BMG CLONE extruder issues
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@oliof, while it had occurred to me that I could just buy the drive gears, I think I will always wonder what I am missing by not using the full product. If things didn't work for some reason or other then I would have no real answer if the original parts are better than the cloned parts.
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@jens55 correct, you would at least want the shaft gear and the POM gearwheel as well, and then the internal geometry of the clone could still be detrimental to filament path etc....
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The old adage comes to mind - "Buy cheap, buy twice".
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@jens55 said in BMG CLONE extruder issues:
what I am missing by not using the full product.
Long time ago I understood the "I'm not rich enough to buy cheap things" but still from time to time I go and purchase a clone. And EVERY SINGLE TIME it cost me so much time and nerves and ... every time I ask myself wtf I did it.
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deckingman and arhi ......
Yes, I bought the clone version. Yes, buying cheap does bite me in the ass more times then not.
In this case, if I remember correctly, I even asked (possibly in this forum) about clone vs real thing and the general consensus seemed to be 'the clones work real well'.
In deliberations about buying clone vs the real thing, I generally am more than wiling to pay roughly twice the money for the real thing. In this case it was a $15 vs $120 decision (Canadian) and that actually made the decision quite easy. Just like my decision to buy a real Duet vs a clone - I think the up charge was less than 50% so no question.
Believe it or not, the bowden adapter that does not seem to come with the real thing costs the same as the entire clone extruder which comes with the bowden adapter. It just seems to be WAY over priced for what you get.
Given all the grief I am currently experiencing, I am STILL thinking that the clone BMG was a good buy even if it means just using the bowden adapter from it!My latest test print using black filament instead of white is humming along nicely with no apparent issue as of yet. I even went back to my previous pressure advance settings. What I did do though is changed to the second extruder path because I have a 'hunch'.
I consider myself suitably chastised for buying a clone product and I am hanging my head in shame ...... but the story isn't finished yet and there might be a surprising plot twist coming up (or so I hope)
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@jens55 said in BMG CLONE extruder issues:
'the clones work real well'.
I have BMG clone that works awesome, identical to original, two original's and two awesome clones (that were not much cheaper than original, I ordered because originals were impossible to get at the time) but I also have few clones that are unusable
so ..$15 vs $120
when the difference is that much there's usually a reason. the good bmg clones I have were 70eur each
Anyhow, even the totally crappy clones should work. They don't have the force of original one, nor can dig in as original one, but if they are grinding like yours have they are experiencing issue in the hotend. The different filament can have few C higher Tg and that will make it just enough to not block the heat break. So that, imho, proves that the problem is poor cooling of the heatbreak.
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@arhi said in BMG CLONE extruder issues:
the good bmg clones I have were 70eur each
That's very expensive for a clone. Did you order directly from China or from a local store?
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Apologies for going off topic but it's the old story. OEMs plough some of their profits back into developing new products. They also support those products. The cloners sit back and wait, then when a new product gets released, they make a cheap copy that everyone buys. Part of the reason why the clone is cheaper is that they don't have any development costs or support costs. If an OEM produced an item that was faulty or otherwise not fit for purpose, they would get an exchange or refund. Not so the cloners. Try asking for your money back from AliExpress. Try getting support.
The stats for my blog show a great deal of interest from China every time I post something related to the 6 input hot end I'm trying to develop. This could be the first hot end that is cloned before the original has been made into a working prototype. I'm sorely tempted to publish the design with known flaws and claim that it works, wait for the cloners to make their tooling, then release the real design.
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Queue evil scientist laughter ...
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@zapta said in BMG CLONE extruder issues:
@arhi said in BMG CLONE extruder issues:
the good bmg clones I have were 70eur each
That's very expensive for a clone. Did you order directly from China or from a local store?
directly from PRC .. but as I say there are good and there are not so good ones, I have some that were 30$ that are utter garbage ...
@deckingman amen! but not all of the cloners are like that, I know at least one company that shoot % of the money to the original designer and one company that offered to pay royalties
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@arhi said in BMG CLONE extruder issues:
@deckingman amen! but not all of the cloners are like that, I know at least one company that shoot % of the money to the original designer and one company that offered to pay royalties
That's good. Care to name them?
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Using the secondary extruder path (still a BMG clone extruder), black filament, no retraction but full pressure advance (with the resulting retraction), I have achieved a beautiful model. Disassembly of the extruder showed zero filament dust.
The white filament has been loaded and a new print is on the go.
It is looking like there might be a 'speed bump' in the primary extruder path. When I say 'speed bump' I mean a transition between ptfe tube and some internal structure in the hot end that is causing an intermittent hangup. I suspect it hangs, grinds, retracts and then feeds in correctly eventually. This causes poor extrusion.
If the now loaded white filament is printing successful then this would pretty much confirm this suspicion and I can look at the primary feed path in the hot end.Thanks for all the help guys! I will follow up in about 20 hours when the new print is finished.
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@deckingman said in BMG CLONE extruder issues:
"Buy cheap, buy twice".
Is it so? This implies that more brand name products are sold than clones.
Clones have an important role of popularizing the technology and in the case of OSH, it's by design.
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@jens55 said in BMG CLONE extruder issues:
It is looking like there might be a 'speed bump' in the primary extruder path. When I say 'speed bump' I mean a transition between ptfe tube and some internal structure
Do you have a clean PTFE cut? I clean up and slightly chamfer PTFE cuts with this. (gently, by hand, not with a power drill of course).
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@zapta said in BMG CLONE extruder issues:
@deckingman said in BMG CLONE extruder issues:
"Buy cheap, buy twice".
Is it so? This implies that more brand name products are sold than clones.
If someone buys something cheap that fails after a year, that doesn't necessarily imply that they'll then go on to buy a more expensive replacement. They might buy exactly the same cheap item again - it's still "buy twice".
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@deckingman said in BMG CLONE extruder issues:
it's still "buy twice"
I see. Thanks for the explanation.
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@zapta said in BMG CLONE extruder issues:
Do you have a clean PTFE cut? I clean up and slightly chamfer PTFE cuts with this. (gently, by hand, not with a power drill of course).
WHAT!. You seriously use a centre drill? All it takes is one tiny piece of PTFE swarf to block a nozzle. What you should use to get clean cut with no swarf is a craft knife or better still one of these https://www.ebay.co.uk/itm/Nylon-Tube-Cutters-and-Plastic-pipe-Cutter-snippers-will-cut-any-plastic-Tubing/120720419422?hash=item1c1b7f6a5e:g:suQAAOSwzSdb0fVq
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@deckingman said in BMG CLONE extruder issues:
WHAT!. You seriously use a centre drill?
Yes, I do.
I cut the PTFE with the tool in your link, slightly chamfer the inner cut with a center drill, and make sure there are no leftover PTFE crumbs.
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@zapta said in BMG CLONE extruder issues:
@jens55 said in BMG CLONE extruder issues:
It is looking like there might be a 'speed bump' in the primary extruder path. When I say 'speed bump' I mean a transition between ptfe tube and some internal structure
Do you have a clean PTFE cut? I clean up and slightly chamfer PTFE cuts with this. (gently, by hand, not with a power drill of course).
thats an interesting approach to low cost 60 degree chamfer; should have something like that if i go digging. thanks for the tip!
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@zapta Oh well, each to their own. When I used to install and commission analytical equipment, using anything but a sharp tube cutter would be classed as gross negligence or gross misconduct and would have resulted in instant dismissal, due to the costly damage that any swarf or debris could cause.
