ABS "squeeze"

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LawnD4rt
Posts: 2
Joined: Tue Apr 16, 2019 9:50 am

ABS "squeeze"

Post by LawnD4rt » Tue Apr 16, 2019 10:04 am

Printed my first prints using ABS yesterday. First layers are going down fine then the layers start to "squeeze" inwards for about 5 - 7 mm then goes back out to the correct dimension. Here are the details

Matterhackers Build ABS
The larger print was sliced with current ver of simplify3D, the smaller part is done in Lulz Cura 3.6.3
Nozzle: 240. Bed: 110

I am thinking this is a bed heat issue, Should bringing the temp to 100 be good? I will test when I get home.

Attaching pics.

Loving the Taz 6 so far and this ABS after those few layers prints great.

Image

Brent.I
Aleph Objects | LulzBot
Posts: 497
Joined: Mon Jan 20, 2014 8:21 am

Re: ABS "squeeze"

Post by Brent.I » Tue Apr 16, 2019 3:10 pm

LawnD4rt wrote:
Tue Apr 16, 2019 10:04 am
I am thinking this is a bed heat issue, Should bringing the temp to 100 be good?
It is looking to be a temperature issue, but depending on the size of the print it will point in a few different heating possibilities.

For the small part, it could be due to insufficient cooling time between layers. Printing multiples of those (2-3) separated on the bed would allow more time cooling between layers. If that print looks better, you know it is a layer time/temperature issue on the hot end, and the bed will not be an issue.

For the larger part, I would recommend measuring how high up the part was before it started looking better and compare it to your settings. The fan settings in Cura are set to ramp to the "regular" fan speed over X number of layers, or X height. It could be once the fan kicked in here, it resulted in more cooling, giving you a cleaner part.

The final one as you alluded to will be your bed. We recommend 105c-110c on the first layer to help bed adhesion with ABS, but Cura has a setting for further bed temperatures. That is, you can reduce the bed temp after the first layer to test if that is the issue.

LawnD4rt
Posts: 2
Joined: Tue Apr 16, 2019 9:50 am

Re: ABS "squeeze"

Post by LawnD4rt » Tue Apr 16, 2019 6:02 pm

I am still doing some test prints. But it looks to be related to the layer cooling fan. The larger print was done in Simplify3d and I thought it had disabled the cooling fan. we re-made a version of the model to just past where it was "squeezing" to cut down on print test time. My 1st test print was with no layer cooling using Lulz Cura 3.6.3 and there was some heat related issues in one area of the model. I did 90 on the bed and I thought I changed the nozzle temp to 235, but it printed at 245. ops. The 2nd test print I adjusted the layer fans to kick on at 2mm. That print started out great, but pulled away from the bed at some point. So on test 3 I have the bed at 100 and the nozzle at 235 with the layer fan at 2mm and so far "xfingers" it is looking good. I will try a benchy with these settings to see if the results hold up on a thicker model and not one that is basically 3-4mm thick.

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