Gaps and separation in outer layers
December 12, 2012 01:55PM
Hi,
I just finished my prusa and am having some issues as I build up my layers. As you can see in the picture my layers seem to seperate on the outside as they go up . I am printing with a .4 nozzle at 245C with 50% infill. Im currently having trouble getting my print bed to temp and it will only get to about 90C before it peaks, I have no idea whats going on there.

Im curious if ambient temp could be the cause of this. Currently the room the printer is in is about 45-50Deg F. But any advice would be fantastic.

Thanks,
Joe
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Re: Gaps and separation in outer layers
December 21, 2012 10:43AM
Hi!

i have the same problem with layers not sticking together. I use ABS and extrude at 230°C.
Some help would really be awesome smiling smiley

Thanks in advance,
kugel
Re: Gaps and separation in outer layers
December 21, 2012 11:17AM
It really would. I have it slightly better now. I releveled my bed using a .060" dial test indicator, and that helped some. But Im still having issues. No one can help?
Re: Gaps and separation in outer layers
December 27, 2012 07:18AM
Check for backlash. You can get unpredictable lash if your pulley set screw is not tight enough.
Re: Gaps and separation in outer layers
December 28, 2012 08:36PM
prcdslnc13 & kugel, lower your plastic print temperature to around 230°C and turn OFF any fans/cooling you are using. You have a pretty big cooling issue, your room temperature is quite low for printing ABS. The delamination of the ABS plastic is due to overcooling of your parts. With a room temperature that low, you are fighting a loosing battle.

I would recommend what they call "turkey bagging" your machine, and put a thermometer inside the bag to see if you can increase the temp to around 80 - 85°F. The turkey bag approach also keeps drafts away from your prints. Turkey bagging can do more harm than good if your printer extruder parts are made out of PLA (especially your X Carriage or Small Wades gear), as they might exceed their low Glass transition temp and start to warp. You don't have to use an official turkey bag, a clear HDPE bag or sheeting like at your local home improvement store works well. You mainly want to increase the temperature of the air around the plastic parts you are printing.

Also, for your heat bed temp, check your supply voltage. Low bed voltage will not allow it to heat up high enough, it's just a big resistor. You can turn it up a bit to 13+ VDC in order to heat the bed up a bit more. Sounds like you might currently be at around 10VDC with the load. Check the voltage of you power supply when the heat bed is fully on as bad power supplies will drop like a rock when under a load.

You might consider switching plastic to PLA during the winter months. Remember ABS hates cooling, PLA demands it. The colder room temp would be a benefit for printing with PLA, your delamination problem will totally disappear.
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