = capacitance ... some amount volume before the R.
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Re: Smoothing out Pulsing Air Assist

Postby TLHarrell » Sat Oct 08, 2011 6:16 pm

For my airbrush (very similar compressor) I use an old Freon tank that I picked up for free many years back. It's roughly 2 gallons and smooths out the flow considerably. It's just got a T fitting off the line from the compressor about halfway to the airbrush.
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Re: Smoothing out Pulsing Air Assist

Postby J45on » Sat Oct 08, 2011 8:25 pm

I am pretty sure that I can stop the flow of my aquarium pump with my fingers so I am going to try a soda bottle
I don't have a valve yet I would like something I can panel mount in the control panel but I am still looking
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Re: Smoothing out Pulsing Air Assist

Postby andrewblanejr » Sat Oct 08, 2011 9:28 pm

mine is 110 liters per minute...very easy to stop by pluging the hole with your finger
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Re: Smoothing out Pulsing Air Assist

Postby J45on » Sun Oct 09, 2011 3:13 pm

I added a T piece and a one litre soda bottle in line with my aquarium pump today and it smoothes the pulses out nicely and almost completely.
With a ball valve or a slight restriction in the pipe after the bottle all pulses should be gone.
So I made a 6mm ply bracket to hold it under the bench ( which I have not mounted yet)

Image

I am also thinking about mounting a ball valve behind the control panel on the front
and connecting it to a gutted 5k pot and knob via a shaft ( just a daft idea )
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Re: Smoothing out Pulsing Air Assist

Postby iGull » Mon Dec 05, 2011 8:59 am

J45on wrote:I added a T piece and a one litre soda bottle in line with my aquarium pump today and it smoothes the pulses out nicely and almost completely.


Hi Jason

I meant to ask what effect this addition had on the quality of the final product with the lemonade bottle fitted - do you have any results to share?
Also, did you add a needle valve to adjust the flow (the R part of your RC network as Bart would have it :D )
I notice on some of the 'pro' machines that they have a needle adjuster down on the air assist nozzle - there seems to be a lot of 'black magic' involved in the cutting process to achieve a decent quality - I've always admired 'process' guys (at a distance ;) ) spending many hours/days tweaking at a process to get it homed in - as an engineer, my job was just to get it 'working' :lol:

Cheers

Neil

PS Would it work better if you used Pepsi instead of Coke ?
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Re: Smoothing out Pulsing Air Assist

Postby lasersafe1 » Mon Dec 05, 2011 4:57 pm

If you want the mechanical equivelent of an RC filter, you would put your capacitance (bottle) after your resistor (valve). This is the same as the spring loaded bladders to prevent water hammer. This is not to suggest that anything any of you have successfully working is incorrect.

On my system I use a large oiless compressor with large accumulator, so I see no pressure pulses. Still, since I wanted larger pressure shop air elsewhere in my shop, I tapped off it and have a small local regulator right at the laser where I can dial in the exact pressure I want. (Harbor Freight)
http://www.harborfreight.com/12-air-line-filter-regulator-with-gauge-68281.html
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Re: Smoothing out Pulsing Air Assist

Postby iGull » Mon Dec 05, 2011 5:57 pm

Yes, RC in that order would be correct, but what effect does the 'pulsing' have on the cutting ???

If it doesn't have an effect (no-one seems to mention it), why are we bothering in the first place :lol:

Cheers

Neil
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