If the firmware is Marlin, the 260C is likely a limitation imposed by the firmware. It would require loading up the source firmware in Visual Studio Code, changing the temperature limit, recompiling the firmware, then flashing the new firmware to the printer.
If the firmware is Klipper it would require editting the printer.cfg file, then Save and Restart.
BTW, you may have to change the heater cartridge and sensor in the hotend to get up to 295C. They are not expensive. The printbed should already be able to reach 110C.
OK, let’s step back a bit. I took your post literally: i.e. polycarbonate filament needs 295C hotend. Just now I checked a couple of manufacturers, including PolyMaker. They both recommend temps of 250C to 270C. That’s a long way from 295C. Nylon has the same recommendations.
So, let’s see what your printer is capable of right now. If you connect to the printer with a computer and run Pronterface and issue an M503 command, what does it say your max temp is? Is it actually 260C, or might it be 275C?
OK, I’ve installed Pronterface and communicating with my Ender 5+.
If you recall, I am trying to get my ducks in a row to print Polycarbonite or other high temp filaments. (Installed all metal hotend and direct drive.)
Your proposal was that 275°C would likely be sufficient to melt the Polycarbonite though a couple videos i looked through said 295°C. I rather not change the firmware to reach beyond 275°C since I’m not that experienced.
My Ender 5+ seems to have a safety feature such that it shuts down when the device exceeds some internal circuit breaker setting. There is also a switch to separate PLA prints from ABS prints which seems to have different circuit breaker settings.
Should I use an M155 S4 with the switch set to ABS to ramp up the hot end and wait for the circuit breaker to kick in and shut device? How does the printer know to raise the temperature of the hotend here and not the bed? Temperature Auto-Report | Marlin Firmware
Is there a better way to find the top end temperature of the hotend?
I have read that a number of firmware versions implement a 15C buffer. IOW, if the max temp is set to 275C in the firmware, the actual max temp in practice will be 15C lower: 260C. And, yes, almost all modern firmware versions have a safety feature called Runaway Protection. In the past, printers have caught fire from not having this protection. Think about: what if the nozzle heater is ON but the thermistor is not reporting properly? It could be possible for the heater to remain turned on, no matter how hot it gets. That could lead to filament catching fire and who knows what from there. Runaway Protection will turn the heaters off if it doesn’t get a reasonable temperature report for 30 seconds.
M155 is for host like Octoprint to get a report every so many seconds of the temps so they can so the temps on their (host) screen. Other than reporting it has no control of the temps.
According to the Technical Spec for the Ender 5 the Max hotend temp is 260c so the only way to increase this limit would be to change it in the firmware and recompile. This is a firmware limitation mainly due to the fact that the printer came with a PTFE boden tube that extends into the hotend and will melt at temps above 260c and I think give off toxic fumes. Putting in a all metal hotend eliminated the PTFE tube but the restriction is still in the firmware. You probably will not find precompiled firmware with the max temp set above the manufacture specs. So increase it you will have to compile your it yourself.