Tuesday, May 22, 2012

Initial Field Test Results

At this point in time, one beta tester has tested the J-head Mk V.  For a total of at least 6 hours, PLA was printed successfully.  He is going to try to print ABS in the near future. 

There were two minor issues encountered early on, however.  The first issue was that the hot-end jammed.  This was theorized to be due to dirt and the hot-end was cleaned out.  Afterwards, it printed fine.  The second issue was that some PLA was leaking out of the hot-end.  After the set-screw was tightened down, the leaking stopped. 

As both issues were relatively minor, and were easily fixed, the initial results are fairly positive. 


The Mini J-head has also been successfully tested printing PLA and no issues were reported.

12 comments:

  1. Any reference to the speed of printing in the above test, and if ooze is reduced or worse than before.
    I would be interested to know if the smaller thermal mass of the block allows slower and more fine printing (less ooze) or if it also limits the maximum speed of the nozzle compared to the IV.

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  2. The Mini J-head was printing at 183 mm/sec and the Mk V was printing at 140mm/sec. The Mk V wasn't tried at higher speeds. The mini J-head was tried at 200mm/sec. and there were issues with the stepper motor slipping.

    There was no mention about the ooze being different.

    The weights, of 3 different brass nozzles are as follows:
    1. Version 1--11.1 grams
    2. Version 1.1--14.4 grams (added melt zone)
    3. Version 4--11.3 grams

    The Version 1 and 1.1 can be used for the Mk I through Mk IV hot-ends while the Version 4 is used with the Mk V-B hot-end. While the Mk V-B uses a smaller piece of brass, it has a longer melt zone and a thicker brass wall, for the melt zone. The idea was to keep a thick brass wall in order to increase the thermal mass.

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  3. I am building my first RepRap and was planning on buying the Mk IV-B hotend. When do you expect the Mk V to be ready for sale if everything continues to go well?

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  4. I am planning on having the Mk V-B on sale within weeks, assuming there are no problems.

    At this point, brass has been cut, for nozzle blanks, and I will soon be making a batch of both Mk V-B nozzles and Mini J-Head nozzles.

    In addition, a J-Head Mk V (using an aluminum nozzle) will be sent out for testing within the month.

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  5. Sounds excellent, I will be on the lookout so I can place my order.

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  6. Cant wait for the results on that aluminum nozzle, I too am building my first reprap and in need of a hot end.

    BTW could you clarify what was skipping exactly when trying to print with the mini J-Head? I was thinking about building a direct drive extruder and was wondering if it could fix this issue.

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  7. TCZ:

    The stepper motor was skipping. Most likely, the force to extrude at 200mm/sec was too high. However, I am working on fixing this issue as well.

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  8. On which platform did you reach 140 mm/s ?
    My prusa-mendel i2 doesn't allow +40, but I blame that on not being sturdy enough. Perhaps bracing it, or going for another platform in the future. Happy for now (though my Mk IVb seems to be jammed somehow)

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  9. Are the mini J-head nozzles planned to be made commercially available at any point? I am designing a 3D printer and debating whether to design it for 3mm or 1.75mm filament.

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  10. Hello,

    I don't know which platform 140mm/sec was reached as it was reported to me by more than one person.

    The mini J-Head nozzles will be made commercially and probably within the next 3 weeks.

    Regards,

    Brian

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  11. How are the mini J-Heads coming along? I have a printer under assembly, with nearly all the parts either on hand or on order. Just need a lightweight hot end for 1.75mm filament for it, and I'd prefer to use the mini J-head over the Makergear hot end.

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  12. ellindsey:

    E-mail sent.

    I haven't made up mini J-Head parts, as I have been pretty tied up making Mk V-B hot-ends. Time permitting, I'll make some up.

    Regards,

    Brian

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