Why is the extruder pulley made of Brass ?
My printer was working perfectly for a few prints. Then I had to face my next bugbear -- the extruder pulley would keep coming loose.
I tried to tighten the extruder pulley again. I figured I had worn out the threads - that's why it would keep slipping.. So, now I am stuck. Surely my fault.
I have another printer. The extruder pulley is made of steel on that one. The screw doesn't eat the extruder.
A big question I have for now : Is there a specific reason why the extruder pulley is made of Brass ? (I am not blaming anyone for the choice of material, just wondering if there is any specific reason for this)
To fix the problem, I am considering getting another screw hole made on the same pulley. Is this the right way to go ? If there are other solutions, please let me know.
EDIT: I was actually able to fit another screw in the brass pulley - so maybe it is not completely worn out. Looks like I am unable to extrude. Tried cleaning the nozzle without much effect. Will look at the other things.
Re: Why is the extruder pulley made of Brass ?
Hi Shree
Contact PR to get a replacement.
Don't know if you saw what happened to my drive gear:
Brass has some advantages over Stainless (cheaper, easier to make) but it does have some distinct disadvantages.
The problem I found was that SS replacements tended to be 1mm larger diameter than the Prusa brass one, so they cannot be simply swapped in.
I had to ask PR to send me a replacement (which they did FOC), even though I would happily have bought two or three had they been available in the shop.
So what happened to mine?, Well I do use filament which may have taken up some moisture and I guess the steam from that was pushed up the PTFE tube and corroded the outside of the gear. The the hole - that was simply where the brass was unsupported (on the flat of the motor spindle).
That said, I had used the Mk1 continuously for about 6 months and the gear had never come loose - the grub screw was very difficult to remove, so I do think your situation is not a common one, and is probably due to the supplied allen key.
Peter.
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…
Re: Why is the extruder pulley made of Brass ?
Hi Peter,
Contact PR to get a replacement.
I will do that. Let me hope the replacement doesn't cause any customs issues.
The problem I found was that SS replacements tended to be 1mm larger diameter than the Prusa brass one, so they cannot be simply swapped in.
I saw the same thing today morning. I am thinking of getting the extra material removed. My local machinist with a small lathe can easily manage that I would imagine.
So what happened to mine?, Well I do use filament which may have taken up some moisture and I guess the steam from that was pushed up the PTFE tube and corroded the outside of the gear. The the hole - that was simply where the brass was unsupported (on the flat of the motor spindle).
Whoa ! That is quite some thing to happen. Interesting picture, and thanks for sharing your experiences.
That said, I had used the Mk1 continuously for about 6 months and the gear had never come loose - the grub screw was very difficult to remove, so I do think your situation is not a common one, and is probably due to the supplied allen key.
I think the allen key is surely to blame w.r.t these screws. It first caused me issues with the X axis and now with the extruder. Interestingly, the same allen key worked fine with the grub screw from the other extruder (from another printer).
Thanks!
-- Shree
Re: Why is the extruder pulley made of Brass ?
Shree
There will be no issues with importing a replacement free of charge item. The commercial value of that item will be very small.
Getting an SS gear machined should be OK; the machinist must be experienced in turning stainless (it is nothing like working with brass!), but the problem I can forsee is achieving the "hobbed" drive with the correct angles so that the filament is not chewed up.
Peter
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…
Re: Why is the extruder pulley made of Brass ?
There will be no issues with importing a replacement free of charge item. The commercial value of that item will be very small.
Getting an SS gear machined should be OK; the machinist must be experienced in turning stainless (it is nothing like working with brass!), but the problem I can forsee is achieving the "hobbed" drive with the correct angles so that the filament is not chewed up.
I think you are right on both counts. I hadn't accounted for cutting the hobbed drive.
Re: Why is the extruder pulley made of Brass ?
I have the same problem with this pulley made of brass. I would like to fix it.
Is this Pulley sold here similiar and adatptable ?
http://e3d-online.com/Mechanical/Motion/GT2-Pulley-18-tooth
Re: Why is the extruder pulley made of Brass ?
No, that's a belt pulley, not a filament drive gear.
Contact support via live chat.
Peter
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…
Re: Why is the extruder pulley made of Brass ?
Try this: https://www.aliexpress.com/item/MK8-Extruder-Drive-Gear-Bore-5mm-For-1-75mm-and-3-0mm-Hobbed-Gear-For-Makerbot/32543429677.html
You need MK8 version.
You may need to adjust steps/mm for extruder.
Re: Why is the extruder pulley made of Brass ?
I would also be interested in learning if there is a stainless alternative available anywhere. I take it the E3D hobb goblin is the wrong size?
Re: Why is the extruder pulley made of Brass ?
Try this: https://www.aliexpress.com/item/MK8-Extruder-Drive-Gear-Bore-5mm-For-1-75mm-and-3-0mm-Hobbed-Gear-For-Makerbot/32543429677.html
You need MK8 version.
You may need to adjust steps/mm for extruder.
David
I believe that the diameter is different to the PR brass drive gear. In order to maintain a straight filament feed path, the extruder housing will need to be redesigned and printed.
Peter
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…
Re: Why is the extruder pulley made of Brass ?
We'll see soon 😉 I ordered 4 pcs two weeks ago.
BTW this http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=85008 fits perfectly, but it is made of brass as well.
Re: Why is the extruder pulley made of Brass ?
David
I bought some a few months back... Fitted without mods and the filament won't load without a bend in the end. When loading the filament is pushed out of alignment by the offset.
Peter
EDIT: There are also issues when printing 50 micron layers due to less feed precision. At 50 microns, printing has to be faster than normal.
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…
Re: Why is the extruder pulley made of Brass ?
Well, bad luck. 😆 I hope I will be able to use them in another printer.
Re: Why is the extruder pulley made of Brass ?
Yeah, the problem is that the spindle is 5mm and the drive is only 6mm diameter; that means the brass is only 0.5mm thick (at the centre of the drive.
My first one collapsed at the spindle flat. The steel Mk8 drive pulleys have a drive diameter of 7mm and the extra half millimetre make a huge difference.
Peter
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…
Re: Why is the extruder pulley made of Brass ?
So this one does not fit ?
http://e3d-online.com/Extruders/Hobb-Goblin-5mm
There is no valid alternitive somewhere ?
Re: Why is the extruder pulley made of Brass ?
That one is also a Mk8 and would have a 7mm drive diameter.
You can of course try that and see if it works.
Peter
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…
Re: Why is the extruder pulley made of Brass ?
Anyone found a fitting pulley replacement yet? I am getting some filament skipping and would like to have one spare.
Re: Why is the extruder pulley made of Brass ?
Will this one work?
It has a hobbed diameter of 6mm.
Re: Why is the extruder pulley made of Brass ?
I'm having the same problem after printing some 30-40km of filament
I would be very happy to know from where to get more stable parts. Has anyone found a source for buying replacements?
Re: Why is the extruder pulley made of Brass ?
Same problem here, got my Mk2 in September & today i saw that the extruder pulley has a hole on one side of the groove. Looks like the material is simply too thin oder not rigid enough. I hope i´ll get a free replacement for that.
Christian