so i received the thermistors and fixed everything... got new PLA filament from Zenikinetic.com.. which behaves a bi better but still the performance using canola oil is much better....

now i ordered an infrared thermomether from china(here in CR are 2x or 3x as expensive ads in the U.S.) but my effor on trying to get a good cooking thermometer to measure more than 100°C was futile and only thing i got was a good reference that something is stinky with this thermistors. so i'm waiting for those thermistors from e3d and also a nice stainless steel nozzle ( I've got to put my hands in some nice carbon filament from Colofabb )

I've also replaced the Fan for a new one. and yes it seems like running faster but i also ordered some new fans 30x30 mm that spin at 12k rpm and at least i will know what's the nominal flow (4.7CFM), which i think should be enough.. however, the actual fan keeps the heatsink cool enough that i can touch with my hand and it's not even too warm....

now, . while the parts I ordered Arrive I have a small update.. i have read about the Canola Oil use for the e3d V6 (here: http://forum.seemecnc.com/viewtopic.php?f=36&t=7284 and in some other places) and I must confess even when i read before I did not want to use it (cause it should not be needed, and also, this could affect adherence and well.. many other reasons) however having no other option for the time being, i used some and the results have been as as good as expected. No more under extrusion, but also i lowered the retraction to under 1.5mm and reduce retraction speed to under 25 mm/s... which causes some stringing. I'm yet to test if reducing temps as much as possible will make the stringing to go away but just wanted to give you update. I'll let u know if i can get rid of the stringing by reducing temperature of even if the canola oil let me increase the retraction distance and speed without getting again the so scary under extrusion...

about the fixes on thermistors.. checking temps and ensure airflow... testing some more filament ... well... getting things shipped to Costa Rica is rather.... a good exercise to increase your patience .. so.. don't expect to have the final results any soon

best regards!

Gabe

For printing a wall:
[volume flowrate (mm^3/sec)] ~= [wall width (mm)] * [layer height (mm)] * [x/y speed (mm/sec)]
e.g. v ~= 0.5mm * 0.3mm * 50mm/sec = 7.5mm^3/sec

From the extruder:
[volume flowrate (mm^3/sec)] = [filament cross-sectional area (mm^2)] * [extruder feedrate (mm/sec)]
v = (1.75^2/4*pi) mm * 3.5 mm/sec = 8.42mm^3/sec

So your 210mm/min should be enough to print a 0.5mm wall at 0.3mm layer height at 50mm/sec feedrate.

If it is clogging, which PLA is known for, then increasing the flowrate through the extruder is a good thing (it makes sure there's less time for it to melt/soften in the cold part). Try some of the following:
* Use a larger layer height - 0.2mm should be OK really, but try 0.3mm and see what the effect is
* Increase cooling of the E3D heatsink - make sure the fan/airflow is good, and if you're a bit crazy / have some lying around consider adding thermal compound in the threads between the stainless heatbreak and the aluminium heatsink.
* Minimise the nozzle temperature (test to make sure at a given temperature you can get enough extrusion, as per the above calculation)
* Maybe try reducing retraction length a bit - 4.5mm is the default cura setting for 3mm-using ultimakers, but with 1.75mm filament you might find you can get away with less (try 2.5mm, and if you get stringing, increase. otherwise, decrease!)

You mentioned you'd had some thermistor trouble? Are you sure that the thermistor table selected in the printer firmware matches the thermistor you are using? If the actual nozzle temperature is higher than you expect, then it will be more likely to clog. I would recommend making sure you use a known thermistor (the one's you've ordered from E3D are great - should be type 5 in Marlin), and make sure the correct table is configured in the firmware. This would require you to flash the firmware.

Another option for measuring the actual heater block temperature to check the thermistor reading is a digital multimeter with a thermocouple input - these are often quite inexpensive, and useful for many other jobs too! You can kapton tape the thermocouple right in with the hotend thermistor to check calibration.

With slic3r, flow rate % you can calibrate to make sure the wall width you are outputting is the same as what is input - this is not very helpful in Cura, as the wall width is not set directly. I'm not exactly sure how to approach this with Cura, others might know more than me!

Start with extrusion - can you replicate your problems when manually extruding into free air? Bring the hotend up to temp, lower the bed 50-100mm to give some room, and try manually extruding at various speeds if you can, see whether you can recreate the problem and whether it really does depend on extrusion rate. See what extrusion rate you can get before the extruder starts clicking (missing steps).

Alright, i had some time to test today and here's the result. at 210°C, extruding 10 cm of filament at the time,I start missing steps at about 210 mm/minute (3.5 mm/second)

to be hones >I have no clue about what's a normal acceptable speed for extruding 1.75 mm PLA through a 0.4 mm nozzle at 210°C ...  ??

thanks!

Gabe

Hello Grob! and thanks for taking the time for reading, thinking and helping on this issue.

for manual commands I use normally pronterface but of course that i have octoprint (over raspberry pie) upgrade in my mind for the future

I made that test of extruding in the air and I can do it if it's before it clogs.. however once the problem has happened, if I lifht the nozzle from the bed about 50 mm and send the command to extrude it won¿'t work.. still clogged.. if i leave it alone long enough to drip all what's inside the hotend, it eventually work normally again.... but one thing i've seen is that there is a swollen part of the filament tht if I measure, corresponds to a PTFE area, like if the filament was swolen in a transit area inside of the hotend, instead of the melting area where it should melt..

I've checked the config I have and two things could be affecting that.. one is the duct i changed for the cooling fan for the hot end.. which i have changed back to the original....

the other thing is that as i wrote, my thermistor was broken and i replaced for a Chinese one.. and despite i have no thermometer for more than 100°C (I¿ve looked for one but in CR the infrared ones are expensive... $100), I've measured with the meat thermometer different temps and it's not very accurate even when I chose the recommended table in marlin for that thermistor...

i think this is messing some how with the filament melting temp.. so i've ordered a few more thermistors directly from 3ed-online and an infrared thermometer from aliexpress (hopefully will be here before 3d printing is done at a molecular level)...
but for now.. i think until i don't make sure the temps are what they should be in every moment, it is not useful to blame any other culprits than the thermistors

what do you think?

thanks again!

Gabe

Just use a digital cooking thermometer found in the baking section of your local grocery store.

for manual commands I use normally pronterface but of course that i have octoprint (over raspberry pie) upgrade in my mind for the future

I made that test of extruding in the air and I can do it if it's before it clogs.. however once the problem has happened, if I lifht the nozzle from the bed about 50 mm and send the command to extrude it won¿'t work.. still clogged.. if i leave it alone long enough to drip all what's inside the hotend, it eventually work normally again.... but one thing i've seen is that there is a swollen part of the filament tht if I measure, corresponds to a PTFE area, like if the filament was swolen in a transit area inside of the hotend, instead of the melting area where it should melt..

I've checked the config I have and two things could be affecting that.. one is the duct i changed for the cooling fan for the hot end.. which i have changed back to the original....

the other thing is that as i wrote, my thermistor was broken and i replaced for a Chinese one.. and despite i have no thermometer for more than 100°C (I¿ve looked for one but in CR the infrared ones are expensive... $100), I've measured with the meat thermometer different temps and it's not very accurate even when I chose the recommended table in marlin for that thermistor...

i think this is messing some how with the filament melting temp.. so i've ordered a few more thermistors directly from 3ed-online and an infrared thermometer from aliexpress (hopefully will be here before 3d printing is done at a molecular level)...
but for now.. i think until i don't make sure the temps are what they should be in every moment, it is not useful to blame any other culprits than the thermistors

what do you think?

thanks again!

Gabe

There could be many issues, including firmware limitations! Firstly though, it would be good to check things one at a time, as lots of different stuff is going on during a print.

Start with extrusion - can you replicate your problems when manually extruding into free air? Bring the hotend up to temp, lower the bed 50-100mm to give some room, and try manually extruding at various speeds if you can, see whether you can recreate the problem and whether it really does depend on extrusion rate. See what extrusion rate you can get before the extruder starts clicking (missing steps).

Make sure you clean out the teeth in the extruder gear, in case it's been stripping filament.

How familiar are you with gcode / using the terminal for manual control? I am more familiar with repetier-host, but I assume Cura also has a command thinggy (if it doesn't, consider downloading and using Repetier-Host for this kind of work).
These will be handy, but see here for more commands (note they must be capitalised!):
* M83 - sets the extruder to relative mode
* G1 Exx Fyy - in relative mode, extrudes xx mm of filament at a rate of yy mm/min

e.g.

M83
G1 E20 F150
G1 E20 F300

(note that 300mm/min (5mm/s) should be quite achievable for nearly all nozzles, especially the E3D. Have a play and work out what you can get)

And many thanks in advance for any help you can provide on this topic as I'm fairly new at 3d printing.

So let me give you some details about the configuration of the printer I've assembled:

-Electronics: Ramps 1.4 + Arduino Mega 2560 running Marlin 1.0.2
-Motors: 5x 17HS840 stepper motors (they hold a max operating current of 1.8A)
-Motor drivers: DRV8825 configured at 1/32 micro stepping.
-Hotend:  Single, E3D v6 1.75 mm (initially on direct extrusion and now bowden mount (yes there's the issue)
-Nozzle 0.4mm / for 1.75mm filament
-Not sure what other relevant information i can give you but if I'm missing something please let me know.

Now, at the beginning it was working like a charm, i was able to print on nice quality and didn't have any problems at all except for the speed i could print at. if i set the speed higher than 20 mm/s I had bad quality. Sometimes even steps loosing, which i fixed by measuring and calibrating all axis motors. nevertheless i noticed that sometimes if i raised the speed i had less quality and some times i had some clogging. which i fixed by dissasembing the whole hot end and cleaning part by part with lindustrial thinner (toluene+acetone+alchol...).

So.. after a few of those I decided to print the parts needed and go fo the bowden configuration, as many people says that gies you more precision and better prints by eliminating much of the inertia of the extruder (mainly because you remove the motor weight).

so as i was removing the old extruder i also printed parts for adding couple of cooling fans for PLA ( i had noticed that i strongly needed them) and a support for adding an autolevel sensor (yes now i know it's stupid to change so manuy variables at once, oh well).

So after mounting everything and calibrating the new extruder steps/mm (to 300) i found that i have several problems of under extrusion. i'm not sure if under extrusion or over extrusion it is, but the fact is that at some point the filament starts having problems to be extruded and the printings are all messed up. First the motor starts "clacking" (yes many of you know that sound) and looks like it was missing steps.

I've been trying with changing variables for a few days:
- Increasing/decreasing temperature (tried several, from 185 to 250°C)
- Slowing/speeding print speed,
- reviewed the calculations on my calibration many times
- increased the current to the motor to the point that it actually heats more than I wished (this actually helped a bit not not enough to fix, the problems just delays more in appearing)
- increased the pressure to the filament till it gets deeply marked (and damaged)
- reducing the flow(%) in Cura in steps of 5% from 100% to 85% (not fixed but when got to 85% the extrusion was not even enough for a good print.. still the same clacking and under extrusion eventually appeared)
-cleaning the nozzle with the so called atomic method (does not fix it)
- In cura printing at any speed 10 / 20 / 30 / 40 / 50 or 60 mm/s won't fix the issue.

I've noticed that the first layers are printer perfectly... it is when it start doing the infill (maybe cause it's going faster) that it blocks the nozzle

In fact if I stop the printing when it is blocked or jammed or whatever it is what happens, i have to remove the filament manually cut the tip and immediately reinsert pushing manually, I can make the filament melt and pass thru the nozzle with no effort.

Just some extra information attached, my Configuration.h and my Cura's profile are attachede. Here are some of my speed config settings on the Configuration.h file:

#define DEFAULT_AXIS_STEPS_PER_UNIT   {200,200,8000,300}  // default steps per unit for Ultimaker
#define DEFAULT_MAX_FEEDRATE          {300, 300, 3, 45}    // (mm/sec)
#define DEFAULT_MAX_ACCELERATION      {3000,3000,100,10000} 

#define DEFAULT_ACCELERATION          3000    // X, Y, Z and E acceleration in mm/s^2 for printing moves
#define DEFAULT_RETRACT_ACCELERATION  3000   // E acceleration in mm/s^2 for retracts
#define DEFAULT_TRAVEL_ACCELERATION   3000    // X, Y, Z acceleration in mm/s^2 for travel (non printing) moves

#define DEFAULT_XYJERK                20.0    // (mm/sec)
#define DEFAULT_ZJERK                 0.4     // (mm/sec)
#define DEFAULT_EJERK                 5.0    // (mm/sec)

Do you think i'm having too small torque because of the micro stepping? i really do not know what else to try

I apologize if I wrote too much information but I guess that could save time on the question/answer back and forth for details... Also apologize for the looooooong thread but please believe me.. i'm truly desperate now!

thanks a lot for your help and time!

Gabe