Estimation to completing a Darwin.

You might be interested to hear my estimation for the printing time of a
Darwin corner bracket: Approx 12 hrs. but remember that this is Zaphod,
not a true Darwin. Now a corner bracket is about 60cc, so Ed's
estimation of a litre of parts is equivalent to, say, 17 corner
brackets. To print that would take a roughly idealised time of 17x12hrs
= 8 1/2 days.

So, for a wild-arsed guess at current replication time we'll
conservatively assume that Darwin is twice the speed of a Zaphod and
come up with a figure of about 4 days.

Have I missed anything in this guestimate?

Should be able to provide a better printing time on a Darwin corner
bracket in about, oh, 12 hours...

Vik :v)

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> So, for a wild-arsed guess at current replication time we'll
> conservatively assume that Darwin is twice the speed of a Zaphod and
> come up with a figure of about 4 days.

I've got no qualms with wild-arsed guesses, and that particular one seems
to make sense. Interestingly, that puts manufacturing time the same as the
Strat's replication of Darwin (which took about 110hrs).

eD
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On Tue, 2007-04-24 at 12:38 +0100, Ed Sells wrote:
> I've got no qualms with wild-arsed guesses, and that particular one
> seems
> to make sense. Interestingly, that puts manufacturing time the same as
> the
> Strat's replication of Darwin (which took about 110hrs).

Meanwhiles, back in the real world, my attempt to print a Darwin corner
bracket (the simplified one I derived from Ed's) has now ended.

On layer 20 of an estimated 84, the software crashed with an
Exception in thread "Producer" java.lang.OutOfMemoryError: Java heap
space

I'm using the VM arguments -Dj3d.sharedctx=false -Xms64m -Xmx512m, which
give it half a gig of memory to play with. I have a video which I'll
analyse, but it seems that it was starting to slow down before it died,
indicating that my machine was starting to swap.

Looks like I need more memory, but this might be a bit of an issue. I
suspect Java3D is creating too many little pieces. Might it be better if
we had an option to remove each drawn layer after completion, and
replace it with a less memory intensive truncated object which grows
taller as each layer is complete?

Vik :v)

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bummer, that is definitely something that should get fixed ASAP.

other than that, how did the print go? any chance you could beat adrian to printing me out a set of parts for darwin? i'll cover your costs =)

Well, if those corner blocks are 60 cm^3, I'm not going to be printing any soon. The 25 cm^3 polymer pump is going to take me 9 hours by my estimate, so doing one of those isn't going to leave much left of a day after the print.

As well, doesn't that corner block need support material for all those holes?

The problem is the simulation window - all those rectangular segments
really chew up the memory. There's code in there to get rid of all but
the last layer and replace it with a slice of the original model, but I
haven't debugged it yet. However, it should be simple to get it to
junk all but the last layer (leaving that hanging in space), which'll
save a lot of memory.

Best wishes

Adrian

Dr Adrian Bowyer
[staff.bath.ac.uk]
[reprap.org]

Re all this web traffic: yesterday was our best Google Adsense day ever
at $30.

Quoting Vik Olliver :

> On Tue, 2007-04-24 at 12:38 +0100, Ed Sells wrote:
>> I've got no qualms with wild-arsed guesses, and that particular one
>> seems
>> to make sense. Interestingly, that puts manufacturing time the same as
>> the
>> Strat's replication of Darwin (which took about 110hrs).
>
> Meanwhiles, back in the real world, my attempt to print a Darwin corner
> bracket (the simplified one I derived from Ed's) has now ended.
>
> On layer 20 of an estimated 84, the software crashed with an
> Exception in thread "Producer" java.lang.OutOfMemoryError: Java heap
> space
>
> I'm using the VM arguments -Dj3d.sharedctx=false -Xms64m -Xmx512m, which
> give it half a gig of memory to play with. I have a video which I'll
> analyse, but it seems that it was starting to slow down before it died,
> indicating that my machine was starting to swap.
>
> Looks like I need more memory, but this might be a bit of an issue. I
> suspect Java3D is creating too many little pieces. Might it be better if
> we had an option to remove each drawn layer after completion, and
> replace it with a less memory intensive truncated object which grows
> taller as each layer is complete?
>
> Vik :v)
>
> _______________________________________________
> Developers mailing list
> Developers@reprap.org
> [reprap.org]
>



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Quoting RepRap Forum Mailer :

> As well, doesn't that corner block need support material for all those holes?

Not any. Ed's brilliant design for it (including cavities for loads of
trapped nuts) is such that you can print it without any support at all.

Best wishes

Adrian

Dr Adrian Bowyer
[staff.bath.ac.uk]
[reprap.org]
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"Re all this web traffic: yesterday was our best Google Adsense day ever
at $30."

Super cool! I've made just a shade over $40 total since I activated adsense on my little website back in the middle of February. Glad to hear that the widows and orphans fund is getting some input.

Well, okay. Are we talking about those teardrop-shaped horizontal holes then?

Quoting RepRap Forum Mailer :

> Author: Forrest Higgs

> Well, okay. Are we talking about those teardrop-shaped horizontal
> holes then?

Among other things. The interior cavity is really quite intricate.

Best wishes

Adrian

Dr Adrian Bowyer
[staff.bath.ac.uk]
[reprap.org]
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Oh Lordy!