Filament Width Sensor

Hi there,

I really hope someone can help me. I have enabled my filament width sensor on my Prusa I3 and everything seemed ok. My problem is that my prints just stop after a few layers when the filament width sensor is enabled. The amount of layers printed is not always the same.

First I tried the same print without the sensor and it printed the model. Then I tried different filaments and after a few lines of printing, it stops. Then I tried printing a different model and after a few layers it stopped printing.

I then figured it must be a loose connection but I could not see any.

Before starting to speculate, is there anyway I can catch the problem by having debug info sent to repetier, or maybe another way I can try finding out what the problem is.

And then can anyone clarify the following parameters for me in config.h
1) #define MEASURED_UPPER_LIMIT 3.30 //upper limit factor used for sensor reading validation in mm
2) #define MEASURED_LOWER_LIMIT 1.90 //lower limit factor for sensor reading validation in mm

I use Marlin V1.1.0 - RC8 on a RAMPS 1.4 controller.

The filament sensor is the one on thingiverse designed by Flipper - [www.thingiverse.com]

I print directly from an SD-card.

Thanks in advance

I really would like this going as my prints were never that consistent before, it does not matter which filament I use, it still prints smooth everytime. If I can solve this problem I am never going back to printing without it.

Edited 2 time(s). Last edit at 04/07/2017 04:45AM by scratchbuild52@gmail.com.

Quote
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And then can anyone clarify the following parameters for me in config.h
1) #define MEASURED_UPPER_LIMIT 3.30 //upper limit factor used for sensor reading validation in mm
2) #define MEASURED_LOWER_LIMIT 1.90 //lower limit factor for sensor reading validation in mm

Idk the correct term, but it is 'defining' a variable or constant or someother thing. But it's defining something. In effect 'named' MEASURED_UPPER_LIMIT' and 'MEASURED_LOWER_LIMIT'.

How about the line above?

>#define DEFAULT_NOMINAL_FILAMENT_DIA 3.00 //Enter the diameter (in mm) of the filament generally used (3.0 mm or 1.75 mm)

Is that set to the nominal diameter of the filament you are using. If Github has it as 3.00mm and most of the stuff I buy is 1.75mm nominal diameter, then that could possibly cause a problem.

Otherwise, idk. It's an optical sensor that is measuring the shadow, per the author. That seems like an area ripe for interference.

Also, found reference to FILAMENT_WIDTH_SENSOR in 'temperature.h' and 'temperature.cpp'. So possible something could be at play there? I don't know enough about code to do more than Ctrl+F in the different pages and reinforce my programming noobness.

Edited 2 time(s). Last edit at 04/08/2017 01:22AM by VonRansak.

Hi VonRansak,

Thanks for the reply, I am using 1.75mm and has set my DEFAULT_NOMINAL_FILAMENT_DIA as such. The reason I asked for an explanation of the other two i.e. MEASURED_UPPER_LIMIT 1.95 and #define MEASURED_LOWER_LIMIT 1.55 is that I am wondering is that if the filament diameter goes out of those bounds, what happens? Does the printer stop or should it then carry on at 100% or what should happen.

Come to think of it I never tried setting these to values that cannot be reached and see what happens.

I am not really suspecting that the filament width varies that much but you never know, the filament I am using is not the best in terms of the diameter consistency. The quality however of the filament is very good and really prints well. And when I use the width sensor, it prints very well i.t.o consistent prints and I cannot see the width changes in the print itself.

Regards

Nic

Idk enough about Marlin yet to trouble shoot this, unfortunately. I just saw low hanging fruit and hoped that was the answer

Problem is you could have: software or hardware problem. But I have no idea how to narrow it down between even those two.

FILAMENT_WIDTH_SENSOR may appear in more places than just 'configuration.h' and 'temperature.h/cpp', but I'm coding noob. So I lack the tools to find it without physically going from file to file, hitting Ctrl+F and typing in FILAMENT_WIDTH_SENSOR....So I stopped when I hit 'temperature.h' and got something.

Also, it could be something un-related to the filament width sensor, idk. Best would be to do the prints off SD, just to rule out Windows drivers horseshit, imo.

Hi there,

Thanks for your reply.

Seems like the Filament sensor suddenly works ok now. I did what I said, and moved the MEASURED_LOWER_LIMIT AND MEASURED_UPPER_LIMIT to values outside of the 1.75mm range and did a small print. It printed at 100% the whole time. I then moved the values back to the 1.75 mm range but with a bigger range between upper and lower.

It suddenly started printing the whole model again. I did three prints already and no problems anymore. I hate it when I cannot pinpoint the problem that caused it. So I hope it is fixed now.

Regards

Nic