Heat Block loose? Heat break set-screws really 1.5mm?
Having clogged nozzle problems on my Prusa Mini, possibly due to humidity and generic filament. Took the nozzle out per the instructions in the manual, and I notice the heat block is very loose. It seems to tighten down when I replaced the nozzle, just curious if it is supposed to be that way? I have tried another nozzle and cleaned the original and I continue to have lots of stringing and failed prints. Again, possibly due to humidity and generic filament. Printing PETG that is in a case with 2.5 pounds of silica gel that I recharge once a week or so. Have been printing for nearly 3 months straight up until now.
If I do need to tighten it, it seems like I would need to loosen the three set screws on the heat sink... the manual says to use 1.5mm allen key, but there is a lot of play with the 1.5mm. Having worked on bicycles for years, there is no doubt in my mind it will strip out if I try to use the 1.5mm key. I tried a brand new key, I tried other sizes even imperial sizes... how do you get these set screws out without stripping them?
RE: Heat Block loose? Heat break set-screws really 1.5mm?
I should include more information; the first time I replaced the nozzle I was intimidated by the warning not to overtighten the nozzle in the manual, and filament oozed over the top, that is why the heat block is so nasty.
Also, here is a video of how loose the 1.5mm allen key is in the set screw:
RE: Heat Block loose? Heat break set-screws really 1.5mm?
Ok, I will focus on one question: How do you get these set screws out? 1.5 allen key is too small. 1/16" and 2mm are too big.
RE: Heat Block loose? Heat break set-screws really 1.5mm?
Sorry to say it's definitely a 1.5mm allen key, maybe try a different set? For what it's worth I almost stripped one of mine because I didn't insert the key far enough, it's a deeper socket than it seems.
RE: Heat Block loose? Heat break set-screws really 1.5mm?
@yophosis
Possibly the hexagon socket of the screw is defective or deformed. I think that the 1.5 mm allenkey is already correct. Maybe you try to heat it up to 260 degrees C. The screws are often easier to loosen in hot weather.
I had this problem several times and tried to loosen the screws with this tool remove defective screws or even had to drill them out (last option).
Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen.
RE: Heat Block loose? Heat break set-screws really 1.5mm?
Thank you for the replies. I will go to the hardware store with a caliper and see if they have any sets where the 1.5mm key is bigger than the ones that I have.
However in the meantime, I've discovered the real problem; there was a massive clog in between the hotend ptfe tube and the heatbreak. I have replaced the PTFE tube with a longer one and now everything is printing wonderfully again. I've done some damage to the various parts of the hotend trying to figure out what the problem was. Learning hurts, lol.
RE: Heat Block loose? Heat break set-screws really 1.5mm?
Nice! I'm seeing a lot of clogging and under-extrusion issues and most of the time the problem is located in the hotend.
PS, I saw another thread where people were replacing the 1.5mm grubs with regular allen key screws. There is no reason other than aesthetic to keep the grubs. Maybe after you remove them a good option would be to replace them with something easier to manage, they are size M3x4mm. See thread here: https://forum.prusa3d.com/forum/general-discussion-announcements-and-releases/hotend-grub-screws-potential-problem/
RE: Heat Block loose? Heat break set-screws really 1.5mm?
Ok, I will focus on one question: How do you get these set screws out? 1.5 allen key is too small. 1/16" and 2mm are too big.
Attachment removed
I have worked with precision measuring and mine were clearly not 1.5mm and nothing would fit. I used a carefully hand filed down larger allen key to get them out and replaced the allen screws with new ones which were 1.5mm.
RE: Heat Block loose? Heat break set-screws really 1.5mm?
Same issue with mine. I have other issues with the printer so the whole thing is going back to be checked but they are not 1.5
RE: Heat Block loose? Heat break set-screws really 1.5mm?
Same issue with mine. I have other issues with the printer so the whole thing is going back to be checked but they are not 1.5
I agree, i measure them at 1.54mm which is off enough to cause problems. I started stripping them with the 1.5mm so i switched to a 1/16" and that works great so far.
RE: Heat Block loose? Heat break set-screws really 1.5mm?
@atchleyj
This screw on the heating block is a major weak point. I drilled it out and replaced it with a stainless steel torx screw with a cylindrical head.
Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen.
RE: Heat Block loose? Heat break set-screws really 1.5mm?
Same issue with mine. I have other issues with the printer so the whole thing is going back to be checked but they are not 1.5
I agree, i measure them at 1.54mm which is off enough to cause problems. I started stripping them with the 1.5mm so i switched to a 1/16" and that works great so far.