Oh Blimey I bought a CNC Lathe !!!!

[vtsteam]

Nice to see, Andrew! 

  Steve

[lordedmond]

Well done Andrew

Bring a beast like this from the brink is no mean feat   have a drink on me   


Stuart

[PekkaNF]

.....Just need to arrange a farm sitter for a couple of days - any volunteers ?

I did that couple of summers when I was very young....but I am pretty far away.

Concratulations of  the swarf. You had all guards in place?

Pekka

[awemawson]

Thanks one and all for the encouragement.

I'm trying to work round this tool setting issue: What is supposed to happen is that you move the tool tip under the graticule of an in built microscope, press a special button, and it transfers an 'offset' value for X&Z position into the tool table for that tool. It does transfer a value, but it is scaled in microns not millimeters which results in values too large for the other bits of the program to accept by a factor of 1000. Not confirmed this but I suspect also it is not allowing for X being a diameter not a radius thus it's 2000 times too big. (Later update: no this was not the case, I was getting double offsets as I had a G55 work offset asserted)

By using the graticule, and doing the maths myself I'm getting what seem to be reasonable tool offsets but I need to do more work on it before I'm sufficiently confident to let tools anywhere close to collets and work pieces under program control.

[AdeV]

That would have to be a machine parameter, one presumes? Maybe your up-coming visit to Brum will help clear that one up? Or maybe even worth phoning the manufacturer, perhaps they will be able to tell you which parameter(s) to alter?

Video looks good BTW, will be intersting to see how the camera copes when it's doused in soluble oil... can't wait to see the thing making something complicated (a steel baluster perhaps...?)

[awemawson]

Yes Adev I'm expecting it to be a parameter - my Traub 'mole' is on holiday until Tuesday so hopefully progress after that. I can work round it. Been doing some tests today and proved it is simply a factor of 1000 in each axis when using the "Automatic Tool Measurer" key - every other display is correct as far as I can tell, so I'm just manually editing the entries at present and I can at least now set tools with reasonable accuracy.

It's an odd system, to call a tool the 'T' word takes the form Tmmnn where mm is the tool number (which has it's associated tool offset in X&Z from the tool table) and nn is an additional 'Tip offset' which is another table with entries for each of the 80 possible tools. So I suppose theoretically you could use the tip offset for tool 7 with tool 10 by calling T1007 but why you would want to goodness only knows. The second entry seems superfluous as surely you will always use the tip offset for the tool it was measured on.

Talking of tools, does anyone recognize the letters and numbers on this parting tool holder - I want to identify which tips it takes. It's obviously a cut down 'double ended' self retaining type and is 31mm high and 2.5mm thick the insert 'gap' is about 7mm tall:

[AdeV]

It's an odd system, to call a tool the 'T' word takes the form Tmmnn where mm is the tool number (which has it's associated tool offset in X&Z from the tool table) and nn is an additional 'Tip offset' which is another table with entries for each of the 80 possible tools. So I suppose theoretically you could use the tip offset for tool 7 with tool 10 by calling T1007 but why you would want to goodness only knows. The second entry seems superfluous as surely you will always use the tip offset for the tool it was measured on.

Could the second reading to be to take into account wear? Seems unlikely I'll admit, unless the lathe is capable of resharpening bits (at the expense of length) "on the job".

[Pete.]

I was thinking just the same. In the early 90's I worked briefly in a place that made hydraulic rams and they had a load of 'new' cnc machines. Quite new technology at the time and I do recall one of the operators explaining how the machine could increment the tool forward the tiniest amount each cut to allow for tip wear.

[Henning]

Congrats on getting the beast running and not least making swarf!  

Now i look forward to the first part produced!

[lordedmond]

Not to pollute the other thread re en8

Will the lathe be makings replicating itself by making its own parts 


Stuart

[awemawson]

 It's a nice thought Stuart - by the nature of things no doubt it will be used to make bits for itself and my other machines.

Re 3 metres of 50mm EN8: no specific object in mind. I happen to have (came with lathe) a 48-50 mm 'J56' collet for the main spindle, and needed some chunky material to practice set ups and programming, particularly for the powered rotary tools. This came up locally on eBay so I grabbed it as the price was right.

I'm currently going through the tooling and tool holders, sorting out what is there, what needs fixing, and if I have the correct inserts for the tools themselves. Most driven tools are ER25 collets - I'd swear I had a set but can only find ER11, ER16, and ER32's so a purchase is in order.

The powered tools all need dis-assembly, bearings and seals checking / replacing and a general fettling. Several are partly dismantled but amazingly most of the bits seem to be there.

[lordedmond]

 Hope you get that pesky tool setting problem sorted ASAP

Stuart

[awemawson]

Well I can fairly easily work round it - just a case of writing down the figure it generates, deleting it and putting it back with the decimal point in the right place for each axis.

I decided that I need somewhere to store the tooling so I've started rejuvenating some Versatool cabinets - new thread here:

http://madmodder.net/index.php/topic,8741.0.html

[awemawson]

It's an odd system, to call a tool the 'T' word takes the form Tmmnn where mm is the tool number (which has it's associated tool offset in X&Z from the tool table) and nn is an additional 'Tip offset' which is another table with entries for each of the 80 possible tools. So I suppose theoretically you could use the tip offset for tool 7 with tool 10 by calling T1007 but why you would want to goodness only knows. The second entry seems superfluous as surely you will always use the tip offset for the tool it was measured on.

Could the second reading to be to take into account wear? Seems unlikely I'll admit, unless the lathe is capable of resharpening bits (at the expense of length) "on the job".

Turns out it's more subtle than that.  Re-reading what programming info I have for the umpteenth time I now realise that the second set of values is split : the first 40 (of 80) are for the first tool 'edge' and the second 40 are for the second 'edge' so something like a parting tool can be called up using either edge depending on whether the bar is in the main or opposing spindle, and still get the correct length. However is is also supposed to be used for fine corrections. So you set your tool, put the value in the 'tool table' and use the 'tip offset' to make minor adjustments as you measure the turned part. It's remarkably complicated !

[Pete W.]

Hi there,

This question might be a bit premature.

I've watched John's (Doubleboost) latest video this afternoon, the one in which he turns an eccentric section of the component by offsetting it in the four-jaw.

Can machines like yours turn eccentrics by programming the tool to advance and retreat (radially) in phase with the main spindle rotation?          

[AdeV]

Can machines like yours turn eccentrics by programming the tool to advance and retreat (radially) in phase with the main spindle rotation?         

I would imagine the answer is a definite "yes", but presumably there'd be a maximum spindle speed above which the tool wouldn't be able to accurately move in/out quick enough.

I'd also be interested in the answer, I may very well need a camshaft or two cut if it does...

[John Stevenson]

They can also cut hexagons.
No idea if Andrews can but this is a machine doing it.

[awemawson]

Well the model certainly can do fancy things like that - there is a special firmware package called 'Traub Polyform' that can be incorporated. I don't yet know if it is in my set up. It's called up by special G & M codes. Reading about it it looks quite possible, as it is used when the main spindle has a 'C' axis - ie can be accurately rotated and stopped round the circle, and mine certainly has that feature. Time will tell . . . . . .

[awemawson]

Just some photos I've sent to Traub to hopefully prompt a response to the tool setting issue:

#425 - The parameter page that gives the co-ordinates of the setting 'scope (#15 tlml-)
#426 - View through the 'scope on tool #10
#428 - The Tool Table with automatically measured value on the bottom line, and my edited (div by 1000) value actually in the tool #10 position in the table

[tekfab]

They can also cut hexagons.
No idea if Andrews can but this is a machine doing it.

I can do that on my old Lang ! turn hexagons that is, they're not meant to be its just that there's so much play and backlash that my round jobs feel like hexagons ! 

Mike

[Pete W.]

They can also cut hexagons.
No idea if Andrews can but this is a machine doing it.

Thank you John,

That's absolutely astounding!  We've come a long way from the bodgers' pole lathe!

[Leblondmakino]

Great work Andrew!

The tip offset number after the tool number means you can use the same tool with two different offsets ie. a boring bar can be made to cut slightly deeper by using another offset but still retaining the original length offset in the tool table for reference.

John

[awemawson]

Thanks John. Those photos sent to Traub did prod them into action and I got a response but they are stumped as to the cause. They got me to re-format the memory which made not a jot of a difference. No big issue - I can live with moving a decimal point three places left !

[vtsteam]

Is it a firmware vs software version problem? Or a peripheral version recognition problem?

[awemawson]

Well Traub have no idea about the x1000 issue!

Today's 'downer' is that the servo amplifier for the X&Z axis is playing up again. For the last few weeks it has been fine unless powered off for more than about 10 hours - if after say 8 hours I powered it up again only for 5 minutes it was ok for another 8 hours. It would give an 'error 16' - which is reporting that the a to d converter isn't happy at power up.  If I powered off & on it was then ok.

My first thought was the battery back up, but new battery fitted and the old one measures ok anyway. I then swapped all the logic from the V axis and X&Y axis amps (which includes the A to D converter) and the fault stayed with the power side (which is where the previous fault lay)

However in the recent hot weather yesterday it gave an 'error 32' which is an over current error. I couldn't clear it even dousing the amp with freezer spray. First thing this morning it came on ok as if nothing had happened, but went again shortly afterwards. So today, as several capacitors were faulty last time  I have dismantled it, and made a note of every capacitor value and ordered up enough if necessary to swap out every one except the main reservoir capacitor (2000uF at 350v DC) which I can only find at a silly price (£81 !) which is too physically big anyway. Measuring it it is showing well over 2000 uF so it's probably ok anyway, but realistically is the most stressed one in the unit.

So 29 capacitors to change, but it's an odd fault. Not convinced this'll cure it