70w heater cartridges, safe? Viable?
I'm trying to determine if 70w heater cartridges (seen here) are viable with a Prusa i3 Mk3S.
Some concern over the gauge of wires for powering it from the PSU
if the mainboard can handle it
and if the PSU can handle it.
Hot Stuff
maybe another question is do you actually need a 70Watt heater...?
will the PID profile be able to control the larger heater and prevent overshoot's
there is not a lot of thermal mass in a 3d printer heat block, I suspect you will end up with a lot of thermal ripple...
regards 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
Process Control
With my past experience of process control (I wrote the controller for a scientific research bench waterbath that was, at the time, the most stable in the world!), I feel @joantabb is right. There is considerable risk that a heater 1.75 times more powerful is risking increase thermal ripple to the point where it may well start to impact quality.
I have recently switched to a Phaetus Dragon hotend, and with that the time to heat the bed and time to heat the bed are so close that there is no further advantage to more than 40W (this uses a copper heatblock). With the V6 hotend, I believe similar timings would be achieved using a 50W heater.
What was your objective in proposing to use a 70W heater?
Revive
Figured I’d revive this topic since none of the answers seem conclusive and others might have the same question.
The main board has a dedicated 5A fuse for the hotend. With a 24V supply, this means you’ve got a ceiling of 120W before you blow the fuse. I’d assume all of the electronics are also capable of handling that 120W since the fuse is sized that way.
The wire gauge is a bit more of a challenging approach. My recommendation is buy a 70W heater and look at the wire gauge vs. the 40W heater. I’d be willing to bet they’re about the same since the actual amperage draw is not THAT much different 1.6A vs. 3A. I just swapped in a 70W cartridge on my mk3 so we’ll see how that works.
The PSU is an even more challenging problem… I’d be willing to bet the increase of 30W on the PSU is negligible, however, there is speculation these PSU’s are operating pretty close to their maximum wattage already. So, to keep things from prematurely failing, it might be smart to just upgrade to a beefier PSU at the same time.
Then, of course, there’s the PID’s for the heater as already mentioned. You’ll just have to make sure the PIDs have been re-tuned for the more powerful heater cartridge otherwise you might get some funny behavior.
I’ll report back if I have any issues or burn my house down with 70W haha.