Thermal Safety

Your 3D printer uses high temperatures to melt plastic. This introduces two primary risks: severe burns from hot components and the potential for fire from uncontrolled heating.

Burn Prevention

The hotend nozzle can reach temperatures over 250°C, and the heated bed can exceed 100°C. * Be Aware: These components are hot enough to cause immediate and severe burns. * Cool-Down Time: Remember that the hotend and bed remain dangerously hot for several minutes after the printer is turned off. * Silicone Sock: Using a silicone sock on your heater block is highly recommended. It helps stabilize temperatures and provides a layer of protection against accidental contact.

A close-up of a hotend with a silicone sock fitted snugly around the heater block.

Thermal Runaway Protection

"Thermal runaway" is a dangerous condition where a failure (like a dislodged thermistor) causes the printer's firmware to lose track of the temperature. It may then try to heat the component indefinitely, creating a fire hazard.

• Firmware Protection: Klipper has a built-in safety feature to detect this. It will shut down the printer if the temperature does not rise as expected when a heater is on, or if the temperature is dangerously out of range. You must ensure this feature is enabled and correctly configured in your printer.cfg.
• Hardware Protection (Thermal Fuse): Your heated bed is equipped with a physical thermal fuse. This is a one-time-use safety device that physically cuts power to the bed if it ever exceeds a critical temperature (e.g., 120°C). It is a last line of defense and should never be bypassed.