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1Feb/10Off

Megalomaniac stupidity — ramping up production

Megalomanic-pretencious thoughts
Make you think-you are a god
But let's face reality,
You're a slave of your stupidity,
But let's face reality,
You're a product of naivity?
-- Agathocles
Megalomaniac stupidity

I wanted to scale up the Mendel parts production. The goal was to print the full set of Mendel the fewest batch possible.

So I arranged my parts on the table in a way, that all the big parts was surrounded with small parts (see post picture). To achieve the same effect as Forrest did with his apron technique. I also repeated Forrest's prints on my machine before, and the warping was reduced, but not as much as for Forrest, but definietly worth the (modelling) trouble.

So I had quite high hopes printing as much parts at once as possible. I hoped that I started the machine at the Morning, and when I returned from my work at afternoon my machine was still printing Mendel parts.

So I started the first batch. The total build time was about 18 hours, from which the raft took about two hours. Here are the raft:

It is pretty big. In fact I used up all available space of the bed, only few milimeters left at the edge:

Also at the corner it even printed to the hole, where the machine goes when the temperature changes (at warmup, after the raft, and after the first layer). So I really pushed the machine to its limits:

It was really critical to level the bed correctly. Look at this picture how uniformes are the lines:

Maybe you can also spot the cracks at the middle of the 3mm thick PMMA sheet. It probably caused by alcohol cleaning of the printing bed, this and big parts printing (lot of thermal stress) caused deforming of the sheet. I fixed it with 8 M3 sunked head hex bolts (two at each edge), only a little aesthetic problem, which only affects the first layer of the raft.

The first layer print was gone rather nicely:

But after small curlup occured. Just after some printed layer, there were already some burned corners:

After 8 hours of printing the machine failed. The printing head stuck at one part's edge (due the warping), and the motor skipped few steps. The next layer had about 1 mm offset. So I had to stop the printing.

So having a big raft with multiple big parts on it does not help the warping issue at all. And if I had only printed one big object, then the head wouldn't have stuck at another big part's edge, simply because the head would have never left the object's contour.

Here is a closeup picture how worse was the warping:

The conclusion: A heated bed is essential, even more if I want to use all my bed, especially for multiple big parts.

After this epic fail, I decided to build a heated bed. What I already did, only the blogpost need to be done;-)
Hopefully in the coming days I will publish an article about my heated bed results.

Stay tuned.

Comments (7) Trackbacks (2)
  1. Hi Laszlo,
    Is that HDPE? It doesn’t look like ABS in the pictures.

    The first layer of the objects look completely wrong. The infill looks sparse and does not meet the outlines? That will not help them stick to the raft.

  2. > Is that HDPE? It doesn’t look like ABS in the pictures.

    Nope, I have never tried HDPE. I have only used ABS, so it is ABS from bitsfrombytes (40GBP/kg or 46EUR/kg), the white one. I’m using currently blue ABS, and waiting for the arrival of 50 kg;-)

    > The first layer of the objects look completely wrong. The infill looks
    > sparse and does not meet the outlines?

    I know. This prints are from december (and also this blogpost was in draft state for about a month). I print a bit better now for the first layer, but not much.
    With my heated bed, it does not really count. All my infill is somewhat wrong (in other layers too).

    I’m still waiting for your sourcecode to hit this bug right on its head;-)

    Also if you look at this pictures the thin layer of the raft detached from the base layer (not only the object itself from the thin layer of the raft).

    I also did lot of experiment with different motor speeds, if somewhat my settings are wrong (layer height vs. motor speed). But no matter what speed I’m printing, the infills are not touching each other. I will post an article about that too.

    Just there are some heated bed articles in the queue before it;-)

  3. btw, had you got a chance to look into my proposed arm devel board? (the one with lcd screen, builtin can, ethernet, usb)

  4. That looks like fun, I guess reliability issues are what prevents bulk prints like this. It may be do-able to zone the build space with each zone having enought space around it so that the print head cannot catch on the surounding pieces. If each zone was printed to in order then failure would’nt result in the loss of all the pieces just the ones for that zone……..

  5. If your raft is a bit better, I think there would be less warping and a higher chance of success for the entire build.

  6. > If your raft is a bit better, I think there would be less warping and a
    > higher chance of success for the entire build.

    Typically for an 18 hours printing it is not chance what you want, but reliability. And for this no warping is desirable…

    I will not repeat this experiment without heated bed, thats for sure.

  7. hey, your blog is getting popular!