globs and bubbles everywhere

[drandolph]

So here's my back story. I got the RostockMax V1 almost two years ago and I built it and got it printing really nice. Then I got cocky and starting tweaking left and right, changing settings left and right. then one day it just stopped being able to extrude during a print. It would extrude filament just fine but when I went to print it would stop working. I cleaned and checked everything mechanical. I verified temps, replaced gears, adjusted the extruder steps and no luck. So It sat there collecting dust because I was lazy and I had 4 other printers also in use so I was in no real rush. Well I decided it had collected dust long enough and it deserved to live. So I upgraded the firmware from .80 to .91 and starting going through my EEPROM settings and getting everything back to as close to default as possible and the same problem starting happening again. It took awhile but somewhere along the line I set retraction to 6mm which is way too much. Boom! I changed it to 3mm and what do you know it starts printing again but with globs all over the print. I feel like I've gone through all the EEPROM settings and configured everything back to default. This print is a simple vase using the vase setting in mattercontrol with zero infill. I'm printing at 210c and 80mm. I've lubes the filament with some vegetable oil and replace the PTFE tubing and it doesn't slip at all. I've attached a screenshot of all the settings. I'm running fully stock configuration, extruder,RAMBo. I'm using PLA so I expect some stringing but the globs should not be there. Any thoughts?

[teoman]

Did the filament also sit gathering dust with the printer?

Complete random guess but if your filament has excessive moisture it could barf out the filament in globs and then proceed to have no material for a few consequent mms.

[drandolph]

Nope I store my filament is sealed 5 gallon bins with desiccant in them and I've been printing still with my other printers.

[BenTheRighteous]

You're printing at 80mm/sec? That seems extremely fast. I pushed that speed when I first got the printer and wanted to test its limits, but I'm not sure I'd expect much quality at anything over 50.

[drandolph]

I was thinking 80mm would have been fine on it but I went ahead and tried it at 40mm and there is still the same blobs. It looks almost like filament is being burned. I have my peek fan on full speed and the heater assembly is fully wrapped in insulator tape. I'm really perplexed by it.

[JFettig]

The distance after it retracts to start printing is probably 6+mm. Check your slicer settings

[BenTheRighteous]

Have you verified your thermistor reading with a thermocouple? Maybe it's reading cold and your actual hotend temperature is extremely hot.

[jmpreuss]

I usually print PLA at 190c on my max, if I were you I would definitely try dropping the temp a bit to see if it improves.

[RocketMagnet]

In addition to your temps I'd also check the following...

I notice you upgraded the firmware... if so and you've not changed them it will have the default current settings and if you've got Kysan motors they will be way too high so check Configuration.h
line 702:
#define MOTOR_CURRENT {150,150,150,170,0}
so that's {x,y,z,Extruder1,Ext2}
Or there abouts for Kysans (I found <160 for the extruder1 caused underfeed) (the defaults are #define MOTOR_CURRENT {175,175,175,200,0})

I'd also check your filament diameter and set it in Slicer correctly.
I've personally found globs and gaps can be a result of over and underfeeding so getting the motor current correct for the feed and the filament diameter helps (clearly if the diameter is wrong the feed rate is wrong) in addition to the other stuff mentioned above. Also if the Hot End adaptor isn't bolted down tightly I've seen similar.