Oh Blimey I bought a CNC Lathe !!!!

[Leblondmakino]

I once had a similar problem with drives tripping out ...it turned out to be lack of oil on the slides. The machine had been sat for a long time before I got it and the oil had solidified in the oil tank blocking the lube filter..it didnt show a low oil alarm as the oil tank was always full but no oil was getting pumped round the machine!!

John

[awemawson]

Well I >> MAY << have solved the "coolant splashing on the camera" syndrome 

This little beauty fell in my lap curtsy of eBay the other day

[awemawson]

It has a 10" spinning disk and is actually designed to give a view port into a CNC machine that is awash with coolant. I never realised 'the proper deal' existed.

All the essential bits seem to be there (still in transit so not got my sticky fingers on it). It would originally have had a fancy mounting that fixes on with a ring of  3M VHB extra sticky tape, with a large 'o'ring kept squashed by the adhesion of the tape ( I assume that the tape is thinner than the 'o' ring ) and for initial mounting is sucked on with a vacuum. All the details are here:

http://www.t2k.net/products/visiport220c.php

No doubt I can fabricate something, but my bigger issue is its thickness. The lathe door slides and there is very little clearance between  the fixed panel and the sliding door. One solution is to cut a hole in the door pane so that it is practically flush, but the door pane is re-inforced glass laminate sandwich. Until I physically get it I'm not sure which way to fix it - I suppose I could replace the door glass with a thick polycarbonate and pierce that.

[John Stevenson]

Also used to be known as Kent Screens although the company seems to have folded.

Gert used to have one fitted to her trawler 

I reckon you can make a simple one by breaking the blades off a computer fan and glueing a clean screen on.

[awemawson]

Yes that was going to be my approach until I came across this one. I reckon that you'd have to regard the fan motor as disposable as fairly quickly the water content of the coolant would see it off.

Yesterday I sorted out the bin that the "parts catcher" dumps finished parts into. It's a stainless steel open box with a perforated base to allow coolant to flow out. It was filling with coolant and seemed to have been mounted on some fibre board which was blocking the perforations. WRONG - that 'fibre board' was densely packed fine brass and steel swarf bonded into a solid chunk. Dismantling it and scraping off as much as possible I ended up sand blasting both sides of the perforated base - got the faces of the perforated sheet nice and clean but the holes mainly remained blocked. Ended up pushing a 2mm drill through almost every one and there are hundreds  Anyway nice and clean now and the coolant drains away from it nicely - I'm sure my wrist will eventually recover 

[John Stevenson]

Lovely, brass swarf. Could you separate it ?

Tuesday morning started off with a ten foot length of 2 1/4" AF  hex brass bar.

Thursday dinner finished up with this



By the time the tray was cleaned out and put into another bag there was 40 kg according to the scales at the local scrappy.

Don't know what it is worth, won't get paid until next week but better than a poke with a sharp stick.

[Pete.]

Oooh I can feel those little brass splinters from down here in Kent!

[awemawson]

John, sounds like that job needed to start from brass castings or forgings rather than hex bar !

[John Stevenson]

Looked at various options.
Casting, solid hex  and cored bar.
Material cost per piece was £8.00 in hex. this doesn't include the scrap return.
Round was dearer as it was larger to take in the hex and cutting the hex was another operation.
Cored bar was even dearer than round solid and again more waste.
Casting was slightly dearer but the hex would have still needed a finish operation.

So the only extra operation needed in the hex was belting a 27mm hole thru and this was done in one pass, no centre operation as if the hole was off centre it got straighten up with the two stepped boring operations to follow.

Drilling was done under power by fitting the tailstock in front of the carriage and getting the carriage to push it at scary fast / mm / min.

All the OD turning was again done in one pass as the max removed was only 11mm off the diameter so max depth of cut was 5.5mm.
This was done with tipped tooling hand sharpened on a diamond wheel to zero rake and the tooling was inserted upside down and the lathe run in reverse.

This has the advantage of throwing the chips directly into the tray as opposed to over your shoulder, in your pockets, down your neck and we won't mention foreskins.

[awemawson]

I got fed up tripping over all the manuals that I'd accumulated during the repair of the Traub, and was about to box them up and put them on top of the machine, however realised they'd get 'orribly grimy and dusty after a few weeks. Then I thought, hang on - how much room is there INSIDE the machine.

Originally there had been document pockets on two of the doors, so there were mounting rails comprising two vertical perforated strips already in place, albeit plain untapped holes.

[awemawson]

A bit of careful measurement revealed room in three places for shelves deep enough to take an 'A4' folder. I wanted to avoid the end of the cabinet with the delicate axis and spindle drives so as not to restrict the airflow, and of course nothing must touch any of the control electrics.

My newly resurrected box and pan folder came into it's own - I bent up three shelves.

[awemawson]

The mounting rail holes were a convenient diameter for tapping 6 mm and in went the shelves

[awemawson]

All together worked out very well. Last picture shows that there is clearance behind them. And now I've got some desk space back 

[Pete.]

That's cool, and it'll save you ever having to go through all this headache again, because if one of the drives catch fire it'll burn all the manuals then you'll HAVE to scrap the machine

[John Stevenson]

ROTFLMAO   

[awemawson]

....nah !!!! Most are on disk as well anyway 

[PekkaNF]

Know the feeling. We put the machine control program down/up load instructions on the control system HD. It could be a little of catch 22, without a backup hardware or paper manuals (we call it hard copy).

Pekka

[awemawson]

Know the feeling. We put the machine control program down/up load instructions on the control system HD. It could be a little of catch 22, without a backup hardware or paper manuals (we call it hard copy).

Pekka

No it's all duplicated on a PC in a different building, and also a PC in the same building apart from one programming manual, which I don't have the source of without scanning it's 900 pages ! However I do know where another copy is, as I copied someone else's - that's how I know it's 900 pages !

Andrew

[awemawson]

At last I've been able to finish a 'mini-project' that's been outstanding for months on the Traub Lathe.

There are three 3.6 v NiCd rechargeable batteries within. One backs up the RAM in the controller and is absolutely vital, as the RAM holds not only the parameters, but also various secret squirrel option flags set by Traub and not disclosed to customers. The other two are less critical, they back up the machines 'absolute position' so if they go flat the machine has to be re-referenced.

Although these batteries are brand new and good quality they will only last 5 or 6 days, so I've been running the machine for an hour each morning to keep them charged - a pain

So - what to do. Well the scheme I settled on was to arrange a trickle charge to each battery when the machine is powered off. Three phase power comes in direct to a large isolator switch however the door interlocks are powered by a 415 : 24 volt transformer directly across two phases. This got me thinking. Between Phase 1 and neutral there is 240v even when isolated pick this up, drive a battery maintainer, and arrange that it is switched off when the machine is turned on.

So how to implement? I bring the 240 single phase through a 6 amp MCB to a relay box. Relay contact is normally closed passing mains to the battery maintainer. When the machine is powered up, I pick off 24 v from it's internal supply to drive the relay, which isolates the maintainer.

So first we need to make up the relay box:

[awemawson]

Red light indicates mains is coming in, Green light indicates 24 v DC from the machine - so the machine must have been up and running when that photo was taken.

Now I'm about to run cables in the machine trunking that will be live when the machine isolator is OFF so I am rather paranoid about labelling this fact The mains wires have a warning every half metre along their length, and the three boxes I'm using are painted bright orange and are also clearly labelled. Don't want to fry someone in the future !

[awemawson]

Now I've been monitoring the nominal 3.6 v batteries when they are on charge from the machines internal charging mechanisms, and they rise to about 4.15 volts when the machine has been on a few hours.

I decided to supply power to them from a precision regulated supply set to top out at this 4.15 volts, but via an isolating diode (To stop my charger interfering with the internal machine charger) and resistor to limit the charging current. A normal silicon diode has a forward voltage drop of about 0.6 - 0.7 volts - so the supply needs to provide 4.75 to 4.85 volts. I settled on a little board sold by Rapid Electronics based on the LM317 programmable voltage regulator. I replaced it's single turn adjusting 'pot' with a 10 turn one, and scaled it to lie in my close range of voltages)

Sadly Rapid did not live up to their name, and it was the lack of this part that has held me up, despite assurances that it was in stock when ordered 

So the physical layout of the machine dictated two further boxes. One to provide two isolated supplies for the Servo Amps and one for the main machine controller - so off we go again knocking holes in boxes:

[awemawson]

They of course need a bit of paint and some mounting brackets

[awemawson]

And off we go mounting the electronics inside the boxes

[awemawson]

Then comes the rather nerve racking bit 

They need installing mechanically (dead easy !) then the batteries need disconnecting while the machine is running, and the new bit of kit connecting - any slips and the RAM gets corrupted. Amazing how you can fumble dropping 3 mm screws in such a situation 

Anyway they are in, connected and time only will show if they work ok - I'm leaving the back off so I can monitor them for the next few days anyway 

Andrew

[lordedmond]

Hope you had your marigolds on messing with that live leccy.

H and S would have had a field day

Opps I forgot it's only LV 

Good work as usual why did they not make it like this when they made the machine ,for firms do have shut downs.

What we used to do with boxes like that was to label them as "Isolate else where " and leave it at that makes you stop and think


Stuart