The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)

[PekkaNF]

There used to be...or maybe still is a thin washer kind of socket that had a lindicator LED and you could just slide them between solenoid and socket.

They were pretty cheap to use in a hurry.

This sort of thing:
https://canfieldconnector.wordpress.com/2016/06/10/ilw-interposed-lighted-wafer-indicator-light-2/

Replacing the connector in this case was better choicse ofcourse.

Pekka

[awemawson]

That's a neat idea  Pekka

Well just as I thought I knew where everything is on the mammoth lathe I stumble across another three hydraulic solenoid valves lurking behind the headstock.

I think that these are for clamping and unclamping the chuck, but I thought I'd already found those 

Needs more exploring tomorrow - too late now

[awemawson]

A couple of developments today:

Firstly I was actually contacted at last by the supplier of the replacement FXM-3 field coil driver for the main spindle motor telling me he'd 'sort it today' - this is a 'good thing' as although I've got most of the semiconductors to replace the lot lock stock and barrel I'd rather have a tested spare to save too much excitement

Secondly I replaced all the DIN 43650 solenoid sockets in the 'chuck hydraulic cupboard' and ordered some more for the ones I discovered hidden behind the headstock.

The exercise of replacing these sockets has demonstrated to me the importance of re-labelling all the cables used for these solenoids. Originally they were very clearly marked using wrap round printed labels, but time and handling combined no doubt with a bit of hydraulic oil have proved their undoing.

I intend to use cable ties with an attached 'write on flag' when I find suitably sized ones - you'd be amazed how many sellers omit the size of the write on bit, and only give the cable tie size in their adverts !

[mc]

I'm just getting caught up with this thread.
If you don't mind me asking, how does the live tool dog engage with the tools?
Is it spring loaded, or does it rely on the servo running to ensure the dogs engage, when the turret retracts?


This is my weapon of choice for cable marking - http://www.labelzone.co.uk/brother-pt-e300vp-professional-handheld-label-printer/p15675
I generally use heatshrink for multi-core cables, and tape flags for smaller cables (or when I inevetiably forget to put the heatshrink label on...) plus it avoids any future problems trying to translate my handwriting!

[awemawson]

The Dog mounted in the turret is spring loaded, and the dog mounted on the tool is fixed axially. As the control selects another tool with a 'T' command, the tool disk moves forwards, rotates to the new tool, then clamps back engaging the dogs.

Now my turret is one made by Beaver themselves. Prior to this they were fitting Baruffaldi turrets, and seem to have copied the dog clutch pattern but not the length of the VDI40 shank projecting rearwards.

Power tooling is stupidly expensive - I have bought three genuine Baruffaldi ones that are seized solid and will have to rebuild them. Part of the re build will be to extend the dog clutch rearwards - but that's for the future - a few other things to sort out first.

BTW I'm going to use cable ties with flags to avoid having to disconnect all the cables again. I have a CTK 'brander' that has type wheels that you rotate to spell what you want to say in (I think) 8 or 10 characters, I dug it out to try it this afternoon but the type wheels that I have don't include the letters that I need. It has a heating element inside the type wheels and a wide ribbon of coloured plastic film. The film gets embossed into the cable sheath.

[awemawson]

Adrian the ParcelForce man brought my RS Components order of the extra illuminated DIN 43650 sockets for the three extra ones I'd 'discovered' the other day, so I set too with enthusiasm. Now these devices are tucked away in a dark and difficult to access corner. First original one came off fine and got replaced. Second one was obscured by a hydraulic pipe - no big issue, slacken the fitting and rotate it a bit out of the way. It was when I was disconnecting the cables on this one that the light bulb went on. Hang on, these are wired differently, the cables don't go to terminals 1 & 2 they go to 1 &3 - what gives

Well the answer came along with a hot flush - these are PRESSURE SWITCHES not solenoid valves  My excuse for this plonker moment is that they are in a dark inaccessible corner.

. . . off came the ones I'd done, and back on went the originals, and I crawled away to give my pride time to heal 

The good news is that yesterday I obtained the Beaver Manual for this lathe, and also the detailed manual for the SMCC card as PDF's. The Beaver manual is not hugely informative, and unfortunately the drawings of the turret are for the Baruffaldi version, but never mind there is some useful stuff in there.

[awemawson]

I dusted off the GoPro camera and filmed the machine moving X & Z axis's and doing tool changes - a little diddy program I wrote just to see how you enter code into the controller and exercise the machine a bit.

I think that maybe the issues I was having with the turret were caused by stiff oil seals - with a bit of use it seems to be getting better. I still can't drive the spindle as the field coil current driver hasn't arrived yet.

Not sure why I'm getting that 'fish eye' distortion, I've probably set the GoPro up wrong, I've not used it in over a year.

[mc]

Looking good.
GoPro's do give a fisheye effect, it's just the way they are.

Thanks for the info about the turret. I've got an idea brewing, that involves something a bit bigger than my Denford Cyclone, but still fitting under the existing roof of my workshop, as I make some parts that would really benefit from a lathe with live tooling. Just need to get another couple major projects done and running first.

[awemawson]

I tried altering the field of view of the GoPro and shot a walk round tour of the lathe - not sure if it's any better 

[awemawson]

The cable marker 'flags' and an appropriately fine 'Sharpie' marker are now here, so I cleaned off the sticky mess that was the previous labels and applied the flags.

Useful exercise, as I unearthed another pressure switch that I had treated as a solenoid, so that's probably saved a few hours of fault finding !

[WeldingRod]

When I'm designing hydraulic machines, I specify Turck polyurethane cables with moulded on DIN 43650 ends.  I spec both a light and an MOV.  The whole thing is much cheaper than good cable plus labor for field installed connectors and is actually watertight.  AND field installed 43650's totally suck!
They also make ones with two lights for switches.

Sent from my SAMSUNG-SM-G891A using Tapatalk

[awemawson]

The Field Coil Driver PCB turned up curtsy of the UPS man Mac - motor specifies a maximum voltage for the field coils of 170, I really wanted to set the system by current but the motor plate carries only the max voltage - OK they are related, but the actual current is pulsed DC so not exactly by Ohms Law.

During testing I've set the maximum field voltage to a conservative 100 as the spindle will see no machining load until everything else is sorted. Field current is proportional to torque as I understand it.

  Anyway - we now have a spinning spindle 

[awemawson]

So now I am able to actually do things with the machine it's time to get to grips with the programming. The Sinumerik input method at the console is not exactly intuitive. For example this morning I spent two hours finding out how to delete or edit previously input code. I suppose really it's intended that code is generated off the machine and uploaded, but the controller does have quite a comprehensive graphical set of guides for the various G & M codes

Nothing so simple as a 'destructive backspace' key to delete characters  - there is a complicated sequence you have to go through, which is now printed out and magnetically attached to the cabinet until I've learnt it 

It also seems that programs that are deleted still take up memory, and you have to run some sort of sorting routine on what's stored to release the unused bytes - but that's for later - got to go to a BBQ now - it's  hard life. 

This morning I was experimenting with 'feed per rev' - G96 on this machine - whereby the machine alters the spindle RPM to keep the surface cutting speed constant. It was doing this when the need for 'backspace delete' became apparent 

[awemawson]

I've had an intermittent fault on the Tool Turret for a while - it seems to come and go but I convinced myself that it was heat related. Manifests itself as the SMCC card and or the 820T controller reporting it is at a wrong tool location when a tool change is commanded. Leave it alone for half an hour and the fault clears only to come back later.

So today I've been having fans pointing at things and trying in vain to locate the issue, until . . .

. . . the fault came on, and I happened to read the data word on the controller that indicates tool position, and blow me the least significant bit was missing! Now there is a four way proximity switch in the turret that I'd looked at before and all seemed well, but while the fault was on I was able to chase the wiring and the issue was definitely the proximity sensor - so pull it out. Shame really as having been in here before I'd already sealed the chamber with Blue Hy-Lo-Mar sealant.

Out it came and certainly bit zero is different from the others. Unloaded it's giving about 7 volts not detecting, but goes correctly to about 24 volts when detecting, whereas a good channel sits at about  2 volts and also goes to 24 in the presence of a spanner.

Loaded with 4K7 ohm to ground, so about 5 mA load, both good and bad go close to zero undetecting, but the bad channel stays at about zero in the spanner test.

So the hunt is on for a replacement. I could if necessary make up a bank of four individual proximity sensors but I'd rather avoid that if possible

Incidentally in previous posts I've referred to this sensor as made by Euchner - it's not it's a Balluff BES 516 B4 T0B-08-650 in case you have one in the odds box 

[awemawson]

Not surprisingly it turns out that these  proximity sensors are modular. After much unscrewing the defective module came out revealing another part number. I've traced one to eBay in Germany and am waiting confirmation of postage charges, but it does mean that if the module isn't available, I can get a two or three way version and rob it for spares

[awemawson]

This morning I repeated the test on the individual Proximity module under slightly more controlled conditions, and sure enough it's still faulty. Loaded with 4K7 ohm / 5 mA it takes a matter of seconds before it ceases to work - specification is I(max) of 125 mA. Dowsing it in IPA and blowing with an airline to cool it by extracting the latent heat of evaporation it returned to the working state, then again rapidly failed.

I took the opportunity to blow out the chamber where it lives and take a photo of the 'pegged drum' or Hedgehog that encodes the tool position in binary. It also shows the clutch disk that is used to rotate the turret to the appropriate tool, currently in the disengaged state.

(The same AC Servo motor is used to both rotate the turret to the right tool, and drive the Powered Tooling )

. . . sorry about the blurry pictures but it's a bally difficult place to get a camera at - I did try with my WiFi endoscope but it was even worse !

[awemawson]

Chap in Germany has now accepted my order for the Balluff proximity module and is posting today, so hopefully later this week it can go back together. Actually I bought two, so one to put in the spares box

I found an hour after lunch to attack the internal fluorescent light in the lathe. It was absolutely filthy - the pictures don't do the grime justice. The upper surface was a good half inch thick with a concretion of brass swarf. I'd hoped to be able to take it down to clean it, but no such luck. Where the cable goes through the roof at the tailstock end is inaccessible on the other side without major dismantling. I got it off it's brackets which let me get to the rear. It should really have one of those circular military style plugs and sockets to allow removal to change the tube - maybe a mod for the future.

Hats off to Mr Muscle -  I would usually use IPA to dissolve and soften caked on oily bits, but the tube in which the light tube lives, is almost certainly Poly-carbonate, which I know cracks like fury if wiped with IPA. The Mr Muscle did an amazing job so has gone on the list of workshop cleaners !

Remember - these 'filthy' pictures don't look half as bad as it was !

[Pete.]

I reckon that's why the turret wasn't working properly Andrew - it couldn't see what it was doing

[awemawson]

Very Droll 

Well MORE developments - I've re-made contact with a friend I had years ago but lost touch with - from his garage he has unearthed (amongst many other goodies) a BRAND NEW four position Balluff proximity switch and also one of those field coil drive cards ! (which he designed !!!!! )

[nrml]

I guess its karma paying you back .

BTW why not a LED strip light like the Traub? Better lighting for the obligatory videos when the project is finished.

[awemawson]

At the moment NRML I cannot even get the fluorescent one out never mind installing an LED one 

This evening I decided it was time to get on with the turret tinwork - strip the old tatty paint to give me an idea how much more bashing it needs - it's by no means perfect but actually not as bad as I'd thought.
So first a coat of lethal paint stripper that penetrates your gloves, then a scrape down followed by another application of paint stripper and scraping, followed by a good scrub under cold water in the workshop sink using a stainless steel scouring pad. (Can't use hot water - it's unbearable when the paint stripper has penetrated your gloves and been absorbed into your skin - feels as though it's boiling!)

Hopefully just a light sanding / rotary wire brushing and the odd bit of filler in places, and they can have a light coat of paint blown over them tomorrow. I'm going to use the paint left over from doing the Denford Mirac, which is too white, but will do for a first coat to stop them rusting while I decide whether to have some slightly pinker stuff mixed up. It will need leaving for quite a time to harden before putting back.

[awemawson]

This morning I rubbed down the tinwork, filled a few of the more obvious blemishes, and sprayed a coat of Machine Enamel from Craftmaster Paints in Cambridge in RAL9010 'almost white' - the stuff left over from painting the Denford Mirac - on the insides and undersides. Hopefully I can get the outsides and top sides sprayed this afternoon.

I have ordered up a litre of RAL9001, which is slightly more yellow and pink than the RAL9010 and a good match for the Beaver creamy colour according to my RAL chart.

[awemawson]

As I had hoped I was able to get the other sides of these items sprayed after lunch.  Not perfect as I got a small run that I had to brush out, and will need flatting before I start on the top coat - might have to let it harden for a day or two to be able to do the flatting without tearing the paint.

[RotarySMP]

Are you really considering rubbing out a paint run on internal sheet metal covers within a CNC lathe enclosure? Just turn stainless once and the stringy birdnest will thoroughly rub it out for you
Mark

[awemawson]

Mark

If you're doing a job you might as well do it properly. I was taught to take a pride in my work