Printing with one halogen bulb had worked fairly well, so I advanced to the next stage - adding a second bulb for a total of 300 watts of heat. To do so, I redid the wiring - everything has a properly colored 14-gauge wire now (which is not to say that it's pretty yet).
Unfortunately, the extruder no longer worked properly inside the heated chamber with the extra heat. Interestingly, it didn't seem to be an electrical problem - the filament softened and jammed inside the cold end of the extruder:
You can see the jam on the right side of the filament in the above photo. Since the extruder couldn't push the filament through the bowden tube once the jam formed, it chewed through the filament and then spun freely until the end of the print file.
So, I proceeded to move the extruder to the outside of the heated chamber. I had previously printed two different options for the external extruder mount, and today I chose the one that was the easiest drop in replacement:
I also had to make a longer bowden tube to guide the filament between the cold end and the hot end. Generally, you want as short of a bowden tube as possible to minimize slop, so it's a bit of a bummer that I couldn't keep the cold end inside the chamber.
After I had that system running for a bit, I noticed that the aluminized styrofoam was not handling the increased heat well:
I made myself a quick metal shield from some scrap metal:
Unfortunately, once that was in place, the melamine (the wood) started to blister and smoke!
So at the end of the day, I'm back down to just one bulb. Later on I might put more bulbs in, as one bulb seems to max out at 50C for the chamber temperature. If I do, however, I'll space them out quite a bit more, or put some kind of stand-off between the wood and the bulbs.
One bulb can get the chamber up to 50C. I saw the melamine start to smoke before the chamber had gotten past 60C - not sure what the upper limit is there. Based on forum posts, it seems like the ideal chamber temp is around 70C.
You can see the jam on the right side of the filament in the above photo. Since the extruder couldn't push the filament through the bowden tube once the jam formed, it chewed through the filament and then spun freely until the end of the print file.
So, I proceeded to move the extruder to the outside of the heated chamber. I had previously printed two different options for the external extruder mount, and today I chose the one that was the easiest drop in replacement:
I also had to make a longer bowden tube to guide the filament between the cold end and the hot end. Generally, you want as short of a bowden tube as possible to minimize slop, so it's a bit of a bummer that I couldn't keep the cold end inside the chamber.
After I had that system running for a bit, I noticed that the aluminized styrofoam was not handling the increased heat well:
I made myself a quick metal shield from some scrap metal:
Unfortunately, once that was in place, the melamine (the wood) started to blister and smoke!
So at the end of the day, I'm back down to just one bulb. Later on I might put more bulbs in, as one bulb seems to max out at 50C for the chamber temperature. If I do, however, I'll space them out quite a bit more, or put some kind of stand-off between the wood and the bulbs.
One bulb can get the chamber up to 50C. I saw the melamine start to smoke before the chamber had gotten past 60C - not sure what the upper limit is there. Based on forum posts, it seems like the ideal chamber temp is around 70C.
No comments:
Post a Comment