Announcement

Collapse
No announcement yet.

My New Creality Sprite Filament Feeder/Extruder

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • My New Creality Sprite Filament Feeder/Extruder

    I have been using my Creality Ender 3 Pro filament printer for -- what? -- 2-1/2 years? For most of that time I've had good success printing all kinds of custom slotcar components. But of late I have suffered a lot of filament jams -- filament swelling up in the Bowden tube right above the hot end and jamming tight enough that it cannot be fed. Apparently a common problem and not easily solved.

    So when I discovered Creality was offering a new one-piece filament feeder/extruder for the Ender 3 Pro I was ready for it. At US$110 it was a significant investment, but my hope was it would also be a significant upgrade, extending the service life of my printer.

    Click image for larger version  Name:	Sprite Portrait.jpg Views:	0 Size:	301.2 KB ID:	163566Click image for larger version  Name:	Sprite Profile.jpg Views:	0 Size:	315.9 KB ID:	163567

    No doubt I'll have lots to say about the Sprite unit, and I'll be posting here. But to start with...

    Assembling the Sprite onto my Ender 3 Pro required removing the existing filament feed and extrusion system. Mechanically not a difficult job, especially since I had assembled the machine in the first place -- it comes only partially assembled.

    With the original hardware off the new stuff bolts on with minimal pain. But the electrical assembly is a bit more tedious. Still, I was able to do it without removing the circuit board. The instructions do show you where everything goes, but the print is so small and faint I needed my headband magnifier to read it. You need to bring your inner watchmaker to the task. That circuit board is small and dense. Cool confidence, diligence and patience will get you through.

    But the big, unanticipated pain is that you need to reset the e-step parameter for the filament feed. The instruction sheet shows nicely illustrated instructions for how to do this. What they don't mention is that you need to dial through something north of 40,000 steps on that little push-and-twist knob you use to input commands. I mean that for real -- 40,000 steps. I found I could dial through 1.000 steps in just under a minute, but even so that meant the best part of an hour spent twisting that little knob. Creality Support says, "Uh, nope, no better way to do that."

    So, finally, all bolted in, wired up and reprogrammed. Time for the smoke test. POWAH!!!

    And... No filament is feeding. So why's that? Well it could be the hot end is dead cold. Yup. Cold as the grave.

    So I shoot off an email to the crew at Creality Support. And they respond asking for a whole bunch of background info. Not what I'd hoped for. But its okay because in the meantime I had found the problem all on my own.

    Click image for larger version  Name:	Heater Tag.jpg Views:	0 Size:	286.2 KB ID:	163568

    Turns out there was a loose electrical connector sporting a blue tag that says, in essence' "Plug me in!"

    So I did that, and, gosharooty! It worked!

    The filament fed, faithfully executing my commands. Too bad the instruction booklet said fudge all about any loose connector, or blue tags for that matter.

    In retrospect, the installation and startup was not all that horrible. Worthy of Microsoft but not of Apple. But then I had gone into the project with the realistic expectation there'd be a hiccup or three. No disappointment there.

    More to come. I'll be posting here. Stay tuned.
    Last edited by HO RacePro; June 2, 2022, 01:35 PM.
    Ed Bianchi
    York Pennsylvania USA

  • #2
    Time for an update...

    I have had two problems with my Sprite feeder/extruder -- frustrating enough that I seriously considered swapping my old unit back in.

    The first issue was leakage of molten plastic down the threads of the nozzle right down onto the print. I appear to have solved that by installing a new nozzle that is larger, along with a couple of copper washers. The new nozzle has a 7mm hex as opposed to the 6mm hex of the original nozzle. It is longer than the stock nozzle so I needed to install a couple of washers to take up the difference. They are copper washers I reamed out so their ID's would just fit over the nozzles threads. Being copper they should be soft enough to crush a small amount when the nozzle is torqued down tight.

    The 7mm hex was needed to cover the end of the threaded hole. A 6mm hex isn't large enough and the threads aren't a close enough fit -- hence the leakage.

    The other issue is printing TPU. The twin knurled wheels provide plenty of drive, but the filament kept jamming and buckling. I think I have finally -- after far too many failed prints -- found a fix. I've reduced the temperature of the hot end from 240C to 230C. That seems counter-intuitive but what I believe was happening was the heat break was getting too hot causing the filament to swell and stick.

    I think I can legitimately declare victory on the leakage issue. But I need more successful TPU prints before I'll be satisfied that problem has been put to bed.

    FYI, I picked on those copper washers based on the practice of using 'crush washers' on automotive and aviation oil pan plugs. Crush washers deform when those plugs are tightened down, forming a near-perfect seal and locking those plugs against backing out. Crush washers are typically made from annealed copper, aluminum, or other materials of similar softness. They are only used once, since crushing them work-hardens the material.

    I once heard that aircraft mechanics use 'Milk of Magnesia' on threads in high-temperature assemblies as an anti-seize agent. I might try that on nozzle threads sometime, both as an anti-seize and a sealant.

    Last edited by HO RacePro; June 30, 2022, 09:14 PM.
    Ed Bianchi
    York Pennsylvania USA

    Comment


    • #3
      Originally posted by HO RacePro View Post
      Click image for larger version Name:	Heater Tag.jpg Views:	0 Size:	286.2 KB ID:	163568
      How on earth could you have missed that?...I will say a little prayer for you Ed

      Kevan - Isle of Man
      Life is like a box of Slot cars...🚓🚗🚚🚜

      Comment


      • HO RacePro
        HO RacePro commented
        Editing a comment
        The loose connector was easy to miss because it was hidden inside the assembly. And the instructions said nothing about it. Once it was obvious something was wrong I got down to inspecting things in detail, found the loose connector and read the blue tag. I still had to puzzle out where it plugged in, but got it right the first time.

        I should mention that there are a couple of connectors at the circuit board end that do not have a home. That is mentioned in the instructions. One of them I believe is supposed to connect to a leveling sensor -- an option I do not have installed.

    • #4
      So it turns out decreasing the hot end temperature isn't really a fix for the issue of TPU filament buckling. Subsequent prints failed.

      Instead I drilled out the hole in a new nozzle, from 0.4mm to 0.56mm. That doubled the area of the hole, which reduced the pressure needed to extrude the same amount of material by four. And that worked. I printed out two TPU parts, each large enough to require two hours to print, without a hiccup.

      It isn't a surprise that reducing the pressure to a quarter of what it had been resolved the issue. But it is disappointing that's what was needed. I really expected the twin-drive system to work better than the stock Ender 3 Pro single-drive system. I'm tempted to tear down the Sprint unit to see if I can figure out what the problem is, but I'm a bit intimidated by the compact complexity of the unit.

      FYI, I did the math to figure out that a 0.56mm diameter hole has twice the area of a 0.4mm hole. But I didn't know at the time that Cura wouldn't allow me to input that exact hole size. So I ended up inputing a hole of 0.6mm diameter, and that seemed to work.

      Next I'll try using a nozzle with a 0.5mm hole. Will that work? Stay tuned!

      Ed Bianchi
      York Pennsylvania USA

      Comment


      • #5
        TPU is just plain tricky. For my Prusa, the main changes from a stiff material is to go SUPER SLOW and reduce the idler tension so that it's only barely grabbing. I don't know what other settings you were using, but I assume they were settings for flexible material, so maybe you already did those things.

        Regarding the blob... I don't know much about this upgrade to your machine, but does it come with a new hot end, or did you move that to the new extruder? If it's a new hot end ( which your nozzle info implies) is that an all metal hot end, which uses a metal "heat break" between the nozzle and PTFE? If you're not sure, does this new device say that it can print higher temperature materials?
        Assuming it's an all metal hot end, leaking is most often caused by a gap between the top of the nozzle and the bottom of the heat break. It's advised to install the nozzle one full turn off of tight, then install the heat break snug against it. Assemble everything else, then heat it up to 285, and tighten the nozzle again at this high temperature.
        Putting washers in places they don't belong might fix it, or it might just prolong the failure. Hopefully the former.

        Comment


        • HO RacePro
          HO RacePro commented
          Editing a comment
          Beware the Blob!*

          Yes, my upgrade came with a new hot end that supposedly has a titanium heat break. The hot end is advertised to operate up to 300C.

          I've seen leakage down the threads of a nozzle. There must be a gap between the heat break and the top of the nozzle, but I don't know how to close it up. The nozzle was already all the way tight against the heater block. My copper washers seem to be doing the trick. I've done a number of prints with them and had no issues with blobs.

          At some point I'd like to dissect that Sprite gingy and confirm it has a titanium heat break. I'm not quite brave enough to do that just yet.

          * With apologies to Steve McQueen and the 1950's teen gang!

      • #6
        Yep. Sounds like it was not properly assembled. You're going to have to clean it out and disassemble the hot end in order to get the relationship between the nozzle, heat break, and heat block correct. Are your copper washers between the nozzle and heat block? If so, then you're creating a bad melt zone and you're walking on rice paper if you keep using it like that. Even if things are OK at the moment, I think you should correct the assembly of the hot end ASAP, as per my previous post.

        Or, you know, whatever.

        Comment


        • #7
          The washers are between the nozzle and the heat block, but they are needed because the new nozzles are longer than stock. As best I can tell the top of the nozzle is butted up against the heat break. If I 'cold pull' the filament it comes out easily, which hints that there is no gap between the nozzle and the heat break.

          So the washers serve two purposes, adapting the longer nozzles as well as sealing the assembly.

          I am continuing to use this washer/nozzle setup. Still no leakage and no blobs.
          Ed Bianchi
          York Pennsylvania USA

          Comment


          • #8
            When I had an Ender I used a copper washer from a R/C glow plug which stopped a leak I had.
            Kevan - Isle of Man
            Life is like a box of Slot cars...🚓🚗🚚🚜

            Comment

            Working...
            X
            UA-149438709-1