Maximum heat bed temp

Just so I know, what is the maximum safe temp for the ABS heat bed, and does the firmware have any built in limits to prevent exceeding that?

 

I was wondering this myself
thanks for asking this

 

There are software limits.

If you look at the current version of the firmware (which is a version of Marlin) in Configuration.h you'll see the MAXTEMP limits.

I have an E3D hotend so I've modified my version of the source. Here is what I have. I've included line numbers so you can approximate where they are in the file.

125 // The minimal temperature defines the temperature below which the heater wi ll not be enabled It is used
126 // to check that the wiring to the thermistor is not broken.
127 // Otherwise this would lead to the heater being powered on all the time.
128 #define HEATER_0_MINTEMP 5
129 #define HEATER_1_MINTEMP 5
130 #define HEATER_2_MINTEMP 5
131 #define BED_MINTEMP 5
132
133 // When temperature exceeds max temp, your heater will be switched off.
134 // This feature exists to protect your hotend from overheating accidentally, but *NOT* from thermistor short/failure!
135 // You should use MINTEMP for thermistor short/failure protection.
136 // Robo3D HotEnd: // #define HEATER_0_MAXTEMP 235
137 // E3D HotEnd
138 #define HEATER_0_MAXTEMP 300
139 #define HEATER_1_MAXTEMP 275
140 #define HEATER_2_MAXTEMP 275
141 #define BED_MAXTEMP 150
From what I can tell HEATER_0_MAXTEMP is the hotend max temperature. It was set original to have a maximum of 235. I've set it to 300. BED_MAXTEMP is the heated bed. It's set to a max temperature of 150 celsius.

 

thanks

 

If i change firmware limit to 200 (for example) what will happen if i go over 150 ? Will bed burn up or what ? Why 150 is the limit ?

I understand 135 being nozzle limit for and nylon tube inside will melt but the bed ?


Its funny that board will overhear and stop way before your be able to actually use it for more then 10 minutes with only 100c.

I installed fan to blow at the board while using bed and cranked it up to 120 keeping my ABS straight so far