Differences in the new heatbreak?
I've been sourcing the MM kit parts, I've got everything except the heatbreak and an alternative to the dial drive gears.
The gears are available from bondtech directly, but are $50 for a set, those alone making sourcing the kit more expensive. Anyone know of a knock off?
The other thing is the heatbreak, what is actually different about it? Visually they appear the same.
Edit: Actually I just realized a simple solution to the dual drive gear issue, it won't be perfectly durable, but using two normal hobbed extruder gears, and then designing two gears, one that is hollow and has a key cut into it, and one that is attached to a keyed shaft that the second hobbed gear can slot onto. I'll have to mock something up and post back about that.
Still, any word on what is different about the new heat break?
Edit 2: Here are the gears that I was talking about, not actually measured, but it get's the point across.
Re: Differences in the new heatbreak?
Official response from Prusa via email:
The only differences are a larger heatbreak and different PTFE tube, other than that, everything is the same.
Re: Differences in the new heatbreak?
Official response from Prusa via email:
The only differences are a larger heatbreak and different PTFE tube, other than that, everything is the same.
That's not as I understand it; I will try to get some better information.
Certainly the PTFE tubing is smaller ID at 1.85mm (measured - but will also check).
Peter
EDIT: PTFE Tube info here: https://prusa3d.dozuki.com/Guide/How+to+trim+PTFE+tube+-+MultiMaterial/497
EDIT 2: I believe that the heat break has a 2.1mm hole in the top end running almost to the end of the 7mm thread and then 2mm through to the nozzle.
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: Differences in the new heatbreak?
That's not as I understand it; I will try to get some better information.
Certainly the PTFE tubing is smaller ID at 1.85mm (measured - but will also check).
Peter
EDIT: PTFE Tube info here: https://prusa3d.dozuki.com/Guide/How+to+trim+PTFE+tube+-+MultiMaterial/497
EDIT 2: I believe that the heat break has a 2.1mm hole in the top end running almost to the end of the 7mm thread and then 2mm through to the nozzle.
Good to know, so the PTFE tubing is just thinner and flared at the top? The heat break is also flared slightly at the top too?
If someone with both heat breaks in hand happens to have both out of their machine at once, some close up pictures of both side by side would be awesome.
If it's just some minor flaring in the PTFE and the heat break, I think these modifications could be easily done to the standard E3D hotend.
Re: Differences in the new heatbreak?
Good to know, so the PTFE tubing is just thinner and flared at the top? The heat break is also flared slightly at the top too?
If someone with both heat breaks in hand happens to have both out of their machine at once, some close up pictures of both side by side would be awesome.
If it's just some minor flaring in the PTFE and the heat break, I think these modifications could be easily done to the standard E3D hotend.
The PTFE tubing for the MMU is 1.9mm internal diameter as opposed to 2mm for the single filament machine, is 41mm long and is tapered internally at both ends and chamfered at the lower end (according to the diagram I linked).
The heat break is drilled 2.1mm internal diameter from the top and 2mm from the bottom during manufacture as opposed to 2mm from both ends in the single filament printer; there is no visible difference between the 2 heat breaks, and it is impossible to measure with calipers due to the 4.2mm hole in the top where the PTFE tube is inserted.
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: Differences in the new heatbreak?
>> The heat break is drilled 2.1mm internal diameter from the top and 2mm from the bottom <<
Well interesting, mine is 2.3 mm from the top and 2.0 mm from the bottom. The 2.3 mm bore is quite rough and shows tool marks (due to a worn or damaged drill bit and/or an improper manufacturing process). The 2.0 mm bore is reasonably smooth.
My PTFE tube has no chamfer on the lower end. The inner taper on the bottom end is short, very rough and uneven as if someone had cut it by hand using a scalpel blade instead of a proper sinker or reamer. Interesting enough, in contrast the top end taper is done well.
I experience inconsistent extrusion performance and frequent jams so I asked for updated parts thru live chat. My MM kit might have been an earlier version (delivered end of May) and I understand (and hope) that both heatbreak and PTFE tube are being produced with better quality now.
Re: Differences in the new heatbreak?
>> The heat break is drilled 2.1mm internal diameter from the top and 2mm from the bottom <<
Well interesting, mine is 2.3 mm from the top and 2.0 mm from the bottom. The 2.3 mm bore is quite rough and shows tool marks (due to a worn or damaged drill bit and/or an improper manufacturing process). The 2.0 mm bore is reasonably smooth.
My PTFE tube has no chamfer on the lower end. The inner taper on the bottom end is short, very rough and uneven as if someone had cut it by hand using a scalpel blade instead of a proper sinker or reamer. Interesting enough, in contrast the top end taper is done well.
I experience inconsistent extrusion performance and frequent jams so I asked for updated parts thru live chat. My MM kit might have been an earlier version (delivered end of May) and I understand (and hope) that both heatbreak and PTFE tube are being produced with better quality now.
The top of the heat break is actually about 4.3mm; this is the part where the PTFE tubing is inserted. It is a little difficult measuring the 2.1mm section of the heat break as this is inset below the 4.3mm ID section.
There should be a chamfer on the inside of the heat break between the 4.3 and 2.1 mm sections; this should be visible if you get the light right.
If the chamfer is present (there were a few heat breaks issued without the chamfer) the PTFE tube should also be chamfered to match so that there is no gap between the two parts.
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: Differences in the new heatbreak?
>> The top of the heat break is actually about 4.3mm; this is the part where the PTFE tubing is inserted. It is a little difficult measuring the 2.1mm section of the heat break as this is inset below the 4.3mm ID section. <<
Sure, I was talking about the top bore you're referring to as 2.1 mm which is actually & definitely 2.3 mm in my heatbreak (and is drilled quite roughly as I said). This was measured with a set of watchmaker's bore gauges so it should be precise enough. The bottom end bore is 2.0 mm. I haven't found it necessary to measure the 4.3 mm bore section yet because the PTFE tube fits in snugly.
>> There should be a chamfer on the inside of the heat break between the 4.3 and 2.1 mm sections; this should be visible if you get the light right. <<
Even with a professional inspection microscope I can see no chamfer on the 4.3 mm to 2.3 mm bore transition in my heatbreak (just a few 1/100 mm of inner edge radius caused by the tool cutting edge radius).