Indirect (bearing) laser filament monitor concept
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I think there may be a minor issue with the filament monitor firmware. If the filament monitor detects continuous movement then it will not send its version word again after startup. You can tell that this is happening because the LED on the filament monitor will give green flashes only. Whereas when it is sending status words, the LED flashes red.
So if the filament monitor starts up faster than the Duet, and vibration is causing small amounts of spurious motion to be detected, then the Duet may never see the version word. But if you see red flashes too then the Duet should get the version right.
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So any success with this? The reason I ask is I have a SeeMeCnc Artemis, and I bought 2 Filament Laser Monitors from Duet. Yesterday I spent all day wiring and pulling the wires etc. I finally got them hooked up, and working. So far I am only testing with one. But it just keeps stopping my print saying "Extruder0 has detected minimum movement"... I ran the M591 D0 and it came back with a range of 5% to 200%, so I changed the range to 1% to 215%? but didn't seem to make a big difference.
Here's the thing... I don't want filament "movement" monitoring... I just want RUNOUT sensing. If I am out of Filament, it stops... simple. I was told this was the only sensor I could use... so that's why I have it.
Help please!
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@thelightspeed said in Indirect (bearing) laser filament monitor concept:
Here's the thing... I don't want filament "movement" monitoring... I just want RUNOUT sensing. If I am out of Filament, it stops... simple.
I think this would have been easier with a simple microswitch-based sensor. Is there anything special with this printer that would prevent this solution?
I don't think the laser sensor can act as a simple run-out check reliably because that's not what it is intended for.
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@adrian52 My 693ZZ bearings are 4.3mm wide. Is your version suitable for this width bearing? The bearings on Amazon don't seem to be 4mm as the specs would indicate. Judging by the pictures of most of them. Also, my first print doesn't come close to fitting Capricorn tubing.
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@3dmntbighker I don't think so - my slot is 4.2 mm wide in the stl, so 4mm wide bearings run freely. I think you will need a 4.5 slot for a 4.3 bearing. With 4mm diameter cutout for the tube, I find the capricorn fits firmly - I think its 3.8 on the original design.
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@adrian52 Yeah I had to do the same. When I opened the original stl's in either Fusion or FreeCAD, they show up as 4mm exactly - which is why I had to make the slot larger to 4.2
Oh and my bearings are exactly 4mm wide, but I bought them locally and not from amazon or aliexpress. They cost like proper bearings should cost too
That said, after making the slot larger and painting one bearing with a sharpie - I can now report a tentative success! Needs more testing, but so far so good. Values range between 73% and 97%. Will update as I go on.
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@adrian52 said in Indirect (bearing) laser filament monitor concept:
@3dmntbighker I don't think so - my slot is 4.2 mm wide in the stl, so 4mm wide bearings run freely. I think you will need a 4.5 slot for a 4.3 bearing. With 4mm diameter cutout for the tube, I find the capricorn fits firmly - I think its 3.8 on the original design.
I think I'll be looking for bearings that are actually 4mm. Will you be posting STL or cad files?
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Here are the source CAD files for anyone to modify it
Please be kind and if you publish your mod mark it as a remix. -
@3dmntbighker said in Indirect (bearing) laser filament monitor concept:
Will you be posting STL or cad files?
Done!!!
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@pkos said in Indirect (bearing) laser filament monitor concept:
I can now report a tentative success!
I was thinking of trying some heat shrink tube around the bearing, or some way to make the bearing surface rough (some carefully made chemical attack to the metal).
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@brunofporto I was wondering if something like a commercial anti-slip coating would work - most of them say they'll stick to metal. Unfortunately they come as a spray so the bearing would have to be carefully taped off before painting.
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@steveyyc woul be easy to tape both sides only. No need even to trim the tape.... That should do the trick! Do you have a link for such product, please, so I can look for something similar around here?
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@dc42 I am still having an issue with the version number recognition. I find that if I send M591 D0 A0, the monitor is reported as v1, having previously been recognised as v2. The console output illustrating this is here
0_1557422029306_20190509console.txt
I am still getting rather high results, even having tried 2.03rc1. An earlier print gave min 113, avg 157, max 247 over 754mm print -
@3dmntbighker I have just put the files on thingiverse, 3618968
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@brunofporto I was considering something like this stuff from Rustoleum
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Got mine printed and assembled, but I'm getting an extremely large range of values for min & maximum. Does this mean my bearings are slipping?
M591 D0
produces the following:Duet3D laser filament monitor on input 4, disabled, allow 25% to 440%, check every 3.0mm, current pos 5.7, brightness 110, shutter 35, measured min 4% avg 181% max 492% over 994.7mm
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@steveyyc Unfortunately yes....
The direct bearing seems too slippery for this use.
I'll think about another solution.
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@brunofporto I've put a ring of electrical shrink-wrap tubing around the upper bearing - it's now dark grey but it's not exhibiting any slipping when I push filament through manually. Will let you know once I do some testing with it how it calibrates.
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@brunofporto said in Indirect (bearing) laser filament monitor concept:
@steveyyc Unfortunately yes....
The direct bearing seems too slippery for this use.
I'll think about another solution.
The best answer would be a garnet blast or something similar on the external diameter.
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Update: Shrink-tubing around the bearing worked for a short while, but since the tubing is soft it quickly developed a groove and began to slip again.
Still much better than using the bare shiny metal, but I did wind up getting a negative movement on a section of complex infill. Since negative values for R do not seem to work, even setting minimum to 0 I will still get pausing without actual jams/issues on a job.
Next attempt will be to use salt water and electricity to etch the outer rim of the bearing. I have done this with other SS items and the result is usually an even, "frosted" surface. I don't know if this will be enough "texture" to grab the filament or not.
