Print Quality Degrading mid-print

[cmac]

Hi folks,

Have had a Rostock Max v3 running quite well since October. Happy with the quality of prints and the tolerances that this machine can produce.

Recently, prints have begun to get very grainy during the last hour of the print. The first few hours (or inches) of the print are high quality and accurate, laying down thick solid layers and infill that is perfect. In the last hour, or over the first inch of perfect printing, it begins to lay down layers that seem to be half of the material needed. It makes for a very grainy effect, layers do not bond to one another well, and although it can complete the print in the form its creating, the part breaks very easily.

Im curious as to why this happens? The printer seems calibrated well, and can clearly print well to start, yet it accurately prints garbage mid way through. Has anyone seen anything like this?

[img]https://photos-4.dropbox.com/t/2/AAAphb ... ize_mode=3[/img]

[Tincho85]

Image isn't showing for me.

If had to guess, you are retracting too much/fast and the nozzle gets clogged.
Could also be a temperature issue.

Share your print speeds, temperatures and retractions so we can help you better.

Best of luck.

[cmac]

Hi, thanks for the quick reply: link to photo if still not showing:

https://www.dropbox.com/s/8qbektsohp2s2 ... 8.JPG?dl=0

The machine settings are:

210 extruder, 60 bed. Infill at 35mm/s, inside/outside perimeter at 50mm/s, retraction 25mm/s.

Any other variable worth sharing? Going for another print now.

[Tincho85]

25mm/s is a conservative speed, mine is the same. But, how long your retracts? if they are close to 2mm then it's ok, if they are >4mm then lower them.
When the issue starts, is it retracting a lot or it's just the same as it was a few layers below?

If it's not retract related, then I could only think of:
* The drive gear is eating your filament----> The extruder bearing is pressing too tight.
* Your motor is running too hot----> Gear gets hot. Chew filament.

[cmac]

Thanks for the reply. It appears it was temperature related. Now onto the next can of worms.