Air supply for chip blower

[John HaineParticipant @johnhaine32865]

I've decided finally that I need to rig up something to blow the chips away from the cutter and workpiece on my CNC mill. This after spending about 8 hours machine minding while it carved out a couple of brass nameplates. Nothing went wrong and the only thing I had to do was blow the chips away by puffing down a long tube every few minutes. There has to be a better way…

I don't use coolant on this machine for ali or brass, so I don't think it needs a lot of puff, could anyone that has this advise if an airbrush compressor would have enough oomph to do the job please? I have got the guts out of a tyre compressor which easily does the job but is very noisy when operating so I'm reluctant to use that.

[John HaineParticipant @johnhaine32865]

[Tractor manParticipant @tractorman]

Hi John. I use a small compressor for airbrushing but it does get hot after relatively short use so might not be good for your long term needs. A compressor from a fridge may be a better bet but again I’m not sure on the way you’d modify one to suit. What about the converse way and use a gash vacuum cleaner to suck away the swarf? If it’s brass cuttings it should suck up easy and you could rig the pick up hose to run close to the cutter. Works in woodwork for routers etc. Mick

[John HaineParticipant @johnhaine32865]

Thanks for that suggestion, I do use a vac but it's very noisy and gets equally hot! I was thinking with a blower that I'd arrange a timer so it isn't going all the time anyway, and if it's the type with a tank then maybe the pump will operate even less frequently.

[Russell EberhardtParticipant @russelleberhardt48058]

I use a vac as well for brass. Must think about making an annular nozzle attachment so I don't have to stand there!

Russell

[richardandtracyParticipant @richardandtracy]

I have seen something used on the small diameter high speed cnc routers that with a bit of ingenuity/adaptation may be useful, possibly not in this case, but maybe in others.

It's a silicone rubber moulded shape that is a fan with 4 blades, about 1/2" diameter, 1/8" thick and stretches over the cutter so as the cutter spins, it spins, creating a downdraft and blows the swarf away. Can't find a photo, but the idea should be enough.

Regards,

Richard

[John HaineParticipant @johnhaine32865]

Richard that's a neat idea! Ideally I'd like something that mainly blows the chips into the far corner of the mill enclosure, a fan like that would blows it over 360 degrees I think…

[pgk pgkParticipant @pgkpgk17461]

I set up a simple mist sytem on my mill.. one of those cheapo far east mixing blocks.. and the lidl compressor I had. Considering the compressor happily inflates tractor tyres it's suprising how often it fires up to provide air to the mist system. To run mist it has to be goign almost continuously.. just to blow cold air over the cutter with airflow reduced so the mist isn't drawn up and it still fires up very often.

My point is that you probably underestimate the efficiency of lungs. A smaller 'real' compressor would still need some sort of timed solenoid to give regular puffs to have enough power to blow chips away without constantly firing up.

[richardandtracyParticipant @richardandtracy]

Posted by John Haine on 11/01/2017 11:32:18:

Richard that's a neat idea! Ideally I'd like something that mainly blows the chips into the far corner of the mill enclosure, a fan like that would blows it over 360 degrees I think…

I agree, which is why I remember it. Just looking around there's this:

Regards,

Richard

[Clive FosterParticipant @clivefoster55965]

Maybe one of the square cooling fan assemblies used with computers, power supplies and other electronic gubbins would be sufficient if connected to a suitable funnel and tube assembly. Those things are made to run all the time and even the smaller ones shift a fair amount of air. Big question will be whether you can feed the output into a small enough tube to get a usefully powerful blowing jet without creating too much back pressure and seriously reducing the amount of air delivered.

I think RS or one of the other industrial suppliers used to provide graphs and formulae for this sort of calculation to verify that enough air could be delivered when venting was limited.

Clive

[Another JohnSParticipant @anotherjohns]

John;

I have heard about someone using an aquarium air pump for clearing chips – have not tried it yet, but it would be much better than my loud, large compressor, and aquarium air pumps are designed for a 100% duty cycle.

If you do try it before I get around to it, please tell us how well it works.

Regards – JohnS.

[Tractor manParticipant @tractorman]

In additoN to the above I have a die filing machine that is fitted with a compressor and blow pipe to clear filings away. I will nip down to the shop and take some snaps of the system. Mick

[I.M. OUTAHEREParticipant @i-m-outahere]

 

Almost sounds like how a large diaphragm pump operates giving a puff of air out the outlet every few seconds and it is the same for my air brush pump just running faster , i will go and hook it up and see if it will blow chips around .

Maybe you could rig up something using a car windscreen wiper motor and hook up a con rod , piston and cylinder arrangement to the wiper arm on the motor ?

As there is no real pressure a piece of tube for the cylinder , delrin or nylon for a piston , o ring seal on the piston and rubber flap valves in the closed end of the cylinder .

 

I took to a chunk of brass with a 3/8  drill and it did keep the area arond the drill chip free just using the air hose that connects to the air brush i then inserted some copper  tube ( 1.5 to 2 mm ID &nbsp and it worked better . If you are machining a deep pocket it would struggle to blow the chips out of a pocket 

Another option is modifying an old car air con pump and run it off a mains powered motor or  possibly  the compressor from a fridge .

Ian.

Edited By XD 351 on 12/01/2017 00:40:43

[I.M. OUTAHEREParticipant @i-m-outahere]

Please ignore the bl**dy winky thing , i hate those things with a passion !

Ian

[Enough!Participant @enough]

Posted by John Haine on 11/01/2017 10:11:12:

I've decided finally that I need to rig up something to blow the chips away from the cutter and workpiece on my CNC mill. This after spending about 8 hours machine minding while it carved out a couple of brass nameplates. Nothing went wrong and the only thing I had to do was blow the chips away by puffing down a long tube every few minutes. There has to be a better way…

 

See my posts in this thread. You don't need a lot of air pressure but a reasonable tank size may help.

Edited By Bandersnatch on 12/01/2017 01:30:01

[Michael GilliganParticipant @michaelgilligan61133]

The Hegner scrollsaws use a fairly compact [and rather pricey!] bellows unit **LINK**

http://www.hegner.co.uk/bellows-for-hegner-scrollsaws.html

It shouldn't be beyond the wit of man to build something like that onto the end of a small [say 1/16 HP Parvalux?] motor to make a dedicated 'puffer'.

MichaelG.

[Nick HulmeParticipant @nickhulme30114]

Fridge of freezer compressors work extremely well for this, large bore hypodermic needles with the sharp end ground neatly off make very good nozzles,

– Nick

[John HaineParticipant @johnhaine32865]

Well, thanks for all the suggestions. I am getting an airbrush compressor off a well known auction site, will report back.

[John HaineParticipant @johnhaine32865]

OK, have finally got everything set up. It's the standard airbrush compressor without a tank. I've arranged a nozzle with a 1mm hole on an adjustable stalk that I can direct at the cutter tip. The compressor runs continuously at the moment and I found it was getting rather hot, so have arranged a 90mm fan to suck air through it that keeps the temperature rise tolerable. I've also finally got round to arranging a polycarbonate guard across the front of the machine with plywood cheeks at the sides to stop chips blowing all round the workshop. TIt all works fine, plenty of airflow to blow the chips away, and satisfying aluminium "chip drifts" in the chip tray! I've also bought a cheap solenoid air valve that I may put in line so I can just blow the air intermittently.

[Neil WyattModerator @neilwyatt]

Posted by richardandtracy on 11/01/2017 11:07:31:

I have seen something used on the small diameter high speed cnc routers that with a bit of ingenuity/adaptation may be useful, possibly not in this case, but maybe in others.

It's a silicone rubber moulded shape that is a fan with 4 blades, about 1/2" diameter, 1/8" thick and stretches over the cutter so as the cutter spins, it spins, creating a downdraft and blows the swarf away. Can't find a photo, but the idea should be enough.

Now that would be an excellent 3D-printing exercise… unlike a propellor the forces on a tiny fan aren't high enough for a printed fan to tear itself a apart.

Neil

[Another JohnSParticipant @anotherjohns]

JohnH – thanks for reporting back. Work is keeping me out of the workshop so have not done much CNC work since late 2016.

Also, thanks for putting in the end hole size – interesting, and much smaller than my current loc-line wand, that eats air.

JohnS.

[john carruthersParticipant @johncarruthers46255]

In the glass works we had an old bike pump in a couple of jubillee clips, but he was tight.

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