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A problem I've had for a long time is a Barking Extruder. It prints the first few layers fine, and then the extruder makes a weird noise which I think is from the extruder forcing more filament in the Bowden tube than it can handle. I was using some old filament (like five years old), and despite this, it was printing okay. Today new filament arrived (silk Gold PLA+). The problem seems to have gotten worse.

So since I recently pulled this out of storage and did a lot of troubleshooting to get it working, I decided to check the steps on the extruder, but it came out perfect on a 10mm push. I also changed the nozzle from a .8mm to a .4mm and updated this in cura.

This is a Rostock v2 with an E3D v6 hotend and motor silencers. It is otherwise stock. I am slicing in Cura and loading the code in repetier so I can monitor and control the prints. I thought I used to do this on cura, but Cura 5 seems to require a network which the v2 doesn't have.

The nozzle is tight, heat break is tight, Bowden tube is tight. extruder calibrates perfectly. running 200 degrees on PLA+ with a 50 degree bed. brand b-new PLA+

Ok, I vote for "Barking Extruder" to replace whatever the previous term was - it's so awesome I can no longer remember what it used to be called!

What is happening is that because the extruder can't push filament through the system quickly enough, the bowden tube and filament are forming a kind of spring. When the force in that spring exceeds the ability of the extruder stepper to fight against it, the stepper motor will rotate backwards a few dozen steps as the force is released. This is making your "barking" sound. (gah, that is just too awesome. *laughs*)

In order to fix this, you either need to decrease your print speed or increase your nozzle temp. You also don't want to "lie" to the slicer about your nozzle diameter unless you know exactly what you're doing and why you're doing it. That path leads to madness and mayhem.

This can also happen if you've got a partial clog in the hot end.

g.

I didn't know what to call my problem, but I figured you all would get the idea of my terminology.

I agree with what you are saying about the reason.

I am not lying to my computer about my nozzle size. I had a .8 installed and changed it with a new .4, then updated the system accordingly.
The caveat is that I did not change this in Repetier, but I'm not slicing in it, only running the code. It shouldn't make a difference, right? I'm going to change in now anyway.

So I need to reduce the flow % then? I would need to do that if my extruder steps were too high, but the calibration was perfect.
I'll play with higher temps in the meantime.

I wouldn't mess with the flow % - it's not relevant to the extruder skipping problem you've got. The nozzle diameter in Repetier doesn't matter if all you're using it for is to send gcode to the printer.

g.

So it goes back to Gene's original suggestion, slow down the print speed, or raise the temperature of the hotend. It really sounds like the heater isn't able to keep up.

I tried both of Gene's suggestions. I still get 20 minutes into a print and start having issues with a barking extruded and no filament.

Since I feel like I've checked just about everything on this printer, I decided to check the one thing I hadn't, the extruder. I did not find any issues here, but I did notice the molded plastic connecting the extruder to the Bowden tube felt tight on the filament. So I flipped it, so I'm now using the larger side. This might cause its own issues, but we'll see if anything improves.

If it's a *reliable* 20 minutes to failure, you're experiencing heat creep into the cold section of the hot end. This results in the filament swelling inside the cold section and that will cause that particular dog to bark like mad. Is the cooling fan on the cold section working properly?

g.

geneb wrote: ↑Tue Jun 14, 2022 9:25 am If it's a *reliable* 20 minutes to failure, you're experiencing heat creep into the cold section of the hot end. This results in the filament swelling inside the cold section, and that will cause that particular dog to bark like mad. Is the cooling fan on the cold section working properly?

It is.

I decided to pull apart the hot end. I found that the new filament got stuck in the cold end where a random section of the old filament did not. I got everything put back together and decided to change the filament again. I assume the new SIlk Gold PLA+ from Dikale (Amazon) doesn't retain the tolerances my machine needs. I have a new role coming from a company with significantly more reviews (Overture).

In the meantime, I am running some red T-glase. This stuff has got to be seven years old. I had bed adhesion problems, but the tape and glue stick combo seemed to work. I usually do one or the other, never both. My slicing speed is 60mm/sec, with the outer layer at 30 and the first layer at 20. I then slowed the machine down to 25%. The nozzle is at 242C (the site says 245-252). I got a great start. Over the 45-minute print, I increased the speed to 50%. The print came out okay—lots of strings.

On the next print, I increased the retraction from 3.5 to 5 and reran it beginning at 50% speed and working up to 100%, and things came out a little better.

On the next print, I bumped up the retraction to 10 and dropped the nozzle to 240. the tiny bits failed, and the strings did not seem to be any less. I did get barking again from the very first layer. I dropped the speed down to 50% until layer 5, when I put it back to 100%. The remainder of the print was unsupervised.

When I set this machine up, I did several bed and nozzle calibrations to get them dialed in, but I see a 2.5-degree deviation from my set point, especially to the cold side. What is the standard method for verifying nozzle temp?

The photo below are the prints. The last print is on the left, and older prints are to the right.

If my memory is correct, T-Glase is going to suck up water, so you should really dry it out (google "filament dryer" - you can make them out of food dehydrators) and it won't print well until you do.

The skipping on the first layer is because your nozzle is too close to the bed and the filament can't flow well enough to prevent a lot of backpressure from building up. This will also cause "elephant's foot" in your prints.

Cura 5 shouldn't require a network - it should be able to save gcode files as it always has. That being said, I haven't up graded to it yet.
What do you have configured for retract speed? I'm currently running retract distance of 6.5mm @25mm/sec.

You might want to give Atomic Filament a try. It's not the cheapest out there, but I feel it's worth the money for the quality.

g.

1) I got another roll of gold silk PLA. This time from Overture and I'm back to having extrusion issues. Why is my old filament printing and the new filament having issues?

2) I'll take a look at the filament dryer. Do you think its possible to dry filament this old?

3) Skipping. Why was the old filament not skipping on the first layers if the nozzle is too close?

4) I can save gcode with Cura 5. What I want to do though is print to my printer from Cura 5. There is no USB connection option.

5) Retract speed is set at the stock 45mm/sec

6) I ordered some of the Atomic. We'll see how it goes.

1. Each roll of filament is going to have its own "sweet spot" for printing. Try bumping the temp up 5c and see how it prints.

2. I tried it out on a 7 year old spool and it worked great.

3. No idea.

4. Ahhh, I didn't know you were printing from Cura over USB. I thought it only did that with UltiMaker printers.

g.

geneb wrote: ↑Sat Jun 18, 2022 9:40 am 4. Ahhh, I didn't know you were printing from Cura over USB. I thought it only did that with UltiMaker printers.

Maybe that's the problem. Just annoying to slice in cura and then load in Rep. but its fine.

geneb wrote: ↑Wed Jun 15, 2022 10:20 am You might want to give Atomic Filament a try. It's not the cheapest out there, but I feel it's worth the money for the quality.

My Atomic filament came in yesterday. I just ran a print with it at 230c (210-230 recommended). I ensured I had good flow, cleaned the bed, and told it to start. I am still trying to print the same 3" crown as before. Plastic came out nice right from the skirt lines. By layer eight, it was barking again.

What else can I check?

I appreciate the help. It would be so easy to buy a Prusa, but I love this delta and would love to see it running parts regularly.

This is very strange. I had to do some digging to refresh my memory on how the E3D v6 was put together. I couldn't recall whether or not it has a PTFE liner or not. (according to the doc sheet I found it doesn't)

The repeatable timing on the skipping is just *screaming* "heat creep" at me - you're absolutely positive the fan on the heatsink is running and blowing air AT the heatsink?

I missed this in a previous question - you can check your hot end temp by bringing the hot end up to temp and inserting a thermocouple probe down into it until the tip touches the inside of the nozzle. Before you do that, you'll want to do a cold pull to make sure the hot end is free of filament - heat up the hot end, extrude a bit by hand and then turn it off. When it hits 160c, swiftly pull the filament out of the hot end. If it worked properly, you should be able to see a dot of light when looking down through the hot end and with a small light aimed at the nozzle opening from the outside.

g.

geneb wrote: ↑Sat Jun 25, 2022 9:10 am The repeatable timing on the skipping is just *screaming* "heat creep" at me - you're absolutely positive the fan on the heatsink is running and blowing air AT the heatsink?

Yes, it runs at 100% all the time. I can see it running, hear it running, and when not paying attention, felt it running. When I tore the E3D v6 apart recently, I had the nozzle heater on max and had no issues holding the cooling fins with my bare hand while the fan was connected.

That doesn't mean I'm not getting a small amount of heat creep.

I'll try the cold pull.
When you say I can insert a thermocouple probe, can you give me recommendations?

Something like this will work: https://www.amazon.com/dp/B07DLW3MNV

The idea is to put that tiny metal bead at the end of the probe all the way down into the hot end so that it touches the inside of the nozzle.

g.

Rostock V2? If you haven't already, I would take a screwdriver to the heater connections on the RamBo board.

Mac The Knife wrote: ↑Mon Jun 27, 2022 8:22 am Rostock V2? If you haven't already, I would take a screwdriver to the heater connections on the RamBo board.

Can you give me some more details on this?

Sorry, Take a screwdriver to all of the connections, making sure they are snug. With the power cycles, and all the vibration, they can loosen with time, which will only get worse as they develop more resistance at the connection, causing even more heat and resistance. There have been pictures posted of the connections at the board pretty melted.

I have not had a chance to use the temperature probe or check the screws, but I have made some progress. I slowed the machine down from the stock 60mm/sec to 30 and turned off retraction in decent but stringy prints. The retraction speed default is 45 mm/sec. I got the printer up to 38mm/sec, rarely barking. Then I turned the retraction back on, and it started barking a couple of layers into the part. I slowed retraction down to 30 mm/s to more closely align with my print speed and helped stop the barking. This was, however, a primarily flat part and did not have much retraction. In my crown test at the beginning of this, each finger in the upper half would require a small print area and a retraction. I'm wondering if this might cause an issue.

My printer now seems like the slowest printer I've ever seen run. I printed a spiked cuff for a Bowser costume, which took over 10 hours. What is everyone else using for print speeds?

I'm running retracts at 25mm/sec and the retract length is 6.5mm. I'm printing at 60mm/sec with an infill speed of 100mm/sec. This is for my BOSSDelta 300 though. (it uses an SE300 hot end, so basically anything that uses the SE300 can use those speeds)

I'm wondering if your retract speed and length is the root cause of your issue... What retract length are you using?

g.

geneb wrote: ↑Tue Jul 19, 2022 9:44 am I'm running retracts at 25mm/sec and the retract length is 6.5mm. I'm printing at 60mm/sec with an infill speed of 100mm/sec. This is for my BOSSDelta 300 though. (it uses an SE300 hot end, so basically anything that uses the SE300 can use those speeds)

I'm wondering if your retract speed and length is the root cause of your issue... What retract length are you using?

g.

At the begining of this my retraction speed was set at the default,3.2 mm at 45 mm/sec.
In playing with the settings, i felt that this was not enough distance. I had not found the sweet spot, but felt that 5mm was not quite enough and 7.5 - 10 had about the same results, so i had left it at 7.5 mm.

As for the speed, because i was printing at 30 mm/sec, i reduced the traction speed to 30 mm/sec and it seemed to help.
I have changed to your settings: 6 mm @ 25 mm/s and will print another crown.