[Closed] I3 Mk3 - Max temp on hot end and heat bed  

Re: I3 Mk3 - Max temp on hot end and heat bed

Unfortunately Prusa designed the i3 mk3 to run the power supply at 100% load while warming up even at PLA temps so no matter what you do(short of replacing it with a higher output unit)the PSU is going to be stresses to the max each time you fire it up. That said obviously Prusa thinks this is ok even if alot of people do not, personally i consider it a design flaw but so far no evidence this is a large issue just a minor issue. Lots of people reporting them failing in the thread about it on these forums but with 4-5k or even more printers shipped now the failing % is very small.

I hear the hot end can do 295-300C stock but thats really stressing the stock thermistor, you can however replace the thermistor with a higher temp capable one to go even higher than 300C.

I hear the bed can do up to 100C or so, maybe more with an enclosure. Ive seen a few posts where users have said if printing with fan on the bed can sustain 100C but not more, so likely will do more with no fan and an enclosure. But i think this is hot enough for most things.

Re: I3 Mk3 - Max temp on hot end and heat bed

Thanks Nathan,

Can a larger power PSU be added by just swapping it - or fitting a larger unit as a stand alone so the wiring can reach easy enough?
Regards

Mick

Re: I3 Mk3 - Max temp on hot end and heat bed

Thanks Nathan,

Can a larger power PSU be added by just swapping it - or fitting a larger unit as a stand alone so the wiring can reach easy enough?
Regards

Mick

i cant comment to much because my printer will not arrive till next month. However from reading this thread:

https://shop.prusa3d.com/forum/original-prusa-i3-mk3-f30/power-supply-failure-t13443.html

It appears like swapping it out is not that hard. I mean its just a few wires but im a electronics guy so maybe to someone who knows nothing about electrical it may be an issue.

I already have a 24V 20 AMP(twice the stock power output) unit on hand and intend to install it if my stock unit has any issues. I may end up installing it anyways just to save myself the worry about the stock one causing a fire when im not home. Im not to worried about it when i am home but the people who are reporting failures are also reporting burning smells and hearing something break inside and IMO thats more reason to worry than the unit itself failing.

But as i said only a very small # are failing(so far anyways) so this may be a over reaction on my part to get another PSU.

I dont think a larger replacement will fit in the stock location, however from all the pics i have seen having the stock one connected to two frame pieces is a bad idea anyways, as the machining on a cheap china PSU IMO is not good enough to be exactly square on all the mounting holes, and thus using it to connect the frames will cause them to be off square IMO, users have reported this to be the case. There is a brace you can print to replace the PSU on the frame if you feel the frame bracing is needed.

Re: I3 Mk3 - Max temp on hot end and heat bed

I hear the bed can do up to 100C or so, maybe more with an enclosure. Ive seen a few posts where users have said if printing with fan on the bed can sustain 100C but not more, so likely will do more with no fan and an enclosure. But i think this is hot enough for most things.

Just FYI.... I have had my bed hold 110C in an enclosure for 8 hours with no noted issues.

Re: I3 Mk3 - Max temp on hot end and heat bed

I hear the bed can do up to 100C or so, maybe more with an enclosure. Ive seen a few posts where users have said if printing with fan on the bed can sustain 100C but not more, so likely will do more with no fan and an enclosure. But i think this is hot enough for most things.

Just FYI.... I have had my bed hold 110C in an enclosure for 8 hours with no noted issues.

Good to know, i figured if 100c is sustainable with no enclosure i would hope we can hit 11-120 with one. Im going to build a cardboard one for mine and see what i can manage with it.