bhk
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Posts: 458
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Post by bhk on Oct 24, 2014 18:11:06 GMT
So is that a push/push type switch for the coolant then? Yes that's correct, it's a momentary switch which controls a latching contactor, it is interlocked so that it can only be switched when the inverter is stopped.
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Post by andyhigham on Oct 24, 2014 18:35:19 GMT
I think you may need to start/stop the coolant independently of whether or not the spindle is running. You have not included a spindle start button. If the enclosure you fit the inverter in is too small you will need to fit a ventilation fan (its a good idea any way)
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bhk
Part of the e-furniture
Posts: 458
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Post by bhk on Oct 24, 2014 18:51:08 GMT
I think you may need to start/stop the coolant independently of whether or not the spindle is running. You have not included a spindle start button. If the enclosure you fit the inverter in is too small you will need to fit a ventilation fan (its a good idea any way) Andy the reason behind the interlock is that the coolant pump will also be running from the inverter and switching any type of load with the inverter on is a big no no. The spindle, fwd start/stop/revers start are all on the original switch controlled from the apron.
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Post by Roger on Oct 24, 2014 20:38:23 GMT
I think the best long term answer is to have a single phase coolant pump and run the logic for the forward and reverse through the apron switches. That way you can go from forward to reverse freely and the pump isn't involved. What you have is fine to get started but I think you'll find it a pain.
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steam4ian
Elder Statesman
One good turn deserves another
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Post by steam4ian on Oct 24, 2014 21:36:32 GMT
Sean
I fully agree with Roger on the suds pump. Reversing the main drive will reverse the pump and probably screw the impeller off the shaft. Being able to quickly reverse out of a cutting a bastard thread is an asset of VSDs to a lathe.
Seriously, how much cutting will you do using suds. If you have compressed air you might be better off with a misting system, much less fluid floating around.
Your enclosure looks much too small, I have sent you pictures of my installation and most of the space is as specified by the drive manual.
Ian
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Post by andyhigham on Oct 24, 2014 21:44:15 GMT
My coolant system is a can of wd40. Ok if I was ripping huge amounts of metal I would commission the coolant system
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Post by Roger on Oct 24, 2014 22:48:20 GMT
Personally, I use coolant on everything, including non-ferrous materials. If you've got a system, why wouldn't you use it? There are very few materials that will cut better without it, Cast Iron being the most obvious one. Parting off is so much easier with coolant, and I'd venture to suggest that a neat cutting oil is noticeably better than suds. It would be interesting to see how many CNC shops use each system. I think you'll find more and more going over to neat cutting oil. I've used both and I'm convinced that it's easier to get a good finish with neat cutting oil which has better lubricating properties than soluble oil. I'm sure that parting off is less of an adventure with it too. I'm sure not everyone will agree though, you'd need to try both to see for yourself. I don't think compressed air systems are practical for home use, I couldn't live with a compressor going all the time.
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bhk
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Post by bhk on Oct 25, 2014 0:43:42 GMT
I did consider the pump would run in reverse when reversing, but then also thought about how much time i would actually spend running in reverse, it will also run too fast when I've got the frequency wound up. But for now it will work as long as I'm thoughtful as to when its on or off. the switch gear will do single phase if I decide to change at a later date.
Ian the enclosure is small compared to what the manual says, The makers spec 200mm clearance on each face of the inverter, this is absurd in my eyes. I should have added that the enclosure will be fitted with a fan and baffle plate, along with the fan fitted to the inverter.
I would use suds most of the time on the machine, I actually consider it essential to proper machine operation and finishing, I even use it on cast iron as it aids greatly in keeping the dust down. As for misting coolant I personally feel its a ridiculous system that is outright dangerous.
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Post by Roger on Oct 25, 2014 6:52:02 GMT
Although I don't think mist cooling systems are appropriate for the home workshop, they can be very effective. One machine I take care of uses a system called 'Koolmist' which uses a coaxial delivery system ie the coolant in a small central pipe and the compressed air in a pipe that shrouds it. It delivers only a small amount of suds and the machine is used without any form of return system because the coolant is swept up with the swarf. It's great on fine aluminium work and high spindle speeds where you need to guarantee that the lube is blasted into the cutting surface. I look after another machine that uses a product called Boelube which is fed drop by drop from a lubricator. That uses so little lube that unless you hold a piece of card under the nozzle for several seconds, you can't see that it's delivering anything. That stuff is magic and is used for high speed routing of aluminium for the same reasons as stated for the other type of system. Pouring lubricant onto that kind of work with fairly open routers is incredibly messy and it's hard to get the lube right into the cutting zone. It's certainly not dangerous, unlike the use of IPA which was supplied to a machine and exhausted through a vacuum. I wouldn't sign off the system because it's a serious fire hazard and potential bomb in the making.
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Post by ettingtonliam on Oct 26, 2014 15:10:26 GMT
So is that a push/push type switch for the coolant then? Yes that's correct, it's a momentary switch which controls a latching contactor, it is interlocked so that it can only be switched when the inverter is stopped. My lathe is driven off a (very old) Jaguar Cub inverter. The switching for the main spindle (On, Off, Rev) is done on the input side off the inverter, but the 3 phase output goes to a junction box. One cable out of the junction box goes direct to the main motor, the other goes to the switch panel, then via a switch to the pump, which means the pump is switched on the output side of the inverter, but will only run when the main motor is running. (This was done before I got it) I suppose that with the 1 1/2hp main motor running, the inverter doesn't notice the tiny additional load when the pump stsrts up - its probably less than the change in load when a big cut starts. It seems to work OK, and as I said, the inverter is very old, so being wired like this hasn't had any bad effects. I admit I don't use the coolant very often,(too messy generally) but the previous owner certainly did. This will mean the pump reverses when the motor does, but it does seem to run happily that way. How the pump would perform if driven off an inverter with the speed dialled right down, I don't know, mine dooesn't have speed control. Richard
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bhk
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Post by bhk on Dec 2, 2014 6:15:52 GMT
Been a while but I've finally got the lathe up and running, the wiring of the inverter and switch gear certainly took longer than I expected it too, but with professional study getting in the way I've had very limited time.
I've still got a few things to finish off, the control box still needs a final home, for now it's sitting on the top of the headstock, it will eventually be mounted along with the DRO readout.
Fault and run lights are yet to be fitted once I get hold of some good quality ones, the ones I bought from eBay were terrible quality.
My landlord was not keen with idea of me putting anchor bolts into the garage floor, so I've had to level the machine without it being bolted down, I've got it turning with only 3 microns (just for Roger I used my digital micrometer) taper over 150mm unsupported.
All in all, happy days
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Post by ejparrott on Dec 2, 2014 8:46:10 GMT
Even our work Colchester isn't bolted down, I've never worried about it!
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Post by Roger on Dec 2, 2014 9:40:25 GMT
That's extremely good parallelism, I'm sure mine isn't anywhere near as good as that. Mind you, with that amount of unsupported length, you can get more taper than that due to deflection unless you have the lightest of light cuts. Mine's bolted down, but to be honest, it was a waste of time because the Warco stand is like a piece of jelly. As you say though, happy days indeed!
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Post by Deleted on Dec 2, 2014 15:59:38 GMT
Quote}----"That's extremely good parallelism",.....Eh ?? OK matey, I'm being picky here but there's only one, true parallel *..Anything else is either convergent or divergant depending on your point of view ( Literally and metaphorically )..... And never mind about Einstein, bent light or lines returning from infinity etc....LoL ! * GWR track is regarded as the TOOLROOM MASTER from which all others take their reference !!...........That should pull in a few !!
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Post by GWR 101 on Dec 2, 2014 16:08:12 GMT
Tin Hats at the ready Alan ?
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Post by Deleted on Dec 2, 2014 16:13:14 GMT
2014, Alan starts WW3 on the ME Forum !!
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Post by Roger on Dec 2, 2014 17:29:42 GMT
Quote}----"That's extremely good parallelism",.....Eh ?? OK matey, I'm being picky here but there's only one, true parallel *..Anything else is either convergent or divergant depending on your point of view ( Literally and metaphorically )..... And never mind about Einstein, bent light or lines returning from infinity etc....LoL ! * GWR track is regarded as the TOOLROOM MASTER from which all others take their reference !!...........That should pull in a few !! My favourite pedant strikes again. I think you'll find the term was used correctly though in the context of 'Geometric tolerancing'.... Geometric Tolerancing
From memory, these definitions only came out in the seventies, I have no idea what they used before that.... Maybe 'pretty straight' or 'not like a starting handle' who knows....
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bhk
Part of the e-furniture
Posts: 458
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Post by bhk on Dec 2, 2014 18:07:36 GMT
Yep I'm turning shafts and not bananas. I only received my digital micrometer the other day, I got it from Cromwell tools, it's a Oxford precession unit (made in the UK) it comes with a serial down link so I can data log the measurements, it cost a arm and a leg but its accurate to 4 microns though on testing with slip gauges it easy kept to 1 micron and is for a commercial venture. For those interested www.cromwell.co.uk/OXD3315010K
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Post by Roger on Dec 2, 2014 18:39:49 GMT
That looks like a nice piece of kit, I'd never go back to a mechanical one now, they're so much more convenient and no chance of misreading it. I usually go for Mitutoyo but that's just because I've found them to be well made and the batteries last more than five minutes unlike some of the cheap ones. I bet yours will repeat to a micron or two, mine does if the surface I'm measuring is precise enough.
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