RE: MK3S part melted
latest heatbed cover has screw facing down
Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
RE: MK3S part melted
Anyone know if the newly shipped printers come with the R5 redesign? I have a printer that was shipped on Tuesday (6th August) currently in transit. Just wondering what rev of part will come with it. How quickly to Prusa update their production line compared to updating the GIT Hub files? As the R5 files were uploaded 2 weeks ago, before I ordered my printer.
RE: MK3S part melted
To answer my own question, no, newly shipped printers do NOT come with the new parts. At least mine didn't and the packing slip was stamped on the 6th August.
I have decided to print off the R5 extruder cover as that has been fairly beefed up on the hot fins. The R5 extruder body only has a slightly thicker mounting point for the PINDA, but not a lot in it. Most people seem to be suffering from the hot fins melting with only a few suffering from the PINDA mount failing, generally they seem to be the ones who print a lot of high temp stuff, at least that seems to be what I have seen from people in this thread.
Also printing the new R5 cover in Prusament Orange PETG, quite simply because I don't have black PETG, but it should also fare better because it will absorb less radiant heat energy than black does. Obviously the main body has to be black for the filament sensor to operate properly, but no reason we can't use lighter colours on other parts of the extruder that do not absorb as much heat as black does.
RE: MK3S part melted
After a 6 hr PETG print, I noticed that support is sagging and disconnected on the pinda end. Not sure printing new parts is going to do much more than hold me for another another few hours of printing. Not looking forward to a major disassembly and rebuild.
RE: MK3S part melted
After a 6 hr PETG print, I noticed that support is sagging and disconnected on the pinda end. Not sure printing new parts is going to do much more than hold me for another another few hours of printing. Not looking forward to a major disassembly and rebuild.
Interesting! I printed off the new extruder cover with the beefier hot fins (2 hours I think), then proceeded to do a 9 hour PETG print. First layer at 240c nozzle & 85c bed temps, all other layers at 250c nozzle and 90c bed temps. First 3 layers had no fans on, max PINDA probe temp was 58c during the 2nd or 3rd layer, then dropped once the fans came on.
Woke up this morning to a successful print and the PINDA appears to be in the same place?? What are your ambient / room temps? By the time I went to bed the digital thermometer sitting next to the printer said between 23-24c room temp.
RE: MK3S part melted
Printed a new R5 extruder cover. Looks like it will work with the existing extruder body and looks like it will hold up better. Hoping that I can just remove extruder cover and fan bolts to accomplish replacement.
RE: MK3S part melted
Yes, you can swap it out by just removing the print fan and a couple of extra bolts, took me all of 15 minutes to replace. Works fine with the R4 body. I currently have an R4 body and R5 cover. Printing an R5 body just now to have as a "just incase". Again, having to print in orange as I have no black PETG, but at least it should get me out of a bind if the probe mount ever sags, but as I said above, that doesn't seem to be an issue for most. Even the guy on the 1st page that printed for 20h at 250c nozzle and 110c bed temps only had minor PINDA sagging issues, looking at his pics on page 1 & 2 it looks like it hasn't moved at all, but he said it did. Pictures on page 2 show it cracked during disassembly, but was still in 1 piece when he took it off the printer. He was also printing in a 45c enclosure, so the PINDA mount is a lesser problem than the hot fins for sure.
The main problem most are experiencing is with the extruder cover which is an quick replacement. You will also notice when you fit it, that the part which was melting that they have made thicker now also "butts up" against the PINDA mount, I suspect in an effort to "hold" it and prevent sagging should the plastic reach glass transition temps.
RE: MK3S part melted
I suspect this issue is also confounded by prevalence of "low temp" PETGs which print around 230, whereas ones like prusament print at 250.
RE: MK3S part melted
Thank You Also printing extruder body now and also in orange as I am out of black and seems like most places out of stock. Yes looks like the piece that melted has been beefed up. Sorry for confusion, I don't think Pinda mount has sagged or if it has has not effected prints.
RE: MK3S part melted
I suspect this issue is also confounded by prevalence of "low temp" PETGs which print around 230, whereas ones like prusament print at 250.
Quite possibly, but as I said above, all my PETG prints have been with Prusament Orange PETG at 240c nozzle and 85c bed for 1st layer then 250c nozzle and 90c bed for all other layers with print fan off for the first 3 layers. Those are the default settings in PrusaSlicer and what I use.
The extruder cover did get VERY soft at the hot fins immediately on my first ever PETG print with the R4 cover design, but the R5 cover is definitely a lot better. Done about 12 hours of PETG prints with the above temps using the new R5 cover so far.
RE: MK3S part melted
RE: MK3S part melted
Sorry. The "Add Media" software rotated my picture and deleted my text. Here is the text:
I do not have PETG and have never printed it, so I am going to ask Prusa Support to include the new R5 part with the extended PINDA probe support into their on-line shop. Or would someone reading this sell me one?
Meanwhile, even though 1/3 of the probe holder melted through and fell off, I am printing again by tightening a plastic tie at the point where the cable from the PINDA probe crosses over itself. The probe is upright and still now. (And I am trying to avoid high temperature cleaning sessions.)
- Chris Salander
RE: MK3S part melted
Here is an upright image. All that is visible of the tie is the block, blocking the view of the top of the probe.
RE: MK3S part melted
Prusa support sent me plastic parts... so that I can tear my extruder down, install the R4 parts....
And THEN print the R5 parts, then tear the extruder down, and install the R5 parts...To see if it's the parts or the PINDA changing its Z height... lol....
So they’re basically experimenting with their own users... that’s cost efficient I gotta give kudos to them tbh
Don't rebel, or call them on it. They'll call you "ridiculous, having too high expectations," or even better... "a difficult customer" on work order sheets when they take your printer for repair for a month. 😉 haha... I've had less trouble out of crappy Chinese clones.
To be fair, when I reported it on Github they offered to send me out the part, but I still had a working printer so it was almost certainly quicker to print the new part than wait a week for it to arrive from Prague.
RE: MK3S part melted
That is a shame to hear - I've printed a good few PETG, HIPS and Colorfabb XT prints, but nothing higher.
I had printed the R4 parts originally in Inofill PETG rather than Prusa because I had to wait 2 months for the MK3S upgrade to arrive. I didn't really have the issue until printing in XT and Polymax PC - I will give these a go over the weekend to see if the issue recurs.
RE: MK3S part melted
Sorry. The "Add Media" software rotated my picture and deleted my text. Here is the text:
I do not have PETG and have never printed it, so I am going to ask Prusa Support to include the new R5 part with the extended PINDA probe support into their on-line shop. Or would someone reading this sell me one?
Meanwhile, even though 1/3 of the probe holder melted through and fell off, I am printing again by tightening a plastic tie at the point where the cable from the PINDA probe crosses over itself. The probe is upright and still now. (And I am trying to avoid high temperature cleaning sessions.)
- Chris Salander
Looking at your image it looks like the part that has melted is the hot fin from the Extruder Cover, not the PINDA probe mount. If the prob mount had melted and fallen off then tying the cable to itself would do nothing. That probe cable has no structural integrity to provide any support to the PINDA.
The part which has melted is merely to direct airflow and aid in cooling of the heatsink, so it will not affect printing at all, but obviously is not ideal. The new R5 Extruder Cover will cope much better and is a lot thicker in that area.
RE: MK3S part melted
Oh, and just to add (can't edit my last post)...after printing the new extruder body last night the difference is nearly negligible where the PINDA probe is mounted. Instead of a 90* angle at the bottom it steps out higher up at a 45* angle and attaches across the full width of the probe, this might reduce probe vibration during fast movements, but other than that, will not prevent sagging from high heat, as it is pretty thin and probably won't withstand much extra heat itself vs the R4 design. They have also added an extra 3 or 4 layers at the chamfer where the probe mount meets the extruder body. This might help a little, but it really is so minor that it almost doesn't seem like it will make the probe mount withstand much more heat than the R4 design.
The real difference in the R4 to R5 redesign is the hot fins on the extruder cover where it has gone from being approx 1mm thick to now being approx 4mm thick and clearly able to handle the heat better due to the increased mass available. I would also recommend printing the extruder cover in a colour other than black, as black absorbs the most radiant heat, other colours will absorb less and therefore heat up less and less likely to fail prematurely.
RE: MK3S part melted
@casey-b6
Sorry for the old post revival. Going through this right now with a few of my Mk3s printers. I just picked up some 3DXTech CarbonX PC/ABS blend with a glass TG of 135ºC. I am doing my first print today and will post results if anyone is curious. Also may try this in straight PC. Not sure the CF or ABS is actually needed.
If they come out clean, I can do a run for anyone that needs a set.
RE: MK3S part melted
@colemorgan
Let us know how it goes. I would recommend putting the nozzle temperature at 250 C for a while, as if you were cleaning the nozzle, as a test.
The one thing I can add: this problem is very sensitive to the orientation of the hot end. I can go a long time without the sensor support melting if the hot end is exactly "square" with the plastic parts. However, if the hot end gets rotated so that some corners and sides are closer to the plastic, melting happens pretty quickly. - Chris Salander
RE: MK3S part melted
@colemorgan
I used PC and ABS extruder for quite some time. The result is: not suitable for this case in the long run. PC parts will crack over time. ABS will get brittle as-well. So far PETG is really the only material I would recommend for all parts which are under changing load all the time. Maybe Nylon-CF can be an alternative but the glass transition temp in compare to PETG is so close, that I haven't tried it yet.
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