Laser Filament Monitor - test results

wilriker

Last test with black PLA is done and entered into my Spreadsheet. This was done with the diverging housing and it was a tiny bit below the quality of the default housing.

I now loaded grey PLA and also recalibrated my steps/mm (they were to low). I did not do this with the black PLA but I think this would only introduce a relative shift because all tests with black PLA were performed with the same steps/mm. I still have the diverging housing mounted and will use it to set a baseline for the grey PLA.

wilriker

Added some results for the grey PLA now to my Spreadsheet. AVG and MAX values are somewhat consistent (among all results for grey PLA) though still wider spread than with black PLA. The MIN values however have an enormous range.

I will switch back to the straight housing tonight and see how this influences the results.

keyz182

Hey, sorry, work has been busy for me, so I've only now had a chance to get back to printing. I'm still finishing off a run of parts I need that are in Spannerhands Yellow translucent PETG, which is a far cry from the Black PLA requested! Here are the sensor readings for that anyway:

M591 D1
Duet3D laser filament monitor on endstop input 4, disabled, allowed movement 30% to 100%, check every 3.0mm, current position 9.0, brightness 82, shutter 13, measured minimum -22%, average 30%, maximum 92% over 8353.5mm

Once these are printed, I'll get the black PLA running

wilriker

@keyz182 You should print with whatever you just print. Only the sensor housing is supposed to printed in black PLA.

keyz182

@wilriker As usual, I've misread something then! I really should pay more attention

tinkerz

Hey all, been a bit since I was here. Getting ready for our local MakerFaire but had the SD card on the Duet die today so I ended up with a pre-filament sensor backup config and had to come get the filament sensor running again.

Tony, wanted to share the results I do have, I haven't updated (completed all the columns) but it's a living document and will get updated from time to time. Hardest part is remembering to do a M591 before hitting print again. Doh. Feel bad I keep forgetting it. Hmm, maybe I need a sticky not on the PanelDue.

Anyways results doc is here:
https://docs.google.com/spreadsheets/d/1yy3DLxXhCFD81EiPyyuIEZaPnIgQgkvuVNcFQiZ7ceU/edit?usp=sharing

Tinkerz

wilriker

@tinkerz said in Laser Filament Monitor - test results:

Hardest part is remembering to do a M591 before hitting print again. Doh. Feel bad I keep forgetting it. Hmm, maybe I need a sticky not on the PanelDue.

I put it in my end codes, so I cannot forget it.

keyz182

I have a suggestion for the M591 command. I did look at adding it myself, but having issues getting the firmware to build.

The suggestion is two-part:

Add a parameter to set the filament name going through the sensor
Add a parameter to append data to a CSV file, using the set name as the first col.

That way, we can add start and end GCode in our slicer start+end code per filament. Start code would have the settings for that filament with the name, end gcode would then add data to the CSV file. That way, data gets built up over time without thinking about it.

T3P3Tony

@keyz182 thats a really good idea. @dc42 can we add this to the firmware wish list, maybe naming within M591 or integrate with the ecisitng filament system but then the output via the logging subsystem?

tinkerz

@wilriker In your end codes you say, then where does the response show up? Is it on the console page of the WebUI or console of the PanelDue (output is limited to 100 chars so the real data gets cut off doing it here).

Thanks,
Tinkerz

tinkerz

@wilriker disregard, wrote a quick gcode file and figured it out, comes out on the WebUI. Perfect. Adding to end scripts. Now we just need logging.

Tinkerz

wilriker

I switched housing again to the cone-shaped interior one on Thursday night and printed something on Friday. At the end of the print the statistics looked awfully low and I was already blaming the housing. When I inspected the prints, though, it turned out the sensor was right. I had massive under-extrusions especially on one layer because my filament spool had fallen off the rolling spool holder and the friction was too high for the extruder to pull where lots of filament where required quickly.

So, now I decided to enable the sensor for the current filament though I am still testing. Let's see how often my prints will be paused.

P.S.: A third option for the sensor would be nice. Currently there is just

ignore issues (but collect statistics) and
pause the print on issue detected

I would like to see a third option where issues would just send a warning but the print still continues.

KeeganB

Hi All!

First, sorry it has taken me so long to join in on this thread! Life has been keeping me away from printing lately.

I am testing the monitor on a SeeMeCNC Artemis. As such, I designed a mount for it that attaches it directly to the EZRstruder. Here are a few pictures of the mount. I have only done one print with it, and everything seemed to work fine. I will get a spreadsheet going with my results. I will also upload the mount STLs to Thingiverse and drop a link here.

One thing that I realized after my first print, was that my mount doesn't have an enclosed side on the opposite side of the filament from the laser. On David's Thingy file it has a small extruded box there, but I didn't even think about that when modeling.

alt text

Well, there are photos there I think. I can't figure out how to do them I guess?!

Thingiverse Link: https://www.thingiverse.com/thing:3111798

brunofporto

@t3p3tony said in Laser Filament Monitor - test results:

@guyaros That looks great. actually during test on the filament we used etc we got the best readings at 9mm gap but that is not conclusive. worth trying a variety of gaps.

I'll print the first with 9mm then

brunofporto

I am designing my casing. Please, what is the recommended aperture angle for the sensor window/channel?

I remember reading it somewhere at this category but could not find it anymore.... Thanks!

brunofporto

Here are my results so far.

The first two prints where made with Blue and Dark Purple ABS. One of the things that made me extremely happy was that these first two prints where slightly under extruded (little gaps at top layers). And as the average readings where consistent I used them as reference to tune the steps/mm. Based on the average (93%) I increased the steps/mm of the extruder from 85 to 91,4 and the next print was flawless.... With average of 100% and perfect top layers (IMO).

Then I started to test different materials and colors. The two translucent tests where with PETG and PLA. The curious thing is that besides the readings differ a lot from the reference blue ABS they ratio of predicted length to read length is better!!! While the ABS was between 94% and 98% the transparent generic PLA was better than 99%!

@T3P3Tony and @dc42 I am compiling all my prints at https://docs.google.com/spreadsheets/d/14YdQkZd0Ojso2ye2EpN1kS2Y_nZz_KdEbPJ7vjNBh50/edit?usp=sharing

I am planning to swap the housing to the reference one and then compare results for the same materials.

As soon as I get at least 5 prints per material I'll switch the sensor to test X and Y movement instead (not sure how to to that yet....).

Please let me know If you would like any specific test to be done.

fma

Is you sensor before or after the extruder? In Bowden config, the marks on the filament seem to help reading the movement.

As I'm using a direct-drive extruder, I'm wondering if I could not build a system which draw some marks on the filament before the sensor, and clean them up after... Any idea what I could use as 'paint'?

brunofporto

@fma I proposed that too, somewhere here I think

It was not recommended due to the possibility of fragments dirtying the sensor. Also it could buckle there... Then I decided to increase the exposed length of filament with the housing design.

But the readings are not bad! They are within a margin and the average is very consistent for each filament so far.

They could just design the decision logic based on the average variation... If it keeps within the average for some length it is ok... If the average starts to diverge too much than trigger the alarm

I only have 7 prints registered so far so... it may be too early to any assumptions. But I am really impressed by solving my under extrusion issue in one shot based on the average reading!!!

fma

@brunofporto said in Laser Filament Monitor - test results:

It was not recommended due to the possibility of fragments dirtying the sensor.

Mmm could it be possible to find something which does not make dirt? Like a marker? Ideally, something translucent, but reacting with the laser IR, so no need to clean it up...

brunofporto

@fma A marker would tint the filament.... It is even used for that purpose Like this: https://www.thingiverse.com/thing:11742

But it had no problems so far reading transparent or translucent filaments (one test each....) Besides % readings been different from the base blue ABS they even had a much better approximation of the predicted filament length by the slicing software.