Lulzbot Budasnozzle PLA Retraction help needed

Ok, reprap Prusa Mendal. Running Marlin Firmware (within 2 week old version). Using Slic3r Version 0.9.7, Tried 0.9.8 also with same results as picture above. I am printing 3mm PLA filament and have adjusted the retraction speed from 5 to 45 in slic3r and the length from .5 to 3mm. I have also changed the e jerk setting from 5 to 35 in about ever variation I can think of. The issue is when crossing from one object to the other, I am getting a significant small blob and stringing. I am running my new Buzasnozzle 1.2 with a .35mm nozzle. I have added a temporary fan blowing at 100% on the cold part/copper heat sync of the hot end (maybe not close enough), I also added a cooling duct to blow on the filament to cool as I print small objects. I also have changed my extruder temperature from about 175 (any lower, I have issue with sticking to the glass) to 195C. I have adjusted my head bed from 55 to 70 (Not that it should be related except for the bonding of the print to the glass. I have to say I am stumped. I am primarily printing with PLA now but ordered ABS today as well and will try it for the first time later. I have been printing for a few months with a jhead and wanted to try a budasnozzle and that's what I am working with now. You can barley see it in the photos because i have wrapped it with a ton of kapton take to insulate it from the cooling fans. I do have some ceramic tape coming with my filament too. I do not appear to have any slipping issues with my hobbed bolt, but I as mentioned above, slowed down the retract as well. This is not happening on the z move it is definatly just when crossing islands/perimeters. Anyone with a Budasnozzle, please help. I have probably tested about 1/2 lb of filament now trying to tune it in and not having great success. I am using repitier host as my print engine to run my gcode produced from slic3r as well. The is a lag when it moves as it does a retract but I have sped it up until I thoght my gears were going to break teeth. Suggestions please. All suggestions and questions are welcome and appreciated.

John AKA Unlucky1

Have you tried PID tuning your hotend? Step 1, make sure PID is enabled in the firmare. Step 2, send M303 commend and that will start an automated PID tune cycle (assuming you have a somewhat recent marlin firmware). Step 3, once complete take the 3 numbers they give you and enter them into your firmware. This should help smooth out your hot end temp range. It helped me out a lot.

I have pid tuned and no luck with that. My Marlin was downloaded about a week or two ago from github. I also played with the temperature settings really high and really low. To low and I get layering issues. My issue if you watch it carefully when its printing, is like it smears the filament when it moves across the bed to a new island. I also tried raising the z on retract just for fun with no help. Very frustrating. It actually prints great as long as it does not have to jump to another section on the same layer, but that makes it not good at all. My understanding is that ABS prints much better with it and I am going to give it a try as well in a couple of days. I have been printing with a j-head V-b for a few months and wanted to get the budaschnozzle worked out before I mount it up to an i3 I am in the process of building.

Not getting much feedback here. Are most people printing with ABS using the budaschnozzle?

While I don't use very much pla I do have lots of experience with the budaschozzles. Try this, set retraction speed between 14 to 18. Set retraction length between 5 to 8. Then set your travel speed about 10 percent lower than your perimeter print speed. Then watch carefully as it prints. Most of the time I've found that the stringing from these comes from the print head taking off too fast when going from one section to the next. Retraction doesn't fully take effect before the print head is on its way to the next section.

The other thing to watch is whether the stringing/blobs are from the side of the print the print head just completed or whether it is excess plastic at the nozzle being deposited on the next area of the print. I know it sounds weird but I fought this for awhile until I realized the strings and blobs I was seeing were actually coming from excess plastic being deposited after a travel move. I will see if I can find a picture to show the issue. Slowing down the travel speed helped as well as setting the retraction speeds/distances in the ranges above.

These actually are great hotends they can just be a bit counter intuitive to get dialed in.

I print predominantly with PLA with a buddaschnozzle and don't see anything like that sort of stringing. I run 3mm of retraction, but I get less stringing than that with retraction disabled.

That looks like an awful lot of extra plastic.

My GUESS would be you're over extruding, and when it jumps, the excess pressure is released dumping the plastic.
Have you done the single wall test and verified the extrusion width?
Have you tried printing a 100% filled test cube? it's usually a good indicator if the flow of plastic is too high.
I would run both tests with retraction disabled, if you are losing steps during retraction it can make the stringing worse and it's better to isolate the tests.
PLA does tend to string more at higher temperatures.

As an aside I'd recommend using paragraphs if you expect people to read your posts, big blobs of continuous text are conducive to reading.

I appreciate all the info. 1. belaive you me, I have done the single wall test about 20 times and adjusted my esteps accordingly. 2. The 5 to 8 mm retraction distance seems ridiculous but I have tough also that the filiment was not having enough time to cool and it was catching it ever so slightly and dragging it. I have also printed at 10mm per second for that reason to see if that would stop it and the same thing happened. 3. I am the king of overextrusion and have had that issue before. I test everything again and again now. 5. I am pretty certain that I am not skipping steps, I can retract slow or fast into the air and it seems to be working fine, thats the puzzling part. The end of my cooling fan is about an inch from my hot end and I am not to proud of the 40mm fans and their ability to crank out air. I even have the high output ones that are twice as thick. On my jhead, I made my own circular fan duct adapted from a couple of designs on thingiverse to put the air right at the print without cooling the hot end at all.

Last but not least, I took off my glass from the heatbed last night and noticed that there was a terrible wobble. I have adjusted a few things but still need to level my heat bed. I even adjusted my smoothrods a little and took off the belt to ensure a smooth ride back on forth on my y axis. My x axis is like butter. I will tune it in again later and try again. I will also try the huge retract. i am thinking slow retract to give the printed material time to cool a little. I have already tried small slow big slow and increased speed and length in all sorts of combinations up to about 3 or so mm. Maybe its my glass moving a little on me. Not sure yet. I will post and update and thanks again for the info. Did either of you run a fan blowing on the cold part of the hotend for pla? I put a temporary one on and it seemed to help a little but no luck.

I run a single 40mm fan with a shroud pointed at the nozzle, but there is enough air motion to keep the thermal break cool enough for PLA.

I have used a .35 Budasnozzle since right around day one. ABS was always perfect, PLA required a fan pointed at the print surface. I use a 80mm fan clipped to the rail though. I've never had any real stringing issues, well none that a good sharp knife couldn't cure anyhow.

I just got my Lulzbot AO-101 printer and have been playing with it quite a bit. Mostly with ABS, but I have started with PLA now. I am using KISSlicer as my slicing method for most prints and I found to get PLA to look good you have to slow your printing speed way down. In the Slow - High Quality setting I use 5 for perimeter, 15 for solid infill & support, 30 for sparse fill and things seems to come out pretty clean.

Bridging has been a problem for me with both ABS & PLA, but I think the speed just needs to be dropped for that, at least that what I am seeing so far with my testing.

I am also not using any fan setup so far. The only thing that bothers me is I can print 2-3x faster with ABS.

I tried a bit of what recommended, mentioning lowering the travel speed.
I didn't put mine lower than my print speed, but lowered it from 45 to 30.

I print everything at 15mm/s and have a big fan from a powersupply now sitting ontop of the prusa frame, With a 0.5 mm nozzle, 1.75mm filament,
Retraction settings:
length 4mm
lift z 0.1mm
speed 18 mm/s

I've been printing retraction settings today and right now it looks very clean with these settings.

For bridging, and pla in general, fans will make a big difference, but it is possible if you blow a fan directly at the print, it can make the object start warping off the bed.