Laser filament monitor
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@fma:
Does the section of your filament vary that much?
You need to measure the diameter in both directions, as the filament can be oval, and the section remaining the same…
Over a whole 2.5kg spool, it can vary quite a lot.
Yes, checking for OVALness will be very difficult, I have not thought of a solution to it yet
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There are some very expensive laser-based diameter and roundness testing devices but they're $1500… Its whether there is a way to do it for a lot less, rotating the laser filament monitor that Duet3D are playing with around the filament?
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…The idea I've had so far is to use a digital tire gauge caliper, it's inexpensive, fairly accurate, and has a built-in serial output.
http://www.ebay.co.uk/itm/NEW-Digital-Tyre-Tire-Tread-Brakes-Shoe-Pad-Wear-Depth-Gauge-Caliper-0-25mm-/321762696307
Reading the output with a small microcontroller (ESP8266) I can then adjust the flowrate.Nice idea, but would you press the gauge against the filament using a spring or something? I guess when a whole spool of filament passed this plastic toy, there would be a huge abraded hole in it.
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I've just had notification that the prototype PCBs for the laser filament sensor are on their way to me from HK! I only ordered them last Sunday.
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That's good news David
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Nice to hear.
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…The idea I've had so far is to use a digital tire gauge caliper, it's inexpensive, fairly accurate, and has a built-in serial output.
http://www.ebay.co.uk/itm/NEW-Digital-Tyre-Tire-Tread-Brakes-Shoe-Pad-Wear-Depth-Gauge-Caliper-0-25mm-/321762696307
Reading the output with a small microcontroller (ESP8266) I can then adjust the flowrate.Nice idea, but would you press the gauge against the filament using a spring or something? I guess when a whole spool of filament passed this plastic toy, there would be a huge abraded hole in it.
Idea was to have a small pulley attached to the end of the guage, (similar to pulleys found in extruders) so there will be no friction.
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I've just had notification that the prototype PCBs for the laser filament sensor are on their way to me from HK! I only ordered them last Sunday.
Great news!
Is there still space on the Beta List? -
Sorry to jump in but what is the advantage of this compared to a simple micro switch?
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Sorry to jump in but what is the advantage of this compared to a simple micro switch?
These monitors track the amount of filament passing through the system. You can use that to tell if the extruder drive is slipping, not just if there is filament present.
David has raised the possibility of auto-calibration of e-steps using the system, which would be very neat if it works.
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Ah I see, very clever!
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When will either sensor be available. I'm definitely adding a filament sensor to the printer I am building now and rather buy from the makers of the duet than some no-name AliExpress company.
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I'm sorry, we can't give a date yet. I expect to have a few prototype laser filament sensors by the end of this week, which should put us on track to decide which version to manufacture at the end of this month.
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First Laser Filament Monitor prototype.
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I'd buy one. Is there already an estimate for the price?
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Would love to betatest one
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looks promising
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Would look better in Blue.
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The production boards will be blue, these are prototypes so I accepted the default PCB options for fastest turnaround and lowest cost.
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Laser filament monitor assembled:
Installed and working on delta printer:
During a test print using black filament (probably one of the worst cases), the average detected motion was 7% low, and the tolerance was quite wide at +44% - 32%. I know from earlier tests that the optical sensor has difficulty tracking fast moves when using black filament. To improve accuracy, we may need to compare actual vs. commanded motion only during printing moves, not during retraction and re-prime moves. Would this be acceptable?
