Don't use the laser cutter

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Mark Steward

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Nov 20, 2011, 5:58:30 AM11/20/11
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We're not entirely sure what's going on (nobody in the space was co-operating last night), but cooling is definitely broken:


Please don't use the laser cutter if you're planning to today.


Mark

tom

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Nov 20, 2011, 6:20:40 AM11/20/11
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I'm on my way in now and was planning to, shall i take a look at it
when i get there?

Tim Storey

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Nov 20, 2011, 7:43:04 AM11/20/11
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I was using it last night trying to get it cutting circles properly
again after Jo had issues with it yesterday. I Put it on the wiki

\t

Adrian Godwin

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Nov 20, 2011, 7:46:12 AM11/20/11
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Can you correlate your use with that graph, for the purposes of debugging ?

-adrian

Charles Yarnold

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Nov 20, 2011, 7:47:30 AM11/20/11
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From the sounds of it one of the motors has stalled causing it to generate heat in the tank.

Tim Storey

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Nov 20, 2011, 7:55:34 AM11/20/11
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I used it between approx 22:00 and about 02:00 and I made about 10
little cuts of about 1 minute to 1.5 a time, I did check the temp with
the infra red thermometer which read 26/27. Guess I didn't put that
(temp issue) on the wiki logbook, apologies, it was late.

\t

Adrian Godwin

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Nov 20, 2011, 8:30:44 AM11/20/11
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On Sun, Nov 20, 2011 at 12:55 PM, Tim Storey <tim.s...@gmail.com> wrote:
>
> I used it between approx 22:00 and about 02:00 and I made about 10
> little cuts of about 1 minute to 1.5 a time, I did check the temp with
> the infra red thermometer which read 26/27. Guess I didn't put that
> (temp issue) on the wiki logbook, apologies, it was late.
>

Seems to have got a fair bit higher than that (though in any case
that's above the point where you should leave it to cool). I wonder if
the IR thermometer agrees with coolbot's measurement ? And if not,
which is right ?

That does at least explain why there was something happening, but I
can't see the usage graph moving. perhaps this is just because the
scale has got a bit too large to see a change. Maybe Cactus could be
configured to give an expanded scale ?


-adrian

Mark Steward

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Nov 20, 2011, 9:10:45 AM11/20/11
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Thermometer seems to match coolbot, which appears to be running fine still.  I think it's just not clear enough at the moment what the safe range is.

I've unplugged both motors to see if the temperature drops, and stuck a sign on the laser cutter (should have asked someone to do this last night).


Mark

Jessica Meek

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Nov 20, 2011, 11:46:16 AM11/20/11
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I was going to ask if I could be inducted on the laser cutter next
week but if there are problems, I guess thats unlikely?

I know the inductions are usually on a Tuesday night but I generally
have to work then so if anyone could show me at another time that
would be brilliant.


On Nov 20, 2:10 pm, Mark Steward <markstew...@gmail.com> wrote:
> On Sun, Nov 20, 2011 at 1:30 PM, Adrian Godwin <artgod...@gmail.com> wrote:

Paul Dart

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Nov 23, 2011, 6:14:27 PM11/23/11
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On Sunday, 20 November 2011, Mark Steward <marks...@gmail.com> wrote:
> Thermometer seems to match coolbot, which appears to be running fine still.  I think it's just not clear enough at the moment what the safe range is.
> I've unplugged both motors to see if the temperature drops, and stuck a sign on the laser cutter (should have asked someone to do this last night).
>
> Mark

Was there an outcome to this? I can't see anything else on the mailing list.

My previous understanding was that it was ok to use the laser cutter as long as you manually check the water with the IR thermometer as you go along. Presumably doing this would still be fine?

Paul

Mark Steward

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Nov 23, 2011, 6:27:51 PM11/23/11
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Yup, for very short jobs (a couple of minutes, I think).  I unplugged both pumps, but didn't get round to working out why they weren't working on Tuesday.


Mark

Mark Steward

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Nov 23, 2011, 6:31:05 PM11/23/11
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Interestingly, the graph currently suggests that the water thermometer reads ~0.7 °C below the room one. You normally can't see this effect because the pumps put out heat, causing it to cycle.


Mark

Adrian Godwin

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Nov 23, 2011, 7:48:09 PM11/23/11
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Presumably if the laser pump (as opposed to the cooler pump) is left
unplugged the laser will overheat very quickly indeed and the water
temperature will be irrelevant because it won't be circulating around
the laser tube. The first you'll know is when the tube cracks.

-adrian

Mark Steward

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Nov 23, 2011, 8:54:32 PM11/23/11
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Ahh, good point - yes, don't use it without plugging that in and making sure it pumps first.

I still don't have a very good model of the cooling system in my head, so I've started documenting it below.  Any corrections?



Mark

Mark Steward

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Nov 23, 2011, 9:04:59 PM11/23/11
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Ahh yes, I hadn't realised the laser pump is only powered when the laser is on.  Are there any temperature interlocks/flow sensors remaining?


Mark

Charles Yarnold

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Nov 24, 2011, 4:39:11 AM11/24/11
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Your technically missing the room temp sensor, but thats correct.
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