layer separation on taller prints

I am noticing that every time I print something taller, say above 30 or 40mm, I am getting layer separation.

I am printing with ABS, heated bed at 110.

I never have the problem on shorter prints, even if they are wide.

Here are some pics.

[dl.dropboxusercontent.com]

[dl.dropboxusercontent.com]


Anyone have any ideas of what I can do to fix this?

The shorter prints are receiving good heat from the print bed which enhances layer adhesion. As you get further from the bed so the upper layers cool quicker relative to the lower layers causing stresses to build up resulting in the problem you're experiencing. Having a heat source directed at the print has been found to be beneficial (e.g. heat lamps). or enclosing the printer in a cabinet.

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Waitaki 3D Printer

I kind of figured that.

I was hoping slower speed or something like that may help, but it does not seem to.

I think a enclosure is going to be really tough on my mendelmax.

I may see if I can give heat lamps a shot.

Are there any pictures of heat lamps being implemented that anyone knows of?

Usually when I get that, I just up the head temp a few degrees and it works fine.

I actually tired that, and unfortunately when I did that my filament ended up slipping in the hobbed bolt and the filament stopped feeding and print failed.

I will try this again, thanks for the feedback.

The print looks to have some form of Z banding and it looks like they split where the layers are further apart than they should be.

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[www.hydraraptor.blogspot.com]

Nophead.

If I understand banding correctly, that would be caused by using an incorrect layer height based on the Z axis threaded rod.

My layer height is set to 0.2 in the pics above, and I am using a 8mm normal pitch threaded rod, so I was under the impression that I can use any multpile of .1 for my layer heights?

I ran another one yesterday, at 0.3 layer height, and at a much slower print speed.

Here are the pics:

[dl.dropboxusercontent.com]

[dl.dropboxusercontent.com]

The print itself looks much better, and I don't see banding, but Im relatively new.

This print looks far better, and much less layer splitting, but its still there and I stopped it soon after I noticed it, so it probably would have gotten worse.

If it is Z banding, am I incorrect in my layer height assumptions, or is this hardware related?

Thanks!

Nothing wrong with you're layer heights. It seems from feedback from others that black is a devil of a colour to use!

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Waitaki 3D Printer

I had delaminating on lager prints, until I changed filament supplier. What a difference!

Now my ABS doesn't detach from the bed anymore, even the tiniest prints works fine without a brim, and delaminating on high prints doesn't happen either.

So, filament quality also influences these properties a lot!

Ohmarinus Wrote:
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> I had delaminating on lager prints, until I
> changed filament supplier. What a difference!
>
> Now my ABS doesn't detach from the bed anymore,
> even the tiniest prints works fine without a brim,
> and delaminating on high prints doesn't happen
> either.
>
> So, filament quality also influences these
> properties a lot!


very interesting. If you don't mind sharing, can you tell me your filament supplier? I'd love to give it a shot.

The filament I'm currently using is the 'Clear ABS' from www.filamentenmeer.nl BUT this vendor gets it's filament from Repraper, so thats where it's from.

It's the filament I'm showing in this topic, last post:
[forums.reprap.org]

In the last photo you can clearly see the ABS sticks to the bed very well, even with a small contact surface (the bottom of the object that is printing is tapered a little) and I've also been printing high, wide and thin-walled parts that had no delamination problems. In fact, I tried to stress them by hand and they are very strong.

Edited 1 time(s). Last edit at 07/10/2013 06:53AM by Ohmarinus.

Quote
Ohmarinus
I had delaminating on lager prints, until I changed filament supplier. What a difference!

Now my ABS doesn't detach from the bed anymore, even the tiniest prints works fine without a brim, and delaminating on high prints doesn't happen either.

So, filament quality also influences these properties a lot!

It is possible that the new brand works at a lower temp. You could up the temp on your old ABS and may have the same result.

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[www.matter-replicator.com]