Hello - Prusa I3 experimenting with the Marlin firmware

[brover]

Hi all,

I am Steven, living in a small country that's called Belgium. I am 43 years young proud father of 3 boys.
I have 2 3d printers, a Prusa I3 where I am experimenting with the Marlin firmware, started from scratch because I did not have the original files for this printer. I can tell you, it's not easy. My second printer is the XYZ Davinci 2.0
This last printer is working fine, I like it because this one is already printing ;-)
I have a question regarding my XYZ printer, it prints fine in ABS only with larger object it shows gap (see image)



second picture it's worse, there the gap is large.



Anybody have some tip to prevent this

[smskeeter23]

I have literally no experience with ABS but from what I have read about it, and believe I understand, this appears to be a problem of the print cooling too much during printing.

This appears to be an open air printer correct? ABS is VERY picky about ambient temp and even worse about even the slightest of drafts. I would suggest building an enclosure to retain heat during the print or even a large cardboard box while printing.

[brover]

I am using the davinci 2.0, that in a box.

I found this info on the S3D website regarding gaps:
Layer height is too large

Most 3D printing nozzles have a diameter between 0.3-0.5mm. The plastic squeezes through this tiny opening to create a very thin extrusion that can produce extremely detailed parts. However, these small nozzles also create some limitations for what layer heights can be used. When you print one layer of plastic on top of another, you want to make sure that the new layer is being pressed against the layer below it so that the two layers will bond together. As a general rule of thumb, you want to make sure that the layer height you select is 20% smaller than your nozzle diameter. For example, if you have a 0.4mm nozzle, you can’t go too far past a layer height of 0.32mm, or each layer of plastic will not be able to properly bond to the layer beneath it. So if you notice that your prints are separating and the layers are not sticking together, the first thing you should check is your layer height compared to the size of your nozzle. Try reducing the layer height to see if it helps the layers bond together better. You can do this by clicking “Edit Process Settings” and selecting the Layer tab.

Print temperature is too low

Warm plastic will always bond together much better than cold plastic. If you notice that your layers aren’t bonding together and you are certain that your layer height isn’t too large, then is is possible that your filament needs to be printed a higher temperature to create a strong bond. For example, if you tried to print ABS plastic at 190C, you would likely find that the layers of your part will easily break apart. This is because ABS typically needs to be printed around 220-235C to create a strong bond between the layers of your print. So if you feel this may be the problem, verify that you are using the correct temperature for the filament you have purchased. Try increasing the temperature by 10 degrees to see if the adhesion improves. You can do this by clicking “Edit Process Settings” and selecting the Temperature tab. Simply double-click the temperature setpoint you wish to change.

can someone confirm if this is maybe my problem?

[Guest]

Welcome to the forum, brover! Those tips are correct, but it might be something else as well. It sounds like you have the printer covered with a box while printing? Something as simple as lifting the box to check on the print or opening the enclosure door could cause something like this.

[brover]

Thanks :-)
Yes I did open the door a few times to remove filament from the nozzle.
Maybe you are right
I cannot change the degrees of my filament, it's default 90 degrees, I read that 100 or 110 is better for ABS.
Can I repair this gaps with acetone? keep in mind that I have to put some pressure on the object to close the gap.

[Guest]

You could probably fuse the gap with acetone, but it will change the look of the surface finish in that area. It will be smoother. Have you tried printing without opening the door at all during the print? I know it's tempting to mess with it, but it can cause all sorts of proplems with ABS.

[brover]

You could probably fuse the gap with acetone, but it will change the look of the surface finish in that area. It will be smoother. Have you tried printing without opening the door at all during the print? I know it's tempting to mess with it, but it can cause all sorts of proplems with ABS.

I did a new test with ABS, during the test I did not open the box.
This is the result, still gaps



What do I need to do to prevent gaps in my ABS prints?

[Guest]

Have you tried raising your nozzle print temp a bit?

[brover]

Not yet
but what about filling the model, does it effect this also?

[Guest]

Raising the nozzle temp can help your layers fuse together better and hopefully prevent the warp cracking you are seeing. Also, what is your layer height and nozzle size/diameter?