air blast cooling for mill - solenoid control ?

I have been playing around with a cheap air blast unit for my Warco VMC for chip clearing. All is looking good so far. I quite like the idea of fitting a solenoid valve in the air line so that air only comes on when the spindle is running. I can get a 230V solenoid air valve very cheaply. Is there any reason why I shouldn't just wire this in parallel with the motor run connections? Motor is 1125W single phase.

I would run it through a separate power relay. If the solenoid coil fails it could pull down the motor as well.

I would power it separately as it is useful to turn on and off whilst cutting or after cutting to clear swarf. You can also put a ventory to put a coolant or oil in the air quite easily controler by a hand controle valve.

David

I don’t see a problem with picking up the switched active on the motor power switch , if you think about it all of the mains powered equipment in your workshop is connected in parallel and you are just switching in or out what you want to turn on .

I would add a fuse and a mains rated switch on the active line to the solenoid so you can turn it off if you don’t want to use it ( edge finding would be one case ) and the fuse is there in case the solenoid does fail dead short ( i have yet to see this but I wouldn’t say it cannot happen ) and if the solenoid has to be earthed make sure it is .

So give us a link to the 'cheap air blast unit', re-cutting chips is a serious cause of poor surface finish in my opinion

I too would love to find a cheaper version of a proper air cooling venturi unit, industrial ones cost the earth.

Mick

Here you go **LINK**

Ah shame, thought this was a link for a cheap vortex tube cooling unit.

Re using a misting device, I would be worried about breathing in finely atomised cutting fluid.

You should use a separate fuse and control switch in series with the valve solenoid. All wiring should be proper mains rated cable with an outer sheath or inside flexible conduit. Don't forget to earth the body of the valve. If you don't use a separate fuse then the wiring must be rated at more than the rating of the main fuse feeding the machine. Ideally you would use a low voltage (24 or 12V) solenoid for safety,

Robert G8RPI.

My Bijur Spraymist units are independently switched on the lathes whilst the one on the Bridgeport is linked to the motor circuit.

Bridgeport motor direction switch has a central motor off position so the air blast / lube can be run without the spindle turning. Handy for extra clearing and much safer during set up. Probably the best way overall even though if means an extra switch to select between run with spindle and run independent modes.

Especially so if you are using lubrication because it needs to be directed fairly precisely at where the tool meets the work. The whole idea of such systems being to use the minimum amount of lubricant put exactly where its wanted rather than spraying all over the place so adjustment may take bit of time. Having the spindle running whilst you get things just so is potentially somewhat unsafe.

Ideal would probably be another solenoid, rather than a simple valve on the lubricant, too but thats getting complicated.

The inexpensive import Locline replicas don't have the best of reputations for joint sealing. There is reason why the real thing is expensive. I'd not expect it to be air tight and would run a concentric flexi tubes up the middle, outer one for air, under one for lube so the "cheap-loc" line just gives you a bendy but stiff tube for adjustment purposes. That was what I planned to do when looking into using the inexpensive offerings as an alternative to DIY but I was lucky enough to find Spraymist units at affordable prices. About two or three times upper end of new cheap units. Hafta say I'm not incredibly impressed by them but they can be got to work OK (ish). At full price (never gonna happen) it would have been seriously angry sabre toothed bunny (extremely large breed) time.

Clive

Edited By Clive Foster on 13/07/2019 10:16:55

Thanks for all the feedback, some very good points to consider. The unit is well put together and has no leaks. I did try the oil pickup last night. It also works well, but as others have mentioned, the atomised oil is pretty unpleasant. So I expect I will be using it with air only for chip clearing.