how to make the filament extrude and stick to the hot bed w/ a i2 printer

You should definitely go through the checklist by Cheung Weng. Filament jamming is common. Based on the checklist, the following would be how I typically go about troubleshooting for my printer usually.

Just to build on the checklist for points 1-4:

1. Check if the distance between nozzle and hot bed is too close.

- Ensure your print bed is clean. Put a piece of A4 paper under the nozzle. Home Z. Once the nozzle comes down, move the A4 paper around a bit. Adjust the z-axis until the paper the paper and slide with minimum effort.

2. Raise the temperature of extruder.

- Extrude filament for 10mm. If it is extruding properly, then wait 5-10 mins. Try again. Then retract the filament to check if the end has more than 5mm which is still soft, the nozzle may be too hot. Having an extruder fan will help in this situation. Once you start printing, the temperature may need to be readjusted.

3. Check if the nozzle is jammed.

- If nozzle is jammed, if filament is pla, I would typically change the nozzle or us that nozzle for other higher temperature filament such as nylon. At high temperature, the pla would melt and be extruded together with nylon when I start the flushing process. For ABS, there are some chemicals which you can use to melt it away.

4. Check if the extruder motor driver is fine.

- There may be a case where due to insufficient cooling, either your motor is too hot or stepper driver is too hot.

For warping or filament not sticking to heatbed after everything else is remediated, I typically use glue stick and do without heatbed for low temperature materials. In somecases, I would use glue stick in combination with heatbed to increase the "sticking". if you still want to use heat bed, do ensure your power supply is sufficient as heatbed draws a lot of current.

You should definitely go through the checklist by Cheung Weng. Filament jamming is common. Based on the checklist, the following would be how I typically go about troubleshooting for my printer usually.

Just to build on the checklist for points 1-4:

1. Check if the distance between nozzle and hot bed is too close.

- Ensure your print bed is clean. Put a piece of A4 paper under the nozzle. Home Z. Once the nozzle comes down, move the A4 paper around a bit. Adjust the z-axis until the paper the paper and slide with minimum effort.

2. Raise the temperature of extruder.

- Extrude filament for 10mm. If it is extruding properly, then wait 5-10 mins. Try again. Then retract the filament to check if the end has more than 5mm which is still soft, the nozzle may be too hot. Having an extruder fan will help in this situation. Once you start printing, the temperature may need to be readjusted.

3. Check if the nozzle is jammed.

- If nozzle is jammed, if filament is pla, I would typically change the nozzle or us that nozzle for other higher temperature filament such as nylon. At high temperature, the pla would melt and be extruded together with nylon when I start the flushing process. For ABS, there are some chemicals which you can use to melt it away.

4. Check if the extruder motor driver is fine.

- There may be a case where due to insufficient cooling, either your motor is too hot or stepper driver is too hot.

For warping or filament not sticking to heatbed after everything else is remediated, I typically use glue stick and do without heatbed for low temperature materials. In somecases, I would use glue stick in combination with heatbed to increase the "sticking". if you still want to use heat bed, do ensure your power supply is sufficient as heatbed draws a lot of current.