UM2+ w/ Bondtech DD - Extruder Calibration

[3D-Blaster 0]

Hi - first post on this forum - banging head on wall doesn't seem to help.

 

I chose to purchase a UM2+ several weeks ago as first printer - found one on eBay w/ relatively low run hours - surprised at the futz factor to make parts but happy with the open source nature of this machine.

 

Using Atomic brand PETG because of desired material properties over PLA - the following are machine and Cura 4.3 settings applied for best results (still not perfect).

 

Nozzle size: 0.4mm

Nozzle Temperature: 240C (excessive stringing occurs @ 245C)

Nozzle to Glass leveling Gap: 0.15mm

Bed Temperature: 70C (good adhesion achieved using glue stick)

 

Printed the standard Benchy part w/ stock filament feeder using Ultimaker CPE profile - the only parameter altered in Cura was the layer height in an effort to mitigate plowing after first layer.  Realize, I'm blasting thru this w/o prior knowledge or good sense that I know what I'm doing.  The biggest issues that resulted was excessive particle generation from stock feeder to where the filament locks up in Bowden tube.  The grinding effect is continual hence I start researching alternatives and settled on Bontech DD feeder as recommended by many on this forum.

 

Made the swap and altered Marlin firmware "E-steps per mm" to 311 as recommended for Bontech DD.

 

To control the extrusion level again I'm using Ultimaker CPE profile w/ some running tweaks as follows.

 

Flow is reduced generally to 50% for all print modes inclusive of first layer which is set to 0.27mm height and I still find the extruder motor stalling trying to feed more than is necessary to hold filament force - on complex parts the feeder will make loud clicking noises - on simple parts the feeder stall is subtle but occurs at about 20% duty time.  The motor current was played w/ and the effect to Bowden tube is minimized when current is reduced to 950mA w/o increasing stall frequency.

 

Also, having to dynamically inject a z-offset of 0.1mm after the first layer due to nozzle plowing (prior layer issue) - best results seem to occur at 0.18 layer thickness versus 0.15 layer thickness - nozzle buildup from plowing is reduced but understanding Cura is compensating for flow which is not desired - I just want a z-offset for PETG and don't understand how to achieve it.

 

Sorry for the winded background - looking for step-by-step method to calibrate the extrusion system beside the blind trial methods applied to date.  Forgot to mention that all hot end components are newish and installed correctly and that temperatures were verified to be accurate.   Is the Bondtech extruder designed to stall on occasion as it does?  Is the UM2+ feeder designed to grind as it does?  Both conditions indicate something else is at play or as I suspect the Cura flow calibration applies to PLA and not PETG because of the different viscosity? 

 

How does one alter a viscosity value and does such exist?  

 

Advance thank-you .

[tinkergnome 926]

3 hours ago, 3D-Blaster said:

Made the swap and altered Marlin firmware "E-steps per mm" to 311 as recommended for Bontech DD.

 

Just to be sure:

That means you have installed the Firmware from Bondtech and made a factory reset as described in the instructions?

Or did you made something different...?

 

And on a second hand printer one has to ask... Are you sure it still has the genuine feeder motor (e-steps were at the default 369 before)?

 

 

3 hours ago, 3D-Blaster said:

Flow is reduced generally to 50% for all print modes

 

That sounds wrong... It should never be necessary to use a flow rate other than 100%.

 

some more questions...

 

You use the default printer definition in Cura (gcode flavor "Ultimaker")?

All material settings on the printer are correct (filament diameter)?

How have you verified the printing temperature?

 

 

[3D-Blaster 0]

Initially yes, I installed the firmware from Bondtech then it seemed reasonable to test the Arduino IDE and Marlin firmware variant which in terms of feeder characteristics behaves the same as Bondtech's.  I still don't know how to query the machine w/ Cura and g-codes - total newbie w/ a busy schedule in other realms.  Marlin original has 282 count which is far different than 369.

 

I realize 50% sounds wrong hence the title of this thread but that's what makes repeatable prints.  I'm at 800mA on the extruder stall to keep it at an occasional chirp and yes, using Ultimaker base settings for material w/ a realization that deviating too far makes it a goat rope to control.

 

Temperature verification was conducted w/ second thermister w/ 110C full scale reading, so an abbreviated check not at running temps - stringing increases at higher temps and force required when hot end fed by hand is not significant in any way.

 

Wrong motor but still plenty of torque...seems as though I can calibrate by effecting the e-steps, yes?  Thanks for the reply.

[tinkergnome 926]

11 hours ago, 3D-Blaster said:

Marlin original has 282 count

 

282 is the default value for the (older) UM2 with non-geared feeder (and motor with 400 steps/rev).

Default for UM2+  - with the geared feeder (and 200 steps/rev. motor) - is 369

 

You can use and modify the source files from Ultimaker, but don't forget, that the changed e-steps is not the only modification from Bondtech. The feedrate during material change was reduced as well.

 

Link to UM2+ Configuration.h:

 

https://github.com/Ultimaker/UM2.1-Firmware/blob/UM2.1_JarJar/Marlin/Configuration.h#L369

 

 

11 hours ago, 3D-Blaster said:

I still don't know how to query the machine w/ Cura and g-codes

 

The easiest way is: use "pronterface/printrun" to get a serial (USB) connection to the printer.

Marlin firmware reports all relevant settings in the terminal window after the connection is established.

Or you can send "M503" to the printer to get the same output.

 

http://www.pronterface.com/

 

Good luck!

 

[3D-Blaster 0]

Thank you again.

 

You are correct the filament loading parameter (don't recall which one at the moment) was altered on the Marlin per the same value Bontech recommends - loading was tested and worked like a charm first time.

 

The Marlin firmware I'm using was sourced from the same github.com/Ultimaker/UM2.1 link you shared.

 

Super appreciate the g-code utility link I will look into this.

 

Lastly, out of all the recommendations made there is one outstanding step that was never invoked and that was a factory reset from the printer's control panel.  I was thinking if firmware updates are being made doesn't that clear running parameters stored in memory?  As I recall the reduced current limit for extruder stepper had to be updated after the firmware update occurs but not certain on this. 

 

I will try a factory reset and see if the 50% flow setting is impacted.

 

[3D-Blaster 0]

No Joy resulting from factory reset. 

 

I briefly looked at the g-code utility as-recommended - will reserve time to learn it but prefer to use Cura for now if possible.

 

Where does the printer message show when an M503 is asserted?  Nothing shows on Cura 4.3 monitor screen - the field for g-code entry is obvious the response from printer is not.  I'm missing something here.

 

To calibrate the feeder would like to assert M83 g-code (relative move command) and measure filament coming out the Bowden tube to then recalculate the counts/mm then stuff this value into the firmware.

 

As a side note, the filament material properties in Cura is a copy of Ulimaker's CPE - noticed there is density but weight =0 grams, does this factor in any way for flow settings?

 

Also, printer was originally UM2 and end-user upgraded to UM2+.  If original motor (400-step/rev) was not changed out for the replacement (200-step/rev) this would result in under extrusion and not what I'm experiencing, correct?

 

Wishing there was more time to research and not ask for help...

[3D-Blaster 0]

>>> M503
SENDING:M503
echo:Steps per unit:
echo:  M92 X80.00 Y80.00 Z200.00 E311.00
echo:Maximum feedrates (mm/s):
echo:  M203 X300.00 Y300.00 Z40.00 E45.00
echo:Maximum Acceleration (mm/s2):
echo:  M201 X9000 Y9000 Z100 E10000
echo:Acceleration: S=acceleration, T=retract acceleration
echo:  M204 S3000.00 T3000.00
echo:Advanced variables: S=Min feedrate (mm/s), T=Min travel feedrate (mm/s), B=minimum segment time (ms), X=maximum XY jerk (mm/s),  Z=maximum Z jerk (mm/s),  E=maximum E jerk (mm/s)
echo:  M205 S0.00 T0.00 B20000 X20.00 Z0.40 E5.00
echo:Home offset (mm):
echo:  M206 X0.00 Y0.00 Z-19.55
echo:PID settings:
echo:   M301 P10.00 I2.50 D100.00
 

Looks like flippen gibberish to me, what do you think thinkergnome?

 

Looking for an M83 example not sure how to setup arguments.

[3D-Blaster 0]

Good news.

 

G1 E20 pays out exactly 20mm of filament.

 

Bad news.

 

Running 50% flow @ 45mm/sec nominal.

 

Looks like this thread is closed - extruder is indeed calibrated.