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Unresolved Filament not feeding

Discussion in 'Troubleshooting' started by crazyshakespeare, Sep 10, 2016.

  1. crazyshakespeare

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    I recently installed an E3D v6 hotend on my R1 plus. Managed to successfully get through my first print but noticed sections where my filament was not laying down. Began to start my second print, only two realize I had a clog at the nozzle and heartbreak. Once cleaned and reinstalled Im not able to get filament to extrude. Filament extrudes fine when pushed by hand and I can get about an inch to come out when manually turning the hobble bolt. I have been playing with the tension and have cleaned the hobble several time....Needless to say Im stumped.

    Material (two different rolls of ABS)

    Temp: 240 -255

    Suggestions?
     
  2. Toro1966

    Toro1966 Active Member

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    Sounds like it's still clogged. Have you taken off the nozzle to confirm it's clear. I would take the nozzle off and check.
     
  3. Geof

    Geof Volunteer Moderator
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    Did you make sure to put the black holder n the top of the cold end to hold the tube? You may need to disassemble the hotend and look for an error in assembly
     
  4. crazyshakespeare

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    Unfortunately...I will be down for a while...snapped the nozzle off and broke the heat break...stress, lack of sleep, and trying to get things done too fast don't mix...learned my lesson...hopefully things will go smoother once I'm up and running again....thanks for yalls help
     
  5. Jaime

    Jaime New Member

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    Play with the temperature. Not all print at recommended temps. The hobbed bolt likes to chew on the filament if not enough pressure is exerted not the filament. One Moe thing, make sure it is no binding around the bolt or in the hastened/ cold end. If you can extruded by hand the nozzle is not clogged up. Raise your temperature a bit and try the hand feeding. When it becomes easy to push through, you have the right temp. As. For the bobbed bolt, I made my own out of a normal bolt with a Drexel and made deep, sharp grooves. I then added a v-taper down the center to increase the contact area. A rounded groove will only apply pressure on one side. Grooved bolt will add pressure at about 45 degrees about the center on two sides. The deep grooves make it harder to plug up. I also made one with long grooves so the the dust rolls off the center. The deep grooved bolt worked forever but then I got a new bolt from robo3d and ran it only to find filament grinding in short order. The deep grooves are the way to go. You can make this using a Drexel.
     
  6. crazyshakespeare

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    Hey Jaime...do you have any photos of the bolt you made?
     
  7. Jaime

    Jaime New Member

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    I'll get you a picture. I'm not a printing guru by any means. I've put several 1000 hrs on my Robo. It's my work horse. Unfortunately, it's hardly plug and print. At least not the one I got. Since the extruded connector is broken right now, I can remove the bolt and take a couple of shots for you. I'm waiting for a new wire with connector ( crimper is some insane 1200-1500). I have now been down a whole week from continuously printing for over a year on it.

    I made the bolt with my Dremel, so it's certainly not pretty, but it does what it's supposed to do. My experience with the original bolt is constant grinding of the filament regardless of the brand. I screwed around with this quite a bit and since I'm not a software guru, I started looking at the main physical components. I figured that all the software in the world cannot fix a flawed design.

    I noticed first of all that the bolt is hardened and so that's what I got. After thinking about it a little, there's no reason to have a hardened bolt. Regular mild steel bolts will work fine. This will make it easier to dremel. The hardened bolt was a pain to grind. The hardness differences between the filament and the bolt is huge even for a regular bolt ( no reason to go more than 10-15 points higher -you are literally on different hardness scales between plastic and steel).

    Once again, I'm not a 3d printing guru, just a tinkerer. I'm not sold on the hardened nozzles either. 250. C is barely putting any thermal load on the metal. This kind of boils down to feeding straight and having a descent leveled bed. Given that these have two threaded rods to level, you have to assume that the glass is relatively level.

    Sticking of the material is the second pain. I use purple elders sticks for both PLA and ABS. I personally don't print much with ABS. Unless you controlled the temperature of the chamber, you will get eleven thermal expansions and then you spend your life chasing layer sticking issues instead of printing neat carp. Even the professional machines struggle with this in heat controlled chamber.

    Ill get you a picture tomorrow.

    Jaime
     
  8. Jaime

    Jaime New Member

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  9. Jaime

    Jaime New Member

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    Here you go. I don't know if this is the proper thing to do, but it makes sense to me. If you threw this on a screw machine, I'm sure it could be made nice.

    The thought here is to make a V-Groove down the center so that the filament is pulled in a more kinematic fashion. A flat set of ridges will give you two points of contact on extrusion. A round set of ridges (normal) will give you two points of contact on extrusion. A V-Groove will give you 3 points of contact on extrusion. Keep in mind that your tensioner pulley is the opposite point of contact to these. I also added a V-Groove on the tensioner to give this 4 points of contact on pulling (theoretically).

    Of course, you will see your filament and say, there's a whole line of contact and that is partially true.

    This works for me. I don't know if it will work for you. Maybe I'll make these things to sell. This design can be replicated for personal use. Anything for sale should have permissions assigned from Oak Engineering (us).

    A product of Oak Engineering, 2016.
     

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  10. danzca6

    danzca6 Well-Known Member

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    @Jaime is that oak engineering near Batavia? If so I know where that is. I have a sister that lives just south of there.

    That's a clever design. I've never seen anyone using that before. How long have you been printing with that design?
     
  11. Jaime

    Jaime New Member

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    This bolt has about 4000 successful print hours on it and I'm sure a few failures in getting it right. I actually made the grooves even deeper than these. It keeps from getting carp caught up in there as well.

    You can make a bobbed bolt with a tap, but you end up rounding and your grooves are slightly angled. Live never made one that way. The dremel was good enough for me. A hobber machine is probably the best thing to use. I'll make some new one using a nursing tool, see how the come out. I looked around yesterday and found a few similar to this. One claimed 20 successful print hours. That's about one job for my stuff.

    Oak Engineering is in AZ. No relation to the one you are familiar with. The OAK specializes in helping people turn potential designs into reality. Lots of designs, not sure how many make it. It's nice working with people who don't necessarily have time to learn all about prototyping and modelling.

    Have fun building one and of course if it works for you, don't forget to give us credit. This design can be licensed to anyone wanting to produce for sale. The reasoning is sound and well proven. We've got an AirWolf as well that this little printer smokes using $20 rolls of filament.
     
  12. danzca6

    danzca6 Well-Known Member

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    That's fantastic! We have a place like that here as well. A friend of my wife used that place to design a product that later went on to get picked up on Shark Tank. It's awesome.

    So this new style of hobb, how does it work for flexible or semi flexible filament? Very clever approach that has sparked my curiosity.
     
  13. crazyshakespeare

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    Love the design and I'm strongly considering it...a couple of questions...how did you know the right depth, or did you just eye it. Secondly, I'm guessing you started with the deep vertical groove then did your horizontal? Lastly...it seems pretty precise...how did you mount your bolt while you were making it?

    Again great work...I really think this could fix several issues I've had.
     
    #13 crazyshakespeare, Sep 16, 2016
    Last edited: Sep 16, 2016
  14. Jaime

    Jaime New Member

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    I'll be honest with you, I'm not big fan of the flexible filaments. I've printed them using this bolt. The issue with the flexible filament isn't the bolt. I think any bolt will work. The issue is that the filament stretches as you pull it in. The stretching happens inconsistently and then you must rely on your tensioner to get you there without issues. I've used 3Dison to make a few gaskets and I really believe that it's much simpler to go down the road, give them a file and have them just cut one out for me. I did play with that for a while and I don't think that there is a good bolt for pulling that well. I was however able to print this stuff at will if I unravel it from the spool. There's simply too much weight to fight with and your tension is always different. I personally don't recommend it, but I see people raving about what all the new kids are using and I guess to each his own. I don't really see a good application, except gaskets. By the same token, I'm not a fan of the exotics because in the end, the mechanical properties are limited to the binder, so there's nothing to be gained by 3D printing a brass exotic when it's basically brass dust empregnated chemical. It's nice to look at. I like making functional stuff and 3D printing is just a tool to get you there quickly (my bias).

    I'd say that one thing that would work better than a metal extruder for these rubbery compounds are rubber rollers. No point in having teeth for that when you can generate all the friction in the world using rubber rollers. Take your hands and rub them together, they generate heat because they are made of the same material. Same thing applies to these items. Physics.
     
  15. Jaime

    Jaime New Member

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    Thanks for the love of the design. I'm sure the bolt is happy to be loved. : ) You have good questions and I'm not sure I have good simple answers for you, but here goes a shot. How did I know how deep to make the grooves? I figured that the material is toughest on the outside, given the smooth finish. This to me, meant that the material is probably hardest on the outside (think of an orange, it's soft on the inside and hard on the outside). I looked at the hobbed bolt that caused problems from day one (I was never able to print reliably with that thing). The teeth are shallow and as previously explained, the kinematics don't make sense. In kinematics, you want to optimize contact, but you must make the right assumptions. With shallow grooves, what you find is that the bolt does no cut into the plastic enough to get past that hard shell. This would be consistent with the grinding (AirWolf calls this MOUSE BITING - Yeah I've fixed the MOUSE BITING on my airwolf as well). I would not pay full price for those printers. With grinding comes FOD, just bits and bits of plastic. You can see how this would cause a clog on the bolt. Build enough of this crap up and you pull nothing. So, God spoke to me and said, "make deep sharp grooves Jaime". You will see how deep you can go on a hardened bolt once you start cutting it by hand (not trivial). If you can make a jig, it helps. On the bolt that you got pictures of, the dremel is just pushed along the grooves of an existing bolt. It's brother is on the printer and was made from scratch on a grade 8 bolt (not needed). My thoughts are that if I could cut across the entire bolt radially I would do it (deeper is better).

    Make the horizontal grooves first. drill a hole in something and stick the bolt in the hole. get your dremel going using thin blades (the ones that break and shatter everywhere). turn and hold the bolt by hand and clock slowly one groove at a time (this is tedious work). cut the vertical groove next. How deep? at least as thick as the filament. How wide? about 1/2 the diameter of the filament.

    How come you broke the sharp edge from the vertical groove? Well, God sent me a message saying to do it. No, not really, the sharp groove works well, but I didn't want to cut excessively deep into the filament and break it (it likes breaking if you bite too much hahah). Take a small file or dremel and just break the edge off. This helps to center the filament and keep it from wandering off to the sides.

    I mentioned earlier that you can use a thread tap to make the grooves and you can (google it). Here's what I don't like about that. The grooves will be at a slight angle and if you decided to just run the filament through there, it would want to move not vertical, but at a slight angle, not really giving you optimum force transfer.

    If you are unable to make one, I'll make you one for $20 + shipping. That applies to anyone.
     
  16. Jaime

    Jaime New Member

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    Here's the Little Printer that Could printing out $15/KG white filament and doing a nice job.
     

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  17. Jaime

    Jaime New Member

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    Here's a few products from this little guy ...
     

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  18. Jaime

    Jaime New Member

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    This design is patent pending. We'll see where it goes. I know everyone likes open source and you are free to build them. If a company is willing to cut a deal, it's up for grabs.
     
  19. crazyshakespeare

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    Just curious if you think it would be possible to just modify the bolt thats already on the machine....just trying to save time and a little money
     
  20. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    You can buy alternative ones. I got two different ones than stock on eBay for 5 bucks each and I have used them for a couple of years.
    One has a pattern not unlike the one posted here. Not identical, but similar. The other one has a finer set of hobbed sections.
     
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