Duet/RRF Big printing problems

Phaedrux

Just looking at the differences between your Marlin and RepRap configurations.

E acceleration Marlin=10000mm/s^2, RepRap=1000mm/s^2
E Jerk Marlin=15mm/s, RepRap=10mm/2

This would greatly slow down your retractions.

So here is my suggestions for what to change and test next.

M556 E1200
M201 E10000

Set retraction to 9mm at 60mm/s with pressure advance off.

Print a retraction test model, every 15 layers increase pressure advance from the console by 0.05.

dc42

Your thermistor config is incorrect, it should be B4725. See https://e3d-online.dozuki.com/Guide/V6+RepRap+Firmware+Configuration/26?lang=en. That means you have been printing at the wrong temperature. HTH David

pro3d

@dc42

Thanks - Does this mean the config online tool gives another value than what it should have?

Phaedrux

@dc42 said in Duet/RRF Big printing problems:

Your thermistor config is incorrect, it should be B4725. See https://e3d-online.dozuki.com/Guide/V6+RepRap+Firmware+Configuration/26?lang=en. That means you have been printing at the wrong temperature. HTH David

The configurator gives M305 P1 T100000 B4388 C7.060000e-8 R4700 when The E3D Semitek-104 GT2 option is selected. It looks like that may have been correct for firmware versions older than 1.16, but the configurator seems to have not been updated to give the new values for firmware versions 1.17 and above.

I recently swapped a burnt out PT100 sensor for the E3D Semitek GT2 and used the values from the configurator for it, oddly enough I didn't notice any temperature related issues for the week or so I used it while waiting for a replacement PT100.

pro3d

@phaedrux

Nice catch about the E accel - I did not ever change this at any point in Marlin so I did not know its value. I will test your recommendations

pro3d

@phaedrux

How ever max accel is overided by these values in Marlin no?

#define DEFAULT_ACCELERATION 1000 // X, Y, Z and E acceleration for printing moves
#define DEFAULT_RETRACT_ACCELERATION 2000 // E acceleration for retracts
#define DEFAULT_TRAVEL_ACCELERATION 1000 // X, Y, Z acceleration for travel (non printing) moves

Phaedrux

@pro3d That would depend on how the slicer is sending acceleration values, if you are using those settings.

Still, the file you posted has higher limits set than 1000,2000

/**
 * Default Acceleration (change/s) change = mm/s
 * Override with M204
 *
 *   M204 P    Acceleration
 *   M204 R    Retract Acceleration
 *   M204 T    Travel Acceleration
 */
#define DEFAULT_ACCELERATION          1500    // X, Y, Z and E acceleration for printing moves
#define DEFAULT_RETRACT_ACCELERATION  3000    // E acceleration for retracts
#define DEFAULT_TRAVEL_ACCELERATION   1500    // X, Y, Z acceleration for travel (non printing) moves

pro3d

@phaedrux

I dont know how slicer sends values I am sorry

Phaedrux

Regardless of what the differences in settings between marlin and reprep, the issue as presented is retraction related. And the solution to reduce the blobs at the layer seam is to try and make the extruder more responsive. Faster retractions in combination with pressure advance to reduce the need for retraction distance.

Phaedrux

@pro3d said in Duet/RRF Big printing problems:

@phaedrux

I dont know how slicer sends values I am sorry

For Cura you'd have to specifically enable it. By default the accel and jerk settings are hidden.

In RepRap the M204 command works differently than in Marlin though. In Marlin it controls acceleration for Print moves, Travel Moves, and retraction. Where as in RepRap it's only Print and Travel moves. Retraction acceleration is dictated by M201.

pro3d

Update - Progress is present

So I changed 3 things and I know this is stupid but at least it shows progress. It might just have been the thermistor but I need to run more tests later today

I changed thermistor to B4725
Upped E-accel from 1000 to 3000
Upped E-jerk from 600 to 900

PETG test at same model and filament as before

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.