Pros and cons with dual

Discussion in 'BigBox General Chat' started by Large, Jan 9, 2016.

  1. Large

    Large Active Member

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    I've started to rethink my pledge for a single extruder BB. Since I'm among the last backers (#485) a switch to a dual machine won't really change my position... :)
    This makes me think about the pros and cons of a dual machine. What's your opinion about this and how relevant would you consider each pro/con (in which case would the pro/con really matter)?
     
  2. Henry feldman

    Henry feldman Well-Known Member

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    I too am considering upping, although I'm #68, so it could have an effect on delivery. The big tradeoff for me is I will lose build volume (I more need x-y than huge z, as I don't need to print helmets or vases) but get dissolvable support material (and I suppose the ability to make parts with different functional materials like nylon + t-lyne or whatever). I was hopping @Clare - E3D or @Sanjay could give some rough estimate of the change in delivery # from the upgrade. If it takes from 68->300 that's out, but if it is #68-85, I'll do it...
     
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  3. Colin

    Colin Well-Known Member

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    It is definitely worth it. And to Henry's concern of lost build volume that is only true when using both nozzles. If you print something with a single nozzle the X travel and X print space are the same as a single nozzle pro. There is a large savings over buying the parts separately and it saves the headache of redoing the wiring if you upgrade later. There is no lost Y with the dual.
     
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  4. Colin

    Colin Well-Known Member

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    I am just going to add a star to that last comment with the note that I believe that was said during the campaign, I'm going to go test right now and confirm one way or the other.
     
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  5. Colin

    Colin Well-Known Member

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    I lied, I apologize. The Y has full travel but a single extruder on the dual can only reach about 260mm of the 300mm bed. One thing you could do if you put the same filament in both hot ends is split the file between the hot ends, but that isn't ideal. I do plan on printing the single X carriage just to have, and the carriage comes apart off the bearing with a few screws. In my opinion the dual is more than worth the lost 40mil in the X, what with support materials, multiple colors, electrically conductive filament, two material prints with different temps, etc. Whatever you choose the printer is great, you will be happy. But for £100 you get a second extruder, motor, stepper, pt100, second spool holder for the back of the machine, fans, etc. You can always easily 'downgrade' to a single yourself with a printed X carriage if you choose to.
     
  6. Henry feldman

    Henry feldman Well-Known Member

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    Thanks @Colin that was super helpful, I think you are right, that it makes sense... Any idea how you change your order at this point?
     
  7. Colin

    Colin Well-Known Member

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  8. Henry feldman

    Henry feldman Well-Known Member

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    As a total non-sequitur, I note I am a "well-known member" on the profile. In certain professions that's not a good thing. "The individual was well known to the police" doesn't mean because he gave regularly to the widows and orphans fund. In my line of work, when I write "the patient is well-known to this service" that's not a good thing either... Hopefully, being well-known in 3D printing is a good thing!
     
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  9. Large

    Large Active Member

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    Any opinions regarding the dynamics of a dual? Will the extra mass of the second extruder limit the max print speed noticeably or create any other side effects? I'd guess that the wear of the belts will increase although not sure wether it's significant.

    I think that , alongside a single carriage, I'd investigate the need för a dual carriage with a 2:nd extruder snap on/off for real easy conversion without unmounting an extruer from dual and mount it on single extruder carriage. This is depending on how easy it is to change between single/dual in the original design. The 2:nd extruder snap on/off carriage would then have the printing area as the dual but with the weight of the single extruder setup. But first I'll have to wait and see the design for real... :)
     
  10. Kanedias

    Kanedias Well-Known Member

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    That's the option I prefer - a single extruder on a carriage to which a second extruder can be added and removed. The second one could either be for supports, dual colour or a Volcano printing on its own. Having the extra print head there all the time is just something to catch on from personal experience.

    Can anyone who has theirs yet confirm the headers with the P0 and P1 terminals are populated? I've made a basic filament detector using a roller ball microswitch which will pause the print if you run out of material.
     
  11. Clare - E3D

    Clare - E3D Active Member
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    Colin is correct, the best way to proceed with any changes or additions to orders already placed it to email support@bigbox-3d.com, where Catriona or a member of support will be able to help further :). I honestly don't know the delay it would add to swap to Dual at the moment, but I think from what you're saying it will be worth the wait for you. :)
     
  12. Mike Kelly

    Mike Kelly Volunteer

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    I would tread lightly in the world of dual extruders. It is no picnic.

    First off you should strongly consider what sort of objects you'll be printing. If you have plans of printing a significant amount of dual color prints, then you could consider it. Just ask yourself, is painting a better option? Often times it is as you have more configurability and would do some post processing to start with.

    A big draw of dual extrusion is soluble/breakaway support. I won't lie, this is the best feature of duals. However this is not without some caveats. Honestly these days I tend to just print with simplify3d on a single extruder because it breaks away just as cleanly.

    These are the two major draws. Some people can manage to do other cool stuff like combining different materials to achieve unique effects and since the BB is direct that's even easier.

    Now for the negatives:

    Clipping: Clipping is a very real problem and almost certainly will occur at some point. Granted clipping can just as easily occur on a single extruder print, but on a dual it tends to exacerbate the issue. The common cause for clipping is the part has poor first layer adhesion and/or comes unadhered to the build surface. It can also occur because of oozing which then catches a nozzle, but if their method of purging the nozzle is as good as they claim that might be less of an issue.

    Oozing: It's been a major headache and problem which causes ugliness in prints or the necessity to use shields, etc. It's a nuisance, though like I just said, might be gone

    Nozzle height calibration: The bigbox employs a decent method of leveling he nozzles, but it's still a constant battle, especially since the bed is not static and needs to be calibrated against.

    Carriage weight: Typically dual extruders use bowden drives to keep the carriage weight down, but the bigbox is dual direct which adds a significant amount of weight. You'll be limited on top speeds you could achieve but 60mm/s seems fine.

    Loss of travel: You do lost a bit of travel since the dual carriage is wider than the single.

    Slicing complexity: Software like cura 15.04 handles dual extrusion well but in general it's a chore to set up. Especially in simplify 3d where you have unique profiles for each extruder for dual color prints.

    Material compatibility: Depending on your materials your support material may have difficulty sticking to your part, so you'd need to reduce the spacing meaning you typically end up with an uglier surface to use the support material than to use the same material with easier to break away settings

    It's nice to have on occasion, but honestly single extrusion is so much easier and nicer to work with I'd suggest it unless you're looking for the challenge.
     
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  13. theTroll527

    theTroll527 Well-Known Member

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    The reason I am getting duel-heads is because I want to do some research into the materials and how we can use duel printing to improve the specific characteristics of the printed parts. I might need to create a custom slicer to do what I am trying to do, but I think we need more materials science in this field.
     
  14. Halvard Fosse

    Halvard Fosse Member

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    After reading and thinking about the PRO vs. DUAL, I figured I would be dissapointed with myself if I did not try to get it upgraded to a Dual.

    I sent an email to support@bigbox-3d.com and asked if I could upgrade to Dual and also change the color of the acrylic.
    The day after I got a nice reply from Catriona. I just had to pay £100 extra for the upgrade, and everything would be good.

    Don't know if it will affect the shipping date, but atleast now I get the box I really wanted, and it's worth the wait.

    Super service from E3D as always, always going the extra mile to make people happy!
     
  15. Henry feldman

    Henry feldman Well-Known Member

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    She told me no change in ship date (I suspect the delay allowed therm to catch up)
     
  16. mike01hu

    mike01hu Well-Known Member

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    I've had almost 3 years of single nozzle experience and have been frustrated by the inability to produce relatively clean support structures in any slicer and having to resort to multi-part structures where a single structure would be stronger. Therefore, the primary advantage for dual is that a different material can be used for support that is easy to remove.

    A second feature that I am particularly interested in is the ability to have two different types of filament e.g. XT and XT-CF, incorporated in the same part to alter mechanical stiffness in different zones. I wont be sprinting Benchys or vases, not because I don't like the idea but because my interest is in mechanical structures. I admire the work that members like Livi and Richard do and really appreciate their aesthetic design skills although Richard is a good at mech structures too.

    I changed my order to the dual option and am happy to accept any minor delay, although I suspect the nut problem is causing more of a delay. It's a bummer having to rely on external suppliers doing their job properly!

    Mike
     
  17. Large

    Large Active Member

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    I've made up my mind and decided on going for the dual BB. Since I'm (more?) into experimenting with the machine itself rather than actually produce something with it I think that's the way to go.
    However, the decision makes me wonder what parts I'll be missing to convert it to a single extruder BB. Are there only printed parts that I'll need for the convesion or are there other parts as well?
     
  18. Colin

    Colin Well-Known Member

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    The X carriage is the only difference, and it snaps onto the same single bearing for single or dual. You will have extra parts that I detailed above but if you printed the single X carriage, removed the dual X carriage and loaded up the single you would be able to print with the reclaimed 40mil. The only item you will need to convert to a single extruder is the X carriage for singles. You will need to put the extra parts somewhere but they could be zip tied up out of the way.
     
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  19. UlrichKliegis

    UlrichKliegis Well-Known Member

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    For practical reasons, you may also want to purchase/make an extra extruder, otherwise a change between the two heads could be a bit awkward. That includes at least one stepper, but probably also a complete hotend like the E3D-V6. An extra air nozzle for parts cooling is also desirabl. That adds one fan to your bill. You will also have to regard the different offsets somewhere in the firmware or your software. Some sort of universal hotend-plug would also make sense to switch between the two.
    But it is feasible, yes. Just simulate everything mentally before you start.
     
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