Twicx's Dual E3D Direct-Drive Extruder

Discussion in 'E3D-v6 and Lite6' started by twicx, Mar 6, 2014.

  1. twicx

    twicx Well-Known Member

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    Cheers! All I need to print now is the motor bracket, the arms for the bearings, and the fan ducts. Getting close now!
     
  2. Eaglezsoar

    Eaglezsoar Administrator

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    We have to see pictures when she's done.
     
  3. Josh

    Josh Administrator
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    How are you going to level the two HotEnds relative to each other?
     
  4. twicx

    twicx Well-Known Member

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    I haven't really gotten a chance to do much on this in a while. We had a family wedding, and I've been in bits with a bad flu for the last week. Because the base printed well, the hot ends fit into it with the lock pieces pretty tight, so when I put it on a level surface and sit a laser level on top, the figures are 0.02mm off which seems to be a good tolerance. I also had a little investigation into getting the whole extruder printed in one piece and its not that expensive. There's also some interesting material options, like a ceramic or something like that. It would save me a lot of hassle too
     
  5. twicx

    twicx Well-Known Member

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    Ok, so considering I'm still not getting the printing just right, I'm looking to get the whole thing printed elsewhere. I found somewhere that can print it in a ceramic (heat resistant to 600C) for about $15. Ceramic seems like a good idea. I'd imagine it's seriously durable and pretty damn rigid. Any opinions?
     
  6. Chavaquiah

    Chavaquiah Active Member

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    3D printed ceramics - at least the budget kind available from the likes of Shapeways, Sculpteo or i.materialise - usually have very stringent design rules and lousy strength. Oh, and very, very poor tolerances. Is this the kind of ceramics you're looking at?
     
  7. twicx

    twicx Well-Known Member

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    unfortunately so. But at that price, it might be worth the gamble? At this rate, I just want to be done with it.
     
  8. Chavaquiah

    Chavaquiah Active Member

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    Well, these services usually allow you to upload a model and perform a quick rule check. That will tell if they will even try to print the object. Then you just have to consider whether you can live with dimension errors of 1mm+ in some places and no details smaller than 2mm.

    Another option might be using the "I need stuff made" of the reprap forum... Or using a 3D printing service but having the part made from ABS.
     
  9. twicx

    twicx Well-Known Member

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    are those companies better with other materials though? I'd consider paying a bit more for a better material with lower tolerances.... within reason....
     
  10. Chavaquiah

    Chavaquiah Active Member

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    The problem is not with the companies but with materials and printing method. For ceramics, they start with a coarse powder (think wet sand), which immediately rules out any fine detail or thin structures. The glaze is applied at the end. It is thick and very viscous (think fudge), and that makes for nice looking tea cups os vases, but further destroys any coarse detail there might still be.

    Before having my own printers, I used both Shapeways and i.materialise for plastic parts. I was very pleased with quality (not so much with cost). Objects that require support or have interlocking parts do come out much better than with our fused filament deposition printers. However, any small error will take several weeks and quite a few Euros to correct.

    Honestly, in your situation, I would try instead to solve printing problems.
     
  11. twicx

    twicx Well-Known Member

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    see, I think I've identified two new problems

    The first is that the aluminium print surface is very slightly warped, it's like it has a slight dip in the middle. Using glass on top alleviates this, but then there's approximately a 5 degree temperature difference from the bed. The bed currently peaks at about 95C, so 90C is about 10C short of where I'd like it to be.

    The second is the temperature. The new heater has washers between it and the aluminium. Now air, as we all know, is an insulator, and a very poor conductor, but the washers are there so that it's not in direct contact with the aluminium in case it conducts the electricity and screws the heater up.

    So I'm now thinking that if i take out the washers, and use 2 layers of kapton between the bed and the aluminium to isolate it, then use a glass surface with kapton and hairspray, it might work. I've also heard good things about frosted glass as the slightly rough surface helps with adhesion. Any thoughts?
     
  12. Chavaquiah

    Chavaquiah Active Member

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    Would it be possible to lay the glass directly over the heat bed? Or are there screws preventing this solution?

    Aluminium helps with spreading the heat but you did a great job with the heat bed and have a very even coverage of the copper tracks.

    Also, and going back to the start of this thread, do you have isolation below the heater? Cork, cardboard, foam, something like that?
     
  13. twicx

    twicx Well-Known Member

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    I've no isolation beneath the bed, the current buildup is:

    heater>kapton>separation washers>aluminium bed>kapton>print

    but I could go to:
    cork>heater>aluminium>glass>kapton>print
     
  14. Chavaquiah

    Chavaquiah Active Member

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    Could you do

    cork > heater > glass > kapton > glue > print ?
     
  15. twicx

    twicx Well-Known Member

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    Unfortunately not. The glass doesn't have any screws in it, and the heater isn't strong enough to support it. I'll try the 2nd option i had there and see if it makes a different. As far as the glue goes, I have prittstick, a PVA based glue stick, that any use?
     
  16. twicx

    twicx Well-Known Member

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    Safety lesson #73: Importance of an emergency power cut-off switch

    As you all will remember from when I was replacing my PSU, I included an 8A fused power supply cut off switch. This is why:
    [​IMG]

    Lots of smoke and melting plastic, but nothing's damaged except the wire. I took out the spacers, leveled the bed, got it up to the right height, then pressed heat bed. Two seconds in, lots of smoke and melty plastic, then i hit the cutoff switch. Nothing's damaged except the wire, so I got lucky! I THINK something's shorting out the bed, or possibly there's contact between the quadrants and it's getting WAAAY to much amps. Thing is, I got a lucky escape but now I don't know where I need to look to try and solve this.
     
  17. Eaglezsoar

    Eaglezsoar Administrator

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    Are you sure the wire is large enough to supply the needed Amps?
    I am curious why your 8 Amp cutoff did not open automatically.
     
  18. twicx

    twicx Well-Known Member

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    It could be the wire actually, but its also worrying about the fuse, good point. I checked the resistance of the heater at the board end, and it's still around 9R. I thought it might be getting shorted via the screws or something. I think I have some very heavy duty wire, but I think its speaker cable. That would still do though, right?
     
  19. Eaglezsoar

    Eaglezsoar Administrator

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    It is the gauge of the wire that is important. Wire and ampacity charts are found all over the Internet.
    If an 18 gauge wire is required then I always step it up a size so I would use a 16 gauge if an 18 gauge is required,
    that way I am sure to have a safety margin built into the wire. Speaker wire would be fine if it is the correct gauge.
     
  20. twicx

    twicx Well-Known Member

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    Is that the most likely cause of the problem? Is there any other things I should check? Especially as the bed was working fine till now. It was the wire from the PSU to the board.
     

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