Duet/RRF Big printing problems

dc42

@pro3d, I'm glad you are making progress. It sounds that the online configurator is setting the incorrect thermistor B value when you choose the Semitec thermistor. I'm sorry this has caused you so much trouble. We'll get it fixed.

deckingman

If you take a gander at Semitec specs, the GT-2 is now superseded by the NT-4. http://atcsemitec.co.uk/product-category/glass-thermistors/

The 104NT-4 has a quoted B value of either 4267 or 4390 depending on type https://atcsemitec.co.uk/wp-content/uploads/2019/01/Semitec-NT-4-Glass-NTC-Thermistor.pdf

But what is interesting is that the resistance tolerance is quoted as +/-3% and the B value tolerance is +/- 2%.

Which brings me back to what I said earlier that there is no substitute to finding what temperature actually prints best. e.g. if you have one machine that prints fine at 200 deg C and the thermistor is at one end of the tolerance band, then the actual temperature could be 3% or 6 degrees lower so 194 deg C. A second machine using the same thermistor but at other end of the tolerance band might actually print 6 degrees higher so setting 200 deg C could result in an actual temperature of 206 deg C which would likely lead to blobs and stringing. That's an extreme example but I believe it serves to illustrate the point I have been trying to make.

dc42

Bear in mind that the B value quoted in the data sheet is invariably over a small temperature range, typically 25C to 75C. It's not accurate over the larger ranges of hot end temperatures. Also, when you use the C parameter in M305, you need to use a lower B value. So B4388 is correct if you don't use a C parameter, but B4725 with the C parameter is more accurate.

pro3d

@phaedrux

I am struggling to get the plugin activated. I did not find it in marketplace but downloaded it from a um forum post - Is is jsut to drop in the plugin folder?

[0_1549572902627_PrinterSettingsPlugin.curaplugin](Uploading 100%)

Phaedrux

I think you double click on the plugin file to install it? I can't remember, but I'm pretty sure it's available in the market place now. I'll have to double check. There should be some installation instructions where you downloaded it from.

pro3d

I might have been a little early to celebrate. Guess its time to look for component trouble or filament issue

Phaedrux

Is the extruder idler tensioned properly?

pro3d

@phaedrux

I was thinking NO so I did re-tension it now so it extrudes fine at 30mms without skipping/ripping the filament and re printed the part above so no luck there

looks to hot and this is the suppliers suggestions for everything. I think speed and temp look to high but wanted to test their settings /add.North

grizewald

@dc42 said in Duet/RRF Big printing problems:

@pro3d, I'm glad you are making progress. It sounds that the online configurator is setting the incorrect thermistor B value when you choose the Semitec thermistor. I'm sorry this has caused you so much trouble. We'll get it fixed.

@dc42 Please can you also update the text at: https://duet3d.dozuki.com/Wiki/ConfiguringRepRapFirmwareCartesianPrinter#Section_Heater_and_thermistor_section

This states: "The Semitec 104GT-2 thermistor supplied with the E3Dv6 hot end has a quoted B value of 4267, but the actual value over 25C to 220C is 4388."

Given that text, and what the online configurator suggested, that's what I'm using.

I'm chasing similar problems to pro3d as well, also on a CoreXY with a 700mm long Bowden tube (Capricorn) fed via a Bondtech BMG extruder. While I am getting there, I'm still seeing what look like over-extrusions at the layer changes, so I'm following this thread with interest.

dc42

@grizewald said in Duet/RRF Big printing problems:

@dc42 Please can you also update the text at: https://duet3d.dozuki.com/Wiki/ConfiguringRepRapFirmwareCartesianPrinter#Section_Heater_and_thermistor_section
This states: "The Semitec 104GT-2 thermistor supplied with the E3Dv6 hot end has a quoted B value of 4267, but the actual value over 25C to 220C is 4388."

Thanks, I've updated it.

pro3d

@phaedrux

Apparently the machine settings plugin does not support all cura versions and at this point I cant get Cura back to its regular state... lol

No luck finding the firmware retraction setting I am sorry

Phaedrux

@pro3d the other option to test firmware retraction more easily would be to use Slic3r. But I don't think firmware retraction will solve anything for you. It just makes it easier to test retraction settings while a print is running.

pro3d

Updates on my troubleshooting

I added the ramps board to see what it could do with my normal settings as have been working for ages. It did not perform well so I have some issues in the component department

However Marlin do seam to handle retractions better as stringing part is almost gone with same settings. Is this due to absolute extrusion maybe?

Here are the last models in various temp/flow and speed and the two Marlin prints in the middle - Pretty much the same issue so filament bad or hotend / extruder/ thermistor trouble I guess

dc42

The stringing may be a temperature issue. Have you tried reducing extrusion temperature?

pro3d

@dc42
Yes I have tried so many variations of temp, flow and speed, retraction I think it is the filament or some component. I have tuned one roll of petg now.... Currently mailing with add.north for advice on filament

But will absolute extrusions be better for the long bowden you think? Retraction seams better

dc42

There shouldn't be any difference between absolute and relative extrusion. Both get converted to the same steps.

pro3d

So troubleshooting my way through this extrusion/retraction problems

It now looks much better after changing the complete hotend. I did not expect this as it was a brand new e3d V6 now replaced with a new clown and I need to test other filaments but it looks right now

Left: Befor change of hotend - Right: After change

pro3d

More tests - This will do just fine. Not sure if we can get rid of the seam more than moving it to the inside

this was with 0.2 PA enabled

Before: