Problems with new Laser Filament Monitor

insertnamehere

@wilriker Thanks for the explanation.

I have 3 filaments that regularly give negative minimum percentages. I've also seen black PETG give a negative average percentage. I just wonder how effective a filament sensor is that gets the direction wrong on movement?

Does that make sense at all?

insertnamehere

@dc42 said in Problems with new Laser Filament Monitor:

How did you mount the filament monitor? Might dust have go on to the image sensor, reducing its sensitivity? The instructions on our wiki advise against mounting it with the image sensor facing upwards, to guard against dust building up on it.

Thanks for the reply.

I've used 2 different mounts and currently using your the reference mount design. The sensor is mounted vertically, looking down. Checked for dust, nothing I can see.

I'm seeing wide variations of movement detected with some filaments showing negative values. Even the same filament on different days gives a huge difference in result.

I'm using a Bondtech BMG and I tried it with maximum tension on the filament. That extruder would literally pull the reel off the stand before slipping. I see no sign of under-extrusion on several 20mm test cubes printed during this process.

To me the sensor is either faulty or the design isn't reliable.

There are many things that you have to cope with and adjust for when printing, the filament sensor should not be one of them.

insertnamehere

@dc42

Well I found the likely cause. Clearly I have a faulty sensor.
This is an image showing the sensor through the mount aperture.

I don't know how this happened. I took great care in handling and mounting. It's been checked several times for dust and I certainly didn't see it.

My best guess is that because the reference mount design uses the mounting screws through the pcb to also provide tension on the bowden tube to clamp it tight, this tension cause the pcb to flex and cracked the sensor.

Clearly it could also be my fault, so I'll just forget about it.
Thanks for your help.

T3P3Tony

@insertnamehere please can you submit a warranty claim:
https://www.duet3d.com/Warranty

Reference this forum post in the comments.
Thanks for your patience.

dc42

@insertnamehere, in addition to submit a warranty claim, please can you:

Check the printed parts that the filament monitor PCB fits between, to make sure that the surfaces that mate with the PCB are flat, and there are no blobs or other blemishes that might stress the PCB when the screws are tightened.
Tell us what material you printed them in.

I have just added a note in the fitting instructions to advise looking for blobs that might stress the PCB. It may be that we also need to increase the thickness of the lower printed part, perhaps depending on what material it is printed with.

insertnamehere

@dc42

I couldn't see any blobs or contamination on the surface.

I used eSun PLA+ with 100% infill.

Honestly, I took all care, but I can't be sure it wasn't something I did that damaged the sensor. Are you sure you want me to claim warranty?

dc42

We don't know whether the cracked sensor is our fault because of a manufacturing defect or because we didn't make the printed part thicker in our housing design, or something you did. In these cases we give the customer the benefit of the doubt. So please make a warranty claim.

insertnamehere

@dc42
Thanks you.

3dmntbighker

Printing with eSun olive green PLA tonight. Pretty crap numbers.

Duet3D laser filament monitor on endstop input 3, disabled, allowed movement 40% to 120%, check every 3.0mm, current position -7.3, brightness 91, shutter 17, measured minimum 27%, average 81%, maximum 204% over 4232.4mm

3dmntbighker

Back to eSun yellow PETG, and my average was 84%. My minimum was -1%.

ShawnC

Regarding the filament monitor, can we use Prusa MK3 filament sensor as well? Can it be connected to E0 end stop?

T3P3Tony

@shawnc said in Problems with new Laser Filament Monitor [SOLVED]:

Regarding the filament monitor, can we use Prusa MK3 filament sensor as well? Can it be connected to E0 end stop?

No it cannot be used because it does not have the control circuitry on it.

dc42

@shawnc said in Problems with new Laser Filament Monitor [SOLVED]:

Regarding the filament monitor, can we use Prusa MK3 filament sensor as well? Can it be connected to E0 end stop?

No. The Prusa filament monitor uses a raw I2C interface to communicate between the sensor and the processor (and it's level shifted to 5V). We rejected that approach because I2C is a bad choice for connecting devices over more than a few cm, because of its poor noise immunity, the lack of any error detection, and the difficulty of recovering from I2C protocol errors. It may be possible to get it working reliably enough in a closely controlled system like a genuine Prusa i3, but it would be a support nightmare if used more widely, e.g. in home-build printers.

3dmntbighker

Solutech clear green PETG

Duet3D laser filament monitor on endstop input 3, disabled, allowed movement 40% to 120%, check every 3.0mm, current position -1.7, brightness 107, shutter 17, measured minimum 31%, average 79%, maximum 97% over 17533.6mm

3dmntbighker

Matterhackers Ryno clear:

Duet3D laser filament monitor on endstop input 3, disabled, allowed movement 40% to 120%, check every 3.0mm, current position -5.7, brightness 99, shutter 17, measured minimum -4%, average 69%, maximum 93% over 7284.9mm

So far my filament success rate hardly warrants using this sensor. Many dip into negative numbers.

hayseed_byte

This post is deleted!

insertnamehere

@hayseed_byte said in Problems with new Laser Filament Monitor [SOLVED]:

hayseed_byte 5 Nov 2017, 23:09

I really thought if I spent $180 on a board that it'd pretty much work out of the box and come with some clear instructions. I'm pretty handy with tools (I'm an industrial maintenance tech) but I've been working on this thing for two solid days and I'm still not printing. One of my Z steppers wouldn't do anything but stutter so I poked around with my multimeter for about an hour but didn't really change/repair anything and now both Z steppers are working fine but the Y stepper is going in the wrong direction. It was working fine before. Seems like random problems. Damn thing doesn't want to stay connected over wifi, either.

The cheap GT2560 I had wouldn't let me update the firmware and I got tired of having to change the stepspermm for the z-axis (upgraded to leadscrews from threaded rod). I ordered a $40 RAMPS that was basically DOA so I thought I'd go ahead and spend the money and get what everyone said was the best controller on the market because I was starting to get tired of working on my printer more than I was printing. Dropped $180USD and I've been working on it all weekend. A lot of that was spent re-crimping those damn PITA connectors, though.

I don't mean to rant. I'm just really disappointed. The cheap board had some annoying problems but at least I could print. A lot of time and money spent to make my printer worse off that it was before.

https://www.wildbot3d.com

Right back at you maintenance boi.

3dmntbighker

3D Solutech black PLA

Duet3D laser filament monitor on input 3, disabled, allow 40% to 120%, check every 3.0mm, current pos 4.0, brightness 95, shutter 17, measured min 15% avg 47% max 77% over 3105.0mm

I thought I had improved things by installing a clip on top of the Bondtech to keep the sensor from moving around as much with retraction. There goes that theory.

3dmntbighker

3D Solutech silver PLA

Duet3D laser filament monitor on input 3, disabled, allow 40% to 120%, check every 3.0mm, current pos -0.5, brightness 104, shutter 17, measured min -2% avg 91% max 196% over 986.7mm

That's about the worst I have seen.

dc42

Yes, that's bad! I'm surprised, I would have expected silver PLA to be easy for the sensor to track.