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  1. #1

    Feedback request: Idea for a Filament Roller with Integrated IR Detector and Alarm

    Hi guys, this is my first post on this board. My name is Chris and I started printing on a clone i3 back in April of this year.

    I have a pretty weak direct-drive extruder and experienced lots of filament feeding problems. Does anybody else run into this problem?

    I built my own filament sensor which detects feed speed & direction using a Gray encoder wheel and IR sensors. Since then, I have been able to deal with feeding issues before my prints have irrevocably failed.
    FilamentRollerLeftProfile.jpgFilamentRollerBoardPerspective.jpg

    If you are interested in how it works, I made a quick tutorial here: http://www.filamentroller.com/how-it-works/

    You can download the OpenScad and precompiled STL files on: http://www.thingiverse.com/thing:1801190
    Even without the control board, you can make a decent roller for your filament spools.

    In any case, I am planning a Kickstarter to build a small quantity of boards and wanted to see if you guys have any interest in this idea or not.

    ---> I am interested in answering your questions and, generally, hearing both positive and negative criticism of this idea. Thanks!

  2. #2
    Engineer-in-Training ralphzoontjens's Avatar
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    That is a very good idea.

    However measuring the spool angle doesn't work because it unrolls with jerks.
    So what you want to do is measure the filament pullthrough rate so you have to invent something to mount onto the extruder drive.
    It's a good idea for a Kickstarter project, in the spirit of AlignG. You also want to be able to make decisions based on the input - pausing or stopping the print, adjusting feed rate etc.

    I have another idea but I have no schedule where I can develop it.
    The idea is to add binder /adhesive between each print layer to drastically improve part strength by adding a ball roller next to the nozzle attached to a liquid container.
    Special software will have to be written to determine the gcode path for the roller. Printing a layer would go like this: extrude filament - apply binder - move fan over the layer until desired level of dryness of binder is reached - print next layer etc.

  3. #3
    Staff Engineer printbus's Avatar
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    Seems like an oversight to not include an output that could be used with firmware out-of-filament detection. Various firmware already supports it. Or is that what the sensor contact pins are for? (Sorry - didn't read the external links for details)

    How narrow of a spool can be used with this? I think the thinnest I have is around 35mm. How much of a hassle is it to reconfigure from one spool width to another?

    I personally don't trust any of the spool mounts where the spool just sits on rollers. As the spool empties, you lose all the weight that keeps it place. The large metal disks might help with this, but I'm still not sure I'd trust it, especially on a few of my spools with really small hub diameters.

  4. #4
    Quote Originally Posted by ralphzoontjens View Post
    That is a very good idea.

    However measuring the spool angle doesn't work because it unrolls with jerks.
    So what you want to do is measure the filament pullthrough rate so you have to invent something to mount onto the extruder drive.
    It's a good idea for a Kickstarter project, in the spirit of AlignG. You also want to be able to make decisions based on the input - pausing or stopping the print, adjusting feed rate etc.

    I have another idea but I have no schedule where I can develop it.
    The idea is to add binder /adhesive between each print layer to drastically improve part strength by adding a ball roller next to the nozzle attached to a liquid container.
    Special software will have to be written to determine the gcode path for the roller. Printing a layer would go like this: extrude filament - apply binder - move fan over the layer until desired level of dryness of binder is reached - print next layer etc.
    Topic 1: jerkiness
    You are correct that most filament spools "jerk" or unroll at an uneven rate. However, though not perfect, I believe my design unrolls much more smoothly than your typical hanger/roller. At the link is a short 20 second video to show an example of what I am talking about.
    https://youtu.be/nfBTYKQTa1g
    Notice the tensioner that is inserted through the hub of the spool. With just 2 rubber bands, it adds just enough light tension so that the spool unrolls only as much as the extruder pulls it. As well, the spool rolls smoothly on 4 ball bearings. Without the tensioner, the spool would unwind far too much. I also considered adding Bowden tubing (the pull becomes even smoother) but I like my designs to be as unconstricted as possible.

    Thanks for your observation, that was certainly a problem I worked on solving. After watching the video please let me know if the unrolling is still too jerky. I am interested in your evaluation.

    Topic 2: Pausing, stopping, adjusting feed rate, etc
    Unfortunately, this involves modifying printer software which is an area where I have very little control. I am constantly revising the mechanical, electronic, and software characteristics to make this product easily compatible with as many existing printers in the market as possible. Currently I am pursuing the following actions:
    a) I revised the interface so that the board can be remotely shutdown and hard-reset via GPIO
    b) I revised the interface to add a simple GPIO error signal (0: okay, 1: error detected) so it can be used as a "smart switch" and integrated with other "out-of-filament" solutions already developed
    c) I am beginning testing with OctoPrint to ensure that these two products are compatible --> pause print functionality
    d) I am assembling and testing an inline version of this sensor that can be mounted anywhere on your printer

    My main goal is easy integration and simple-to-use interfaces. I thought my initial design was correct, but feedback is telling me otherwise. I appreciate your feedback.

    Topic 3: filament binder and application apparatus
    I think your idea will take a lot of effort and money to develop and test. The simplest method would be a homemade applicator such as you find for canola oil and PLA. Another method would be to develop a formula for ABS + bonding agent and then manufacture this into its own filament. I am not knowledgabe in chemistry and am not aware of any commercially available binding or bonding agents for ABS (or any other filament material). An electromechanical solution sounds elaborate (i.e. expensive and prone to breakage). However, you will never know unless you try and find out.

    Best of luck to you in developing your idea.

  5. #5
    Quote Originally Posted by printbus View Post
    Seems like an oversight to not include an output that could be used with firmware out-of-filament detection. Various firmware already supports it. Or is that what the sensor contact pins are for? (Sorry - didn't read the external links for details)

    How narrow of a spool can be used with this? I think the thinnest I have is around 35mm. How much of a hassle is it to reconfigure from one spool width to another?

    I personally don't trust any of the spool mounts where the spool just sits on rollers. As the spool empties, you lose all the weight that keeps it place. The large metal disks might help with this, but I'm still not sure I'd trust it, especially on a few of my spools with really small hub diameters.
    Topic 1: output for out-of-filament detection
    Yes, it was an oversight to not initially include this signal. I revised the interface to include the following signals:
    1) 5-24 V input (OR use the DC jack but not both at the same time)
    2) Ground
    3) IR sensor 1 raw output
    4) IR sensor 2 raw output (sensor 1 and 2 form a basic quadrature signal)
    5) Filament error condition via GPIO (0: okay, 1: out-of-filament, jamming, clogging, grinding --> whenever the extruder is not pulling filament)
    6) Remote shutdown and hard-reset of the board via GPIO (0: board is running, 1: board is shutdown and held in reset)
    I also added a physical switch to enable/disable the buzzer alarm.


    People who want to simply connect the board to their printer and use it as a "smart" switch can use signal #5. Developers who want to modify their printer to detect filament speed, etc can use signals #3 and #4. The IR signal output is much cleaner and does not require debouncing like you would with a mechanical rotary encoder.

    I would include pictures of my current progress, but I am having trouble inserting them on this board.

    Topic 2: small spools
    I just revised the platform design so that the rollers can actually touch each other. They will be able to hold your 35 mm spool. I also added a footer to each pylon so the nuts are embedded in the footer. This way, you can adjust screws from the top without having to fiddle with M3 nuts on the bottomside of the platform. Again, I wish I could show you pictures, but I seem to not be able to insert them on this board. If you check my Thingiverse page, I will be updating it this weekend.

    Topic 3: spools falling off
    The metal disks are actually ABS with gold paint. I need paint to block IR.

    https://youtu.be/nfBTYKQTa1g

    The long base of the platform allows you to create a more stable wheelbase to hold your spool securely. The tensioner keeps reliable tension through the hub. The encoder on each roller do help prevent the spool from tipping over. I have run multiple spools from beginning-to-end (I don't care about color) and I have not had one spool fall off so far. Granted, the spools I use are ~80 mm wide.

    The only problem I have run into is where the last few winds of filament come loose and no longer pull the spool. To solve this, I tape the end to the hub so that the roll completes. The extruder pulls the taped end off the hub and alerts me when the spool stops rolling.

    Addendum:
    I am currently designing and testing an inline filament roller that can be attached between the extruder and spool. I will attach a link once I am satisfied that it works well.

  6. #6
    Quote Originally Posted by printbus View Post
    Seems like an oversight to not include an output that could be used with firmware out-of-filament detection. Various firmware already supports it. Or is that what the sensor contact pins are for? (Sorry - didn't read the external links for details)

    How narrow of a spool can be used with this? I think the thinnest I have is around 35mm. How much of a hassle is it to reconfigure from one spool width to another?

    I personally don't trust any of the spool mounts where the spool just sits on rollers. As the spool empties, you lose all the weight that keeps it place. The large metal disks might help with this, but I'm still not sure I'd trust it, especially on a few of my spools with really small hub diameters.
    Topic 2: small spools
    I made a mistake -- the smallest width spool that my design can accommodate is 5cm. The base itself can handle very small widths; however, I did not consider the width of the PCB in my original answer.

    You can find more details about the new mechanical version of the Filament Roller here: http://www.thingiverse.com/thing:1888159

  7. #7
    Hello Raph Zoontjens;

    I previously promised a mechanically inline version of the filament roller that can be mounted near the extruder, separately from the spool. You can see it here: http://www.thingiverse.com/thing:1904929

    Eventually, I hope to make custom cases that are easy to mount in a given printer.



    Unfortunately, I also noticed that the AlignG campaign failed and will not receive funds to enter mass-production. I was a little taken aback that the team was asking for $100,000. I am going to try for a funding limit of $2-3kUSD +10%(KS fees), and hopefully a unit price of $40USD. There are too many variables remaining (shipping, packaging, final circuit revisions,...) to make a final quote but I will try my best.

    To all;

    This has been a depressing amount of effort, I am still terrible at most of this work (especially marketing); nevertheless, this experience has been quite educational! =)

    Currently, I have working prototypes and development is largely finished. I have been using this item myself (roller version) since August and it does not have any problems.

    I hope to finish the remaining work for KS and whatever else (fulfillment options) as soon as possible.

    Thank you for your interest.

    =)

  8. #8
    I've got a Kickstarter campaign currently underway:

    https://www.kickstarter.com/projects...ilament-roller


    Check it out!

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