bapro
Posts: 65
Joined: Mon Mar 02, 2015 11:11 am

Compensate for high builds

Mon Mar 09, 2015 8:42 am

Hi,

Can anybody tell me how to compensate for the shrinking i ABS.
When I try to build large and high objekts they delaminate. The first 20mm is good but the it starts to happen.
As far as i see it must have to do with the material shrink of ABS.

JoeJ
Posts: 1435
Joined: Sun Feb 16, 2014 10:52 am

Re: Compensate for high builds

Tue Mar 10, 2015 7:53 am

People typically use a heated bed to keep the first few layers of the ABS print from shrinking too much. This way they help avoid delamination from the build surface. You could also potentially try a brim or a raft to help get a larger surface area for adhesion. The ultimate solution would be an enclosed heated chamber to prevent the shrinking all together, but few have that option :D

KC_703
Posts: 238
Joined: Tue Aug 26, 2014 5:23 pm

Re: Compensate for high builds

Tue Mar 10, 2015 5:50 pm

He might be saying the print is delaminating from itself... rather than curling/warping from the bed.

If that's the case, try increasing extrusion temp so that the new filament bonds better with the previous layer. And/or reduce cooling.

If that doesn't work, increase extrusion flow... but this may require tweaking retraction, coast... etc.

If the print is lifting from the bed, try:
- slowing down the first layer
- increase first layer temp
- tweak the squash of the nozzle with the G-Code Z-Offset setting.
- Brim (as suggested above) for more surface area on the bed, thus better adhesion

As always try one thing at a time... too many changes and the sweet spot for your printer may be overlooked.

JFettig
Posts: 72
Joined: Tue Dec 30, 2014 3:13 pm

Re: Compensate for high builds

Tue Mar 10, 2015 9:01 pm

Its quite difficult to print ABS without an enclosure of some sort. The air around the print needs to be still and warm, just ambient air and moving around the print alone can cause it to cool unevenly and crack.

bapro
Posts: 65
Joined: Mon Mar 02, 2015 11:11 am

Re: Compensate for high builds

Wed Mar 11, 2015 3:41 am

I have no problem getting the part to attach to the building plate. It is delaminating from it self.
Part of the problem is certainly due to the presence of a radius at the bottom. I changed it to the next print.
This part size is 100 x 120 x 110. So I think it's quite a challenge.
I´m printing on a Duplicator 4S, heated bed 110deg, Filament ABS 230deg. The PLA fan is switched off, no cooling. And everything is built in a chamber (Not very well heated thou).
Everything is leveled and calibrated as good as it can for what I know.

Now as you say I should try increasing temprature and extrusion flow. I could use a hint here how much to increase the multiplier.
By using a spcified startpoint I probably get as close to the most cooled down area for the next layer.

The sad part of problems like this is that it takes half a day to se the result. So anyone that knows howe to, plaese!
Attachments
P1040872.jpg
Cracks in ABS

SockMonkey
Posts: 22
Joined: Thu Feb 26, 2015 7:22 pm

Re: Compensate for high builds

Wed Mar 11, 2015 5:58 am

bapro wrote:I have no problem getting the part to attach to the building plate. It is delaminating from it self.
Part of the problem is certainly due to the presence of a radius at the bottom. I changed it to the next print.
This part size is 100 x 120 x 110. So I think it's quite a challenge.
I´m printing on a Duplicator 4S, heated bed 110deg, Filament ABS 230deg. The PLA fan is switched off, no cooling. And everything is built in a chamber (Not very well heated thou).
Everything is leveled and calibrated as good as it can for what I know.

Now as you say I should try increasing temprature and extrusion flow. I could use a hint here how much to increase the multiplier.
By using a spcified startpoint I probably get as close to the most cooled down area for the next layer.

The sad part of problems like this is that it takes half a day to se the result. So anyone that knows howe to, plaese!
I would suggest trying to enclose the build volume somehow to keep the temperature consistent throughout your part to prevent the cracking

JoeJ
Posts: 1435
Joined: Sun Feb 16, 2014 10:52 am

Re: Compensate for high builds

Wed Mar 11, 2015 8:27 am

Enclosure would definitely help. You could also try increasing the number of perimeter outlines by 2-3 and then increase your extrusion multiplier a bit as well. That will help the layers bond together better. A slight increase in the extrusion temperature may also be helpful for the same purpose.

tenaja
Posts: 143
Joined: Wed Dec 17, 2014 5:16 pm

Re: Compensate for high builds

Wed Mar 11, 2015 11:28 am

bapro wrote:And everything is built in a chamber (Not very well heated thou).
For those who speak English as a second language, a chamber means it is enclosed.

bapro, I had better results after putting a heat gun (hot air blower) in my enclosure. You probably also need to raise your extrusion temp up by 5 or 10* C.

KC_703
Posts: 238
Joined: Tue Aug 26, 2014 5:23 pm

Re: Compensate for high builds

Wed Mar 11, 2015 4:04 pm

bapro wrote: Now as you say I should try increasing temprature and extrusion flow. I could use a hint here how much to increase the multiplier.
By using a spcified startpoint I probably get as close to the most cooled down area for the next layer.
You can increase the flow of filament through the extrusion multiplier setting on "Primary Extruder Toolhead" page. Click "Edit Process Settings" from the first page, then click "Show Advanced" to see the "Extrusion Multiplier" setting. Adjust to 1.1 or 1.2 to increase the flow 10 or 20 percent respectively.

Before you adjust the flow, increase the extrusion temps.... found under the "Temperature" tab, in the "Primary Extruder" section. From the "Cooling" tab, you can adjust the layer and amount of fan flow... I like to use 20-30% as max fan for ABS.

Hope that helps... and yes its a painful trial and error process to tune the setting to your printer.

bapro
Posts: 65
Joined: Mon Mar 02, 2015 11:11 am

Re: Compensate for high builds

Thu Mar 12, 2015 7:03 am

Thanks for all the advice. I have tested a lot of different settings now and it seems like I'm starting to get to it. So in a few days I'll have a hopefully perfect detail in my hands.

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