Extruder Feed Controlls in MatterController

[taggedzi]

I was attempting to calibrate the feed rate coming out of the extruder because I was getting some "weird' symptoms in my prints that might be over/under extruding... and was trying to fix up.

• I removed the bowden tube from the hot end and clipped the filament at the end of the tube
• In Matter controller told it to Extruder 100mm of filament. The printer did so. I measured it.
• Then I manually wound it back up to the spool and lined it up with the bowden tube with the nice blue knob with the eyes on it.
• In Matter Controller I told it to extruder 100mm MORE filament. Nothing Happened. All the other controls responded Home/Z/Fan
• I tried E+/E- larger and smaller numbers 1/10/100mm. Nothing happened.
• I disconnected the printer from MC and re-connected, then tried to extrude again. Nothing happened.
• I disconnected the printer from MC. Turned OFF the printer. Physically unplugged from USB and power. Opened up the top and checked all the cable connections to the extruder. There are no signs of damage and the connector is plugged in tight. I unplugged it and plugged it back in to check. And followed the cables back to the motor with no obvious sign of damage.
• I reconnected everything and tried again... still nothing.
• Just for the heck of it, I decided to try to print... and see if THAT could move the extruder motor. It did! It printed.
• I removed the bowden tube from the hot end, clipped the filament, and told it to extrude 100m more. It did. I measured.
• I tried for a 3rd so I could get an average... nothing happened, again.

All of the other commands worked as expected. I could open the terminal and watch the "G91 G1 E100 F150 G90" commands being sent to the printer every time I requested filament. I could even see the "E*" value change to the value extruded/retracted, but it did not do anything. I was also able to successfully change settings in the EEPROM.

Any ideas as to why after extruding 100mm of filament I can't get the extruder to respond to MC again without physically starting a print. Queuing the print it didn't do it, it actually had to start the print process. Once it started, it was good to go for one more try.

I am on a Rostock Max v3 on Windows 10 with MatterControl 1.6. Connected via USB. If it matters I'm using com7 and 250000 Baud Rate. (Side note I am running UN-modified Firmware 20170201 Repetier_0.92.2)

Willing to work on figuring out. I know I have a work around by printing something, but I'd like to be able to extrude more than once at a time without having to stop and print.

And just in case it makes a difference the "weird" results I was getting to start the whole thing off were that while printing the flow rate would just seem to stall or slow down without reason. Sometimes the extruder would click once or twice, but not always. I have been working on adjusting the temperature/flow since I switched to a new filament roll.

Thanks much, and in advance you guys have been great.
Matthew (TaggedZi)

[geneb]

Keep in mind that extrusion commands will be ignored if the hot end isn't up to operating temperature.

When calibrating the extruder, dont' wind filament back through the extruder - you want to use fresh filament each time as it's slightly distorted when going through the first time. Just clip it flush with the push-fit connector on the bottom of the extruder.

g.

[djarmag]

+1 with Geneb, hotend has to be in use to prevent filament grinding. Like stepping on gas with engine off.

You can also try clicking the disconnect/reconnect button in MC each time you plan to send extrusion commands if you are trying to measure 100 mm filament with Bowden disconnect and hotend off. Probably have to do the same disconnect/reconnect procedure when you test flowrate mentioned next...

To calculate max flowrate based on Mhackneys guide, just click preheat or set the temp for your filament to the nozzle in MC, send the command (I used G1 E100 F60 --Fxx in multiples of 60 to figure out max feedrate I've seen no higher than 240/300 when filament extrudes nicely from the nozzle) then use his formula for the flowrate.

Describe your symptoms, thin walls, voids, pimples, etc, it might just be a setting issue.

[taggedzi]

Well thanks for the info. I had no idea. I was able to get an average with the 3 samples I made using the print, remove, extrude method. But knowing I have to heat up the hot end helps.

@geneb Thanks for telling me about not backing the filament back up. I'll make sure to not do that any more. And for letting me know about the temp requirement to extrude.

@djarmag: I was following the guide on Matter Hackers website on how to calibrate your extruder rate http://www.matterhackers.com/articles/h ... r-extruder. They used the SeemeCNC Rostock Max as an example. (v2, but it was pretty much same layout) I have to admit it was MUCH easier to measure 100mm from the end of the bowden tube to the end of a clipped filament, than going from the top of the extruder to a mark somewhere on the spool (what others on youtube recommended.) After I finished and told it to extrude 100mm, I get exactly 100.0mm. So it seemed to work, I was getting about 102.4 before which I don't think is off by that much.

The problem I was seeing is seemingly at random the flow of filament from the nozzle will just slow down to a trickle. The bead will get so small it barely touches the nozzle (I guess that is called voids? I'm not sure on that...). It only lasts about 1-3 seconds, and it goes back to an amazing bead profile. When I printed a 20mm x 20mm test cube I did not get a single layer that this did not happen on somewhere on. Sometimes on the outer edges... sometimes in the middle of a line. When the flow slows down I can usually hear the extruder strain and sometimes it will click once or twice.

Based on what I'm reading online... (and that is online... so it is not gospel) it sounds like I need to calibrate my flow rate and temperature. And I was trying to do that when I discovered this oddity. Now that I've got the extruder rate calibrated I'm going to try to calibrate my temperature. I don't think I have any kind of mechanical problem or software issue. I think I just need to work out how to best get the printer setup for this new filament. Because I'm new to 3d printing it will probably take me a while to get the hang of the art form.

Thanks for the info guys, you're great.
Matthew (TaggedZi)

[geneb]

That filament starvation issue may be indicative of a block in the hot end caused by an insufficently(sp) seated bowden tube in the hot end.

g.

[djarmag]

It's good that you are knocking it out procedurally, too many variables to make everything go bad quickly. It could also be your filament, what kind is it and does it measure the same at different parts of the spool? When you seat the Bowden, make sure you are still pushing the tube down while using your other hand to lift the retaining ring thingy, otherwise that will create the gap Geneb speaks of.