Rounded Overhangs Not Printing

[magicwiser]

I have recently been experimenting quite a bit with different print settings and can not seem to print rounded overhangs no matter what I do (straight overhangs and bridges seem to print fine though). For example, I tried printing the Inception top with support for the entire bottom half and it still came out terrible (see picture). I have tried using all different layer heights and nothing seems to help. Is there any other settings that would help?

[dkightley]

It would be really useful if you could upload the factory file for the print you've shown in the photo. That will allow the boffins on here to see what the starting point is...

[magicwiser]

Sorry for the delay but I assumed that the fourm would email me if anyone responded. Anyway, here is the factory file. Set support for a 35 degree angle.

[tri-lite]

I love working with supports so I was glad you posted your Factory File. I believe the problem can be seen by rotating your model in Preview Mode to see the underside of the model construction.

In the images attached, you'll see that with 4mm supports, there are no supports placed under the very center of your model. But if you change the support resolution to 2 mm, you'll see that a network of 4 supports are placed in the very center of your model. I didn't print your model, but I believe this center support structure will be vital to the construction of your model if you print it in this orientation.

Here's a rule of thumb: The smaller your model (like your thumb-sized model), the smaller your support resolution should be.

[tri-lite]

Sorry for the delay but I assumed that the fourm would email me if anyone responded. Anyway, here is the factory file. Set support for a 35 degree angle.

I think I figured out why you didn't get notified! When you are creating your Forum post, you need to place a checkmark in the box labeled "Notify Me when a Reply is Posted". Options are located under the green Preview/Submit buttons.

Then you'll be sure to get your answers as soon as someone responds!

[magicwiser]

I love working with supports so I was glad you posted your Factory File. I believe the problem can be seen by rotating your model in Preview Mode to see the underside of the model construction.

In the images attached, you'll see that with 4mm supports, there are no supports placed under the very center of your model. But if you change the support resolution to 2 mm, you'll see that a network of 4 supports are placed in the very center of your model. I didn't print your model, but I believe this center support structure will be vital to the construction of your model if you print it in this orientation.

Here's a rule of thumb: The smaller your model (like your thumb-sized model), the smaller your support resolution should be.

Ahh thanks for the advice. Since printing that top I have had similar problems with other rounded objects but now that I think about it, they are all pretty small. The few larger objects I have printed have all come out just fine. I’ll have to make that change and try reprinting. I’ll let you know tomorrow how it turns out.

[magicwiser]

So I reprinted the top using a smaller support resolution (1 mm) and it definitely improved the quality of the print. As you can see, the basic shape is perfect. However, the bottom of it just doesn't look very nice. At the end of the day I can live with these results but it would be nice to be able to print perfect objects. I was wondering if using a slower print speed would fix this?

I have attached the updated factory file as well.

[DarthRevan]

So I reprinted the top using a smaller support resolution (1 mm) and it definitely improved the quality of the print. As you can see, the basic shape is perfect. However, the bottom of it just doesn't look very nice. At the end of the day I can live with these results but it would be nice to be able to print perfect objects. I was wondering if using a slower print speed would fix this?

I have attached the updated factory file as well.

Hi Magicwiser,

Rounded overhangs have usually caused problems for me as well. I've found that if you have the setup to print dual extrusion then soluble supports are the best tool to overcome this obstacle. You can print with 0 separation between your supports and your part. Dunk the finished part and supports into some water for a few hours and you're good to go.

I'd recommend PLA & PVA as HIPS & ABS is more difficult to get to stick together.

In no time you'll be seeing stuff like this:https://www.youtube.com/watch?v=EoAjaJGA8q0!

[jimc]

in addition to darths recommendation, another way to go is to split the model in 2 then you can print both halves down and have zero support. it will come out very clean. just bond the 2 halves together when done. your bottom surface is fairly typical for a supported surface. you have a 1 layer gap between the support so i can be removed. the gap makes it look like what you have there.

[tri-lite]

That is a GREAT idea JimC!
It would certainly print in 2 perfect pieces, each piece flat-side down and with a nicely tapered point.