The burst plug activates when the pressure inside the extruder overcomes a certain pressure limit. Make sure that the extruder is heated up sufficiently to prevent pressure spikes
The burstplug is added as a fail-safe safety item to prevent (molten) plastic to burst out of unexpected areas when there is a pressure spike in the extruder. Before continuing extruding, the burstplug has to be replaced first.
Replace the burstplug when the extruder is heated up. Make sure you wear proper PPE when replacing the burstplug.
What can cause a pressure spike in the extruder?
- A cold nozzle
If the nozzle is changed, the material inside the nozzle has to heat up before extruding/purging. It is recommended to wait at least 10 minutes before extruding/purging. This gives the time inside the nozzle enough time to heat up. - Wrongly set temperatures
If the temperature is not set to the right setpoints for the to be extruded material, a pressure spike in the extruder might occur. - Foreign granules & small nozzle diameter (2 or 4 mm)
If the extruder and transport system was not cleaned properly, it can be the case that old pallets are still being transported to the extruder and ending up in the barrel. If the melting temperature of these old pallets is significantly higher than the new pallets (e.g. PEEK vs. PP), the granules will not melt and remain solid.
If a small nozzle size is used (2 or 4 mm), it might trap the unmelted pallets inside causing a clog. This causes the pressure to spike fast and will activate the burstplug if extrusion is not stopped. - Foreign material in the nozzle
Similar to point 3, only the nozzle is now completely filled with old material (if the nozzle was swapped without cleaning first this might be the case). If the material has a higher melting temperature than the HZ4 setpoint, this will cause a burstplug to activate. - Foreign objects
If any foreign objects end up in the granules (e.g. when granules are stored without a lid), these objects might end up clogging the nozzle. - Only for G25/F25: Retraction using the gearpump
During purging using JOG-mode & Position, you should always use INC movements. If you use ABS movement, it might be the case that the gearpump is rotating backward instead of forward. This, together with the extruder trying to keep pressure might cause a rapid pressure spike triggering the burstplug.