ABS lifting off supports

[JFettig]

I'm printing a huge part(~32 hours, 13" tall) and I'm having a few issues with lifting. The first time I started it, it lifted real bad at the bottom, I increased the temp and removed the layer fan all together - it was a bad idea.

Its lifting in a number of places, under a flat flange, and on a boss that sticks out the side. I have 1 layer missing under the boss and flange to the support, should I run them right up to the part? I can't imagine they would clean off very well? Higher temperatures? Slower speeds? I'm running 228C at the extruder with MatterHackers Pro ABS. Max of 40mm/s

[img]http://i.imgur.com/ZFcugly.jpg[/img]
[img]http://i.imgur.com/LD98VAb.jpg[/img]

[BenTheRighteous]

Do you have glue on the glass? It looks like you don't; that would be the first thing I would try.

Edit: actually I'm unclear what the problem is - is the build lifting off the glass, or is the part separating from the printed support?

[BenTheRighteous]

Ok I see in the pictures now - glue wouldn't help here. Maybe try an enclosure? Is that an option?

[JFettig]

I am using glue on the bed, no problems there. I'm now seeing lots of cracks in the part. I was hoping to avoid building an enclosure and heating it.
I definitely have lots of problems with cracking and lifting off the supports, one flange on my part is completely distorted

Is there a better material to run?

[lightninjay]

As most here will attest, if you're going to be printing ABS, you need to either have an enclosure to prevent drafts cooling the part unevenly, or you need to keep an entirely draft-free room. A cheap system that I've found to work fairly well is a clear shower curtain. I have an example of it in my build thread here.

[Mac The Knife]

Printing at 228C is to cold, IMO. Matterhackers recommends 230C-240C for their pro filaments. Secondly, Have you verified your extruder's temperature? Using a contact thermometer I found my temps to be low by 8%, and had to adjust the configuration.h file accordingly. Running higher nozzle temperatures will get you better fusion. As for the warping, It's abs. I found a semi clear trash bag that I can throw over my printer, I imagine a dry cleaning bag may work as well.

[JFettig]

Thanks guys, I'm researching building an enclosure with a heater at the moment.

I bumped up my temperature to 235C a few hours ago and so far there are no cracks in the print in that section. I have not verified the temperature with any thermometer.

This print takes 2/3 of a spool to print so I'm going to have to change spools to print another.

[JFettig]

Only 1 small crack since I raised the temp to 235C. I will print this part again with a different spool(this one will run out shortly). I'll also add some support to the areas that warped really badly(not pictured anywhere above). I am around hour 30 of the part, only about 20-30 minutes left.

One thing to note, quick google search says that there is 400M of 1.75mm ABS on a 1kg spool, the LCD display says I'm at 580m, I have only ever run this one spool on it. I'm going to guess I have another 50 meters on the spool by the looks of it. Steps/rev are left stock as I extruded 100mm of line and measured it very carefully and it measured perfect.

[Mac The Knife]

One thing to take into consideration about about laying down layers, the layer its putting down has to be hot enough to cause the layer below it warm up enough for fusion. Faster speeds require higher temperatures, and lower temperatures require slower speeds.

[JFettig]

should have put up the curtain last night when I started the print, already formed some cracks. I put it up and threw some aluminum bits onto the heat plate to help soak up some heat and disperse it into the air. The curtain is slightly warm so it seems to be doing its job
[img]http://i.imgur.com/rR5vUWr.jpg[/img]

No snapping or popping so far. Some parts did lift before I did this, hopefully the rest of the print will be 100%.

[bot]

Be careful, because you're also basically covering ALL of the electronic cooling intake and exhaust vents.

[JFettig]

Good call. One of my next projects will be brackets for a real enclosure.

I found some old heatsinks in my scrap metal pile, they'll suck the excess heat off the build plate nicely