Problem with Laser filament monitor

Thalios

This is with silk gold filament on the Railcore:

Duet3D laser filament monitor v2 on pin io3.in, disabled, allow 1% to 500%, check every 3.0mm, version 2, quality 222, brightness 15, shutter 131, measured min -2% avg 1% max 33% over 20597.0mm

Thalios

another m591 d0 with silk gold filament, with pressure advance at 0.04

Duet3D laser filament monitor v2 on pin io3.in, disabled, allow 1% to 500%, check every 3.0mm, version 2, quality 223, brightness 18, shutter 135, measured min -1% avg 0% max 6% over 4322.1mm

mitch

I was getting erratic readings with my laser filament monitor. Eventually ordered the mag rotating version. The mag version is still back ordered so I started to experiment with these indirect laser concepts.

https://forum.duet3d.com/topic/18497/indirect-laser-monitor-remix-ii-working

At this point i am really pleased with it to the extent that I am not sure I need the mag version.

It consumes a little time to put it together but in the end I felt I had a monitor that was accurate regardless of the filament I loaded.

Mine was mounted right above a direct drive. I have never seen negative values but the range varied a great deal.

Thalios

Big thanks.

I've been looking at indirect use for these sensors for a while but all reviews i've found were inconsistent.

I'll give yours a try.

mitch

A few tips I have picked up using it.

Having the sensor ridged mounted to the hot end mount helps reduce variability. In the past I just let the sensor flop around on some PTFE tube and depending on the angle from the filament to the head at the time of printing it was possible for the hob to potentially slip.

In the version I pasted above the filament path is more controlled when mounted this way so it passes over the gears the same way regardless of the location of the print head from the filament spool.

The little orange knob was really intended for feeding but it feeds smoothly trough without it. However, the knob has become invaluable for monitoring filament movement since it is very easy to see the knob move versus the black cylindrical carbon fiber axle.

If you build it, please add some pics to this post or thingaverse. I would like to see how it comes out and how you end up mounting it (assuming you have a different setup than mine).

Thalios

@mitch Thanks. I'll get the parts on sunday, so it'll be a monday project probably. I'll document everything.

Thalios

Doesn't work, even with that indirect thing.

Reading I get:

Duet3D laser filament monitor v2 with switch on pin io3.in, disabled, allow 200% to 3000%, check every 3.0mm, version 2, quality 223, brightness 255, shutter 91, measured min -2% avg 152% max 273% over 466.5mm

I will try with a different rod (I have stainless steel coming which i'll sand to make non shiny)

But so far, i'm lost...

dc42

@Thalios said in Problem with Laser filament monitor:

One is semi close (about 8cm). One is very far (25cm) and one is about 85cm.

Those are all too far away, because during retraction the filament will bunch up in the tube between the extruder drive and the filament monitor.

The only way you are likely to get anything approaching sensible readings is by increasing the sense distance (M591 E parameter) from 3mm to a much larger value.

Also, there are some filaments that the laser sensor just doesn't work well with.

mitch

@Thalios Can you take a pic to show how your monitor is mounted near the extruder?

mitch

@Thalios said in Problem with Laser filament monitor:

Doesn't work, even with that indirect thing.

Reading I get:
Duet3D laser filament monitor v2 with switch on pin io3.in, disabled, allow 200% to 3000%, check every 3.0mm, version 2, quality 223, brightness 255, shutter 91, measured min -2% avg 152% max 273% over 466.5mm
I will try with a different rod (I have stainless steel coming which i'll sand to make non shiny)

But so far, i'm lost...

This is what I was getting with the indirect monitor using MK3 hob and a rigid mount right above my direct drive extruder:

9/12/2020, 9:03:10 PM   M591 D0
Duet3D laser filament monitor v2 with switch on pin e0stop, 
enabled, allow 200% to 260%, 
check every 3.0mm, version 2, 
quality 221, brightness 255, 
shutter 84, 
measured min 225% avg 240% max 257% over 13515.3mm