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Prometheus Hot End - Indigogo Project

Discussion in 'Mods and Upgrades' started by JohnStack, Apr 8, 2014.

  1. robocad

    robocad Member

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    My retraction is 2.6mm, i got the two hex nuts of nozzle distance and 3mm transition zone. I just printed a cube again, its defintely better but theres these vertical lines showing up that i cant figure out on the left corner of the pic.

    http://imgur.com/v0vZfec
     
  2. RP Iron Man

    RP Iron Man Member

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    Nevermind, retraction would not be the issue. 2.6mm is more than enough.

    Those vertical lines look a lot like they were produced my backlash of the belts, especially since they appear near the corner when the print head is changing direction quickly. Can you check your belts to ensure that they are tight?
     
  3. robocad

    robocad Member

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    They could be tighter, ill try to print a belt doodad tommorrow. I got the e3d knockoff printing and its not producing the artifacts but the gapping on the walls is present so ill have to wait till the filament is dry tomorrow.
     
  4. Geof

    Geof Volunteer Moderator
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    I dont know how true this this but but i heard its very hard to recover moisture filled filament.

    For the belt tension i cut the belt and used zipties. Ill snap a picture and upload as im working on my printer this weekend. I believe i had asked how tight they need to be and the general.response is the belt shoukd twang not thump lol it sounds silly but it works

    edit- I cant upload a picture from my new phone lol. File is to large. I'll have to play with it to get it figured out
     
    #124 Geof, Apr 29, 2016
    Last edited: Apr 29, 2016
  5. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    If he stores it the way he has it now it will slowly improve. I live in humidity central and I just normally print wet filament. I just live with the minor blemishes since it usually matters not a whit. On filaments that really do matter (like Nylon) I keep them in a bag with the desiccant.
     
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  6. Geof

    Geof Volunteer Moderator
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    Good to know!
     
  7. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
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    I know some people will 'bake' their filament to remove moisture, a 200°F oven for a couple of hours will dry out most filaments.

    Please note that the above temperature is in fahrenheit not celsius.
     
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  8. robocad

    robocad Member

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    Well before i get into modifying the robo itself i wanted to determine the flow characteristics to see if it in fact is extruding properly. ive been playing with the e3d knockoff i got yesterday to see how it performs. The bubbles did not show up with it this morning but to no surprise during a simple extrusion its flowrate was all over the place, however its width was consistent.

    Hooking the prometheus back up i performed the same experiment, the flowrate was much more consistent, about 90% smooth, however i kept hearing a click and noticed the flow suddenly would drop, which i noticed was the hobbed bolt slipping as it fought some apparent backpressure in the nozzle. The realization that something was wrong in the nozzle itself came when i noticed the width of the extruded filament was varying drastically, dropping to half its total diameter randomly.

    We'll its worked quite well in the space of a day, however i have 6 teabags stuffed full of damprid encircling it which can suck the water out of a rock.

    I have used a genuine e3d v6 before on my last printer and observed how smoothly and consistently it would extrude in both flowrate and width, i am just not seeing the same consistency. But not to leave you all empty handed ive gone ahead and ordered a genuine e3d again, i will make a side by side video showing the differences in flowrate under identical conditions, but if it turns out that the prometheus does not work as well i'd like RP iron man to accept the return of it.
     
  9. Geof

    Geof Volunteer Moderator
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    Im sure this isnt the issue but did the thermistor firmware need changed ? Also did the nozzle size get updated in the slicer ?
     
  10. robocad

    robocad Member

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    Just to make it clear i'll only make the video if RP iron man agrees to accept a return should the prometheus not perform as well. Since they are priced the same i would assume that they should and feel slighted if he does not.
     
  11. RP Iron Man

    RP Iron Man Member

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    @robocad If you are not satisfied with the product I can always offer a refund for the cost of your order if you return the hot end undamaged to my address. If this is what you would like to do then please get in touch via the contact form on my website and we can sort this out.

    As for the performance of my product, I am very confident that you can get great results from the Prometheus V2. I have hundreds of happy customers and reputable third party reviews that attest to this. Check out Thomas Sanladerer's review if you are unsure: .

    A significant factor in the performance of any piece of machinery is the way it is used. If you do not properly dry your filament you cannot expect good results. The inconsistent extrusion you are seeing is not related to the nozzle geometry but is almost always dependent on how much moisture is in the filament. If you want an effective solution for drying filament then check out this page on the Taulman 3D website: http://www.taulman3d.com/drying-materials.html

    This is how I keep my filament dry. It works great!
     
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  12. robocad

    robocad Member

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    Well like i said if its the filament it will show on both hotends, i'd like to know because i dont get the sense that its wet anymore from observing simple extrusions yet there are still serious layer adhesion issues from inconsistent flowrate. If it turns out they are both perform the same under identical conditions i'll keep the prometheus.
     
  13. robocad

    robocad Member

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    Ive finished doing some basic geometry tests using both prometheus and e3d side by side. I started with a hollow pillar to see how it did printing round surfaces, these were printed at several different extrusion multipliers as this seemed to have the greatest effect on the outcome of the print.

    The first one was done at 0.8x, all pictures were taken with the v2 on the left and the v6 on the right, the prometheus seems to struggle with underextrusion, the light parts are where it skipped and is single layered. Though you cant see it the v2 snapped in half when i tried to remove it. On the flip side its surface quality was much nicer than the v6.

    [​IMG]

    The v2 seems to have issues with bridging too:
    [​IMG]

    1.1x helped with the gaps on the v2, the v6 still looks solid.
    [​IMG]
     
  14. robocad

    robocad Member

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    The v2 once again had difficulty with bridging and its surface quality diminished at greater multipliers, the v6 still was solid.

    [​IMG]

    At 1.4x the v2 surface became quite fuzzy as it overextruded, however oddly enough the v6 developed clean lines and edges, if you look closely you can see the v2s edges became bumpy and uneven whereas the v6 is straight.
    [​IMG]

    They both seemed to loose definition with bridging at 1.4x.
    [​IMG]
     
  15. Geof

    Geof Volunteer Moderator
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    If you have to play with extrusion then you must understand

    1. Each hotend needs calibrated. Not a fault of the hotend just is what it is

    2.if calibrated correctly-multiple 100mm extrusions taking the average and inputting (your ext will be 100% then) and still have issues sanity check your assembly

    3. Still issues check your print temps and settings with a test file and tweak.

    No hotend is plug and play... At least not the good ones.

    4. If issues persist ask for an exchange and avoid the drill
     
  16. robocad

    robocad Member

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    Next i did a simple 15mm hollow cube to test straight lines and corners. Starting at 0.8x the bottom of the cube varied drastically, keep in mind these both had the same z-offset and were autoleved before each print. The v2 went down better with edge overlap and solidity.

    [​IMG]


    However its side reveals the same underextrusion issues that the pillar had where it would not extrude evenly and thus created gaps evident by the light spots. Notice as well the edges are a bit more bumpier than the v6.

    [​IMG]

    Here it is in the light, while neither did that well the difference is drastic.

    [​IMG]

    And the bridging displays the trouble it has with lower extrusions.

    [​IMG] tp
     
  17. robocad

    robocad Member

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    Moving up to 1.1x things start to look a bit better, still retaining its solidity on the bottom versus the v6 which may require a lower z-offset to achieve the same effect.

    [​IMG]

    Edging was slightly rougher than the v6 but not terrible.

    [​IMG]


    Surface quality is similar.
    [​IMG]

    As is bridging.

    [​IMG]
     
  18. robocad

    robocad Member

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    Lastly up to 1.4x, the bottoms are both solid now and uneven edges from overextrusion are evident.

    [​IMG]

    Focusing on the outer edges they both developed a hoof but the v6 remained relatively straight and the v2 somewhat uneven.

    [​IMG]


    The V2's surface quality is still diminished above 0.8x, but now the v6's surface quality becomes less matte and more refined. Notice the v6's edge against the v2's.

    [​IMG]

    Though this didnt come out as clearly both seemed to suffer a bit with bridging at 1.4x.
    [​IMG]
     
  19. robocad

    robocad Member

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    //////////////

    Having printed a bit on these hotends ive had jams on both, on the v2 the first time i used it and on the v6 a few days into using it. Im still not sure what made the v2 jam right away but the v6 was because i had let the heatsink loosen from the heatbreak and the filament crawled up and stuck to the coldend inside the heatbreak. Now jams are the most frustrating part and are inevitable with any hotend, generally the cheaper you go the more likely they are to happen. What separates the v2 from the v6 (and from the hexagon) is its unified nozzle heatbreak design. This was supposed to eliminate the gap between nozzle and heatbreak and prevent plastic from oozing out all over the nozzle, ive not really had this issue with the v6 and you shouldnt if you tighten it correctly, but this feature turned out to be its fault when it came time to unclogging the jam. So whereas when the v6 jammed i was able to unscrew the heatsink and access the stuck filament on the coldend side of the heatbreak which opens up a bit to accommodate the ptfe tubing allowing you to just pull/snap it out, because the v2 is all one long metal single channel design if your filament gets stuck in the cold side of the heatbreak area of the nozzle it cant be snapped out as its literally stuck to the walls and there is no clearance to access it. So that leaves you with two options, you either torch it out (which the user guide says not to do), or you can drill it out, which i had to do, which apparently i was also not supposed to do.

    But the process is still the same, unscrew the heatsink and access the jam. Overall having printed various high tolerance prints i feel that the v2 produces about 80% the quality of the v6. Given the simple nature of how these hotends work it really comes down to manufacture quality, how well the holes and nozzles are bored and polished, imperfections will lead to tiny pits and bumps that will effect extrusion flow and ultimately to jams and other unpredictabilties. Having shone my light up the nozzle while staring down into it i could make out one or two visual discrepancies in the inner surface but could only see about halfway down and diffraction limits made it hard to resolve finer details. Rotating the nozzle itself made it evident that what i was seeing was actually in the nozzle and not a aberration. For the same price as a v6 i would expect a similar result but unfortunately this was not the case.
     
  20. robocad

    robocad Member

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    Yes i did do a PID autotune for each one, the temperatures stayed flat at 250C throughout. However the 100mm extrusion test from tomsguide, this does not work, and reading the comments on the video it doesnt work for alot of people. Changing the extrusion stepping in firmware from absurdly low to high steps made no difference in the total length of filament used.
     

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