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Dash-X 3D Printer: Innovative design

Discussion in '3D printers' started by Neil Rosenberg, May 21, 2019.

  1. Neil Rosenberg

    Neil Rosenberg Journeyman
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    Neil Rosenberg published a new build:

    Read more about this build...
     
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  2. Shortyski13

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    What about CoreXY didn't you like? Asking because I'm building one (waiting for all the parts to come in).
     
  3. Neil Rosenberg

    Neil Rosenberg Journeyman
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    Hi there and thanks for the message.

    I want to be careful not to criticize CoreXY, as there are some VERY fine printers of this type. Take for example the Fusion series (i.e. F306) -- their printers use string drive in a CoreXY configuration and put out truly amazing print quality very quickly. They also cost over $4k each.

    My comment is based on experiences with belt-driven printers. I have seen symptoms of unwanted flexing of the arms/carriages caused by (I think) interaction between the two axes. It was most pronounced in the H-Bot (a known issue), but I also saw it on CoreXY. In short, many of the movements exert unbalanced forces on the various bars and bearings and thus create the opportunity for positional errors. The Cross-Beam (and Prusa-style for that matter) does not have this issue. In fact the Dash-X Cross-beam goes one step further by having active synchronous drive on both ends of each beam.

    I'm talking about really fine distinctions. I was able to get good parts from CoreXY, but they didn't quite rise to the quality my newly acquired Creality Ender 3 and CR10s Pro. BTW, the main drawback of these two fairly inexpensive Creality printers is their speed, or lack thereof.

    Early results with this Cross-Arm system in Dash-X suggest that I'm getting quite close to Creality quality, while still keeping the speed up where I like it.

    Of course your mileage may vary.

    I'll report more as I dial it in and see how good it can get.

    Neil
     
    #3 Neil Rosenberg, May 25, 2019
    Last edited: Dec 4, 2019
  4. Shortyski13

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    What's your build volume? I don't see it listed but maybe I'm just missing it.
    I decided against the dual gantries due to a bit higher cost (I'm already a little over budget) and it would be tougher making them thick to span the large gap on my design's large volume, without flexing. I could be wrong tho and a bltouch probably negates that last point. Maybe i should have gone that way haha.
    Im hoping i don't get too much ringing with 10mm belts, but ill find out! In the name of experimentation!
     
  5. Neil Rosenberg

    Neil Rosenberg Journeyman
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    My build volume is 300mm cubed. Might be a few mm short of that in the z axis.

    Love to see what you're building, keep in touch!
     
  6. Shortyski13

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    Mine is the Mushu Large CoreXY, if you scroll down a few through the 3d printers. It's not fully modelled but it has most of it. I do still need to add a few pics of the lift frame. It's around 20x26x28in build volume.
     
  7. Neil Rosenberg

    Neil Rosenberg Journeyman
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    Very interesting!

    I designed/built a 24" cube printer a few years back, but when the reality of printing times became apparent I decided it wasn't really suitable for making parts in my lifetime. In that printer I used the Volcano hot end plus a .8mm dia nozzle. Even with that, very large parts took an eternity.

    Best of luck with your project.

    Neil
     
  8. Neil Rosenberg

    Neil Rosenberg Journeyman
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  9. Mark Carew

    Mark Carew OpenBuilds Team
    Staff Member Moderator Resident Builder Project Maker Builder

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    Hey guys just wanted to say that Neils book is fantastic and really goes in depth to help understanding all the fundamental design principles of 3D printers. We have a copy here at OpenBuilds HQ and the Team is enjoying and learning from it. If you are looking at building your own 3D printer please consider utilizing the research Neil has made available.
     
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  10. Neil Rosenberg

    Neil Rosenberg Journeyman
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    STLs, IGES and STEP files now uploaded and available. Thanks all for your interest.
     
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  11. Neil Rosenberg

    Neil Rosenberg Journeyman
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    I have updated the parts list
    1. A few item links needed refreshing, they are corrected now.
    2. 24v bed heaters are becoming scarce, everyone's using 120v with external relays. New links are provided to both in the list.
    3. I neglected to include the aluminum for the bed, it's in the list now.
    4. I also neglected to include the print surface. I am linking to my current favorite, the Anycubic Ultrabase.
    Neil
     
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  12. Evan870314

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    Any updates?
     
  13. Neil Rosenberg

    Neil Rosenberg Journeyman
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    Not at this time. The design has been pretty stable for a while.
     
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  14. Evan870314

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    I was wondering, if you would be willing to make a build guide? I could pay you..not a lot but I could pay you lol.

    I have built a 3D printer before, The Reprap Wilson II Reprap Wilson II complete 3D printer kit by Marty Rice on Tindie using this video assembly series from the creator just give you an idea of my 3D printer building experience.
     
  15. Neil Rosenberg

    Neil Rosenberg Journeyman
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    Hi there and thanks for the message/request. Looks like you're having fun with 3D printers!

    Unfortunately, I don't have the time just now to put further effort into the Dash-X printer, my teaching schedule is very heavy.

    If you have specific questions or concerns, please post them here -- I'll do my best to answer.

    Sorry
    Neil
     
  16. Warren Scelson

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    I have designed a Delta printer that prints outside normal Delta range. Attached is a sketch of the basics.
     
  17. Warren Scelson

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    Hi thanks I bought your book from amazon. It’s great has taught me a lot about 3D printers. Because off this I have put my machine head to work on the Delta printer design. This is what I came up with. Which will make it possible to print outside the frame poles. This is what i came up with. Thanks again Warren
    Ps. I am going to try to attach this file. Tell me what you think. 6B3739EB-F6AB-48F1-8624-EF91A6171288.jpeg
     
  18. Neil Rosenberg

    Neil Rosenberg Journeyman
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    Hi again, and thanks for posting the image. You have definitely hit on one of the big shortcomings of the Delta system, the limitations of printable area.

    A few concerns come to mind, if I understand your sketch:
    1. The current firmware (i.e. Marlin) does support the Delta geometry, but I suspect it's not able to handle varying length rod pairs, at least not without recoding. This could be a big job.
    2. For the Delta geometry it's important to keep the force vectors in mind for each of the pairs of support rods. In particular, if you should go to or beyond "over center" with one of them, the up/down motion of that rod pair could result in motion in the opposite (unwanted) direction. It could become quite unstable.
    3. Using this same logic, it's no accident that the angle between the vertical and any given rod pair never goes below a certain value, say 30 degrees or so. This ensures that the hot end moves in a controllable fashion, never becomes inverted, and operates within an acceptable range. Remember, the controller is constantly calculating a very complex and non-linear geometry -- the narrower the angle between the upright and the rod pair, the greater the ratio between horizontal motion of the hot end and vertical motion of that rod pair's slider.

    I don't know if this is clear, if not please ask again.

    Thanks and good luck!
    Neil
     
    #18 Neil Rosenberg, Jan 25, 2020 at 11:26 AM
    Last edited: Jan 25, 2020 at 11:31 AM
  19. Warren Scelson

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    Hi again Neil. The machine is not only hydraulic it has the normal stepper motors and belts. Also I understand that new firmware and controls will have to be written for it. But there is two level switches on print head sends level info back to hydro controller. This keeps print head level in any angle of arms. Which have 180 degrees of deflection. I may have to build one to find out if I can make it work. Please send more info on what you were trying to explain to me. And any more areas where you think I may have a problem. Thanks Warren
     
  20. Neil Rosenberg

    Neil Rosenberg Journeyman
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    The Delta portion of Marlin uses constants which are compile-time directives. These constants represent certain UNCHANGING values, such as the length of the Delta arms (control rods), the distance from the center to the uprights and etc. Since these are constants rather than variables, if you have a printer in which the length of the rods change during operation, every instance in which these constants are used will have to be examined and likely changed on the fly.

    I urge you not to underestimate the amount of work and complexity in doing this. Sometimes (often) it's hard just to understand what some other programmer did, and doubly hard to change it in a substantive way (which this is) and not break something.

    Of course, I never want to suppress others' creativity. The job is probably do-able, but please proceed with caution. Perhaps the best thing to do is to build a conventional Delta printer to start with, modify Marlin to make it work really well (not an easy task), and then consider your options.

    My more basic question is, why Delta? Yes, it has the potential to print pretty quickly, but it's limited by the extrusion speed of the head. Every Delta printer I've made (4 so far) have topped out at the hot end's ability to melt and push plastic, thus eliminating much of the advantage. Try to go beyond that and the Extruder motor/system will start to overload and lose steps.

    Yes, you could use a "Volcano" hot end, which would help some, but I still don't believe it will allow taking full advantage of the Delta. I invariably come back to a more Cartesian design, such as the Dash. My 2c.

    Best
    Neil
     
  21. Warren Scelson

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    Hi I am not sure if my other reply went through. So doing it again. Sorry. I am not working on the Delta printer at the moment. I am building a Cartesian movement printer with a cubic yard print volume. But it is just build. No brain work. I need something for my brain to work on. So I decided this Delta print volume problem would suffice. Any info you have on the subject would be greatly appreciated. Thanks again Warren.
     
  22. Warren Scelson

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    3E20DF77-B8D6-4CB9-9B57-674DDDCDD1D0.jpeg Hi Neil
    I also have many parts that I have designed and built. If you don’t mind I will be posting them on Open builds. Here is a sample.
    Zero slop trolley.
    Sorry again for earlier mess up. Warren
     
  23. Neil Rosenberg

    Neil Rosenberg Journeyman
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    Hi Warren, glad to see your creative mind is hard at work!

    May I respectfully suggest that you begin a new thread, this is getting less and less about Dash-X. Have a look at the Forums on this website, you'll probably find a section that's a better fit for your postings and you'll reach a broader audience.

    Thanks
    Neil
     
  24. Warren Scelson

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    Hi Neil. I already have. Many as a matter of fact. I hope you don’t mind. I want to thank you again for your book and this site. It is just what I needed to get the feedback I need to keep my brain going.
    I want to thank so very much. By the way I will not sell anything to anyone on or through your site. I may however tell them where to scavenge parts to work in place of purchased parts.
    PS. You may want to check out my post. Thanks one last time. Warren
     

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